Patent Publication Number: US-11039787-B2

Title: Garment MRI antenna array

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to and is a Continuation in Part of U.S. application Ser. No. 14/635,600, filed on Mar. 2, 2015, which is based on and claims priority to U.S. patent application Ser. No. 13/683,602, filed on Nov. 21, 2012, which is based on and claims priority to U.S. Provisional Application Ser. No. 61/563,413, filed on Nov. 23, 2011, each of which is incorporated herein by reference in its entirety. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to magnetic resonance imaging (MRI), and more particularly to flexible and/or elastic MRI antenna arrays for use in receiving MRI signals. 
     2. Description of Related Art 
     A. Magnetic Resonance Imaging 
     Magnetic resonance imaging (MRI) refers generally to a form of clinical imaging based upon the principles of nuclear magnetic resonance (NMR). Any nucleus which possesses a magnetic moment will attempt to align itself with the direction of a magnetic field, the quantum alignment being dependent, among other things, upon the strength of the magnetic field and the magnetic moment. In MRI, a uniform magnetic field B 0  is applied to an object to be imaged; hence creating a net alignment of the object&#39;s nuclei possessing magnetic moments. If the static field B 0  is designated as aligned with the z-axis of a Cartesian coordinate system, the origin of which is approximately centered within the imaged object, the nuclei which possess magnetic moments precess about the z-axis at their Larmor frequencies according to their gyromagnetic ratio and the strength of the magnetic field. 
     Water, because of its relative abundance in biological tissues and its relatively strong net magnetic moment M z  created when placed within a strong magnetic field, is of principle concern in MR imaging. Subjecting human tissues to a uniform magnetic field will create such a net magnetic moment from the typically random order of nuclear precession about the z-axis. In a MR imaging sequence, a radio frequency (RF) excitation signal, centered at the Larmor frequency, irradiates the tissue with a vector polarization which is orthogonal to the polarization of B 0 . Continuing our Cartesian coordinate example, the static field is labeled B z  while the perpendicular excitation field B 1  is labeled B y . B xy  is of sufficient amplitude and duration in time, or of sufficient power to nutate (or tip) the net magnetic moment into the transverse (x-y) plane giving rise to M xy . This transverse magnetic moment begins to collapse and re-align with the static magnetic field immediately after termination of the excitation field B 1 . Energy gained during the excitation cycle is lost by the nuclei as they re-align themselves with B 0  during the collapse of the rotating transverse magnetic moment M xy . 
     The energy is propagated as an electromagnetic wave which induces a sinusoidal signal voltage across discontinuities in closed-loop receiving coils, this signal voltage being inversely and non-linearly proportional to the distance between the target voxel and coil element. This represents the NMR signal which is sensed by the RF coil and recorded by the MRI system. A slice image is derived from the reconstruction of these spatially-encoded signals using well known digital image processing techniques. 
     B. Local Coils and Arrays 
     The diagnostic quality or resolution of the image is dependent, in part, upon the sensitivity and homogeneity of the receiving coil to the weak NMR signal. RF coils, described as “local coils” may be described as resonant antennas, in part, because of their property of signal sensitivity being inversely related to the distance from the source. For this reason, it is important to place the coils as close to the anatomical region-of-interest (ROI) as possible. 
     Whereas “whole body” MRI scanners are sufficiently large to receive and image any portion of the entire human body, local coils are smaller and therefore electromagnetically couple to less tissue. Coupling to less tissue gives rise to coupling to less “noise” or unwanted biologically or thermally generated random signals which superimpose upon the desired MR signal. The local coils may be of higher quality factor (Q) than the body coils due to their smaller size. For all of these reasons, local coils typically yield a higher signal-to-noise (S/N) ratio than that obtainable using the larger whole body antenna. The larger antenna is commonly used to produce the highly homogenous or uniform excitation field throughout the ROI, whereas the local coil is placed near the immediate area of interest to receive the NMR signal. The importance of accurate positioning leads to the development of local coils which conform to the anatomy of interest, yet function to permit ease of use. 
     While the smaller local coil&#39;s size works to an advantage in obtaining a higher S/N ratio, this reduced size also presents a disadvantage for imaging deep-seated tissues. Typically, the single-conductor coil diameter which yields the optimal S/N ratio at a depth ‘d’ is a coil of diameter ‘d’; hence, larger diameter single-conductor coils are required to image regions in the abdomen and chest of human patients. 
     The S/N ratio of the NMR signal may be further increased by orienting two coils, or coil pairs about the imaged object so that each detects RF energy along one of a pair of mutually perpendicular axes. This technique is generally known as quadrature detection and the signals collected are termed quadrature signals. 
     The outputs of the quadrature coils are combined so as to increase the strength of the received signal according to the simple sum of the output signals from the coils. The strength of the noise component of these signals, however, will increase only according to the square root of the sum of the squares of the uncorrelated noise components. As a result, the net S/N ratio of the combined quadrature signals increases by approximately √2 over the S/N ratio of the individual coils. 
     The quadrature orientation of the two coils introduces a 90° phase difference between the NMR signals detected by these coils. Therefore, combining the outputs from the two quadrature coils to achieve the above described signal-to-noise ratio improvements requires that one signal be shifted to have the same phase as the other signal so that the amplitudes of the signals simply add in phase. 
     The approximate net gain of √2 in S/N ratio is achievable primarily due to the lack of inductive coupling between the coil pairs. This ensures that only the uncorrelated noise components add, in lieu of both the uncorrelated and correlated noise components, to reduce the effective S/N ratio. Inductive isolation is achieved by geometrically orienting the coil conductors such that the mutual inductance is minimized between the coil pairs according to the following: 
     
       
         
           
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     where M represents the mutual inductance between coils 1 and 2 and the vector components dl 1  and dl 2  represent segments of coils 1 and 2 with current amplitudes I 1  and I 2 . The denominator represents the magnitude difference of the position vectors of each dl segment. The condition wherein M is approximately zero with respect to the individual self-inductances of coils 1 and 2 is known as inductive isolation between the coils. 
     C. Multiple Channel Receiver/Coil Systems 
     A method of increasing the S/N ratio of the NMR signal over a larger region is to digitally add the post processed signals derived from more than one coil; each sensitive to the precessing nuclei within overlapping volumes. If two coils&#39; signals are processed and converted into image data separately and then added digitally, one can obtain an increase in S/N ratio (SNR) within the larger volume. Separate amplifiers, analog-to-digital converters, sample-and-hold circuits, computer storage, and image processor channels represent an alternative configuration for processing the two signals in lieu of a single quadrature combiner. A system of four channels whose signals are derived from an array of four coils is described in U.S. Pat. No. 4,825,162. The primary advantage of this system is that one obtains the signal-to-noise performance of smaller surface coils over a larger geometric region corresponding to increased anatomical coverage. 
     Yet another method of further improving the SNR is to combine the effective gains of both quadrature coils with those of multiple channel or array systems. Such a system of quadrature arrays is comprised of two sets of linear coils, each element in each set having a phase component orthogonal to the phase component of each element of the sister set. Then, the signals are combined such that each linear signal is paired with its co-volume-sharing paired linear coil signal with the appropriate 90 degree phase shift to yield the quadrature gain in each element pair volume. This coil system is taught in U.S. Pat. No. 5,430,378 (&#39;378 patent) entitled “NMR Quadrature Detection Array”. 
     Limitations exists with the aforementioned configuration of quadrature coils; that being that they are not laid out to provide optimal volumetric coverage—that is sensitivity from more than one side of the patient. Due to the fact that they are described as being positioned along one aspect of the patient; the sensitivity profiles imparted are asymmetrical to the patient. Two patents referenced have made incremental improvements in volumetric signal homogeneity by creating linear arrays that are positioned above (superior) and below (inferior) the patient. Both U.S. Pat. No. 5,548,218 (Lu) and U.S. Pat. No. 6,624,633 B1 (Zou) employ linear arrays of three or more saddle or butterfly elements posterior to the patient and arrays of three or more single loop elements anterior to the patient. Signals from each anterior and posterior element, arranged opposing each other across the patient volume, are then added in quadrature mixers to create quadrature signals from the medial regions where their signals exhibit the same relative signal strength. These configurations are limited as well due to that simple fact that each element of the quadrature pair has substantially different sensitivity (flux) profiles throughout the medial volume due to their positions being on opposite sides of the volume. Quadrature combination of these signals yields a combined signal that is mostly that signal of the saddle or butterfly coil on those coil&#39;s sides of the volume and the combined signal that is dominated by the single loop signal on the single loop side of the volume. It is only in the middle of the volume where the saddle and single loop signals are similar magnitude where effective quadrature gain is realized. So, although the aforementioned patents describe volume coil arrays that provide more homogeneous signal quality throughout a volume, they do not yield the SNR performance locally to the quadrature coil sets described in the &#39;378 patent. 
     The problem of improved volumetric homogeneity without sacrifice of SNR could be solved by arranging quadrature arrays similar as described in the &#39;378 patent on more than one side of a patient, and of course using care to ensure that element sizes, orientations, and resulting signal phases were such that each element&#39;s signals were not destructive to one another. This solution then brings about a two piece coil set that is relatively easy to position about the patient&#39;s torso such as presented by U.S. Pat. No. 6,650,926 B1 (Chan et. al.). This particular patent is based upon creating a series of quadrature paired elements overlapping in the Z-direction (long axis of the patient) and held within position of one another by a semi-rigid spline, or spline that is hinged near its center to facilitate some flexibility along the Z-direction. Flexible components of the antenna elements protrude from the central spline and partially wrap about the subject. Opposing anterior and posterior rigid spline coil sets facilitate wrapping from both sides of a patient and creating a uniform quadrature detection volume. This design is limited in the number of elements, has limited flexibility from a generally planar configuration, and doesn&#39;t address optimization of multiple elements on such a flexible form. 
     In the case of the extremities, in contrast to the potentially much larger diameter torso, a different solution is possible that brings the convenience of a singular coil structure versus opposing two-part structures. One solution, presented in U.S. Pat. No. 6,438,402 B1 (Hashoian) is to wrap larger resonating elements about both legs and lower torso with a series of overlapping elements. 
