Patent Publication Number: US-10314519-B2

Title: Blood vessel sizing device

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 14/248,101, filed Apr. 8, 2014, which is a continuation-in-part of U.S. patent application Ser. No. 13/427,084, which was filed on Mar. 22, 2012, now U.S. Pat. No. 8,971,995, the disclosures of which are hereby incorporated by reference in their entireties for any and all non-limiting purposes. 
    
    
     BACKGROUND 
     The present disclosure relates generally to medical devices and more specifically to systems and methods for determining dimensions of imaged objects on a graphical representation medical devices for determining or measuring blood vessel size during, for example, an angiogram. 
     Determining blood vessel size quickly and accurately is important, for example, when treating stenotic vessels with angioplasty or stent. If blood vessel size is incorrectly determined, a stent that is too large for the actual blood vessel size could be selected. Using an oversized stent can damage, dissect or even perforate the passageway it is included to be filled within. 
     Diagnostic imaging using, for example, X-ray machines, computer tomography machines or magnetic resonance imaging machines, generate images of blood vessels including any narrowing of blood vessels. A clinician uses these images to determine blood vessel size and stenosis. But using such images has inherent limitations. For example, computer tomography imaging accuracy can be affected by sampling, size of display field of view and/or intravascular density of a contrast material. During emergency procedures, computer tomography or magnetic resonance imaging measurements may not be available. 
     A need accordingly exists for medical devices and methods that improve the process of determining blood vessel size during, for example, angiographic procedures. 
     SUMMARY 
     Aspects of the present disclosure relate to systems, devices, and methods that provide a more accurate dimension (e.g., a length) of a feature represented in a graphical representation of an imaged object (e.g., an imaged body portion represented in a radiograph captured by a radiograph process. In one example, the present disclosure is directed to medical devices and methods that more accurately provide the measurements of imaging targets. In one implementation, the devices and methods described herein may be configured to determine blood vessel sizes with greater accuracy, based upon, for example, angiographic images of the vessels. Such blood vessel images can be generated, for example, via angiograms. In one implementation, a blood vessel sizing device is configured for placement on the skin of a patient near an imaging target (e.g. a blood vessel to be imaged). Accordingly, the device may include a plurality of radiopaque concentric-circle elements of known size. When a computer machine generates an angiographic image of the blood vessel, the radiopaque concentric-circle elements cause the circles to be visible on the generated image (along with the blood vessel image). As such, a clinician may quickly and accurately determine the actual size (true dimension/length) of the blood vessel by comparing the blood vessel image to the image of the concentric circles, which have a known or illustrated dimension. 
     In one aspect, the systems and methods described herein include a blood vessel sizing device having a rigid planar base structure with a front surface and a back surface. The blood vessel sizing device further has a plurality of radiopaque concentric-circle elements and a plurality of radiopaque symbols positioned on the front surface of the base structure. Additionally, the device has a deformable structure attached to the back surface of the base structure, and an adhesive layer attached to a back surface of the deformable structure. 
     In another aspect, a blood vessel sizing device is described as having a rigid planar base structure with a plurality of radiopaque concentric-circle elements positioned on a front surface. Additionally, the front surface of the base structure has a plurality of radiopaque symbols representing dimensions of the concentric-circle elements. 
     In yet another aspect, a non-transitory computer-readable medium comprising computer-executable instructions is described for automated determination of a true dimension of a biological feature present in a radiological image. The instructions include receiving data corresponding to a biological feature in a radiological image, determining a length property of the biological feature, and identifying elements from image data last corresponds to radiopaque concentric-circle elements of known size. The instructions further include identifying dimensional properties for the identified elements, determining a longest axis of the identified concentric-circle elements, and comparing the length property of the biological feature to the concentric-circle elements along the longest axis. Subsequently, the determined length property may be converted into a true dimension value, and communicated to a user. 
     It is accordingly an advantage of the present disclosure to provide a medical device that simplifies and improves blood vessel size determination, and without errors of parallax 
     It is a further advantage of the present disclosure to provide a method for improving the process for blood vessel size determination. 
     Additional features and advantages are described herein, and will be apparent from the following Detailed Description and the figures. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a plan view of a blood vessel sizing device. 
         FIG. 2  is a plan view of an alternative implementation of a blood vessel sizing device. 
         FIG. 3A-3B  depicts alternative implementations of blood vessel sizing devices. 
         FIG. 4A-4B  schematically depict side views of blood vessel sizing devices. 
         FIG. 5A-5B  schematically depict side views of alternative implementations of blood vessel sizing devices having deformable structures. 
         FIG. 6A-6B  schematically depict radiographic images produced by blood vessel sizing devices. 
         FIG. 7  schematically depicts a radiological image including one or more biological features. 
         FIG. 8  is a schematic block diagram of an imaging system. 
         FIG. 9  is a flowchart diagram of one or more processes for automatically determining a true dimension of a future captured in a radiological image. 
         FIG. 10A-10B  schematically depict a blood vessel sizing device being used on a human patient. 
         FIGS. 11A-11D  schematically depict various implementations of a device that may be utilized for locating an area of interest within a radiological image. 
     
    
    
     DETAILED DESCRIPTION 
     In one example, the present disclosure is directed to medical devices and methods that allow more accurate determinations of one or more dimensions (e.g., length, height, depth) of target objects targeted to be captured by an imaging technique. Such target objects may include biological features, e.g. living passageways (such as blood vessels), items within living passageways (e.g., blood clots), and/or any object that may be imaged with one or more imaging techniques. Yet, other embodiments may capture one or more objects in a target area that is targeted by an image technique. Using a medical example, a user may be experiencing pain in a general or specific area of their body. Therefore, it may be desired to utilize an imaging device to capture an image of the area without specifically targeting a specific object or feature. Thus, the device may be configured to capture a target area with one or more objects of interest. 
