Patent Description:
Breast ultrasound may be used as part of breast cancer diagnosis to determine whether a lump is a benign fluid filled sac (i.e., a cyst) or a solid mass potentially indicative of cancer. Ultrasound can also be used during a breast biopsy procedure to determine three dimensional coordinates of an identified tumor in order to guide a medical professional during a biopsy or aspiration procedure. Ultrasound may be used to confirm correct needle placement and also validate removal of suspect tissue.

Ultrasound imaging is recognized as a relatively low cost, safe imaging modality which provides information similar to that of conventional mammograms (and in some cases superior) for breast cancer detection without adverse effects of radiation. However the time required to perform a thorough ultrasound image capture makes the modality less desirable for breast cancer screening. During breast ultrasound examinations, an ultrasound transducer is typically manually moved over the portion of the body to be imaged. Two dimensional images are captured from various perspectives and assembled using image processing techniques known to those of skill in the art to construct a three-dimensional representation of the breast. Although the ability to manually manipulate the transducer allowed the medical professional the freedom to more thoroughly examine regions of interest during the scan, the time required to perform a complete scan could quickly accumulate.

US patent application <CIT> discloses a compression paddle of a mammographic diagnosis apparatus provided with an opening portion which allows an ultrasonic probe to be fitted therein and slide.

German patent application <CIT> discloses a mammography device with a compression configuration for an x-ray examination device with a first compression unit comprising a first ultrasound unit, and with a second compression unit comprising a second ultrasound unit.

In one aspect, the technology relates to an ultrasound breast imaging system according to claim <NUM>.

In another aspect, the technology relates to a method of imaging a breast with an ultrasound imaging system according to claim <NUM>.

An upright breast ultrasound system is shown and described that provides several advantages over ultrasound systems of the prior art. The rotatable compression assembly allows ultrasound imaging of a breast from multiple positions and orientations. The pivoting compression paddles allows the system to be used for single breast scan as well as dual breast scan, depending on the size of the paddles, breast size, position, etc. Providing ultrasound transducers in each of the compression paddles enables relatively simultaneous image capture from different sides of the breast (for CC, MLO, and lateral scans). This is particularly advantageous for larger breasts, where the sound waves may not be able to penetrate through the entire breast thickness if scanned from only a single side. In the case of a frontal scan, two different breasts may be scanned simultaneously, also improving workflow times. The material of the patient surface of the paddle stabilizes the breast with minimal patient discomfort, while providing a smooth surface along which the ultrasound transducer can glide during the scan of the breast. By securing the breast for ultrasound imaging, movement of tissue is reduced, thus allowing for improved imaging. A user interface mounted on the gantry allows a user to customize their scan workflow.

<FIG> illustrate an exemplary embodiment of an upright ultrasound breast imaging device <NUM> of the present technology in various positions and orientations. The imaging device includes a gantry <NUM> coupled to a compression assembly <NUM> via a rotatable support arm <NUM> (<FIG>). The compression assembly <NUM> includes a pair of generally parallel disposed compression paddles or elements 105a and 105b mounted on a paddle support and control structure <NUM>. Each compression paddle 105a, 105b includes a housing <NUM> containing one or more ultrasound transducers 300a, 300b, 302a, 302b (<FIG>). The housing <NUM> is generally parallelepiped in shape and includes a patient contact surface <NUM>. The housing <NUM> may be composed of a rigid material such as plastic and the like. In various examples, the patient contact surface <NUM> may be removed from the housing <NUM> for cleaning and/or disposal.

The patient contact surface <NUM> is may be a non-rigid compression material or a rigid compression material, as required or desired for a particular application. If a flexible material, the compression material may be stretched over a frame of the housing <NUM>, for example, at an outer edge thereof. Examples of elastic materials include, for example, an elastic or substantially elastic material such as a flex plastic or mesh material, nylon, lycra, and the like. In alternate examples, the compression material may be made of a texturably couplant porous material sheet as described in <CIT> assigned to U-Systems, Inc. In the case of rigid materials, the compression material may be a rigid plastic such as TPX polymethylpentene polymer. In general, it is desirable that any compression materials utilized transfer sound waves in a manner similar to human breast tissue. As such, other materials meeting such performance metrics are contemplated. If rigid materials are utilized, it may be desirable for the patient contact surfaces <NUM> thereof to be to be striated, grooved, or otherwise textured, so as to resist undesirable movement of breast tissue when the breast is compressed in the compression assembly <NUM>. Movement thereof may be caused by sweat, coupling gel required for ultrasound imaging, or a combination thereof.