     Another solution, considering the smaller diameters and lengths of extremities versus the human form, is to place a singular structure of reducing diameter about a single extremity, and with sufficient length and number of elements to optimize the SNR throughout the entire length of the extremity or body part. This concept may appear similar to that of U.S. Pat. No. 6,438,402 B1 (Hashoian), but there exists significant conceptual differences. 
     First, Hashoian teaches the creation of quadrature pairs of elements within a singular cylindrical wrap, then teaches that multiple wraps can be added in an overlapping fashion; hence creating an array providing considerable longitudinal coverage. For proper tuning to be maintained, the relative flexible antenna structures must maintain their relative shape and position relative to one another; a difficult feat with this mechanical design as there is little that will keep the adjacent structures with the proper critical overlap for the requisite inductive isolation. If the isolation or tuning of an individual element is perturbed due to improper flexing or placement, the uniformity of the exam will be seriously compromised. Secondly, the design requires latching each and every wrapped element separately; a cumbersome task and time sensitive task considering the need for the patient to remain motionless throughout the entire exam and the nature of throughput requirements in MRI. 
     Thirdly, Hashoian does not teach how to create an array of more than two adjacent quadrature elements; hence compromising the possible SNR compared to an array with all quadrature elements. 
     Finally, Hashoian does not address optimization of the element size, number, tuning stability or isolation. 
     Similar antenna geometries of Hashoian are incorporated by Szumowski in U.S. Pat. No. 6,137,291 and Vij in U.S. Pat. No. 6,498,489 B1; however, Szumowski and Vij teach rigid, separable saddle coil pairs or helmholtz pairs versus the flexible elements that Hashoian uses. Both Szumowski and Vij utilize the similar concept of reducing cylindrical diameter to ensure closer coupling to the anatomies in question but neither teaches quadrature elements “surrounding” the anatomies along the entire length of the anatomies. 
     U.S. Pat. No. 5,435,302 discloses flexible antennas wherein a singular resonator is constructed on a flexible substrate. This patent divulges a method of mounting thin conductors of a single resonator on a pre-shaped pseudo-flexible form for scanning one unique patient anatomy. 
     Although U.S. Pat. No. 5,594,339 also teaches some construction methods for creating a flexible coil substrate, it is restrictive in practice as the sheet plastic layers flex in an arch tangential along one axis only. Neither of these two previously mentioned patents teaches coil arrays, or quadrature arrays or the methods required for making such arrays operable (i.e. tuning stability, maintaining isolation, and flexing in three dimensions) in a highly flexible environment. 
     Two more recent patents address the need for multiple elements on shaped forms with contours along all three axes such as a helmet-like coil form or shoulder-torso form. U.S. Pat. No. 6,084,411 (&#39;411 patent) and U.S. Pat. No. 7,663,367 B2 describe the construction of a 3-dimensional form-fitting rigid or fixed position substrate on which independent coil resonators are attached (&#39;411 patent) or manufactured as a traditional overlapping or non-overlapping (for parallel imaging sequence performance optimization) multi-element array as is taught in the scientific literature (many such articles in the Journal of Magnetic Resonance Imaging). Neither patent anticipates a highly flexible antenna array that maintains proper operational capability while being flexed in infinite positions. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is directed toward an MRI antenna array including a flexible housing, and a flexible substrate, flexible antenna elements and circuitry encapsulated by the housing. The housing is sufficiently flexible to allow it to be draped over or wrapped about a portion of a patient and distort in three dimensions to closely conform to contours of the patient. The antenna elements are attached to the substrate in a manner that permits each element to maintain a desired resonance when the housing is distorted in three dimensions. The circuitry is attached to the substrate and electrically coupled with the antenna elements for maintaining tuning and isolation between the elements when the housing is distorted in three dimensions. The array may be formed as a blanket that may be draped over a patient. 
     The present invention is also directed toward an MRI antenna array including a flexible and elastic housing, and a flexible and elastic substrate, flexible and elastic antenna elements and circuitry encapsulated by the housing. The housing is sufficiently flexible and elastic to allow it to be worn by a plurality of different sized patients so that the housing is in close contact with the patient and conforms to contours of the patient. The antenna elements are attached to the substrate in a manner that permits each element to maintain a desired resonance when the housing is distorted in three dimensions. The circuitry is attached to the substrate and electrically coupled with the antenna elements for maintaining tuning and isolation between the elements when the housing is distorted in three dimensions. The array may be configured to be worn over any portion of a patient&#39;s body, including the pelvis, shoulder, and the entire body. 
     In another embodiment, the invention is directed toward an MRI antenna array including a flexible housing and a flexible substrate, plurality of antenna elements, and circuitry that are encapsulated by the housing. The housing is lightweight, load bearing, compressible, and insulative and includes a surface for covering a designated portion of a patient. The housing is cut or pressed into a set of connected geometrical shapes positioned between the cut or pressed areas, which allows for smaller bend radii than a non-cut or pressed thick layer. The antenna elements and circuitry are mounted to the substrate, and the circuitry is electrically coupled with the antenna elements. 
     The present invention is an MRI antenna array constructed in such a way so as to be highly flexible and drape, fit, or conform to a myriad of different shapes and sizes associated with the human anatomy—all while offering optimal S/N ratio from the anatomy in question. Preferably, the invention includes the design of high Q resonating elements from highly flexible conductors whereby they are attached to a flexible, thin, durable substrate which, in combination with element sizing, spacing, and location, keeps them in relative position to one another and maintains isolation amongst the many elements. In addition, one embodiment is to employ elements that are constructed from a conductor which has the properties of expansion/contraction to accommodate stretching with the substrate material to which they are affixed. The attachment points serve also as circuit mounting locations for tuning, matching and isolation components as well as miniature isolation preamplifiers mounted directly in each element&#39;s radio frequency current pathway; thus significantly reducing coupling mechanisms and stray loop currents associated with larger circuit boards and component spacing. Preferably, the elements, their isolation and amplification circuitry, and output cabling are embedded in a lightweight, durable, water resistant, biocompatible, cleanable, highly flexible, foam housing. Preferably, the foam housing is thick and compressible enough to be comfortable for the patient to lie upon, yet exhibit a high degree of flexibility along three axes so as to conform to wide ranges of anatomical variations. This accommodation to fitting a range of anatomical sizes ensures that the coil elements are positioned as closely as possible to the target tissues; hence, optimizing the signal derived from the target anatomy based upon minimizing the distance from the target to the antenna elements. 
     In one embodiment of the invention, stiffeners are added within the encapsulating foam so as to restrict the bending in certain situations whereby the desire is for the flexible array to be self-supporting within a certain region. 
     In accordance with another embodiment of the invention the elements and associated circuitry are miniaturized and enclosed within the flexible foam housing as described to create garments that may be worn by the subjects in order to specifically target certain anatomies with the best possible anatomical fit of an antenna array so as to yield more optimal S/N ratio from that anatomy. The flexible antenna elements may be attached to a stretchy or elastic material and covered with another layer of the same type of material to create a stretchable garment that fits a range of patient sizes. 
     The invention also includes a flexible garment with embedded antenna elements that are allowed to contort in shape by a controlled amount and facilitate a certain amount of stretching in the directions of stretch of the garment. 
     The present invention preferably optimizes coil size, configuration, the number of coil elements or resonators, and the positioning of those resonators about the subject via their being mounted on a flexible substrate, in order to achieve the desired performance, both in terms of S/N ratio, coverage and homogeneity. Further, the resonators are isolated from one another to such a degree so as not to interfere with one another&#39;s tuning and performance, and are preferably housed in a water-proof container that facilitates close fitting to the desired patient anatomy via draping the coil over, around or embedding the array within a pull-on garment. Further, these arrays will withstand high degrees of flexing in three dimensions and also withstand the weight of the patient distributed over the surface of the coil housing. Isolation amongst elements is achieved via a combination of two or more mechanisms: 1) geometric isolation between two elements sharing a common sensitivity volume—meaning that their exists little to no inductive coupling between the elements due to their net orthogonal vector sensitivity profiles within the common volume; 2) inductive isolation by means of overlapping elements such that adjacent coil elements have net mutual inductance; 3) reactive isolation by means of a given capacitance or inductance connecting two nearby elements such as to cancel any mutual inductance between the two elements; 4) transformer isolation between two nearby elements whereby currents from each element flow through separate windings of a dual winding transformer in opposite directions and with the proper transformer coupling coefficient to cancel the mutual inductance of the two elements; and 5) the use of low impedance amplifiers and matched input isolation reactances that create a high impedance “trap” to the mutually induced currents from one element to another. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a blanket MRI antenna array in accordance with the present invention draped over a person representing one of many complex surfaces that may be covered by the blanket array; 
         FIG. 2  is a plan view showing the layout of antenna elements and circuit boards of the blanket array of  FIG. 1 ; 
         FIG. 3  is a detail view of three circuit boards and a portion of three antenna elements of the blanket array of  FIG. 1 ; 
         FIG. 4  is a detail view of a low profile, magnetic field neutral, cable Balun of the blanket array of  FIG. 1 ; 
         FIG. 5A  is a perspective view of one corner of the blanket array of  FIG. 1  showing a foam housing which is partially separated showing a substrate encapsulated by the housing; 
         FIG. 5B  is a perspective view of a portion of the blanket array of  FIG. 1  showing a pattern of grooves in the foam housing; 
         FIG. 6  is a perspective view of a chest and volume neck MRI antenna array in accordance with an alternative embodiment of the present invention; 
         FIG. 7  is a perspective view showing the antenna elements of a pelvic MRI antenna array in accordance with an alternative embodiment of the present invention; 
         FIG. 8  is a perspective view showing the layout of the antenna elements of the pelvic array shown in  FIG. 7  with each antenna element&#39;s associated magnetic flux vector indicated; 
         FIG. 9  is a perspective view of an elastic or stretchable conductor of the pelvic array shown in  FIG. 7 ; 
         FIG. 10  is a detail view of an isolation transformer network of the pelvic array shown in  FIG. 7 , which maintains isolation between non-adjacent and/or non-overlapping coil elements; 
         FIG. 11  is a perspective view of a pelvic array to which the antenna elements shown in  FIG. 7  are mounted; 
         FIG. 12  is a close-up detail view of one embodiment of a disposable patient liner for use with the pelvic array shown in  FIG. 11 ; 
         FIG. 13  is a perspective view of a shoulder MRI antenna array in accordance with an alternative embodiment of the present invention; 
         FIG. 14 a   . is a representation of a close up view of a conductor that is a flat weave mesh. 