     The terms “graphical representation” and “image” are used herein to refer to an output of an imaging technique. Such imaging techniques that generate the graphical representations/images may include one or more processes (which may not be mutually exclusive, and may be combined with other processes, including non-image based processes), to provide an output comprising a graphical representation or image of a target area and/or target object, including an angiogram, MRI, X-Ray, CT scan, myelogram, thermograph, MRN, ultrasound, and/or combinations thereof or other mechanisms that can produce a graphical representation or image of a target object or target area. Further, those of ordinary skill in the art will readily appreciate that the systems and methods described herein may be utilized for non-biological purposes (e.g. for imaging of synthetic materials, and the like), and without departing from the disclosures herein. 
       FIG. 1  schematically depicts a device  100  configured for providing a mechanism to determine one or more dimensions of features in a graphical representation of an imaged object or area. In one implementation, device  100  may be configured to be placed in an area to be imaged, such as, contact with an area of skin of a patient prior to a medical imaging procedure, and such—device  100  may be utilized to determine a true dimension/length of one or more biological features to be imaged using an imaging technique (e.g. an angiogram using x-rays, and the like). 
     In particular, device  100  may comprise a base structure  102 . Positioned on the base structure  102  or another surface are shown a plurality concentric-circle elements, numbered as elements  104   a - 104   h , and a plurality symbols, numbered as symbols  106   a - 106   g  and  107   a - 107   g . In one example, the elements  104   a - 104   h , and symbols  106   a - 106   g  and  107   a - 107   g , may comprise a radiopaque (radiodense) metal, a radiopaque alloy, or another radiopaque material known to those of ordinary skill in the art, and wherein radiopacity will be readily understood to those of ordinary skill in the art as a property of a material that substantially reduces and/or prevents electromagnetic radiation of a certain wavelength/range of wavelengths from passing through the material. In particular, radiopacity may be understood as a property of a material that substantially reduces and/or prevents x-rays from passing through the material. In yet other embodiments, materials that are reactive to certain imaging techniques or chemical processes may also be utilized. In this regard, the elements and symbols herein (including elements  104 , symbols  106  and/or  107 ) may be configured to reduce or prevent transmission of wavelengths such as to appear opaque. In yet other embodiments, they may contain materials known to contrast with an intended target object or target area, such as would be similar to the use of contrast agents in radiological sciences. In yet another embodiment, at least one element and/or symbol may comprise a material that is configured to be fluoresce as a result of being imaged or some mechanism utilized prior to or during the imaging process(es). 
     In one example, one or more of elements  104   a - 104   h  and/or symbols  106   a - 106   g  may be provided directly, e.g., printed, onto base structure  102  using, e.g. any appropriate printing method known to those of ordinary skill in the art. In other examples, one or more of elements  104   a - 104   h  and/or symbols  106   a - 106   g  and  107   a - 107   g  may be molded into base structure  102 , fastened to base structure  102  by any appropriate fastener, or adhered/welded to base structure  102 , and the like. 
     In one example, base structure  102  may comprise one or more of a polymeric material, a glass, a metal, an alloy, or any other material with material properties that give rise to a contrast between base structure  102  and one or more of elements  104   a - 104   h , symbols  106   a - 106   g  and  107   a - 107   g , and/or location marker  108  when imaged using electronic radiation of a particular wavelength/range of wavelengths (e.g., x-rays). In one example, base structure  102  may comprise a polymer that is substantially transparent to electromagnetic radiation in the visible spectrum (e.g. visible light). As discussed above, certain elements ( 104 ) or symbols ( 106 , 107 ) may be configured to be opaque and/or react to different imaging processes. 
     In one implementation, base structure  102  may comprise a material with mechanical properties exhibiting a level of rigidity such that base structure  102  does not readily conform to one or more undulations of a surface onto which it is positioned. In one example, this rigidity may be achieved by selecting base structure  102  with a material thickness corresponding to an appropriate level of rigidity. Specifically, in one example, base structure  102  may comprise a polymeric material with a thickness of 0.25 mm, 0.5 mm, 0.75 mm, 0.9 mm, among many others. 
     In one implementation, concentric-circle elements  104   a - 104   h  may have known diameters. In one example, the diameters of the elements  104   a - 104   h  may measure 2 mm, 4 mm, 6 mm, 8 mm, 10 mm, 14 mm, 16 mm, 20 mm or 30 mm. However, as will be readily apparent to those of ordinary skill in the art, differently sized concentric-circle elements  104   a - 104   h  may be used without departing from the scope of this disclosure. Furthermore, a different number of elements than those eight elements represented as  104   a - 104   h  may be used on device  100  without departing from the scope of this disclosure. In one example, elements  104   a - 104   h  may have a thickness (line thickness) of approximately 0.25 mm, and wherein the diameter of each of the elements  104   a - 104   h  is measured to the center of the radiopaque line that makes up each of the elements  104   a - 104   h . In one implementation, and as depicted in  FIG. 1 , one or more symbols (e.g., symbols  106   a - 106   g  and/or  107   a - 107   g ) may intersect one or more of the elements  104   a - 104   g . In this way, a symbol may serve as an indicator of a dimensional property of a element with which it intersects. For example, a symbol may denote a radius or diameter of a concentric-circle elements with which it intersects. In another example, a symbol may not intersect with a element for which it denotes a dimensional property. In the specific example depicted  FIG. 1 , a plurality of symbols denote a plurality of diameters of respective concentric-circle elements. Specifically, symbols  106   a  and  107   a  are shown as being diametrically opposed on the concentric-circle element  104   b , and indicate that concentric-circle element  104   b  has a diameter of 4 mm. Similarly, symbols  106   b  and  107   b  indicate that concentric-circle element  104   c  has a diameter of 6 mm; symbols  106   c  and  107   c  indicate that concentric-circle element  104   d  has a diameter of 8 mm; symbols  106   d  and  107   d  indicate that concentric-circle elements  104   e  has a diameter of 10 mm; symbols  106   e  and  107   e  indicate that concentric-circle element  104   f  has a diameter of 14 mm; symbols  106   f  and  107   f  indicate that concentric-circle element  104   g  has a diameter of 16 mm; and symbols  106   g  and  107   g  indicate that concentric-circle element  104   h  has a diameter of 20 mm. Yet in another embodiment, one or more elements may have a diameter of 30 mm. 