The compression paddles 105a, 105b are pivotably mounted on the paddle support and control structure <NUM> via paddle support arms <NUM>. According to one aspect, the compression paddles 105a, 105b may be pivoted on the paddle support arms <NUM> through at least two secured positions: a first position wherein the patient contact surfaces <NUM> of the paddles 105a, 105b of the compression assembly <NUM> face each other (e.g., <FIG> and <FIG>), and a second position wherein the patient contact surfaces <NUM> are disposed so as to be generally coplanar (e.g., <FIG>). In the first position, the compression paddles 105a, 105b may be disposed in a number of orientations, for example, wherein an axis A extending generally orthogonally to both patient contacting surfaces <NUM> may be disposed parallel to the horizontal, orthogonal to the horizontal, or at an angle to the horizontal. These orientations are described in further detail below and correspond generally to ultrasound images obtained for lateral scans, cranial caudal (CC) scans, and mediolateral oblique (MLO) scans, respectively. In the second position, ultrasound images of the breast can be obtained using a frontal scan. In examples, when in the first position, typically only a single breast is compressed between the paddles 105a, 105b at a time for imaging. In the second position, both breasts may be imaged substantially simultaneously (e.g., one breast in contact with each patient contact surface <NUM>. More detail regarding the various types of scans enabled by this invention will be described with regards to <FIG> and <FIG>. Additionally, in the first position, transducers in each compression paddle 105a 105b may scan opposite sides of a breast substantially simultaneously.

The paddle support and control structure <NUM> includes a track <NUM>, on which the compression paddles 105a, 105b are mounted and a motor (not shown) for moving the compression paddles 105a, 105b along the track <NUM>. More specifically, the paddle support arms <NUM> are moved by the motors. In various examples the movement of the compression paddles 105a, 105b may be coordinated (e.g., substantially simultaneous in rate while opposite in direction), such that they both move towards and away from each other relative to a common datum disposed therebetween. Alternatively, the positions of the compression paddles 105a, 105b may be independently controlled, such that one compression paddle moves while the other compression paddle remains fixed. For CC, MLO, and lateral scans, the compression paddles 105a, 105b are typically advanced towards each other so that patient contact surfaces <NUM> of the paddles contact opposite surfaces of a patient's breast. In another example, movement of the compression paddles 105a, 105b may be coordinated until the breast is contacted by one of the compression paddles 105a, 105b. Thereafter, the other compression paddle may be moved until the desired compression is attained, while the first paddle remains fixed in position. This may be especially desirable in the CC scan position, for example, so as to more easily accommodate patients of different heights without unnecessarily lifting the breast up or pushing the breast down.

The degree of contact between the breast and the paddles should be sufficient to stabilize and hold the breast yet need not fully compress the breast, as is typical for other imaging modalities such as mammography and tomosynthesis. Regardless, some compression of the breast invariably occurs; as such, the term "compression" is used primarily within. For frontal scans, the compression paddles 105a, 105b are rotated towards the patient, and moved towards locations which generally center the paddle at the patient's nipple or otherwise move the paddles to close proximity to capture both breasts. One aspect of the present technology is the capability of the system to quickly obtain an ultrasound scan of both breasts using the frontal scan without patient repositioning. Given contact between the breast and the patient contact surfaces <NUM> is required for proper imaging, it is contemplated that, depending on breast size, breast density, degree of compression, and other factors, a complete ultrasound imaging procedure of the breast may be performed in a scanning in a single configuration (e.g., for small breasts), or in two or three configurations (e.g., for larger breasts). At least one benefit of the technology described herein relates to the ability of a technician to adjust the system <NUM> quickly between the various positions and orientations so as to improve workflow.

The compression assembly <NUM> also includes positioning handles <NUM> coupled to the paddle support and control structure <NUM>. The positioning handles <NUM> may be used to manually rotate the compression assembly <NUM> to various positions relative to the gantry <NUM> to enable breast imaging in multiple different perspectives. In the case of this manual rotation, a locking mechanism between the rotating arm <NUM> and the compression assembly <NUM> secures the assembly <NUM> in any one of a variety of positions as described elsewhere herein. For example, <FIG> illustrates the compression assembly positioned in a CC position which is regularly used for breast imaging. In another example, a motor (not shown, but disposed within the gantry <NUM>) may be used to rotate the paddle support and control structure <NUM> based user input controls. In this example, the positioning handles <NUM> may still be utilized so as to provide a location for the patient to grip for greater comfort or support during procedures. In either the manual- or motorized-rotation examples, an interlock that prevents rotation of the paddle support and control structure <NUM> when pressure above a certain threshold is applied to both paddles 105a, 105b may be utilized to prevent inadvertent rotation of the paddle support and control structure <NUM> when a breast is compressed. Such an interlock may include a strain gauge or other types of sensors on each of the support arms <NUM>.

