Abstract:
A patient table adapted for use in association with an MR scanner for neonatal infants is provided. The patient table has an extendable patient bed attached to and extendable from the patient table. The patient bed may be at least partially inserted into an MR scanner without requiring the patient table to enter the MR scanner. A transport mechanism is on the underside of the patient table so that it may be readily moved over the floor on which it rests. The patient table includes a latching mechanism that may operate to releasably attach the patient table to a patient table docking assembly. The docking assembly is operative to selectively move the patient table towards, into and away from the MR scanner.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present disclosure claims priority benefit of U.S. Provisional Patent Application Ser. No. 61/693,937 filed Feb. 2, 2012 and is further related to U.S. Provisional Patent Application Ser. No. 61/429,612 also filed Jan. 4, 2011. 
     
    
     FIELD OF THE DISCLOSURE 
       [0002]    The present disclosure relates generally to magnetic resonance imaging equipment suitable for use in neonatal care, and, more particularly, to an MRI transfer station and dock for receiving an infant from an incubator and to assist with preparing the infant for an MR scan. 
       BACKGROUND OF THE DISCLOSURE 
       [0003]    Today premature infants weighing less than 1 kg may be stabilized and allowed to develop in neonatal intensive care units (NICUs). Magnetic resonance imaging (MRI) is a powerful technique for diagnostic purposes but is not routinely performed on these infants due to a number of technical and logistical challenges. 
         [0004]    When a mother has a high-risk pregnancy, it is possible that the baby could be born prematurely and would require treatment in a neonatal intensive care unit or NICU. Also, unexpected early delivery may require that an infant be treated in an NICU. 
         [0005]    One difficulty in utilizing MRI for these premature infants is monitoring the vital signs and life support of the infant during MR examination. Parameters that must be monitored during examination include electrolyte levels, hydration and temperature. A second difficulty in utilizing MRI is that the infant must be moved from an incubator or isolette into and out of the MR scanner. This movement places the infant at risk for injury. 
         [0006]    Despite challenges, MRI has the potential to play an important diagnostic role in the care and management of neonates. The full use of this imaging technique requires that the imaging take place as early as the first few hours of life. At this stage, however, the infants are hemodynamically unstable. Accordingly, transporting and maintaining homeostasis in these fragile infants presents difficulty. 
         [0007]    Another challenge in using MRI for neonates is that MRI systems are frequently located in Radiology departments outside of and perhaps distant from the NICU. Consequently, the neonate must be escorted out of the NICU. This may present certain logistical and technical challenges with respect to controlling the neonate&#39;s environment. Furthermore, removing staff from the NICU to transfer and attend to one baby outside the NICU can place the remaining babies in the NICU at increased risk of a reduced level of care due to decreased staff coverage. 
         [0008]    An MR compatible transport incubator and imaging system has been developed (Dumoulin et. al.) and is currently in use. Concepts in Magnetic Resonance (Magnetic Resonance Engineering), Vol. 15(2) 117-128 (2002). This system is a self-contained MR compatible transport incubator which carries the infant from the NICU to an MR scanner located in or near the NICU. With this approach the baby must first be transferred from its “home” incubator or isolette in the NICU into the transport incubator. The transport incubator is then moved to the MR scanner where it is docked with the scanner. A portion of the transport incubator containing the baby is then moved into the center of the MR imaging system magnet where MR imaging is performed. While this approach has the advantage of not disturbing the baby while it is in the transport incubator, even during MR scanning, it has several limitations including: a) infants must be fully detached from the monitoring equipment in their home incubator to be transferred into the transport incubator, b) the MR system that is used for imaging must have a bore large enough to accommodate the portion of the transport incubator containing the baby (thereby requiring a large heavy magnet), c) the baby and its attending staff need to leave the NICU for scanning, and d) because the transport incubator must be fully MR compatible while providing full life support for the baby, the system is heavy and expensive. 