     In one example, and as depicted in  FIG. 1 , symbols  106   a - 106   g  are embodied as numerals (e.g. Arabic numerals). Those of ordinary skill in the art, however, will readily understand that any symbol may be used to denote a dimensional property (e.g., a diameter) of one or more of concentric-circle elements  104   a - 104   h . for example, symbols  106   a - 106   g  may be computer-readable shapes and/or patterns (e.g. barcodes, and the like). Indeed, in certain embodiments, a symbol or marker may provide computer-readable indicia that may be detected (including automatically) before, during, or after an imaging process. In certain embodiments, the symbol or indicia may not readily convey the dimensional property represented without prior knowledge to its correlation to the dimensional property. 
     In one implementation, device  100  has a location marker  108 , wherein location marker  108 . Location marker, like the elements and symbols described herein, may comprise a radiopaque area, contrast materials, and/or fluorescent materials. In one implementation, location marker  108  has a surface area of between 18 and 22 mm 2 . Location marker  108  may be distanced a predetermined distance from at least one or more of elements  104 , symbols  106  and/or symbols  107 . In one embodiment, the diameter of the a concentric circle, such as circle  104   h , may be less than, equal to, or larger than the distance from location marker to that circle, the center of the concentric circles  104   a , or another location associated with the circles  104  or symbols  106 / 107 . In yet another embodiment, a dimension (e.g., diameter) of marker  108  may be proportional to one or more aspects of the circles  104 , and/or symbols  106 / 107 . 
     In one example, electromagnetic radiation of a certain wavelength (e.g. x-rays) may not pass through, and/or the transmission of the radiation may be substantially attenuated through elements  104   a - 104   h , symbols  106   a - 106   g  and  107   a - 107   g , and/or location marker  108 . Accordingly, a radiological image (otherwise referred to as a radiograph, or x-ray, and the like) of a biological and/or synthetic feature may include a representation or image corresponding to one or more of elements  104   a - 104   h , symbols  106   a - 106   g  and  107   a - 107   g , and location marker  108 . 
     In one implementation, location of one or more of elements  104   a - 104   h , and/or symbols  106   a - 106   g  and  107   a - 107   g  may be aided by location marker  108 , wherein location marker  108  has a comparatively larger radiopaque surface area than anyone element  104   a - 104   h  or symbol  106   a - 106   g  or  107   a - 107   g . As such, the comparatively larger radiopaque surface area of location marker  108  may correspond to a larger feature within a radiological image produced using device  100 . Accordingly, location marker  108  may be relatively more visible to a user, and hence, more quickly recognized in a produced radiological image. One or more of elements  104 , symbols  106 / 107 , and/or marker  108  may be configured to have a first appearance when imaged under a first imaging process and second appearance when imaged under a second image process. This may be beneficial for a few reasons. In one embodiment, it may allow the detection of whether the proper procedure was used, and/or what type of procedure was used. In one embodiment, the first appearance may be configured to present itself on a graphical representation when a first wavelength was used and the second appearance may be associated with a second wavelength, such as one that may be erroneously used for a specific instance. 
       FIG. 1  depicts device  100  having base structure  102  with an outer perimeter  103  having a discrete shape. Those of ordinary skill in the art will recognize that base structure  102  (and/or entire device  100 ) may have any shape, and without departing from the scope of this disclosure. In this way, one alternative implementation of device  200  is depicted in  FIG. 2 . 
       FIG. 2  depicts device  200 , which may be similar in one or more aspects to device  100  from  FIG. 1 . In particular, device  200  has a base structure  202  that may be similar in structural features to base structure  102  from  FIG. 1 . In this example, base structure  202  is embodied with outer perimeter  210 , which exhibits a different shape than outer perimeter  103  of device  100 . Device  200  further includes a scale  206  located thereon. In one example, scale  206  may comprise one or more elements like or similar to elements  104   a - 104   h  and/or symbols  106   a - 106   g  and  107   a - 107   g  from  FIG. 1 , including in relation to one or more of their quantity, size, shape, proportional dimensions, radio opacity, and combinations thereof. Further, location marker  208  may be similar (in terms of dimension, location, and/or other attributes, such as those described above) to location marker  108  from  FIG. 1 . 
     One or more devices, such as devices  100  or  200 , may include a unique identifier. In one example, device  200  comprises a unique identifier  212 . Unique identifier  212  may be provided, e.g., printed, onto base structure  202 . In one specific example, unique identifier  212  may comprise a radiopaque material. In one example, unique identifier  212  may be used to associate one or more data points with device  200 . For example, unique identifier  212  may be used to identify a patient imaged using device  200  (e.g. to produce, in one example, an x-ray), the specific imaging equipment, personnel employing the imaging technique, date, time, locational information, and combinations thereof, among others. Those of ordinary skill in the art will readily understand that unique identifier  212  may be utilized to associate a device, such as device  100  or device  200 , with any type of stored information, wherein the unique identifier  212  itself may store said information, or wherein unique identifier  212  may comprise a sequence of digits and/or symbols that may be used to look up information stored in a collection of information, whether electronic or not, separate from the device  100 / 200 . 
       FIG. 3A  depicts a blood vessel sizing device  300  which may be similar in one or more aspects to one or more of devices  100  and/or  200  from  FIG. 1  and  FIG. 2 , respectively. Device  300  is shown as comprising a base structure  302 , wherein, in one example, base structure  302  may be similar to base structure  102  and/or  202  from  FIG. 1  and  FIG. 2 , respectively. Furthermore, device  300  has a scale  306 , which may be similar to scale  206  from  FIG. 2 . 
     In the example depicted in  FIG. 3A , base structure  302  comprises a substantially transparent (e.g. to light in the visible spectrum) polymeric material. Accordingly, this transparency may be utilized when positioning device  300  on an area of skin of a patient and/or other surface (biological or synthetic) prior to an imaging procedure (e.g. an x-ray). 