The gantry <NUM> includes at least one user interface <NUM> including control buttons and knobs that may be used to control various aspects of the imaging system <NUM> including but not limited to movement of the compression assembly <NUM>, paddle support and control structure <NUM>, paddles 105a, 105b, and transducer. The interface <NUM> also may include a display <NUM> and/or touch screen that allows a user to select certain views, initiate scan sequences, move components of the system, etc. It is appreciated that various control mechanisms may be manifested by different features, and no limitation is placed on the form or function of the interface <NUM>.

<FIG> is a top view of the breast imaging system <NUM> of <FIG>. In this example, two user interfaces <NUM> are advantageously provided on the gantry <NUM>, allowing a user to access the patient from either side of the system <NUM>. The user interfaces <NUM> may include a graphic user interface (e.g., in the form of a touch screen <NUM>), and one or more tactile features in the form of buttons <NUM>, knobs <NUM>, switches, etc. In addition, a shutdown or release switch <NUM> is provided on the top of the device, providing a mechanism for the technician to quickly release the breast from compression, while limiting the potential that the release switch <NUM> is inadvertently activated via the user interface <NUM>. In the top view of <FIG>, the compression assembly <NUM> is shown in a MLO position for ultrasound image acquisition.

<FIG> illustrates a perspective view of the compression assembly <NUM> of the breast imaging system of <FIG>. In <FIG>, the compression paddles 105a, 105b have been rotated into a second position so that the patient contact surface <NUM> faces the patient for a frontal scan. In such frontal scans, the patient may lean into the compression paddles 105a, 105b from a seated or standing position. In <FIG>, the patient contact surface is depicted as transparent for ease of view of the transducers. <FIG> shows a pair of transducers 300a, 302a, 300b, 302b in each compression paddle 105a, 105b. A vertical scan transducer 302a, 302b and a horizontal scan transducer 300a, 300b are disposed in each compression paddle 105a, 105b. The transducers 300a, 302a, 300b, 302b are coupled to a scanning arm (not shown) which controls the speed of and path taken by the transducer 300a, 302a, 300b, 302b during its scan. The scanning arm controls movement of the transducers 300a, 300b in the x direction (as depicted in <FIG>), and transducers 302a, 302b in the y direction. This enables scanning of the full contour of the immobilized breast in as little as a single scan (depending on breast size and position, transducer size, etc.). The two transducers 300a, 302a, 300b, 302b are positioned so as to not interfere with each other's scan. Indeed, by using two transducers located on opposite sides of the breast (in certain orientations) a 3D reconstruction of the breast may be generated, with features detected in the opposing scans being identified as matching pairs. The opposing scans may then be combined, using the matching pairs of features as points of alignment between the two scans. It should be noted that the present technology envisions other transducer arrangements, for example different numbers and configurations of transducers. In addition, although a simple vertical and horizontal scan path is shown, other scan paths, including a helical scan path or the like, could be substituted readily herein by one of skill in the art. In such a configuration, it may be advantageous to utilize transducers having smaller dimensions. The transducer scanning arm also controls the speed with which the transducer scans the breast. In various embodiments, the speed may be constant, may vary depending upon breast characteristics (such as size, density, regions of interest, or patient age), or may be manually controlled.

<FIG> is a schematic view of an ultrasound imaging system <NUM> that includes a gantry <NUM> and a compression system <NUM> that includes a paddle support and control structure <NUM> and a pair of compression paddles 408a, 408b. The gantry <NUM> includes a paddle support motor <NUM> for rotating the paddle support and control structure <NUM> at the end of an arm <NUM>. An additional paddle motor <NUM> may be utilized to move at least one of the paddles 408a, 408b towards and away from the other paddle 408a, 408b. Last, at least one motor <NUM> may be disposed in each paddle 408a, 408b and be configured to move a transducer <NUM>. Multiple transducers <NUM> in each paddle 408a, 408b may require multiple motors <NUM>. Each of the various motors <NUM>, <NUM>, <NUM>, as well as the transducers <NUM> may be controlled by one or more controllers <NUM> disposed in the gantry <NUM>. A user may program, control, or otherwise operate the controller <NUM> from an interface <NUM>, such as the user interface(s) described above. A remote interface <NUM> in the form of a standalone computer may be utilized alternatively or additionally. In examples, the standalone computer may also include software required to act as a remote controller, thus obviating the need for the depicted controller <NUM> disposed in the gantry <NUM>. A shutdown or release switch <NUM> may also be included. The release switch may be communicatively coupled to the controller(s) <NUM>, <NUM> such that activation thereof automatically controls the motor <NUM> so as to move the paddles 408a, 408b away from each other so as to release the breast. In another example, the release switch <NUM> may be mechanically coupled to a component of a compression track or mechanism <NUM> that moves the paddles 408a, 408b. In such a configuration, the release switch <NUM> may serve as a mechanical release of the mechanism <NUM>, which can release the breast from compression in the event of a power failure or software error.