         [0009]    An alternate approach to provide MR imaging to newborn babies has been disclosed by Feenan in U.S. Pat. No. 7,599,728. In this approach a relatively smaller MR magnet is employed and MR-compatible incubators are docked to the magnet thereby permitting the baby to be slid into the magnet for imaging. While this approach has the benefit of providing a magnet that is more easily installed in the NICU, it does have several limitations including the need for MR compatible incubators to be used throughout the NICU, or the transfer of a neonate from a non-MR-compatible home incubator to an MR-compatible incubator. This approach also limits the access to the attending staff as they prepare the infant for MR scanning. In particular, the staff must reach through the incubator to push the baby into and out of the magnet. 
       SUMMARY 
       [0010]    A patient table adapted for use in association with an MR scanner for neonatal infants is disclosed. The patient table may include an extendable and movable patient bed attached to a top surface of the patient table. The patient bed may include an extending mechanism that, when extended, causes the patient bed to be extended and at least partially project from the patient table. The patient bed may be dimensionally constructed such that it may be at least partially inserted into an MR scanner without requiring the patient table to enter the MR scanner. A transport mechanism, such as a set of wheels, may be attached to the underside of the patient table so that it may be readily moved over the floor on which the patient table rests. The patient table also includes a latching mechanism that may operate to releasably attach the patient table to a patient table docking assembly. The docking assembly may be operative to selectively move the patient table towards and away from the MR scanner. 
         [0011]    The present disclosure will now be described in more detail with reference to exemplary embodiments thereof as shown in the accompanying drawings. While the present disclosure is described below with reference to exemplary embodiments, it should be understood that the present disclosure is not limited thereto. Those of ordinary skill in the art having access to the teachings herein will recognize additional implementations, modifications, and embodiments, as well as other fields of use, which are within the scope of the present disclosure as described herein, and with respect to which the present disclosure may be of significant utility. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    In order to facilitate a fuller understanding of the present disclosure, reference is now made to the accompanying drawings, in which like elements are referenced with like numerals. These drawings should not be construed as limiting the present disclosure, but are intended to be exemplary only. 
           [0013]      FIG. 1   a  is a perspective view showing an exemplary MR imaging system, an exemplary docking mechanism, and an exemplary patient table containing a neonate in accordance with the present disclosure; 
           [0014]      FIG. 1   b  is a perspective view showing the attachment of the patient table to a docking mechanism to prepare the neonate for movement in accordance with the present disclosure; 
           [0015]      FIG. 1   c  is a perspective view showing the extension of the neonate on the MRI transfer station towards the magnet in the MR scanner; 
           [0016]      FIG. 1   d  is a perspective view showing a further extension of the neonate on the MRI transfer station towards the magnet in the MR scanner; 
           [0017]      FIG. 1   e  is a perspective view that shows the movement of the neonate into the exemplary MR imaging system caused by motion of the docking mechanism that motion brings the patient table closer to the magnet and brings the neonate into the chamber of the MR scanner for imaging; 
           [0018]      FIG. 2  is a perspective view of one embodiment of an MRI transfer station suitable for preparing a neonate for MR imaging; 
           [0019]      FIG. 3  is a top plan view of an exemplary MR magnet with barrier poles to limit access to the magnet; and 
           [0020]      FIG. 4  is a top plan view of an exemplary MR magnet with an elevated floor barrier to limit access to the magnet. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    The use of MRI techniques for infants, and in particular neonates, is highly desirable. MRI techniques provide diagnostic information without patient exposure to ionizing radiation, and are suitable for extended and repeated studies. 
         [0022]    MR techniques provide excellent anatomic visualization and functional information. They can be used to measure neural fiber track development and have a number of potential clinical uses including, but not limited, to diagnosis of brain trauma, cardiac abnormalities, congenital defects and the assessment of lung development. 