     In one example, device  300  may comprise a perimeter area  304 , wherein perimeter area  304  may represent an area of the base structure  302  to which one or more of an adhesive layer or a deformable structure (described further in relation to  FIG. 4  and  FIG. 5 ) may be affixed. In one example, that adhesive layer and/or deformable structure (not pictured) affixed to perimeter area  304  may be opaque to light in the visible spectrum and/or spectrum of wavelengths utilized by an imaging process. In one implementation in which the perimeter area  304  is opaque to light in the visible spectrum, perimeter area  304  encloses a window  308  of base structure  302 , wherein that area of base structure  302  designated as window  308  remains substantially transparent to light in the visible spectrum. As such, window  308  facilitates visual positioning of device  300  on an area of interest prior to an imaging procedure while perimeter area  304  is substantially opaque. In certain embodiments, the perimeter area may be opaque with respect to only one of (a) light in the visible spectrum and (b) spectrum of wavelengths utilized by an imaging process to capture the target object or target area. 
     It will be readily apparent to those of skill in the art that while perimeter area  304  is depicted in  FIG. 3A  with a particular shape, many alternative shapes for perimeter area and/or window  308  may be realized without departing from the scope of this disclosure. Furthermore, in another example, perimeter area  304  may cover substantially the same area as base structure  302 , and without departing from the scope of this disclosure. 
       FIG. 3B  depicts a device  340 , wherein device  340  may be similar to device  300  from  FIG. 3A . Similarly to device  300 , device  340  may have a substantially transparent base structure  342 . Furthermore, base structure  342  may have a perimeter area  344 , wherein perimeter area  344  represents an area to which one or more of an adhesive layer and/or a deformable structure may be affixed. Accordingly, perimeter area  344  may be substantially opaque to light in the visible spectrum. As such, visual placement of device  340  on an area of interest may be facilitated by a substantially transparent window  348 . It is noted that window  348 , and similarly for window  308 , while being substantially transparent to light in the visible spectrum, include radiopaque scales  346  and  306 , wherein scales  346  and  306  may be substantially opaque to light in the visible and/or x-ray spectrum, among others. 
     In one example implementation, device  340  comprises a tab structure  350 , wherein tab structure  350  may be an area of base structure  342  that is non-adhesive. As such, structure  350  may facilitate removal of device  340  from an area to which device  304  he was adhered prior to an imaging procedure. An adhesive layer may be positioned on the entirety of or just a portion of the 
       FIG. 4A  schematically depicts a side view of an imaging device  400 , similar to devices  100 ,  200 , and/or  300  (wherein  FIG. 1 ,  FIG. 2 , and  FIG. 3A-3B  depict plan views of devices  100 ,  200 , and/or  300 ). As such, device  400  comprises a base structure  402  having a front surface  404  and a back surface  406 . A scale  408 , which may be similar in one or more aspects to scales  206  and  306 , is positioned on the front surface  404  of base structure  402 . As previously described scale  408  may be printed, adhered, welded, or joined by any other means known to those of ordinary skill in the art to a surface, such as the front surface  404 . The thickness of base structure  402  is represented as thickness  412 , and which may be, in one example, 0.25 mm, 0.5 mm, 0.75 mm, or 0.9 mm, and the like. 
     Turning to  FIG. 4B , device  400  from  FIG. 4A  is depicted having an alternative configuration, and including an adhesive layer  410  on the back surface  406  of base structure  402 . In one example, adhesive layer  410  may cover the entire surface area of the back surface  406  of base structure  402 . In another example, adhesive layer  410  may only partially cover the back surface  406 . Specifically, in one example, adhesive layer  410  may cover an outer perimeter area, such as perimeter area  304  from  FIG. 3A . 
     It will be readily apparent to those of skill in the art that adhesive layer  410  may comprise any known adhesive. In one example, adhesive layer  410  may comprise a medical adhesive configured to temporarily and removable bond a structure, such as device  400 , to an area of skin of a patient. 
       FIG. 5A  schematically depicts device  500 . In one example, device  500  may be similar in one or more aspects, to devices  100 ,  200 ,  300 , and/or  400  previously described. Accordingly, device  500  may comprise a base structure  502 , which may be similar to one or more aspects described herein of base structure  102 ,  202 ,  302  and/or  402 . A scale  504  may be positioned on a front surface  503  of base structure, and a deformable structure  506  may be positioned on a back surface  505  of base structure  502 . 
     As such, a front surface  513  of deformable structure  506  may be adhered to the back surface  505  of base structure  502  by any methodology known to those of ordinary skill in the art, and including, but not limited to, adhesion, molding, fastening, and/or welding, among others. Additionally, an adhesive layer  508 , similar to adhesive layer  410 , may be positioned on part or all of a back surface  515  of deformable structure  506 . It should be understood that deformable structure  506  and adhesive layer  508  may be the same layer. Therefore, discussion of a deformable structure or adhesive layer should be interpreted as a single layer that has both properties. 
     Deformable structure  506  may comprise a material with physical properties (e.g. hardness) allowing for deformation (compression, and the like) without failure of the material. Accordingly, deformable structure  506  may comprise a sponge-like material which may be a synthetic foam, or any other material with mechanical properties suitable for deformation. Furthermore, in one example, deformable structure  506  may have a thickness  514  of 1 mm, 2 mm, 5 mm, 10 mm, 15 mm, among others. 
       FIG. 5B  schematically depicts device  500  adhered to an uneven surface  510 . As such, deformable structure  506  is depicted in a compressed state, wherein the back surface  515  of deformable structure  506  conforms to the undulations of uneven surface  510 , while the front surface  513  of the deformable structure  506  remains substantially planar. Accordingly, base structure  502  of device  500 , in addition to the radiopaque scale  504  thereon, also remain substantially planar while device  500  is adhered to uneven surface  510 . 