         FIG. 14 b   . is a representation of a close up view of individual strands of a conductor that is a flat weave mesh. 
         FIG. 14 c   . is a representation of one or more indentations to moveably fix the flat weave mesh to a flexible substrate. 
         FIG. 15 a    and  FIG. 15 b    illustrate a comparative example of the durability of a conductor that is a flat weave mesh as compared to a conductor that is an elongate hollow cylinder. 
         FIG. 16  illustrates a comparative example of the range of tuning frequencies of a conductor that is a flat weave mesh as compared to a conductor that is an elongate hollow cylinder. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     Referring to  FIG. 1 , a flexible blanket MRI antenna array in accordance with one embodiment of the present invention is shown generally as  1 . The blanket array  1  includes sixteen flexible antenna elements (two of which are identified in  FIG. 2  as  21 ) attached to a flexible substrate  2  that is similar to a thin blanket. The elements  21  and substrate  2  are encapsulated by a flexible housing  1  B ( FIGS. 5A-B ), which is preferably constructed from foam and/or fabric as discussed in more detail below, in such a manner that the entire blanket array  1  is sufficiently flexible to drape over or be wrapped about a human body  3  and distort in three dimensions to closely conform to contours of the body  3 . This positions the elements  21  closer to the human tissue where they maintain more constant electromagnetic loading and yield more consistent performance results. Consistency is also improved by ensuring a minimum distance between the actual elements  21  and the target anatomy since signal reception decays inversely to distance. 
     Substrate  2  is preferably constructed of a fire retardant fabric, such as used in some tent fabrics, which exhibits excellent stability and withstands significant sheer stresses. These properties make such a fabric suitable for the substrate  2  to which the elements  21  are attached. An alternate substrate and conductor configuration is very thin Teflon or similar ultrathin sheet plastics to which highly flexible conductors are adhered. The substrate  2 , attached elements  21 , and foam or fabric housing  1  B ( FIGS. 5A-B ) in combination are sufficiently flexible in order to flex in all three axes and closely contour to protrusions of the human body, such as the legs, breasts or stomach of the human body  3  shown in  FIG. 1 . This is in contrast to a conventional rigid or hinged rigid coil form that does not facilitate placing the conductors in such close proximity to the desired tissues due to bending and flexing restrictions. A three dimensional coordinate system  10  is shown in certain of the drawings relative to the patient and MRI antenna array. The Z axis of the coordinate system  10  is aligned with the long axis of a patient (from head to toe), the Y axis is aligned with the anterior/posterior direction, and the X axis is aligned with the left/right direction. 
     Referring to  FIG. 2 , blanket array  1  includes sixteen elements, two of which are identified in the drawings as  21 , each of which mounted to flexible substrate  2  in a manner described below that permits the array  1  to drape over a patient and closely follow a myriad of contour variations, such as shown in  FIG. 1 . Blanket array  1  is suitable to be used for imaging the more broad ranging target anatomies of whole body or spine MRI; yet, smaller versions of the embodiment could be used to wrap around extremities or pediatric torsos. Elements  21  are preferably sized to allow adequate penetration to deep seated tissues. Elements  21  are configured to overlap and may be non-overlapping and positioned in order to optimize parallel image processing speed (acceleration factors) and/or image quality. Blanket array  1  includes sixteen elements  21  in order to correspond with the increasingly popular MRI platform containing sixteen simultaneously active channels wherein each channel has its own analog-to-digital (A/D) converter and data processing. Blanket array  1  results in better image quality from the deeper seated tissues, and accommodates acceleration sequences. 
     Each of the sixteen elements  21  includes a loop of high Q extremely flexible conductor, preferably a coaxial cable with the outer insulator removed and split at a minimum of two junction points by rigid circuit boards  30  or  40  and  22 . More preferably, each of the sixteen elements  21  include a loop of high Q extremely flexible conductor that is a flat weave mesh. There are three overlapping columns of elements  21 . The leftmost and rightmost columns each include five elements  21 , and the centermost column includes six elements  21 . Adjacent elements  21  within each column overlap, and the elements  21  of adjacent columns overlap. Circuit boards  30  are positioned at the locations where the centermost column of elements  21  overlaps elements  21  in the right and left columns, and also at the locations where adjacent elements  21  within the centermost column overlap and at one of the two locations where adjacent elements  21  within the left and right columns overlap nearest the center column. Circuit boards  40  are positioned at the other of the two locations where the elements  21  within the right and left columns overlap away from the center column. There are twenty-two circuit boards  30 , although only a few are numbered in the drawing for clarity. On the top two circuit boards  30  and bottom two circuit boards  30 , an element  21  from the centermost column overlaps a single element  21  from either the left or right column. For half of the remaining eighteen circuit boards  30 , adjacent elements  21  from the centermost column overlap, and one of the elements  21  from the left or right columns overlaps each of the adjacent elements  21  from the center column. For the other half of the remaining eighteen circuit boards  30 , adjacent elements  21  from one of the left or right columns overlap, and one of the elements  21  from the center column overlaps each of the adjacent elements  21  from the right or left column. There are eight circuit boards  22 , although only a few are numbered in the drawing for clarity. Circuit boards  22  are positioned at locations where adjacent elements  21  in the right and left columns overlap. There are ten circuit boards  40 , although only a few are numbered in the drawing for clarity. Each circuit boards  40  is positioned at a location on one of the elements  21  from the right or left columns that is positioned farthest from the center column of elements  21 . 
     As described in more detail below, circuit boards  22 ,  30  and  40  contain the distributed capacitance required for resonance of the elements  21 . Boards  30  and  40  also serve the purposes of decoupling and impedance matching. Not all of the larger boards  30  and  40  have identical electrical circuitry because each element  21  only needs one board  30  or  40  with all of the aforementioned circuitry. The larger hexagonal boards  30  also serve the purpose of stability attachment plates for the flexible elements  21  crossing them (see  FIG. 3 ) in order to, in part, maintain the desired overlap or gap between adjacent elements  21 . All circuit boards  22 ,  30 , and  40  are preferably small in dimension or footprint so as to have less negative effect on the overall flexibility of the blanket array  1 . Elements  21  are made from coaxial cable due to its high conductivity properties or Q (clad copper) resulting from high shield effectiveness (&gt;99%) of the original coaxial cable. The shield of the coaxial cable is used as the radio frequency current carrier or coil inductive conductor, and the center conductor of the coaxial cable is used, when desirable, for carrying decoupling DC currents to other circuit boards  22 ,  30 , and/or  40 . More preferably, elements  21  are made from a conductor that is a flat weave mesh. 
     All circuit boards  22 ,  30 , and  40  and the flexible elements  21  are fastened to the flexible substrate  2  at select points so as to have minimal negative influence on the general three dimensional flexibility of the blanket array  1 . For example, each of the circuit boards  22 ,  30 , and  40  is preferably mounted to substrate  2  near its center using plastic rivets or nylon screws. Other mounting methods are within the scope of the present invention. Each element  21  is joined to substrate  2  with a plurality of loosely fitting tie clamps or eyelets  24  of plastic or thread at points  23  which are generally equidistant from each other and boards  22 ,  30 , and  40  along the longest span of the element  21  between two boards  22 ,  30 , and  40 . Tie clamps  24  are positioned such that a section of element  21  will slip/move through the clamps  24  and distort nominally with flexing, yet distort a restricted amount such that the element  21  maintains its general shape, and therefore resonance when the array  1  is draped over or wrapped about a patient and distorted in three dimensions. The clamps  24  may be simple arch shaped loops as shown in  FIG. 3 , or have a slightly more complex two piece design as shown in  FIG. 9 . 
     Further, the shield portion of the coaxial cable elements  21  are mounted to boards  22 ,  30 , and  40 , preferably by soldering, in certain locations as more fully described below in order to maintain the relative positioning of the adjacent elements  21  and general shape of each element  21 . Referring to  FIG. 3 , which shows an assembly  35  including one of the boards  30  on which three of the elements  21  overlap, those elements referred to as  21 A,  21 B, and  21 C, portions of the elements  21 A,  21 B, and  21 C are joined to board  30 . Element  21 A includes element portions  21 A 1  and  21 A 2 , element  21 B includes element portions  21 B 1 ,  21 B 2 ,  21 B 3 , and  21 B 4 , and element  21 C includes element portions  21 C 1  and  21 C 2 . Element portion  21 C 1  is mounted to board  30  at locations  27   a  and  27   g , element portion  21 B 1  is mounted to board  30  at locations  27   b  and  27   f , element portion  21 B 3  is mounted to board  30  at location  27   c , element portion  21 A 1  is mounted to board  30  at location  27   j , element portion  21 A 2  is mounted to board  30  at location  27   k  and to board  22  at location  271 , element portion  21 B 2  is mounted to board  30  at location  27   i  and to board  22  at location  27   d , element portion  21 C 2  is mounted to board  30  at location  27   h , and element portion  21 B 4  is mounted to board  22  at location  27   e . Another portion of element  21 A is mounted to board  22  at location  27   m . At each of the tie points  27   a - m  where  FIG. 3  shows a gap in one of the elements  21 , the shield portion of the coaxial cable element  21  is mounted to the board  30 . Board  30  is constructed to provide a continuous connection of the above-mentioned locations  27   a - m  such that each of elements  21 A-C is continuous as it passes through the board by way of vias at locations  27   a - m  which connect to traces (not shown) on the back side of the board thus providing a circuit path underneath the overlapping element  21 . For example, element portion  21 B 3  enters the board  30  and is soldered at  27   c , which is connected to a via which passes through the board  30  to a conductor on the back side of the board  30  and runs generally straight to underneath point  27   b  of element portion  21 B 1  where it connects to another via which passes through the board  30  and is connected to point  27   b , thus completing the circuit continuity of element portions  21 B 3  and  21 B 1 . Similarly connected point pairs on board  30  are  27   g  to  27   h  and  27   f  to  27   i , and on boards  22  are  271  to  27   m  and  27   d  to  27   e . The remainder of the elements  21  shown in  FIG. 2  are mounted to respective boards  22 ,  30 , and  40  over which they pass in a similar manner as described above with respect to elements  21 A,  21 B, and  21 C. The locations, or tie points,  27   a - m  are strategically placed in order to maintain a relatively constant gap between those adjacent elements  21 A,  21 B, and  21 C ( FIG. 2 ) and more specifically, with respect to the portion of the elements that pass over board  30 , maintain the area circumscribed by element portions  21 A 1 ,  21 A 2 ,  21 B  1 ,  21 B 2 ,  21 C  1  and  21 C 2 . This maintains tuning and isolation between adjacent and nearby elements  21  when the array  1  is draped over or wrapped about a patient and distorted in three dimensions. Routing the shield conductor portions of the elements  21  underneath the board  30  in this manner allows the shield conductor portions to be continuous, but also keep a low profile so that it is not uncomfortable for a patient to lie upon the board  30 . There are additional tie points  23 , shown in  FIG. 2 , which restrict the shape distortion but facilitate flexing of elements  21 . 