         [0023]    There are, however, a number of challenges in the use of MRI for neonatal imaging. Patient access during scanning can be difficult as MR magnets are typically large and surround the patient. Safety concerns include forces on ferromagnetic objects, potential for rf heating and acoustic noise. Also, logistics may be difficult, as MR scanners tend to be in radiology departments, while neonate infants are typically in the NICU. 
         [0024]      FIGS. 1   a - 1   d  depict an exemplary MRI and incubator system  100  in or for which the techniques for the MR imaging of neonates in accordance with the present disclosure may be implemented. The illustrated MRI system comprises an MRI scanner  102 . Since the components and operation of the MRI scanner are well-known in the art, only some basic components helpful in the understanding of the system  100  and its operation will be described herein. 
         [0025]    The MRI scanner  102  may comprise a cylindrical superconducting magnet  104 , which generates a static magnetic field within a bore  105  of the superconducting magnet  104 . The superconducting magnet  104  generates a substantially homogeneous magnetic field within the magnet bore  105 . The superconducting magnet  104  may be enclosed in a magnet housing  106 . 
         [0026]    A set of cylindrical magnetic field gradient coils  112  may also be provided within the magnet bore  105 . The gradient coils  112  can generate magnetic field gradients of predetermined magnitudes, at predetermined times, and in three mutually orthogonal directions within the magnet bore  105 . With the field gradients, different spatial locations can be associated with different precession frequencies, thereby giving an MR image its spatial resolution. An RF transmitter coil  114  is positioned within the gradient coils  112 . The RF transmitter coil  114  emits RF energy in the form of a magnetic field for the purpose of exciting MR signals during image acquisition. The RF transmitter coil  114  can also receive MR response signals. The MR response signals are amplified, conditioned and digitized into raw data as is known by those of ordinary skill in the art. 
         [0027]    The present disclosure provides an apparatus and a technique for safely and effectively transferring an infant from the primary care area to the MR magnet. In one particular embodiment, the present disclosure provides the means to transfer a neonate from the NICU to an MR magnet located either in a radiology department or in the NICU itself. The present disclosure accomplishes this by providing an MR-compatible transfer station that can be attached to the MR magnet. This station creates an MR compatible environment that, if desired the baby can be moved into without being detached from patient monitoring or life support systems. Once stabilized on the transfer station, the baby can then be moved into the magnet for imaging. Note that the in the present disclosure an incubator does not need to be fully MR compatible and can be constructed with some MR incompatible elements such as electrical motors. 
         [0028]    Referring again to  FIGS. 1   a - 1   e,  a patient table  130  containing a neonate  110  is shown. Neonate  110  may be placed on a movable patient bed  120  attached to the top of patient table  130 . Movable patient bed  120  may be disposed on and may roll on a track  125 . In alternate embodiments of the present disclosure the function of track  125  can be performed with alternate designs incorporating slides, cables, pulleys or the like. The patient table  130  may have wheels and may be designed to roll on the floor, so that the neonate can be placed on the patient table in a location remote from MRI scanner  102 , such as near an incubator. Patient table  130  also have a latching mechanism  124  that may permit the patient table  130  to be temporarily and releasably attached to a docking assembly  140 . 
         [0029]    Docking assembly  140  may include a hitch mechanism  150  that may be attached to a moving tractor assembly  160 . Moving tractor assembly  160  may be attached to a belt  170  which may be moved by a dock motor  180 . Turns of the motor shaft may result in belt motion which in turn may cause the moving tractor assembly  160  to move relative to the fixed portion of docking assembly  140 . In alternate embodiments of the present disclosure, the function of belt  170  may be accomplished with any suitable drive device as known in the art including but not limited to a screw drive, a chain drive, or a gear assembly. 