       FIG. 6A  schematically depicts a radiographic image  610  resulting from electromagnetic radiation of a certain wavelength (or range of wavelengths), e.g. x-rays, incident on a device  601  which may be laid over a passageway of a living being, such as a blood vessel of a human. Accordingly, device  601  may be similar in one or more of the aspects described herein to one or more of devices  100 ,  200 ,  300 ,  400 , and/or  500 . In particular,  FIG. 6A  schematically depicts a source  608  emitting electromagnetic radiation that is incident upon a base structure  602 , a radiopaque scale  604 , and a location marker  606  of device  601 . In one example, part, or all, of the electromagnetic radiation incident on scale  604  and location marker  606  is absorbed. Yet, other embodiments may have materials that get excited or otherwise react to the imaging process or other process used in conjunction with the imaging process. Accordingly, the radiographic image produced upon detection of the electromagnetic radiation transmitted through base structure  602  includes a radiopaque scale image  612  and a location marker image  614 . 
       FIG. 6B  depicts the same device  601 , but angled, at angle  607 , with respect to source  608  along a defined plane. Those skilled in the art will appreciate that the device may be angled with respect to the source along multiple planes, however, for sake of understanding aspects of the innovative embodiment, only a single plane is discussed. Because the device  601  is angled with respect to the source, the electromagnetic radiation emitted from source  608  is no longer orthogonal to base structure  602  (electromagnetic radiation now incident upon base structure  602  at an angle of (90°-[angle  607 ]°)). As such, the radiographic image  620  produced as a result (of the angle between the incident radiation and device  601  results in a radiopaque scale marker image  624  and a location marker image  622  having ellipsoidal shapes, as depicted. 
     The distortion of the radiopaque scale marker image  624  and location marker image  622  may be regarded as an error of parallax, wherein, among others, minor axis  627  of radiopaque scale marker  624  no longer represents a true length. However, due to the concentric-circle design of scale marker  604  (e.g. radiopaque concentric-circle elements  104   a - 104   h  from  FIG. 1 ), the resulting radiopaque scale marker image  624  includes at least one true length. In particular, the true length of concentric-circle elements  104   a - 104   h  is represented in radiopaque scale marker image  624  along the longest axis (major axis)  626  of that ellipsoidal image of radiopaque scale marker  624 . As such, a user may determine the longest axis of radiopaque scale marker image  624 , and measure one or more true lengths of one or more concentric-circle elements  104   a - 104   h  along said axis  626 . In this regard, although there are two axes shown ( 626  and  627 ), those skilled in the art will realize that any straight line that passes through the center of a concentric circle can serve as an axis. In this regard, the closest axis to the true axis may be set to the nearest degree, of the circle, or nearest half degree or whole number of degrees. Advantageously, device  601 , and in particular, the concentric-circle elements  104   a - 104   h , thereby allow a user to avoid errors of parallax. 
     In one example, device  601  may not comprise a rigid structure. In particular, in one example, base structure  602  may bend in one or more directions. For example, base structure  602  may substantially conform to one or more areas of curvature of the human body onto which it is a fixed. As such, due to bending of base structure  602  along one or more axes, a resulting marker image  624  produced by source  608  may be distorted along multiple axes. For example, distortion of marker image  624  may result in a first major axis associated with the depicted 20 mm (which may be other dimensions, such as 30 mm or 3 cm) concentric circle of marker image  624  (e.g. circle  104   h  from  FIG. 1 ), and a second major axis associated with, in one example the 10 mm concentric circle of marker image  624  (e.g. circle  104   d  from  FIG. 1 ), wherein the first and the second major axes are not parallel. As such, in one example, it may be advantageous for a user to determine a concentric circle size, from those concentric circle sizes depicted in marker image  624  (e.g. 2 mm, 4 mm, 6 mm, 8 mm, 10 mm, 14 mm, 16 mm, 20 mm, or 30 cm among others) that most closely matches a dimension of an imaged feature. In this way, a user may identify a first major axis in marker image  624  to be used in association with a first imaged feature, wherein this first major axis is a most accurate axis visible in marker image  624  having a dimension that is close to a dimension to be measured in the first imaged feature. Accordingly, a user may identify a second major axis in marker image  624 , due to distortion of marker image  624  as a result of bending of base structure  602  along one or more axes. As such, the second major axis may not be parallel to the first major axis identified. Accordingly, the second major axis may be a most accurate axis visible in marker image  624  having a dimension that is close to a dimension to be measured in a second imaged feature. 
       FIG. 7  schematically depicts a radiological image  700 , that defined a field of view or target area including one or more biological features (which may include a target object. In particular, the image  700  of  FIG. 7  may be an angiogram. Those of ordinary skill in the art will readily understand various methodologies for carrying out an angiogram, which include, among others, use of contrast agents to view blood vessels, and the like. Accordingly, any known technique for angiography or other radiographic imaging may be employed with the systems and methods described herein, and without departing from these disclosures. Furthermore, image  700  may be computer-generated, or may be produced by the detection of electromagnetic radiation (e.g. x-rays) by a film. 
       FIG. 7  depicts a plurality of blood vessels comprising at least a portion of the carotid artery  701 , and one exemplary branching blood vessel is labeled as vessel  702 . In one example, it may be desirable to obtain one or more dimensions of biological features from a given radiological image  700 . Accordingly, in one example, one or more dimensions of a stenosis  704  may be obtained from radiological image  700 . In one implementation, a device, such as device  100 ,  200 ,  300 ,  400 , and/or  500  may be positioned on a surface of interest, and within the field of view of a radiological image to be produced. In one specific example, a scale image  706  (which may comprise a plurality of elements and symbols) may be included in a radiological image  700  produced. As such, one or more true dimensions of one or more biological features (e.g. a blood vessel width  708 ) may be determined using one or more concentric-circle elements of the unknown size (e.g. elements  104   a - 104   h  from  FIG. 1 ) of scale image  706 . 
