Patent Description:
X-ray imaging systems have become a valuable tool in medical applications such as for the diagnosis of many diseases. As standard screening for breast cancer mammography <NUM>-dimensional (2D) x-ray images are taken across the entire breast tissue. These known 2D mammograms are limited by tissue superimposition. That is to say, lesions may be masked by the tissue above or underneath, or normal structures may mimic a lesion. In order to minimize limitations of standard 2D-mammography caused by tissue superimposition, digital breast tomosynthesis using digital receptors has been developed.

Current tomosynthesis systems employ at least one x-ray tube, which is moved, e.g., in an arc, above a stationary detector. In digital breast tomosynthesis (DBT) the volume information of an object of interest can be derived from a series of images, known as projection images or projections, which are taken at various angles by means of one or more x-ray sources. Objects of different heights in a breast display differently in the different projections. From the 2D projection images 3D volumes can be generated for review. The generated 3D volume portions offer advantages to overcome the limitations associated with tissue superimposition.

However, if a potential lesion or other abnormality is identified on a 2D or 3D tomosynthesis X-ray image, a follow-up visit is scheduled for an ultrasound exam or MRI of the breast to confirm or check the initial diagnosis based on the X-ray image. Such rescheduling typically involves a delay of days or even weeks between exams. This amount of time can lead to patient anxiety and concern between the examinations. Further, because the exams are conducted at separate visits, and also because upright positioning and compression is typically used for mammographic X-ray exams and supine positioning is used for ultrasound or prone for MRI, it is very difficult to co-register the X-ray image and ultrasound image such that the radiologist or other practitioner can view the same areas imaged using the different modalities. Present techniques for performing ultrasound examinations of the breast have additional drawbacks, such as the time associated with such examinations.

In addition if the patient is found to have dense breasts she may be referred for whole breast ultrasound screening to be performed on the same visit or subsequent visit. The ultrasound imaging can be performed either by hand by an experienced sonographer technologist and a standard ultrasound imaging system or with a specially designed automated breast ultrasound system (ABUS).

To address this issue with regard to the need for tomosynthesis and 3D ultrasound imaging of the breast, combined imaging systems have been developed such as that disclosed in US Patent Application Publication No. <CIT> entitled SYSTEMS AND METHODS FOR X-RAY AND ULTRASOUND IMAGING. In these systems, an imaging system including X-ray and ultrasound modalities can be articulated to position and/or compress an object, such as a portion of a human anatomy (e.g., a breast) to perform an X-ray scan or exam. Using information obtained via the X-ray scan or exam, one or more portions of interest of the object may be identified for further analysis using ultrasound imaging on the same system.

While combined imaging systems of this type facilitate the obtaining and review of combined 2D and 3D images of the tissue, in order to effectively review the images, the images are displayed separately to the radiologist or other practitioner. During review of the images, the radiologist will typically separately view the 2D mammography and 3D ultrasound images for one patient, and search for suspicious areas in both images. Radiologists very often need to verify on mammography images suspicious areas of regions of interest (ROI's) found in ultrasound and vice versa. Because the patient or breast positioning used in acquiring mammograms and 3D ultrasound are often very different, it is not immediately obvious to the radiologist what location in an image of one modality corresponds to an ROI found in another modality. In practice, the manual method practiced by radiologists is quite tedious and prone to error. For example, the radiologist will measure the distance of an ROI from the nipple and estimate the clock face position of the ROI on the mammogram and then find the corresponding ROI on the 3D breast ultrasound images based on that measurement.

In order to address this issue and attempt to speed up the workflow of the review of the combined images, one solution that has been developed is disclosed in US Patent Application Publication No. <CIT> entitled VIEWING AND CORRELATING BETWEEN BREAST ULTRASOUND AND MAMMOGRAM OR BREAST TOMOSYNTHESIS IMAGES. In this solution, mammography images, that is, images taken along the mediolateral-oblique (MLO) and cranial-caudal (CC) planes, and a 3D ultrasound image are each obtained of the tissue being imaged. In response to the selection of an identified ROI on one of the mammogram images or ultrasound images by the user of the system, the system automatically calculates the coordinates of the selected ROI within the other modality image(s) and provides navigation aids on those image(s) to assist the user in determining the location of the ROI on the other of the images.