     The difference between boards  30  and  40  is the shape of the boards  30  and  40 , and that the boards  30  include the physical tie down points  27   a - c  and  27   f - k  for three overlapping elements  21 , while boards  40  only include physical tie down points for one element  21 . Each of boards  30  is hexagonal with a first set of three sides of approximately equal length and a second set of three sides of approximately equal length that are shorter than the first set of sides. The shorter sides alternate with the longer sides to form the board  30 . The shape of boards  30  allows the boards  30  to maintain a desired spacing between the elements  21 A-C. Each of boards  40  is rectangular. As shown in  FIGS. 2 and 3 , boards  30  and  40  are encapsulated by protective layers  26 , which are preferably constructed from foam and/or flexible rubberized plastic similar to an automobile tire inner-tube patch. There is one layer  26  positioned on each side of the boards  30  and  40  to serve as insulative covering as well as strain relief for elements  21  and preamplifier cables  33  exiting the boards  30  and  40 . In  FIG. 3 , only one of the layers  26  is shown so that the rest of board  30  is visible. In  FIG. 2 , only certain of the boards  30  and  40  are shown with layers  26  for clarity. The layers  26  provide strain relief by adhering strongly to the elements  21  and preamplifier cables  33  from both sides and providing a restriction on the bending moment of the elements  21  and preamplifier cables  33  as they exit the boards  30  and/or  40 . 
     Eleven of the boards  30  and five of the boards  40  contain the same electrical circuitry, which is shown on the board  30  in  FIG. 3  and described in detail below. Referring to  FIG. 2 , the boards  30  containing this electrical circuitry are the five boards  30  positioned between the left and center columns of elements  21  and having a short side pointing to the left of the array  1 , and the six boards positioned between the center and right columns of elements and having a short side pointing to the left of the array  1 . The five boards  40  containing this circuitry are the boards on the right hand side of the array  1 . Each of these eleven boards  30  and five boards  40  includes the matching, tuning, active decoupling, and amplifier circuitry shown in  FIG. 3  for one of the sixteen elements  21 . Board  40  is smaller in footprint than board  30  in order to optimize the overall flexibility of the blanket array  1  while housing the same requisite circuitry as board  30  less the added footprint for stabilizing the intersection of three elements  21 A,  21 B, and  21 C such as shown in  FIG. 3 . The remainder of the boards  30  and  40  shown in the drawings do not include this circuitry, but do include tie down points similar to the points  27   a - l  shown in  FIG. 3  for maintaining the desired shape and relative position of the elements  21 . 
     Referring to  FIG. 3 , the circuitry on the eleven of boards  30  and five of boards  40  identified above is described below. The circuitry is compact, which reduces or eliminates unwanted stray reactances of stray loop currents and long lead lengths among the components. The compactness also aids the flexibility and durability of the blanket array  1 . A matching capacitor  28  and decoupling capacitor  29  are connected in series with the shields of element portions  21 A 1  and  21 A 2  across the gap between those portions as follows. One side of capacitor  28  is connected to (the shield of) element portion  21 A 1  and the other side is connected to one side of capacitor  29 , to the shield  33   b  of preamplifier cable  33 , to the preamplifier  31  ground, and to a decoupling diode  38 . The other side of capacitor  29  is connected to (the shield of) element portion  21 A 2 . An isolation inductor  32  is connected on one side to the shield of element portion  21 A 1  and on the other side to a preamplifier  31  input. The other signal connection to the input of the preamplifier  31  is the common connection  33   b  described above. Signal developed across capacitor  28  is delivered to preamplifier  31  via isolation inductor  32 , and the amplified signal output from preamplifier  31  is connected to the cable  33  center pin  33   a . Signal output is then connected across the center pin  33   a  to shield common  33   b . In this preferred embodiment, the preamplifier  31  operating voltage is also brought to the amplifier via the preamplifier cable  33  (center pin  33   a  with respect to shield  33   b ) and system cable  52  through Balun  50 , which reduces wiring and circuitry. 
     Each of the eleven boards  30  and five boards  40  identified above with the circuitry shown in  FIG. 3  have a preamplifier cable  33 , which connects the board  30  or  40  to the MRI system (not shown) via a Balun  50  and system cable  52  ( FIG. 4 ), as described below. Other mother boards or routing boards (not shown) may be positioned between the Balun  50  and MRI system (not shown). As shown in  FIG. 2 , the preamplifier cables  33  from the boards  30  and  40  enter a Balun  50 , and a system cable  52  exits the Balun  50  and merges into a bundle  47  which is terminated at a system connector (not shown) of the blanket array  1 . For clarity,  FIG. 2  only shows six of the system cables  52  exiting the substrate  2 . There are ten other system cables  52  that exit the substrate  2  at the locations shown on  FIG. 2  where there are horizontal lines perpendicular to the right edge of substrate  2 . 
     Decoupling current is brought to the board  30  circuitry shown in  FIG. 3  via an independent twisted wire  34 , which is twisted to avoid any EMF induced on the wire with respect to the shield of coaxial preamplifier cable  33 . The side of decoupling capacitor  29  that is connected to the shield of element portion  21 A 2  is also connected to one end of a decoupling inductor  37 . The other end of the decoupling inductor  37  is connected to one end of a diode  38 . The other end of the diode  38  is connected between the capacitors  28  and  29 . Wire  34  is joined to one end of an RF isolation choke (inductor)  36  and the other end of inductor  36  is connected between decoupling capacitor  29  and a decoupling inductor  37 . Decoupling voltage and current is applied via wire  34  and inductors  36  and  37  to the diode  38  with return path for this current on the coaxial shield  33   b . When the decoupling voltage provides sufficient forward bias to the diode  38 , it conducts, effectively placing inductor  37  in parallel with capacitor  29 , which creates a high impedance to the designated RF resonance of the element  21 A and decouples it from the transmit pulse. 
     There are two boards  22  shown in  FIG. 3 , the one in the upper right hand portion of  FIG. 3  includes active and passive decoupling circuits, and the one positioned underneath board  30  includes only a passive decoupling circuit. The active and passive decoupling circuits on board  22  are optional. Boards  22  serve two purposes, the first as a minimal mechanical footprint for flexibility reasons that also provides for a low profile circuit crossover of two elements  21  as described with connections  27   a - c  on board  30 . Secondly, the board  22  footprint may be populated with the added decoupling circuitry described below when such circuitry is warranted to increase the power handling capacity of the total decoupling circuitry—more decoupling junctions being required for larger element areas as is well known in the industry. The optional active and passive decoupling circuitry on board  22  are discussed below. A secondary active decoupling circuit can optionally be biased using the same wire  34  connected to the conductor shield  27   k  through an isolation inductor similar to  36 , in which case inductor  36  would not connect to  37  as shown but instead to  27   k  of element segment  21 A 2 . The other end of element portion  21 A 2 , connection  271 , connects to diode  39 , which connects then to decoupling inductor  41  which then serially connects to connection  27   m , then to RF choke/inductor  42 , then to the return bias path via the same conductor segment  21 A 2  center conductor E. Center conductor E connects to one end of another isolation choke (inductor)  36   b  the other end of which is connected to the common return or the shield  33   b  of preamplifier cable  33  thus creating two parallel and equally resistive (DC) circuit pathways to two independent decoupling diodes, one  38  on board  30  and the other  39  on board  22 . 
     The optional DC bias enters independent decoupling board  22  via the shield D and activates decoupling diode  39 , which when on creates a high impedance trap to the tuned operating frequency, the trap consisting of decoupling inductor  41 , and resonant capacitor  43 . One end of decoupling diode  39  is joined to shield  271  and the other end is joined to an end of decoupling inductor  41 . The other end of decoupling inductor  41  is joined to an end of return isolation inductor  42 . The other end of return isolation inductor  42  is connected to center conductor E. Resonant capacitor  43  is connected to shield  271  and the shield  27   m  of the other portion of element  21 A exiting board  22 . Inductor  41  is tuned to resonate with capacitor  43  and create the requisite high impedance to the element frequency during the system transmit pulse—synchronized with the DC bias. A second specially designed Schottky back-to-back (reverse polarity) diode pair  44  with DC blocking capacitor  46  is in parallel with the active diode  39 . This diode pair  44  fires on during the transmit pulse when sufficient energy is developed across the capacitor  43  and inductor  41  in the event that there is no active diode  39  or that it doesn&#39;t activate properly. The diode pair  44  is a safety redundancy when there is an active diode  39 , or it is an alternate decoupling strategy when there is no active diode  39 . This embodiment represents one rendition of decoupling and may vary depending on the MRI system outputs. The board  22  positioned under board  30  and which includes only passive decoupling circuitry, includes the inductor  41 , capacitor  43 , and diode pair  44  connected in the same manner as discussed above with respect to the other board  22 . 
     Capacitors  28 ,  29  and  43 , all effectively in series, are chosen such that their combination results in resonance with the total loop inductance  21 A. The independent values of those capacitors are as follows. Capacitor  28  is chosen to yield approximately 50 ohms to the input of the low impedance input amplifier  31 . The reactance of capacitor  28  is matched by an equal and opposite reactance of inductor  32  such that the pair creates a high impedance to RF current flows on the loop  21 , which provides the desired isolation benefit of the low impedance amplifier  31 . Capacitor  29  creates a ratio of impedances, along with capacitor  43 , with the matching capacitor  28 . Therefore, these capacitors  28 ,  29 , and  43  are all selected by employing reactance formula and iterating by trial and error to obtain the optimal effect of match, isolation given the input characteristics of a given preamplifier  31  and decoupling efficiency. 