       FIG. 8  schematically depicts an imaging system  800 . Specifically, system  800  includes a computer  802  having a processor  804 , in memory  806 , and an interface  808 . Computer  802  is further connected to a user interface  820 , a source  810 , and a detector  816 . It will be readily apparent to those of ordinary skill in the art that connections between devices  802 ,  820 ,  810 , and/or  816  may be wired or wireless, and using any known network type and/or communication protocol. For example, communication between one or more of devices  802 ,  810 ,  820 , and/or  816  may be through a local area network (LAN), a wide area network (WAN), or the Internet, and using a communication protocol including one or more of the Transmission Control Protocol (TCP), the Internet Protocol (IP), or the User Datagram Protocol (UDP), among many others. 
     Processor  804  may be a general-purpose central processing unit, or a dedicated and specialized processing chip. Processor  804  may contain a single processing core, or multiple cores acting in parallel, and the like. Memory  806  may be volatile or persistent, and may include one or more of read only memory (ROM), random access memory (RAM), a solid state hard drive (SSD), or memory using optical disc media (CD, DVD, and the like), among others. Interface  808  may comprise those hardware and/or software components for connection of computer  802  to one or more devices  810 ,  820 , and/or  816  across a network. Furthermore, user interface  820  may comprise one or more of a display and/or a control interface for receiving instructions from user. Source  810  may comprise a source of electromagnetic radiation (e.g. x-rays) suitable for radiographic imaging. Accordingly, detector  816  may comprise an electronic detection device sensitive to electromagnetic radiation emitted from source  810 , and such that the electromagnetic radiation received by detector  816  may be used to construct a digital image. 
     Element  814  represents an area of skin of a patient to be imaged using source  810  and detector  816 . Positioned on said area of skin of a patient  814  is a blood vessel sizing device  812 , wherein the device  812  may be similar to one or more of those devices ( 100 ,  200 ,  300 ,  400 , and/or  500 ) previously described. Accordingly, one or more features of device  812 , such as, for example, a radiopaque scale, such as radiopaque scale  408 , may be included in a resulting image constructed by computer  802 . 
     In one example, a user of system  800  may identify a biological feature within a radiological image, wherein said image may be a real-time digital image produced by computer  802  from data received from detector  816 . For example, a user may identify a one or more passageways (blood vessels) and/or one or more objects within passage ways (blood clots), among others. In one example, it may be desirable for a user to determine a true dimension of one or more biological features present in an image produced by system  800 . Accordingly, a user may input one or more instructions, via interface  820 , identifying one or more biological features of interest within an image produced by system  800 , and visible to a user at user interface  820 . Subsequently, one or more identified features of interest may be compared to an image produced by blood vessel sizing device  812 , wherein said image may be similar to a scale, such as scale  612  and/or scale  624 , among others. As such, one or more known sizes/dimensions of said scales  612  and/or  624  may be compared to the one or more identified features of interest, and a true dimension may be determined. Furthermore, it will be apparent to those of ordinary skill that blood vessel size or device  812  is agnostic to the type of imaging equipment used, in addition to the magnification and/or specific image manipulation processes applied to the data detected by detector  816 . 
     In one example, a user may manually compare a length property of a biological feature visible within an image produced by system  800  to one or more known dimensions of a radiopaque scale present within said image. For example, a user may measure a width of a blood vessel, as shown in an image produced by system  800 , using a calipers. However, due to the magnification/scaling and/or other image manipulation steps carried out on the data received from detector  816 , this length measured by the calipers may not be a true dimension of the width of the blood vessel. Accordingly, the user may compare the length measured by the calipers to one or more concentric-circle elements (e.g. elements  104   a - 104   h  from  FIG. 1 ) visible within a radiopaque scale (e.g. radiopaque scale  612  and/or  624 ), and wherein the radiopaque scale is visible within the same radiological image as the blood vessel of interest (e.g the visible radiopaque scale  612  and/or  624  will have been subject the same scaling and/or other image manipulation processes such that a direct comparison between the length measured with the calipers, and one or more lengths from the radiopaque scale is still possible). In doing so, the user may compare the measured length from the calipers to the major axis (e.g. as discussed in relation to  FIG. 6B ) of the radiopaque scale, and by comparison to one or more of the known dimensions of the concentric-circle elements, determine a true dimension of the blood vessel width. Furthermore, it will be readily apparent to those of skill that any mechanical measurement device may be utilized for measuring a length property of a biological feature. For example, a user may utilize a ruler, measuring tape, or calipers, among many others. 
     In another example, one or more true dimensions of an identified biological feature may be determined by an automated process. One example of such an automated process is described in relation to  FIG. 9 . 
       FIG. 9  is a flowchart that may be implemented in the automatic determination of a true dimension of a feature captured in a radiological image (e.g., radiograph/x-ray). In one example, the description in  FIG. 9  may be used in conjunction with imaging system  800  from  FIG. 8 . Image data may be received from a detector, such as detector  816  (e.g., block  902 ). In one example, this image data may include information related to one or more biological features (tissues, organs, blood vessels, blood clots, and the like). A dimensional property (e.g., a length property) of the one or more biological features of interest within the received image data may be obtained (e.g., block  904 , which may follow block  902 ). 
     In an example embodiment, block  904  may represent one or more processes to determine a length of one or more features within a radiological image using an arbitrary length metric (e.g. a number of screen pixels, and the like). In this way, due to one or more scaling and/or other image manipulation processes carried out on the image data used to create the radiological image, a true dimension of the one or more features is not readily known. 
     One or more elements from image data that correspond to concentric-circle elements, such as those elements  104   a - 104   h  from  FIG. 1 , may be identified (e.g., block  906 ). Block  906  may occur in the absence of block  904 . Those of ordinary skill in the art will readily understand that any computer image recognition processes may be utilized with the one or more processes of block  906 , and without departing from the scope of this disclosure. 