<FIG> are front views illustrating the breast ultrasound imaging system <NUM> with the compression assembly oriented for breast scans at different aspects. <FIG> are perspective views of the breast ultrasound imaging system <NUM>. <FIG> and <FIG> depict the system <NUM> with the compression paddles <NUM> in a first position, where the contact surfaces <NUM> thereof are disposed so as to face each other. An axis A that extends substantially orthogonally to the contact surfaces <NUM> is also depicted. In <FIG> and <FIG>, the axis A is disposed substantially orthogonal to the horizontal. In this configuration, the paddles <NUM> are disposed in a first orientation consistent with a CC scan, where the lower of the two compression paddles <NUM> is utilized to support the breast. Either or both of the compression paddles <NUM> may be moved towards the other, so as to compress the breast therebetween for ultrasound imaging. <FIG> and <FIG> depict the system <NUM> with the compression paddles <NUM> again facing each other in the first position. The axis A extends substantially orthogonally to the contact surfaces <NUM> and is depicted disposed at an angle to both the horizontal and the vertical. As such, the paddles <NUM> are in a second orientation consistent with an MLO scan. <FIG> and <FIG> depict the system <NUM> with the compression paddles <NUM> again facing each other in the first position. The axis A extends substantially orthogonally to the contact surfaces <NUM> and is depicted disposed at an angle substantially parallel to the horizontal. As such, the paddles <NUM> are in a third orientation consistent with a lateral scan. <FIG> and <FIG> depict the system <NUM> with the compression paddles <NUM> in a second position such that the contact surfaces <NUM> are substantially coplanar with each other. In this position, an axis orthogonal to each contact surface <NUM> extends substantially parallel to each other. These axes would also be parallel to the horizontal. As such, the paddles <NUM> are in a position consistent with a frontal scan.

<FIG> depict a breast <NUM> and identifies a plurality of areas <NUM> scanned during the various scans with the ultrasound imaging system described herein. The ultrasound imaging systems described herein may be used to perform one or more scans of a breast. As noted above, the size of the breast, size of the compression paddles, depth of penetration of the ultrasound signals, and other factors, may dictate the number of scans required to completely image the breast. As with other ultrasound systems, the depth of penetration of the ultrasound waves may be adjusted as required or desired for a particular application. Similarly, beam forming may be used to direct the ultrasound waves in various directions relative to the transducer, so as to increase the imaging area within the breast tissue. With these and other considerations in mind, the areas depicted within <FIG> show the areas along which scanning transducers may image the breast in a single pass, specifically areas of the breast in contact with the patient contact surfaces of the compression paddles during compression. The depth of penetration of the sound waves are not depicted and for the purposes of illustration, it is assumed that the sound wave penetration is in a direction orthogonal to the patient contact surfaces. In other examples, ultrasound devices that utilize phased arrays may be employed. With such phased array devices, the ultrasound waves may be steered within the breast tissue, which would enable the systems described herein to image portions of the breast not directly in contact with the compression surfaces.

As such, <FIG> depicts the scan areas 602a when the breast <NUM> is in a CC scan configuration within the ultrasound imaging system described herein. <FIG> depicts the scan areas 602b when the breast <NUM> is in an MLO scan configuration. <FIG> depicts the scan areas 602c when the breast <NUM> is in a frontal scan configuration. <FIG> depicts the scan area 602d when the breast <NUM> is in a lateral scan configuration. As noted above, depending on the depth of sound wave penetration, beam spread, breast size, angle of transducer relative to the breast, and other factors, any one of these scans may provide sufficient imaging of the breast. In other examples, however, it may be desirable to perform multiple scans in various scan configurations to completely image the breast. <FIG> depicts the result of such a scan, where a scan areas for CC 602a, frontal 602c, and lateral 602d are all performed on a single breast <NUM>. The overlap of scan areas between the various positions enable the volume of the entire breast <NUM> to be scanned quickly.