     The preamplifier cable  33 , which connects the preamplifier  31  output to the control board or MRI scanner (not shown), requires isolating the common ground of the system from that of the preamplifier  31  and circuitry of assembly  35 . This is best achieved with a tuned trap or Balun  50  ( FIG. 4 ) created out of the shield of coaxial cable as described below. There are sixteen Baluns  50 , one for each element  21 , each joined with a preamplifier cable  33  leaving one of the eleven boards  30  or five boards  40  identified above and the system cable  52  identified with the board  30  or  40 . Only two of the Baluns  50  are numbered in  FIG. 2  for clarity. The Baluns  50  shown in  FIG. 2  include the top five elongated rectangles positioned in the center of the center column of elements  21 , the five elongated rectangles positioned in the center of the right column of elements  21  along with the single elongated rectangle positioned above the right column of elements  21 , and the five elongated rectangles positioned to the right of the right column of elements  21 . There are six additional elongated rectangles shown in  FIG. 2 , but not numbered, which include no circuitry but are optionally included in the blanket array  1  to maintain symmetry for aesthetics. In the preferred embodiment then, all preamplifier cables  33  run through a separate “floating” Balun  50 , and a system cable  52  exits the Balun and is then merged into a thin bundle of coaxial cables  47 . This cable bundle  47  is strategically positioned near the exit point of the blanket array  1  so as not to impede the flexibility of the blanket array  1 . 
     Referring to  FIG. 4 , each Balun  50  includes a board  54  to which the shield portions of coaxial cables  33  and  52  are mounted. A stacked figure eight set of windings made from a miniature rigid coaxial cable  51  is mounted to the board  54  between the preamplifier cable  33  and system cable  52 . The center conductors of the cables  33 ,  51 , and  52  are connected via wires  55  and  56 , and the shields of cables  33 ,  51 , and  52  are connected via wires  57  and  58 . A capacitor  53  is connected between the shield ends of cables  33  and  52 . The Balun  50  is created by the inductance of the figure eight winding of cable  51 , and therefore it is dependent upon the number, size, length and spacing of the windings of cable  51 .  FIG. 4  depicts only two windings for simplicity; however, several may be required to yield the desired isolation effect. The total inductance of cable  51  is resonated with capacitor  53 . By keeping the cable  51  small and limiting the number of its windings, the height of the assembly can be kept less than 5 mm so as to present a minimal obstacle to cover and pad against eventual patient pressure. Also, by keeping the board  54  small and tethered only by the cables  33  and  52 , the flexibility of the completed blanket array  1  is maintained. 
     Referring now to  FIG. 5A , blanket array  1  includes a flexible housing  1  B, preferably constructed from compressed EVA foam, that encapsulates the substrate  2 , elements  21 , boards  22 ,  30  and  40 , Baluns  50 , and cables  33  and  52 .  FIG. 5A  shows a portion of the foam housing  1 B cut open at points  130  and peeled apart so that a portion of substrate  2  may be seen. The foam housing  1  B includes a top layer  120  joined to a bottom layer  121 . The top layer  120  and bottom layer  121  include aligned grooves  115  and non-grooved regions  116  that are thicker than the grooves  115 . The grooves  115  are preferably cut or pressed into the layers  120  and  121 , to form the geometrical shapes of the non-grooved regions  116 . The grooves  115  allow for a smaller bend radii of the array  1  then if the housing  1  B was formed from layers  120  and  121  that did not include any grooves  115 . The non-grooved regions  116  of the top layer  120  have a thickness of between approximately 0.50 to 0.75 inches, and most preferably approximately 0.625 inches. The non-grooved regions  116  of the bottom layer  121  have a thickness of between approximately 0.25 to 0.40 inches, and most preferably approximately 0.25 inches. The thickness of the non-grooved regions  116  of the top layer  120  and bottom layer  121  in combination is between approximately 0.75 to 1.15 inches, and most preferably approximately 0.875 inches. The thickness of the blanket array  1  at the grooves  115  is between approximately 0.14 to 0.20 inches, and is most preferably approximately 3/16 of an inch. The non-grooved regions  116  of the top layer  120  have a thickness that is sufficient to cover, pad, and seal the circuit boards  22 ,  30 ,  40 , Baluns  50 , cables  33  and  52  and clamps  24 . The non-grooved regions  116  may also be hollowed out, or thinner in certain areas, as necessary to maintain a uniform compression of the foam over the various thicknesses of the components covered by the foam. The thickness of the grooves  115  permits the blanket array  1  to flex at the grooves  115  so that it is able to closely conform to and cover body parts having different contours. 
     Top and bottom layers  120  and  121  of foam extend beyond the perimeter of the substrate  2  to which the elements  21  and their clamps  24 . This provides the layers  120  and  121  with a sufficient area to bond together under compression so that they seal liquid and contaminants from entering between the layers  120  and  121 . Further, substrate  2  is discontinuous in certain areas, one of which is identified in  FIG. 5A  as  124 , in order to provide additional areas  125  where the layers  120  and  121  may bond together. The housing  1 B is preferably light weight, flexible, load bearing, compressible, and insulative. 
       FIG. 5A  also illustrates that conductor  21  has bulges, one of which is identified as  85  and is discussed below in connection with  FIG. 9 , which expand and contract to allow the conductor  21  to stretch thereby creating additional flexibility and elasticity in the conductor  21  and blanket array  1 . The foam layer  120  includes pockets to accommodate the bulges  85  and their expansion and contraction. 
       FIG. 5B  shows the overall textured pattern of grooves  115  and non-grooved regions  116  of the blanket array  1 , which yields flexibility along all groove  115  directions. The grooves  115  form a repeating pattern of circles, one of which is shown as  140 , and lines  142 ,  144 , and  148  intersecting in the center of each circle  140 . There is an angle of approximately 60 degrees between lines  142  and  144 , between lines  144  and  148 , and between lines  148  and  142 . The circles  140  are centered within the circular elements  21 , shown in  FIG. 2 . Two of the hexagonal assemblies  35  are shown in dashed lines in their position within the blanket array  1 . The assemblies  35  are shaped in order to promote flexibility of the blanket array  1 . Grooves  115  are positioned around the perimeter of the assemblies  35  so that the blanket array  1  may flex in all directions around the assemblies  35 . The boards  22 ,  30  and  40  and Baluns  50  are preferably positioned in the non-grooved regions  116 . The antenna elements  21  and cables  33  and  52  cross over the grooves  115 . Inside of the grooves  115 , the elements  21  and cables  33  and  52  are preferably positioned within tubes (not shown) having a relatively small diameter that is just larger than the diameter of the elements  21  and cables  33  and  52 . The tubes (not shown) allow the elements  21  and cables  33  and  52  to move through the tubes as the blanket array  1  flexes in order to prevent the elements  21  and cables  33  and  52  from breaking and to promote flexibility of the array  1 . The outer surfaces of all of the non-grooved regions  116  preferably lie in the same parallel or generally curvilinear plane in order to present a relatively even pressure distribution on a patient using the blanket array  1 . The bundle  47  of cables  52  is routed to a system cable junction board (not shown) housed within a plastic housing  65  that is mounted to the perimeter of the foam housing  1  B. The board within housing  65  connects the bundle  47  of cables  52  to a cable  66  that connects the blanket array  1  to a MRI system receptacle (not shown). The housing  65  may include a quick disconnect receptacle connector (not shown) for the electrical connections within the cable bundle  47 . The housing  65  may also include a strain relief (not shown) for the cable  66  where it enters the housing  65 . 
     Instead of being constructed from foam with grooves, housing  1  B may simply be constructed from flat sheets of an elastic material such as neoprene that encapsulate the elements  21 , circuit boards  22 ,  30  and  40  and Baluns  50 , and cables  33  and  52 . Further, in this construction, a layer of foam may be positioned between the elastic sheets with cut out or compressed regions that are aligned with, and a thickness that corresponds with, the elements  21 , circuit boards  22 ,  30 , and  40  and Baluns  50 , and cables  33  and  52  such that the overall thickness of the array is approximately the same in any given location. Other layers, such as layers that are waterproof or layers for comfort, may also form a part of the housing  1 B. 
     In one embodiment, the components described above making up array  1  are formed from relatively small, lightweight materials so that the array  1  may be draped over an infant patient so as not to compromise the patient&#39;s breathing. 
     Referring now to  FIG. 6 , a flexible, form-fitting chest and volume neck and/or carotid array in accordance with another embodiment of the present invention is shown generally as  60 . Array  60  includes a blanket array  63 , which is similar or identical to the blanket array  1  shown in  FIGS. 1-5B  and described above, with stiffeners added to customize the array  63  so that it may be effectively positioned to image the junction  61  of the neck and torso of a person&#39;s body. The array  60  includes a plastic reinforced neck section  62 , which includes additional antem1a elements  67 - 69 , and is joined in hinge fashion to the blanket array  63  with multiple layers of foam and fabric that maintain flexibility at the junction. The neck section  62  is encapsulated in foam in a similar manner as described above with respect to the blanket array  1 . The elements (not shown) of the blanket array  63  and elements  67 - 69  of the neck section  62  include cables (not shown) that are similar to the cables  33  and  52  described above with respect to blanket array  1 . Those cables are routed throughout the neck section  62  and blanket array  63  to a side of the blanket array  63  where a hollow plastic cable guide 64 routes and protects the bundle of cables. The cables enter housing  65 , which is described above, and cable  66  exits the housing for connection to a MRI system receptacle (not shown) as described above. 
     Array  60  is one example of optimizing antenna element size and configuration to best match a targeted anatomical region. The blanket array  63  drapes over the anterior chest and covers the clavicles, and neck section  62  is structured to image and wrap around the left and right carotids. The neck section  62  includes antenna elements  67 ,  68  and  69 , the position of which inside of the neck section  62  is represented by the lines drawn in  FIG. 6 . Elements  67  and  68  are positioned on the left flap  70  of the section  62 , and element  69  spans the left and right flaps  70  and  71 . There are two additional antenna elements positioned within the right flap  71  of the section  62  that are mirror images of elements  67  and  68  such that the left and right flaps  70  and  71  are mirror images of each other. 