     Symbols, such as for example,  106   a - 106   g  and  107   a - 107   g , may be identified from the image data. This may occur before, during, after and/or in absence of blocks  904 / 906 . In accordance with further embodiments, a major axis of one or more identified concentric-circle elements may be determined, such as at block  910 . In this way, and as described in relation to  FIG. 6B , a longest axis of a radiopaque scale marker image, such as radiopaque scale marker image  624  from  FIG. 6B , may be used to read known lengths of one or more concentric-circle elements  104   a - 104   h  without an error of parallax (and/or with a statistically significant reduction in an error of parallax. 
     A dimensional property (e.g., the length property) of a biological feature may be compared to one or more dimensions (e.g., lengths) of concentric-circle elements along the determined major axis of a radiopaque scale marker image, such as radiopaque scale marker image  624 . Upon comparison of the determined length property of the biological feature to the corresponding concentric-circle elements of the same length (or interpolating/extrapolating from one or more known dimensions of concentric-circle elements), a true dimension value may be determined. As such, the determined dimensional property (e.g., the length) of the biological feature may be converted into a true dimension value (e.g., block  914 ). 
     A true dimension value may be communicated to a user, such as via user interface  820  from  FIG. 8 , which may occur at example block  916 . 
       FIG. 10A  schematically depicts an example implementation of device  1004  being used. In particular,  FIG. 10A  schematically depicts device  1004  positioned on a neck area of a human patient  1002 . Accordingly, in one implementation, device  1004  may be similar to device  100 ,  200 ,  300 , or  400 , and the like. Following from  FIG. 10A ,  FIG. 10  B schematically depicts patient  1002  being imaged using imaging device  1010 . As will be apparent to those of ordinary skill in the art from the foregoing disclosures described herein, imaging device  1010  may be, among others, part of an x-ray device for performing an angiogram. In other implementations, device  1010  may be a part of an MRI device, a CT device, a myelogram device, a thermograph device, an MRN device, an ultrasound device, and/or combinations thereof, among others. 
     Accordingly, as schematically depicted in  FIG. 10B , imaging device  1010  may image a region  1006  that includes both device  1004  and, in one example, blood vessel  1008 . In one specific example, blood vessel  1008  may be a carotid artery, among others. 
       FIGS. 11A-11D  schematically depict various implementations of a device that may be utilized for locating an area of interest within a radiological image. In certain embodiments disclosed herein, the device may be used to locate or estimate the location of a feature or area of interest of: (1) a first image of a first area, wherein a first feature is captured under a first image criteria; and (2) a second image that comprises at least the same first area, wherein the same feature is present but not captured or captured to a less degree, under a second image criteria, Non-limiting examples are discussed in relation to  FIGS. 11A-11D . In one example,  FIG. 11A  depicts a radiological image  1100  that includes a scale image  1102 , which may be similar to scale image  706 , and generated as a result of one or more imaging processes of a device, such as device  100 , and the like. Additionally,  FIG. 11A  depicts a schematic view of a blood vessel  1106  having a feature of interest  1104 , which may be, in one example, a stenosis, and the like. Furthermore,  FIG. 11A  depicts a branching vessel  1108 . In one example, vessel  1106  and feature  1104  may be visible within an image (e.g., radiological image)  1100  through use of a contrast agent. In this regard,  FIG. 11A  may represent a first image of a first area, wherein the feature  1104  may be a first feature that is captured under the specific capturing conditions, such as using a radiograph and contrast agent (or specific type/dosage of agent). 
       FIG. 11B  schematically depicts a radiological image  1140  that is similar to image  1100  from  FIG. 11A . In particular,  FIG. 11B  schematically depicts scale image  1102  being utilized to locate a feature of interest  1104 . Specifically, a position of scale image  1102  may be noted relative to feature  1104 . Accordingly, those lines  1120  and  1122  may represent imaginary lines, or visible lines depicted on an electronic interface (computer screen) or other representation of image  1140  (e.g. a printed copy of image  1140 , and the like) that may be traced out from the center of scale image  1102 , and delimiting of the ends of feature  1104  within vessel  1106 . For example, a user (a clinician or otherwise) viewing image  1140  may note that a “top” end of feature  1104  corresponds to a “3 o&#39;clock position” at an outer concentric-circle element (that largest 20 mm circular element depicted, which may be larger or smaller, including, for example, 30 mm or 3 cm), and delimited by line  1122 . Similarly, the user may note that a “bottom” end of feature  1104  corresponds approximately to a “4 o&#39;clock position” at the outer concentric circle of scale image  1102 , and delimited by line  1120 . As such, while vessel  1106  and feature  1104  are visible in image  1140  through use of a contrast agent, noting a position of feature  1104  relative to scale image  1102  may allow said feature  1104  to be located without using further contrast agent in subsequent images having a same field of view. 
     In furtherance of this example, those of ordinary skill in the art will readily understand various contrast agents, otherwise referred to as radiocontrast agents, or contrast media, among others, may be used to improve visibility of one or more blood vessels, and associated features, when imaged using x-ray-based imaging techniques. Accordingly, in one example, a contrast agent may be utilized in image  1100  to view vessel  1106 , and may include an iodinated (iodine-based) contrast agent, among others. As such, those of ordinary skill in the art will understand that while contrast agents are generally considered safe for use during in vivo imaging, there exist various side effects that may be associated with the use of contrast agents. For example, contrast agents may have a detrimental impact upon kidney function, or may, in some instances, lead to higher rates of blood clotting, among others. As such, it may be desirable for an imaging process to reduce an amount of contrast agent utilized to, in one example, image a vessel for positioning of a stent, among others. Thus, a second image (which may be a subsequent frame in a live video capture) may be the same area and feature (e.g., feature  1104 ), however, blood flow has moved the contrast agent, and as such, feature  1104  may be less visible or not visible. 