However, variations in the images obtained in the mammography and ultrasound modalities, along with any variations in the form or state of the tissue being imaged, such as the upright compression of the breast during the mammography imaging versus the supine compressed tissue in ultrasound imaging, creates significant correlation issues between the locations of the selected ROIs within the mammography images and within the ultrasound images. Further the separate review of the image data of each modality greatly slows down the review and workflow. This, in turn, presents significant problems with the proper determination of the exact location of the ROI in either image, particularly with regard to small ROIs and/or when the images are obtained at different times and with separate compressions, thereby increasing the time required to properly analyze the images and increasing the number of false positive screening callbacks and eventually biopsies.

Accordingly, it is desirable to develop a system and method for the creation of a navigation map utilizing 2D image data obtained from a tomosynthesis acquisition for the identification and location of ROIs in a 3D ultrasound volume that improves upon the state of the art.

<CIT> in its abstract states: "A method for generating an image of an object of interest includes acquiring a first three-dimensional dataset of the object at a first position using an X-ray source and a detector, acquiring a second three-dimensional dataset of the object at the first position using an ultrasound probe, and combining the first three-dimensional dataset and the second three-dimensional dataset to generate a three-dimensional image of the object.

There is a need or desire for a system and method for the detection of ROIs in images obtained of a breast or other tissue of a patient significantly improves the speed and accuracy of navigation between multimodality 2D and 3D images.

The drawings illustrate the best mode presently contemplated of carrying out the disclosure. In the drawings:.

Various embodiments will be better understood when read in conjunction with the appended drawings. To the extent that the figures illustrate diagrams of the functional blocks of various embodiments, the functional blocks are not necessarily indicative of the division between hardware circuitry. Thus, for example, one or more of the functional blocks (e.g., processors, controllers or memories) may be implemented in a single piece of hardware (e.g., a general purpose signal processor or random access memory, hard disk, or the like) or multiple pieces of hardware. Similarly, any programs may be stand-alone programs, may be incorporated as subroutines in an operating system, may be functions in an installed software package, and the like. It should be understood that the various embodiments are not limited to the arrangements and instrumentality shown in the drawings.

Furthermore, references to "one embodiment" are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments "comprising" or "having" an element or a plurality of elements having a particular property may include additional such elements not having that property.

Also as used herein, the phrases "image" or "reconstructing an image" are not intended to exclude embodiments in which data representing an image is generated, but a viewable image is not. Therefore, as used herein the term "image" broadly refers to both viewable images and data representing a viewable image. However, many embodiments generate, or are configured to generate, at least one viewable image.

Systems formed in accordance with various embodiments provide an imaging system including a 2D imaging modality (i.e., X-ray imaging) and a 3D imaging modality (e.g., ultrasound (US) or magnetic resonance imaging (MRI)) for performing scans on the object or patient using both modalities to enhance the scan results and diagnosis.

Some embodiments provide an imaging system having a modified compression paddle that includes and/or accepts a cassette containing an ultrasound probe that can be moved to various locations within the field of view of the imaging system. For example, a control module utilizing appropriately configured software may obtain multiple X-ray images and an ultrasound scan to identify potential regions of interest, such as potential lesions, for further investigation. In some embodiments, a cassette containing an ultrasound probe may be positioned between a compression plate and an X-ray detector.

Some exemplary embodiments provide for improved co-registration of X-ray and ultrasound images, for example by acquiring such images at substantially the same time and/or by acquiring such images utilizing a same or similar amount of compression.

A technical effect of at least one embodiment includes reduced time required to acquire and analyze results of combined mammographic exams, including 2D imaging and 3D imaging exams. A technical effect of at least one embodiment includes reducing errors associated with multimodal imaging examinations. A technical effect of at least one embodiment includes improved co-registration of X-ray and ultrasound images, thereby improving and speeding up navigation between 2D and 3D images during review of the images, consequently improving diagnoses and/or reducing time and skill required by a medical professional for analysis of acquired images.

<FIG> provides an example of an imaging system <NUM> for imaging an object in accordance with an exemplary embodiment, such as that disclosed in <CIT>, entitled SYSTEMS AND METHODS FOR X-RAY AND ULTRASOUND IMAGING. In the illustrated embodiment, the system <NUM> and associated method may employ structures or aspects of various embodiments discussed herein. In various embodiments, certain steps may be omitted or added, certain steps may be combined, certain steps may be performed simultaneously, certain steps may be performed concurrently, certain steps may be split into multiple steps, certain steps may be performed in a different order, or certain steps or series of steps may be re-performed in an iterative fashion.