     Each element  67 - 69  is sized differently based upon the requisite penetration into the patient to optimize SNR from the carotid arteries. Element  67  is larger than elements  68  and  69  because the elements are farther from the target anatomy of vessels at the superior end of the carotid arteries. Because the curvature  72  of the section  62  around a patient&#39;s chin is orthogonal to the Z direction  10 , placing a simple loop element at that location would result in no sensitivity to the XY components of the NMR signal (spin). Therefore, element  69  is created as a Helmholtz coil with loop halves on each side of the apex of the curve  72 . This creates an element that is sensitive to the X component of spin  10 . The array  60  preferably includes a total of either 8 or 16 elements, which includes the five elements within neck section  62 . Thus, the blanket array  63  either includes three or eleven elements. The total number of elements is chosen based on compatibility with the MRI system with which the array  60  is used, and the desire to not multiplex signals together from multiple elements to a common signal line or system channel input. However, it is within the scope of the invention to do so based upon clinical design goals. If there are three elements within blanket array  63 , they are preferably three quadrature elements sized and spaced within array  63  to have their sensitivity profiles cover the target anatomy (e.g., heart, aorta, carotid origins, and clavicles). If there are eleven elements within blanket array  63 , they are preferably eleven single elements. 
     In an alternative embodiment, the array  60  may include another blanket array  60  that is positioned on the posterior aspect of the patient while the blanket array  60  and neck section  62  shown in  FIG. 6  are positioned on the anterior aspect. The cables from the blanket arrays  60  and neck section  62  are preferably routed and combined into one or two common cable assemblies (depending upon MRI system interconnect restrictions) to connect to the MRI system. This further illustrates the convenience of these design building blocks of discrete flexible elements ( FIG. 3 ) built into flexible housings previously described. This assembly is a preferred embodiment of 32 element array with a 16 element posterior blanket coil created such as described above in connection with  FIGS. 1-5B  combined with the 16 element array  60  of  FIG. 6 . 
     The elements of array  60  are preferably positioned and sized to conform to the region of the patient&#39;s chest through the lateral clavicle regions, the neck and ears to provide continuous coverage of the aortic arteries from their origin laterally through the sub-clavicle arteries and superiorly beyond the superficial temporal arteries. 
     Referring to  FIG. 7 , a flexible, pelvic MRI antenna array in accordance with another embodiment of the present invention is shown generally as  20 . Array  20  is a flexible, wearable garment that is designed to be worn by a person  17  to cover and assist in imaging his/her pelvic region. The array  20  includes flexible and elastic elements  11 - 16  that are sized and configured for optimal penetration into the target anatomy  17  given the constraints of distance and physical anatomical barriers, such as legs and superficial structures between the various elements  11 - 16  and the target anatomy of both male and female urological and reproductive organs. The elements  11 - 16  are mounted on a flexible substrate (not shown) that is similar to substrate  2  described above, but that is formed so that it may be worn like a pair of underwear. The substrate is preferably constructed from an elastic or stretchable material, such as a form of “wet suit,” neoprene or similar elastic material. The substrate is elastic or stretchable so that the array  20  is a “one size fits all” array that may be worn by different sized persons. Each element  11 - 16  is mounted to the substrate in a manner that maintains the flexibility and elasticity of the substrate. The substrate and elements  11 - 16  are encapsulated by a flexible and elastic housing, such as the housing  1  B shown in  FIGS. 5A-B , that is preferably constructed from an elastic material such as neoprene and thus does not include the grooves shown in  FIGS. 5A-B . The housing may include a layer of foam positioned between the layers of elastic material as described above in order to maintain a consistent thickness at all points of the array  20 . The housing and substrate stretches with variations in anatomical size of the different persons wearing the assembly to facilitate the array  20  being pulled on and worn like a garment by various sized and shaped patients during an MRI scan. The housing is sufficiently flexible and elastic to allow the housing to be worn by a plurality of different sized patients so that the housing is in close contact with the patient and conforms to contours of the patient. When the array  20  is worn, each element  11 - 16  has a unique shape associated with its position relative to the target anatomy and adjacent elements  11 - 16 . These factors affect the 3-D modeling outcome to optimize coverage and penetration of each element&#39;s  11 - 16  sensitivity profile within the patient. 
     Elements  11  and  12  are the superior, anterior, left and right elements and are larger so that their sensitivity profiles penetrate deeper—as they must due to the increased distance from the inferior torso surface to the target anatomies. These elements  11  and  12  are sensitive to the Y-component of the MRI signal vector due to their orientation generally in the Y plane. Elements  13  and  14  may be single loops such as  11  and  12  and employ critical overlap to ensure mutual inductive null or isolation, with all neighboring elements. Elements  13  and  14  may optionally be capacitively linked together to form a butterfly or Helmholtz coil to create an orthogonal sensitivity profile (X-vector sensitivity), and therefore be intrinsically isolated (aided with some critical overlap as well) from those neighboring elements sensitive to the Y vector. The array  20  may also include in an optional configuration four additional elements (not shown) that mirror elements  11 - 14  and that are positioned on the posterior side of the patient  17  to provide sensitivity profiles from the opposing patient side as the anterior elements  11 - 14  shown in  FIG. 7 . The optional posterior elements (not shown) may be paired as Helmholtz coils in order to keep the total element count at  8 , or left as individual elements so that the total element count is 10. The element count is important to consider for economic factors because the array could be designed for use with common 8-channel MRI scanners without extra switching capabilities, or 16 channel scanners. Element  15  is an hour-glass shaped loop with the two ends of the hour glass on the opposing anterior and posterior (shown in dashed lines) sides of the body and connected between the legs. This element  15  exhibits sensitivity to the Y vector throughout the inferior most aspect of the pelvis or torso, the perineum  18 . Element  16  consists of two halves  16   a  and  16   b , shown in dashed lines in the posterior region, of a Helmholtz coil lying in a saddle shape against the inner thighs with superior conductors in the region of the perineum  18 . This configuration yields a strong local sensitivity to the X-directed vector in the region of the perineum  18   
       FIG. 8  illustrates the optimization of element location, size, configuration and spacing in order to create the wearable pelvic garment array  20  shown in  FIG. 7 . The elements  11 - 16  of array  20  are joined to a flexible, elastic material (not shown) such as neoprene to create a garment similar to high-waist underwear. The array  20  includes circuit boards and cables (not shown) that are similar to the circuit boards  22 ,  30 , and  40 , Baluns  50 , and cables  33  and  52  described above in connection with blanket array  1 . Elements  11 - 16  are preferably elastic conductors, such as the elastic conductor  80  described below in connection with  FIG. 9 , that are joined to a flexible substrate (not shown) of the garment every few centimeters with loose ties  24  that allow the elements  11 - 16  to flex and move within pre-designed limitations. More preferably, elements  11 - 16  are conductors that are a flat weave mesh, such as the flat weave mesh conductors described in  FIG. 14 . a ., that are joined to a flexible substrate (not shown) of the garment every few centimeters with loose ties  24  that allow the element  11 - 16  to flex and move within pre-designed limitations. This allows the elements  11 - 16  to maintain a desired resonance when the array  60  is worn by a patient and distorted in three dimensions. The elements  11 - 16  include gaps  8 ,  9 , and  18 , which represent where circuit boards  22 ,  30  and  40  and/or tuning capacitors and isolation inductors are positioned in order to resonate and isolate elements  11 - 16  from one another. Isolation amongst elements  11 - 16  is created and maintained, even when the array  60  is distorted in three dimensions, by a combination of non-interfering flux sensitivity profiles (described below), overlaps or gaps  4  ( FIG. 10 ), transformers  5  ( FIG. 10 ), and the isolation preamps discussed previously in connection with  FIG. 3 . At the regions  19  where the various elements  11 - 16  cross over one another, the elements may be insulated, or a circuit board may be positioned there, similar to one of the boards  22 ,  30 , or  40 , to allow one of the elements to pass under the other as described above in connection with blanket array  1 . 
     Element  16  is a Helmholtz coil sensitive to magnetic flux vector X  6  in the target region  17 . In the target region  17 , element  15  is sensitive to the Y vector  7  and has a sensitivity profile that is modeled to be symmetrical with that of element  16 , which intrinsically mutually isolates elements  15  and  16 . Elements  13  and  14  are combined into another Helmholtz configuration with sensitivity to the X vector, but are symmetrical and designed to be critically overlapping with the sensitivity profile of neighboring element  16 . Elements  11  and  12 , which are both sensitive to the Y vector are critically overlapped with each other as well as with pair of elements  13  and  14  to obtain isolation. In many instances, critical overlap is either not possible, due to non-adjacent but nearby element geometries, or due to stray capacitances that exist between nearby elements. In these instances, such as in region  5  ( FIG. 10 ), or in any similar instances whereby elements  11 - 16  are close enough to sufficiently couple, isolation transformers may be used as shown in  FIG. 10  between element  15  and elements  11  and  12 . For clarity,  FIG. 8  does not show the circuit boards (similar to boards and Baluns  22 ,  30 ,  40  and  50 ), cables (similar to cables  33  and  52 ), elastic bands of the garment that represent the top waist of the garment, and plastic housing (similar to housing  65 ) that also form a part of the array  20 . The cables (similar to cables  33  and  52 ) preferably form a bundle of cables (similar to bundle  47 ) at the posterior, lateral side of the array  20 . A housing (similar to housing  65 ) is preferably attached to the outside of the garment with multiple plastic rivets.  FIG. 8  also does not show for clarity the optional posterior elements previously discussed which may mirror anterior elements  11 - 14 . 