       FIG. 11C  schematically depicts scale image  1102  being utilized to locate a feature within a vessel  1106  without using contrast agent. As such, respective to  FIG. 11A ,  FIG. 11C  may be considered a second image that comprises at least the same first area, wherein the same feature is present but not captured or captured to a less degree, under a second image criteria (e.g., no or less contrast agent). In one embodiment, at least a portion of the vessel itself may be the feature that is less visible or not visible in the second image (or any image that is not the first image). In particular, an outline of vessel  1106  is depicted in  FIG. 11C , having a first side wall  1110 , and a second sidewall  1112 . However, sidewalls  1110  and  1112  outlining vessel  1106  are included for clarity within radiological image  1150 . As such, sidewalls  1110  and  1112  represent one or more lengths of blood vessel  1106  that were previously visible within the radiological image  1140  from  FIG. 11B  through use of a contrast agent, but which may no longer be visible, or may have diminished visibility, within radiological image  1150  due to an absence of a contrast agent. As such, it may be assumed that sidewalls  1110  and/or  1112  of the vessel  1106  are not clearly visible within radiological image  1150  in accordance to one embodiment. However, having noted the position of feature  1104  (which also may not be visible or is of reduced visibility relative to scale image  1102  from  FIG. 11B ), lines  1120  and/or  1122  may be utilized to locate, approximately, feature  1104  (from  FIG. 11B ) within image  1150 . As such, lines  1120  and/or  1122  may be utilized to position, in one example, a stent, at the feature of interest  1104  from  FIG. 11B , and without using, or using a reduced amount of a contrast agent. Turning to  FIG. 11D , stent  1130  may be positioned in image  1160  relative to scale image  1102 , and utilizing that relative positioning noted using lines  1120  and/or  1122 , and the like. Specifically, stent  1130  may be moved into an area of vessel  1106  (vessel  1106  may not be clearly visible within image  1160  due to absence of contrast agent, and the like) by positioning relative to lines  1120  and  1122 . 
     Those of ordinary skill in the art will understand that images  1100 ,  1140 ,  1150 , and/or  1160  may be still images, or may be “live” images that are periodically updated. In one example, one or more of said images may be updated as a frame rate of six frames per second, however those of ordinary skill in the art will understand that any update/refresh rate may be utilized without departing from the scope of these disclosures. Additionally, those of ordinary skill in the art will understand that&#39;s images  1100 ,  1140 ,  1150 , and/or  1116  may be generated using any appropriate imaging technology including, among others, computed tomography and/or radiography, among many others. 
     Aspects of the Present Disclosure 
     Aspects of the subject matter described herein may be useful alone or in combination with one or more other aspect described herein. Without limiting the foregoing description, in a first aspect of the present disclosure, a blood vessel sizing device includes a marker configured for placement on the skin of a patient, the marker defines a substantially circular shape and includes a plurality of radiopaque substantially concentric circles. 
     In accordance with a second aspect of the present disclosure, which can be used in combination with the first aspect or any one of aspects two to twenty, the blood vessel sizing device includes an adhesive for adhering the device to the skin of the patient. 
     In accordance with a third aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the blood vessel sizing device includes a plurality of different radiopaque symbols, wherein each of the plurality of different radiopaque symbols represents a diameter of one of the plurality of concentric-circle elements. 
     In accordance with a fourth aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, each of the radiopaque symbols is a geometric shape. 
     In accordance with a fifth aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, each of the radiopaque symbols are numbers. 
     In accordance with a sixth aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, each of the plurality of radiopaque concentric-circle elements has a diameter, the diameters ranging from 2 mm to 12 mm. 
     In accordance with a seventh aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, each of the plurality of radiopaque concentric-circle elements includes at least three radiopaque substantially concentric circles. 
     In accordance with an eighth aspect of the present disclosure, which can be used in combination any one or more of the preceding aspects, the at least three radiopaque substantially concentric circles have diameters of about 6 mm, 8 mm, and 10 mm. 
     In accordance with a ninth aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the plurality of radiopaque concentric-circle elements includes at least four radiopaque substantially concentric circles. 
     In accordance with a tenth aspect of the present disclosure, which can be used in combination with the fifth aspect, the at least four substantially concentric circles have diameters of about 4 mm, 6 mm, 8 mm, and 10 mm. 
     In accordance with an eleventh aspect of the present disclosure, which can be used in combination with the fifth aspect, the at least four substantially concentric circles have diameters of about 14 mm, 16 mm, 18 mm, and 20 mm. 
     In accordance with a twelfth aspect of the present disclosure, which can be used in combination with the twelfth aspect, the plurality of radiopaque symbols are at least one of (i) geometric shapes, and (ii) numbers. 
     In accordance with a thirteenth aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the diameters of the plurality of substantially concentric circles range from about 2 mm to about 20 mm. 
     In accordance with a fourteenth aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, a blood vessel sizing method includes placing a device having a plurality of radiopaque concentric-circle elements on the skin of a patient, imaging the blood vessel and the device, and comparing the image of the blood vessel to the image of at least one of the plurality of radiopaque concentric circle elements to determine a size of the blood vessel. 
     In accordance with a fifteenth aspect of the present disclosure, which can be used in combination with the fourteenth aspect, imaging the blood vessel and the marker includes using an angiogram. 
     In accordance with a sixteenth aspect of the present disclosure, which can be used in combination any one or more of the preceding aspects, comparing the imaged blood vessel to the imaged plurality of concentric circles to determine the size of the blood vessel includes measuring the imaged blood vessel and comparing the measured blood vessel to the imaged diameters of the plurality of radiopaque substantially concentric circles. 
     In accordance with an seventeenth aspect of the present disclosure, which can be used in combination any one or more of the preceding aspects, measuring the diameter of the imaged blood vessel includes using a mechanical instrument. 
     In accordance with a eighteenth aspect of the present disclosure, which can be used in combination any one or more of the preceding aspects, the marker includes a plurality of different radiopaque symbols, wherein each of the plurality of different radiopaque symbols represents a diameter of one of the plurality of concentric-circle elements. 
     In accordance with a nineteenth aspect of the present disclosure, which can be used in combination any one or more of the preceding aspects, comparing the imaged blood vessel to the image of at least one of the plurality of concentric circles to determine the size of the blood vessel includes measuring the imaged blood vessel and comparing the measured blood vessel to the imaged diameters of the plurality of radiopaque concentric-circle elements and reading the symbols. 
     It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.