         [0030]      FIG. 1   b  shows the docking of the patient table  130  to docking assembly  140 . In the current embodiment of the disclosure latching mechanism  124  may engage hitch mechanism  150  and the two may then become coupled. Decoupling of latching mechanism  124  and hitch mechanism  150  can be performed manually or automatically by the system when removal of patient table  130  from the vicinity of MRI scanner  102  is desired. 
         [0031]      FIG. 1   c  shows the extension of the neonate  110  and movable patient bed  120  towards MRI scanner  102 . In the current embodiment of the present disclosure, neonate  110  may be prepared for MR scanning while in this general location. Preparations may include safety checks, swaddling, attachment of additional monitoring equipment, placement of MR receive coils, and/or attachment of hearing protection to the neonate  110 . 
         [0032]      FIG. 1   d  shows the further extension of the neonate  110  and moving patient bed  120  into the MRI scanner  102 . Note that during this extension the neonate is not moved with respect to movable patient bed  120 . 
         [0033]      FIG. 1   e  shows the insertion of the neonate  110  and moving patient bed  120  into the MRI scanner  102 . Note that during this insertion the neonate is not moved with respect to movable patient bed  120 , but may be placed in the imaging volume of MRI scanner  102 . 
         [0034]      FIG. 2  shows one embodiment of the movable patient bed  120  in greater detail. Moving patient bed  120  may include a bed surface  122  and cover  220 . The cover  220  may incorporate one or more cover locking pins  230  that are designed for insertion into a like number of corresponding cover pin sockets  240 . The cover locking mechanism shown here is exemplary. It should be understood that alternate mechanisms for attaching the cover  220  to the moving patient bed  120 , including but not limited to hinges, slots, clamps and slides. If desired, neonate access ports similar to those found in conventional neonate incubators can be incorporated into the cover  220 . It should be obvious to one skilled in the art that patient table  130  and all subassemblies exposed to strong magnetic fields may be constructed using MR compatible materials. 
         [0035]    The present disclosure is particularly advantageous in that it minimizes the transfer time from the NICU to MRI scanner  102  and provides less stress on the infant. Another advantage of the present disclosure is that babies do not need to be fully detached from patient monitoring equipment which can be integrated as desired into patient table  130 . This further reduces preparation times and stress on the infant. Once the baby is stabilized, the baby and the patient table  130  can be inserted into the magnet to place the neonate  110  in the imaging region of the MRI scanner. This can be done manually by further extending moving patient bed  120  or under system control with appropriate driving of dock motor  180  to move patient table  130 . This approach ensures that the local environment of the neonate  110  is not altered as it is brought into the center of the imaging system. Furthermore, because a transport incubator is not required to be fully inserted in the magnet, the MR magnet can be small and lightweight. This makes it more easily installed within the confines of the NICU, and provides improved access to MR for premature babies. In addition, the present disclosure permits MR scanning to be performed with fewer support personnel, and/or places support personnel closer to the other babies present in the NICU. With the present disclosure MR imaging can be made available to all babies in a NICU (typically between 10 and 60) using a single MR magnet and a single patient table that may be used for each compatible incubator in the NICU. 
         [0036]    In particular, the present disclosure relates to a transfer station for preparing an infant, including neonates, prior to transfer into the magnet for imaging. The transfer station may have all of the functionality of the neonate&#39;s home incubator, but implemented in an MR-compatible and MR-safe manner. 
         [0037]    Once the infant is on movable patient bed  120 , the infant can be prepared for MR scanning. As will be recognized by those skilled in the art of MR scanning, MR scanning frequently requires that several steps be performed before a patient can be inserted into an imaging magnet. These steps may include: a) immobilization of the patient (in the case of neonatal imaging, swaddling is frequently sufficient), b) the optional insertion of IV tubes for contrast injections, c) the attachment of MR imaging coils, d) a safety check to verify that no ferromagnetic objects are present, e) placement of hearing protection, and f) verification of patient stability and comfort. All of these steps need to be performed while the patient is near the magnet, and require access to the patient which is not possible with most incubator designs. 