       FIG. 9  shows one type of elastic or stretchable conductor  80  that may be used to form any of the elements  11 - 16  of array  20 , any of the elements  21  of array  1 , any of the elements of array  60 , or any of the elements of array  90  described below. The conductor  80  may also be used for any of the cables  33  and  52  for any of the arrays  1 ,  20 ,  60 , or  90  described herein. The conductor  80  includes an elongate, hollow, cylindrical tight weave mesh  81  of fine conducting wires that are similar to the outer shielding of a flexible coaxial cable. Conductor  80  includes an inner insulator  82 , which is an elongate, hollow, cylindrical elastic band positioned inside of the mesh  81 . The inner insulator  82  replaces the non-elastic insulator of a typical coaxial cable. The insulator  82  has an outer diameter that is approximately equal to the inner diameter  83  of mesh  81  where it is stretched out or not bunched together. The insulator  82  assists in maintaining a more constant shape of the conductor  80  as it expands and contracts within the confines of its attachment points  23  and  84 . Attachment points  23  are accomplished with guide clamps  24  similar to eyelets that allow the conductor  80  to slide and stretch in a controlled manner through the opening of the clamp  24 . Eyelet/clamp  24  is affixed to the flexible substrate (not shown) by sewing or rivet through premade holes  88  in the clamp  24 . Attachment points  84  are provided by the physical soldering of conductor assembly  80  to boards  30 ,  40  or  22 , as discussed above with respect to attachment points  27   a - m  shown in  FIG. 3 , and encapsulated by the strain reliefs  26  aforementioned. Expansion and contraction of conductor  80  is facilitated by predetermined bunching of the wire mesh  81  at strategic locations or bulges  85 , and further aided and controlled by the inner insulator  82 . The inner conductor  8  that exists in conventional coaxial cable is removed in this rendition as it is inflexible, although its typical location is shown in  FIG. 9 . If a replacement conductor is desirable for carrying the aforementioned decoupling currents, then a highly flexible, insulated, multi-strand wire  86  is threaded through the mesh  81  and allowed to bunch within the bulge  85 ; thus enabling flexibility and expansion of both conductors, wire mesh  81  and wire  86 . Expansion and contraction of bulges  85  only nominally affects the inductance and frequency tuning of the conductor  80  due to the construction of wire mesh  81 . A signal traveling through the wire mesh  81  must travel approximately the same distance through a bulge  85  whether it is contracted as shown in  FIG. 9  or expanded when the conductor  80  is under tension. Because the distance is approximately the same, inductance and frequency tuning of the conductor  80  are only affected nominally. As an array containing the conductor  80  is worn by a patient and stretched, the bulges  85  expand as necessary, which permits the array to be worn by a patient of virtually any size. The substrate to which the conductor is attached via clamps  24 , such as substrate  2  described above, is preferably elastic and has a memory that causes the bulges  85  to contract back to their original shape when the array is no longer worn by a patient and being stretched. 
       FIG. 14 a   . represents an embodiment of an elastic or stretchable flat weave mesh conductor, shown as a close up view. The flat weave mesh conductor is made from a material with high Q resonating properties, such as copper and copper alloys. The flat weave mesh conductor is from 16 American wire gauge (AWG) to 22 awg. Preferably, the flat weave mesh conductor has a width from 0.254 to 0.9525 centimeters (0.1 to 0.375 inches). For example, the flat weave mesh conductor  80  may be used to form any of the elements  11 - 16  of array  20  in  FIG. 7  and  FIG. 8 , any of the elements  21  of array  1  in  FIG. 2 , any of the elements of array  60  in  FIG. 6 , or any of the elements of array  90  in  FIG. 13 . 
     The flat weave mesh conductor may be considered elastic and stretchable in that it may change its longitudinal length (e.g. expand and contract) by applying a force at a point along the flat weave mesh conductor. For example, when configured in an array, such as in  FIGS. 2, 6, 7, 8 , and  13 , the expansion and contraction of the flat weave mesh conductor allows the array to conform to the contours of a patient to provide three dimensional movement of the array. As the array conforms to a patient&#39;s body (e.g. the array lays against the contours of the patient), the flat weave mesh conductor expands and contracts in the array to be positioned adjacent to the contours of the patient. The flat weave mesh conductor has shape-memory, such that flat weave mesh conductor returns to its original shape when not in an expanded or contracted state. The expansion and contraction results in nominal changes in inductance and frequency tuning, such that the array transmits a signal to a preamplifier without the need for additional tuning (e.g. substantially maintaining the original shape inductance and frequency tuning). 
     The flat weave mesh conductor may be movably fixed to the flexible substrate in a manner configured to provide three dimensional expansion and contraction of the array while substantially maintaining the original shape inductance and frequency tuning. The flat weave mesh conductor may be movably fixed to the array by attachment points,  23  and  84 , as shown in  FIG. 9 , non-conductive tape, or channels formed from the flexible substrate. The flat weave mesh conductor may be movably fixed to the flexible substrate via attachment points  23  and  84 . Referring to  FIG. 9 , attachment points  23  and  84  may include one or more guide clamps  24  similar to eyelets and configured to allow expansion and contraction of the flat weave mesh conductor while the array substantially maintains the original shape inductance and frequency tuning. Guide clamp  24  may be affixed to the flexible substrate of the array by sewing or rivet through premade holes  88  in the clamp  24 . 
     The flat weave mesh conductor may be moveably fixed to the flexible substrate with one or more portions of non-conductive tape, such as polyimide tape. The non-conductive tape moveably fixes the flat weave mesh conductor to the flexible substrate at one or more points on the flat weave mesh conductor. The non-conductive tape is configured to moveably fix the flat weave mesh conductor such that the flat weave mesh conductor may expand and contract, while the array substantially maintains the original shape inductance and frequency tuning. 
       FIG. 14 c   . represents an embodiment of the flat weave mesh conductor that may be moveably fixed to the flexible substrate  2  through one or more indentations  140  formed from the flexible substrate  2 . The flat weave mesh conductor may be moveably fixed to the substrate  2  by laying within the one or more indentations. The indentations  140  may be formed on an interior of the flexible substrate  2 . The one or more indentations  140  are configured to moveably fix the flat weave mesh conductor to allow the flat weave mesh conductor to expand and contract while substantially maintaining the original shape inductance and frequency tuning. 
     The flat weave mesh conductor may be in mechanical communication with the boards, such as rigid boards  22 ,  30 , and  40  of  FIG. 2  and  FIG. 3 . The flat weave mesh conductor may be in mechanical communication through soldering to the rigid board. For example,  FIG. 3  represents mechanical communication via soldering at attachment points  27   a - m . The flat weave mesh conductor is in mechanical communication with the boards in a manner configured to maintain the area circumscribed by elements formed from the flat weave mesh conductor, such as in  FIG. 2  and  FIG. 3 . 
     The flat weave mesh conductor may be considered flat, where preferably the conductor is less than 3 millimeters (0.118 inches) in height. The flat weave mesh conductor may be considered a weave mesh, where the weave mesh may include at least four individual wires that are apportioned into two or more groups, where the two or more groups are braided together. Preferably, the flat weave mesh conductor includes from 72-120 individual wires that are apportioned into groups that are made up of from 3 to 5 individual wires. More preferably, the flat weave mesh conductor includes 96 individual wires that are apportioned into groups made up of 4 individual wires that total 24 groups. 
       FIG. 14 b   . represents a close up view of a group of individual wires of a flat weave mesh conductor. The individual wires of the flat weave mesh conductor are of a material that has high conductivity properties or a high Q material, such as copper and copper alloys. The individual wires may be insulated with a material that reduces arcing between elements, such as polyvinyl formal, polyurethane, polyurethane with nylon overcoat, polyester-imide, polyester with polyamide-imide overcoat, polyester-amide-imide, and polyimide. For example, the individual wires may be insulated 38 gauge direct current (DC) wires. 
     The flat weave mesh conductor has advantages over other conductors, such as an elongate hollow cylinder conductor. As compared to an elongate hollow cylinder conductor, the flat weave mesh conductor has reduced arcing, due to the insulation of the flat weave mesh conductor. For example, the flat weave mesh conductor is preferably insulated via insulation of each individual wire. Such insulation substantially reduces the arcing between the flat weave mesh conductor and adjacent electronics to approximately zero. This is compared to the conductor that is an elongate hollow cylinder that may not be insulated. Without insulation, the conductor that is an elongate hollow cylinder creates arcing with adjacent electronics. 
       FIG. 15 a   . compares the ability of the conventional tight weave mesh that is part of a conventional elongate hollow cylinder conductor, such as described in  FIG. 9 , versus the presently described flat weave mesh conductor to withstand cycles of flexing. The tight weave mesh is the outer shield of radio ground (RG) 316 coaxial cable of 1 centimeter in length, and the flat weave mesh is 18 AWG of 1 centimeter in length. The tight weave mesh and the flat weave mesh underwent cycles of sharp flexing (e.g. flexing sufficient to induce failure at a bending moment) until each exhibited failure. A cycle of sharp flexing simulates the strain placed on the conductor during use with a patient. A cycle is defined as one expansion and one return to original shape of the conductor. Failure of the conductor is defined as the breakage of an individual strand in the flat weave mesh or breakage of an individual wire of the elongate hollow cylinder. While in this instance a flat weave mesh of 18 AWG was used, other flat weave mesh conductors may be used. 
     As shown in  FIG. 15 a   , the tight weave mesh exhibited failure at 20 sharp flexing cycles, while the flat weave mesh exhibited failure at 700 sharp flexing cycles. The flat weave mesh has 35 times more durability than the tight weave mesh. This indicates that a flat weave mesh conductor will withstand usage without failure in a clinical setting up to 35 times longer than the elongate hollow cylinder conductor. The flat weave mesh conductor exhibits flexibility with increased durability as each individual wire is coated with an insulative material. The insulative material coating each individual wire provides strain relief for each individual wire, leading to a reduction in the bending moment of the flat weave mesh conductor, yielding increased durability over the tight weave mesh of the elongate hollow cylinder conductor. 
     As shown in  FIG. 15 b   , the tight weave mesh of  FIG. 15 a   . mounted on a flexible substrate of 0.635 centimeter (0.25 inches) thickness exhibited failure at 1432 sharp flexing cycles, while the flat weave mesh of  FIG. 15 a   . mounted on a flexible substrate of 0.635 centimeter (0.25 inches) thickness did not exhibit failure after 40,000 flexing cycles. The flat weave mesh mounted on the flexible substrate has greater than 25 times more durability than the tight weave mesh. This indicates that a flat weave mesh conductor will withstand usage without failure in a clinical setting greater than 25 times longer than the elongate hollow cylinder conductor. The flat weave mesh conductor exhibits flexibility with increased durability as each individual wire is coated with an insulative material. The insulative material coating each individual wire provides strain relief for each individual wire, leading to a reduction in the bending moment of the flat weave mesh conductor, yielding increased durability over the tight weave mesh of the elongate hollow cylinder conductor. 