The ultrasound imaging system described herein may be used generally as follows. An acoustic couplant may be applied to a breast of a patient to be imaged. Additionally, acoustic couplant is also applied to an interior surface of the compression material (if a solid rigid material is utilized). In examples, the couplant may be dispensed from a nozzle or other feature internal to the compression paddle. A medical professional selects a desired scan configuration at the user interface, causing the compression assembly to pivot into a desired position and orientation. For MLO/CC or lateral scans, the patient's breast is positioned and the medical professional controls the user interface to cause the patient contact surfaces of the compression paddles to move towards each other to immobilize the breast. For frontal scans, the patient is positioned by leaning inwards towards the paddles until the professional determines that the desired contact is achieved. The professional then initiates a scan sequence. As mentioned above, in some embodiments the professional may have the ability to select a scan path and a scan speed. Following the scan, the image is displayed (either on screen <NUM> or at an attached image workstation, coupled to the gantry via a wired or wireless interface as is known in the art), and the technologist can determine whether additional views are required.

<FIG> depicts a method <NUM> of imaging a breast with an ultrasound imaging system having a first compression paddle and a second compression paddle. The method <NUM> includes positioning the first compression paddle and the second compression paddle in a first position, operation <NUM>. In the first position, a compression surface or patient contact surface of each of the first compression paddle and the second compression paddle are disposed facing each other. Further, in the first position, the first compression paddle and the second compression paddle may be oriented in at least one of a first orientation, a second orientation, or a third orientation. These orientations may correspond to the CC, MLO, or lateral scan orientations described above. The method continues with operation <NUM>, which includes compressing the at least one breast in this first position. Typically, in the first position, only a single breast is compressed and scanned, although larger paddles may accommodate two breasts in certain orientations (e.g., the CC orientation). This compressing is between the first compression paddle and the second compression paddle by placing a first surface of the breast in contact with the first compression paddle and a second surface of the breast in contact with the second compression paddle. Once compressed, operation <NUM> is performed. In operation <NUM>, an ultrasound imaging procedure of the at least one breast is performed while the at least one breast is compressed in the first position. In general, this imaging procedure includes scanning opposite surfaces of a breast (each surface being in contact with a patient contact surface) substantially simultaneously with two transducers. In other examples, only a single transducer is used adjacent a single breast surface. One or more passes of the transducer(s) may be performed, depending on the side of the breast and the size of the transducer. In optional operation <NUM>, the first compression paddle and the second compression paddle are positioned in a second position. In this second positon, the compression surface of each of the first compression paddle and the second compression paddle are disposed substantially coplanar to each other. Once positioned, at least one of the first compression paddle and the second compression paddle is contacted with a third surface of the breast, optional operation <NUM>. Optional operation <NUM> includes performing an ultrasound imaging procedure of the third surface in the second position while the at least one breast is contacting at least one of the first compression paddle and the second compression paddle. If scanning is performed with two compression paddle surfaces, both breasts may be scanned substantially simultaneously. More specifically, a first breast may be in contact with the first compression paddle, while a second breast may be in contact with the second compression paddle. Unlike operation <NUM>, where two transducers may be utilized substantially simultaneously on the same breast, operation <NUM> generally requires the use of only a single transducer in each compression paddle (thus, one transducer per breast). Multiple scans by one or two transducers may be performed, however, typically only a single transducer in the associated compression paddle need be utilized. Further scans may be performed, with scan areas generally overlapping until the entire breast has been imaged.

This disclosure described some examples of the present technology with reference to the accompanying drawings, in which only some of the possible examples were shown. Other aspects can, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein. Rather, these examples were provided so that this disclosure was thorough and complete and fully conveyed the scope of the possible examples to those skilled in the art.

Claim 1:
An ultrasound breast imaging system (<NUM>) comprising:
a gantry (<NUM>); and
a compression assembly (<NUM>) coupled to the gantry, the compression assembly comprising:
a pair of compression paddles (105a, 105b) mounted on a positioning track, each compression paddle housing a transducer and having a patient contact surface comprising a compression material; and
a motor for moving at least one of the compression paddles along the positioning track to immobilize a breast for ultrasound imaging;
wherein the compression paddles are configured to be oriented in a first position where the patient contact surfaces of the compression paddles are facing each other and to be oriented in a second position where the patient contact surfaces are coplanar to each other.