         [0038]    Another aspect of the moving patient bed  120  of the present disclosure is that it can provide full environmental control for the neonate when used with cover  220 . Many neonates are too young to be able to fully control their internal temperature, and it is well known to those skilled in the art that small neonates must be kept warm. In the present disclosure, this can be done with warm air and/or a radiant heater driven by a temperature controller. In one embodiment of the disclosure, a thermocouple or similar temperature sensor modified for use in the MR environment with non-ferromagnetic parts and appropriate rf filtering may be used to provide feedback to the temperature controller to provide suitable temperature control. In another embodiment of the present disclosure a physiologic monitoring system may be utilized. This system may be MR compatible and MR safe. It can be used if desired in place of the patient monitoring systems found in the neonate&#39;s home incubator. 
         [0039]    As shown in  FIG. 3 , a safety barrier constructed with in-room barriers such as poles  350  in the floor may be used and may be spaced to prevent incubators or other devices from getting within a predetermined fringe magnetic field strength  360  (typically chosen to be 5 Gauss) at a selected distance  370  of the magnet. With such an approach the patient table  130  can be placed into a safe position  340  from which the neonate  110  is moved and prepared for MR scanning. With an incubator in safe position  340  the neonate  110  may be moved towards MR scanner  102  along an axial route  380 . Alternatively, the incubator can be placed in an alternate safe position such as  340   a  and the neonate  110  may be moved to the transfer station  200  along an alternate route such as  380   a.  Once the neonate is prepared for MR scanning, it can be moved together with the patient table into the isocenter  320  of the MR scanner  102 . 
         [0040]    Alternatively, the barrier can be augmented with a step design as shown in  FIG. 4  in which the floor that accommodates the NICU incubator is lower than a raised floor  410  surrounding the magnet. The step created by the two levels of the floor acts to prevent the incubator from approaching too close to the magnet. 
         [0041]    The patient table  130  may in one embodiment, as shown in  FIG. 1 , be open like an isolette. In one embodiment, the open isolette may be configured with radiant heating. In another embodiment, the transfer station may be enclosed like an incubator with the addition of a cover. In one embodiment, the enclosed transfer station may be configured to provide warm circulating air. 
         [0042]    As mentioned, in one embodiment, patient table  130  may be equipped to include all necessary life support and monitoring equipment. Such equipment includes, but is not limited to, EKG monitoring, IV tubes, oxygen monitors, ventilators, breathing gases, and bilirubin treatment. If needed, patient table  130  can be powered by an external supply or an on-board MR-compatible battery. Alternatively, the patient table  130  may be manually advanced or extended as desired. 
         [0043]    In one embodiment of the disclosure, patient table  130  may include physical barriers to prevent extraneous objects being sucked into the infant when the infant is inside the magnet. In one embodiment, the barrier may include a substantially full enclosure made of clear engineering plastic that is resistant to impact damage. This arrangement may provide full visual access of the baby but may provide a barrier to the entry of other objects into the magnet. 
         [0044]    In one embodiment, a Faraday cage may be built into patient table  130  to prevent RF interference from degrading the MR image. This would be particularly advantageous if the MR system is not placed in an RF screen room. Should a Faraday cage be incorporated into the transfer station, an internal rf tight panel or door may be added between the magnet and the transfer station. It may also be desirable to provide penetration filters for monitoring leads to minimize rf interference during MR imaging. 
         [0045]    In an even further embodiment, the transfer station may incorporate a scale for weighing the infants. 
         [0046]    While the foregoing description includes many details and specificities, it is to be understood that these have been included for purposes of explanation only, and are not to be interpreted as limitations of the present disclosure. It will be apparent to those skilled in the art that other modifications to the embodiments described above can be made without departing from the spirit and scope of the disclosure. Accordingly, such modifications are considered within the scope of the disclosure as intended to be encompassed by the following claims and their legal equivalents.