       FIG. 16  compares the range of capacitances to tune test coil arrays, where a first test coil array has a conductor that is an elongate hollow cylinder conductor of RG 316 coaxial cable, and the second test coil array has a flat weave mesh conductor of 18 AWG. Tuning at a frequency is determined by an S12 measurement using a network analyzer, where the test coil array is tuned when the resonant frequency of the test coil array substantially equals the resonant frequency of the MRI system. While in this instance a flat weave mesh of 18 AWG was used in this illustration, other flat weave meshes may be used. 
     Referring to  FIG. 16 , the flat weave mesh conductor was tuned with a capacitance from 9 pico Farads (pF) to 150 pF in a 3 Tesla field strength, whereas the elongate hollow cylinder was tuned with a capacitance from 0.5 pF to 9 Pf in a 3 Tesla field strength. Due to the inverse relationship between capacitance and inductance, the tuning capacitance range from 0.5 to 9 pF of the flat weave mesh means that the inductance value of the elongate hollow cylinder is large at a resonant frequency. This large inductance value requires a capacitance from 0.5 to 9 pF for resonance. This is a narrow range of capacitance to achieve resonance limits the practical control over achieving a resonant frequency for the element made from an elongate hollow cylinder conductor. This is as compared to the flat weave mesh, which has a tuning capacitance range from 9 to 150 pF, meaning that inductance of the flat weave mesh is a lower value at resonance. This allows for a larger range of capacitance over which resonance may be achieved, thus increasing the amount of flex the substrate can undergo and still maintain the original shape&#39;s resonance frequency. Further, a low inductance value at resonance allows more expansion of the flat weave mesh conductor without incurring a significant frequency change of a corresponding element, as compared to an elongate hollow cylinder conductor with a larger inductance value at resonance. This smaller change in frequency for the flat weave mesh conductor in relation to the conventional hollow cylinder conductor is due to the net change of inductance (due to the larger capacitance range) per unit length that occurs during tuning if the flat weave mesh conductor being less than the net change of inductance per unit length of the elongate hollow cylinder conductor during tuning. 
     Referring then to  FIG. 10 , the anterior elements  11  and  12  of the pelvic array  20  are positioned near, but not overlapping the anterior aspect  5  of element  15 . Therefore, isolation may be improved between these elements  11 ,  12 , and  15  by employing transformers  8  and  9 . RF currents flowing in element  11  pass through a winding  8   b  of transformer  8  while RF currents flowing in element  15  pass through a winding  8   a . Windings  8   a  and  8   b  are wound in opposite directions and coupled such that their mutual inductance exactly equals the mutual inductance  89  of the two loops  11  and  15 ; hence, the total mutual coupling between the two elements  11  and  15  is nullified. Transformer  9  is similarly employed with elements  12  and  15 . Elements  11  and  12  require no transformer due to the critical overlap  4 . 
     Referring now to  FIG. 11 , a preferred garment forming a part of and incorporating the pelvic coil array  20  shown in  FIGS. 7 and 8 . The garment is a diaper-like foam housing  110  that encapsulates the elements  11 - 16  and associated circuit boards and cables. The housing  110  has an adjustable latching mechanism including web belts  101  terminated with a pair of mating plastic clips  102 . The belts  101  have an adjustable strap length  103  to firmly attach the garment  110  generally just above a plurality of different sized patients&#39; waists  104 . The belts  101  and clips  102  are duplicated on each side of the housing  110 . The garment also includes a cable housing  65 , as described above, which receives the cables from the elements and their associated circuit boards. The cable housing  65  insulates and protects the cable bundle and houses a mating connector (not shown) that allows for a quick disconnect of the system cable  66  from the housing  65 , which makes it convenient to strap on the garment  110  in a dressing room before the patient is positioned on the scanning table and system cable  66  is connected to housing  65 . 
       FIG. 11  also shows a superposition of the flexible elements  16   a - b  contained within the foam housing  110  with a variation of their location to accommodate an opening  105  in the foam housing  110  and substrates in the region of a patient&#39;s anus. An alternative location for the opening  105  would be in the region of a patient&#39;s vaginal canal. This optional configuration of the design would include a rubber (or similar plastic material) grommet  106  which seals the many layers of substrate and foam on the inside of the opening  105  diameter with lips around the opening  105  on both sides (patient side and outside) of the housing  110 . The grommet  106  maintains a generally cylindrical canal opening to provide access to either the rectum and prostate glands or vaginal canal. This is to facilitate the insertion of endocavitary probes or biopsy needles to access suspect tissues while co-registering location using MRI. 
       FIG. 12  further illustrates detail of the diaper-like pelvic housing  110  and the use and attachment of a disposable liner  111  which lines the entirety of the inner or patient contact surface  112  and protrudes through the access grommet  106  similar to a funnel from the inside. The flexible plastic liner  111  then flairs out again after tunneling through the grommet  106  and temporarily attaches to the outer surfaces of the housing  110  at adhesive strips  113  well away from the opening  105  on the anterior, posterior and lateral surfaces of the housing  110 . The liner  111  also attaches to the patient&#39;s inner thighs at adhesive strip locations  114 . After the insertion procedure, scanning is accomplished, and the probes are removed, the surface of the external portion of the liner  111  is wiped. Then, the liner  111  is unstuck from the adhesive locations and bunched into a tight bundle protruding from the grommet  106 . The housing  110  is then removed from the patient, and the liner  111  is withdrawn from grommet  106  from the inside and discarded. This procedure keeps the surfaces of the housing  110  clean of biological contaminant. 
     Referring now to  FIG. 13 , a seven element flexible, wearable shoulder antenna array in accordance with another alternative embodiment of the present invention is shown generally as  90 . The array  90  further illustrates the solution of selecting variations in element geometry, configurations, size and isolation mechanisms in order to obtain more signal from a given common volume—the shoulder joint and surrounding anatomy of subject  100 . Elements  91 - 97  are shown in  FIG. 13  in a similar manner as elements  11 - 16  are shown in  FIG. 8 . While the elements  91 - 97  are shown without gaps, they preferably have gaps where they are joined with circuit boards (similar to boards and Baluns  22 ,  30 ,  40 , and  50 ). Circuitry on the circuit boards is electrically coupled with the elements  91 - 97  for maintaining tuning and isolation between the elements when the housing is worn by a patient and distorted in three dimensions. The array  90  also includes cables (similar to cables  33  and  52 ) and a plastic housing (similar to housing  65 ) where the cables terminate. 
     Element  91  is a solenoidal coil that slips under the armpit and over the collar bone such that it is oriented and sensitive to the X vector MRI signal. Solenoid  91  bisects the superior Helmholtz  92  which is sensitive to the Y vector and therefore geometrically isolated. Elements  93  and  97  are single loop elements also bisected by element  91  and are both sensitive to the Y component and also geometrically isolated from  91 . Elements  94  and  96  are the superior and inferior saddle coils which fit over the outside (lateral aspect) of the arm and shoulder and are sensitive to the X component, critically overlapped with each other for isolation and also with elements  93 ,  97  and  91  for isolation. Their distance from element  91  creates nominal coupling with  91  and are therefore operable as is; however, different sized coil assemblies may require isolation transformers between these elements as previously discussed and shown in  FIG. 10 . Finally, element  95  is an Helmholtz saddle coil configuration which bisects elements  94  and  96  and is geometrically decoupled with its symmetry and orthogonal sensitivity profile to the two. Elements  94  and  95  are shown moved away from the actual position about the shoulder for clarity. All elements  91 - 97  are fastened to a stretchable material, in a similar manner as previously discussed above with respect to the pelvic array  20 , and are allowed to flex sufficiently to facilitate pulling the garment over the shoulder. Specifically, the elements  91 - 97  are mounted to a flexible and elastic substrate, similar to substrate  2  described above. The elements  91 - 97  are attached to the substrate with clamps, similar to clamps  24  described above, that permit the elements  91 - 97  to maintain a desired resonance when the array  90  is worn and distorted in three dimensions. The substrate and elements  91 - 97  are encapsulated by a flexible and elastic housing, such as the housing  1  B shown in  FIGS. 5A-B , that is preferably constructed from an elastic material such as neoprene and thus does not include the grooves shown in  FIGS. 5A-B . The housing is sufficiently flexible and elastic to allow it to be worn by a plurality of different sized patients so that the housing is in close contact with the patient and conforms to the contours of the patient. The housing may include a layer of foam positioned between the layers of elastic material as described above in order to maintain a consistent thickness at all points of the array  20 . The elements  91 - 97  are preferably constructed in the same manner as flexible and elastic conductor  80 , shown in  FIG. 9 , so that they are able to sufficiently flex and stretch when the garment is worn by patients of different sizes. More preferably, the elements  91 - 97  are conductors that are flat weave mesh, such as the flat weave mesh conductors described in  FIG. 14 . a ., so that they are able to sufficiently flex and stretch when the garment is worn by patients of different sizes. Further, the components of array  90  are preferably sufficiently flexible and elastic to permit a patient to extend his/her arm out to the side of the patient&#39;s body and above the patient&#39;s head. 
     Other types of MRI antenna arrays are within the scope of the present invention besides the blanket array  1 , chest and volume neck array  60 , pelvic array  20 , and shoulder array  90 . The manner in which these arrays are constructed to make them flexible and/or elastic may be used to form an array designed to be placed over any body part or worn by a patient for placement over any body part in such a manner that the array is in close contact with the patient and closely conforms to contours of the patient. By way of example, it is possible and within the scope of the present invention to produce a full body suit using the same techniques as described above that may be worn by a patient to image most or all areas of the patient. Antenna arrays with more than the specific number of antenna elements described with respect to any of the embodiments above are also within the scope of the present invention. For example, in a full body suit MRI garment, any number of antenna elements may be used in order to sufficiently image the patient. 
     From the foregoing it will be seen that this invention is one well adapted to attain all ends and objectives herein-above set forth, together with the other advantages which are obvious and which are inherent to the invention. 
     Since many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matters herein set forth or shown in the accompanying drawings are to be interpreted as illustrative, and not in a limiting sense. 
     While specific embodiments have been shown and discussed, various modifications may of course be made, and the invention is not limited to the specific forms or arrangement of parts and steps described herein, except insofar as such limitations are included in the following claims. Further, it will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of the claims.