In the system and method, an object <NUM> is positioned between plates of an imaging system. For example, the object may be a portion of human anatomy such as a breast. Because X-ray scans effectively view an object in two dimensions (2D), structures such as breast tissue that exceed a certain density and/or thickness may not be readily amenable to X-ray scans. Compression may be used to render a breast more amenable to X-ray imaging. For example, compression may reduce the thickness of the breast, and stretch tissue to a wider viewing area in two dimensions, allowing for improved identification of structures located during a scan. Further, by presenting a thinner overall structure to an X-ray detecting system, the X-ray dosage required to image the breast may be reduced.

The exemplary illustrated embodiment of <FIG> presents a schematic view of an imaging system <NUM> formed in accordance with various embodiments. The imaging system <NUM> is configured to provide both 2D (i.e., X-ray) and 3D (e.g., ultrasound or MRI or contrast-enhanced DBT, or CT) imaging modalities that may be used to perform scans on an object (e.g. a patient) in the same visit to a scanning location. For example, the imaging system <NUM> may be used to perform an X-ray scan and an ultrasound scan substantially consecutively. Substantially consecutively may be understood to describe, for example, scans that are performed with a relatively short time interval therebetween. In some embodiments, the 2D scan and the 3D scan may be performed substantially consecutively with a time interval of less than about <NUM> seconds therebetween. In some embodiments, the 2D scan and the 3D scan may be performed substantially consecutively with a time interval of less than about <NUM> seconds therebetween. In some embodiments, the 2D scan and the 3D scan may be performed substantially consecutively with a time interval of less than about <NUM> minute therebetween. In some embodiments, the 2D scan and the 3D scan may be performed substantially consecutively with a time interval of less than about <NUM> minutes therebetween. However, it should be appreciated that other time intervals are contemplated as well and that the imaging system <NUM> can be formed with separate devices for performing the 2D scan and 3D scan at different times and/or at different locations.

The imaging system <NUM> may be used to image an object, such as a human breast <NUM>. The imaging system <NUM> may be articulable with respect to the object being imaged. In the illustrated embodiments, the imaging system <NUM> is articulable in a rotational direction <NUM> and thus may be used to view the breast <NUM> from a variety of angles for different scans. For example, a first X-ray scan may be performed at a first angle, and a second X-ray scan may be performed at a second angle to provide a different view of the breast <NUM>. Because the breast <NUM> is a three-dimensional (3D) object and the X-ray scan effectively sees the breast <NUM> in two dimensions, a structure within the breast <NUM> may be obscured, blocked, or otherwise un-identifiable at one angle or view, but may be identifiable when viewed at a different angle or view. Thus, improved identification of structures within the breast <NUM> may be achieved by performing X-ray scans at two or more different angles or views.

In the illustrated embodiment, the system <NUM> is configured to obtain a <NUM>-dimensional X-ray image, such as via 3D digital breast tomosynthesis (DBT). In some embodiments, tomosynthesis imaging information may be acquired utilizing a tube or other structure that may rotate between about <NUM> and <NUM> degrees in one or more directions to provide a volumetric image. In some embodiments, the amount of compression applied between plates or paddles may be reduced (e.g., in connection with the use of 3D DBT). For example, an amount of compression that is sufficient to position the object (e.g., breast) may be used. Thus, in various embodiments, various imaging techniques may be employed. Further, various mountings of an X-ray detection unit proximate to a plate or paddle may be employed (e.g., stationary or rotational).

The imaging system <NUM> includes a 2D imaging or X-ray module <NUM>, a 3D imaging module <NUM>, such as an ultrasound or MRI module, a control module <NUM>, and an interface <NUM>. Generally speaking, in the illustrated embodiment, the X-ray module <NUM> is configured to perform an X-ray scan of the object <NUM> at various angles with respect to the object <NUM>, such as in a DBT scan, and to provide X-ray imaging information to the control module <NUM>. The control module <NUM> is also configured to control the 3D imaging module <NUM> to perform a scan of the object <NUM> to facilitate improved analysis and/or diagnosis of the object <NUM> and/or one or more regions of interest within the object <NUM>. For example, the 3D imaging scan may be used to confirm whether or not one or more regions of interest were false positives in the X-ray scan (e.g., not a cause for concern) or whether not one or more regions of interest appear to be of medical interest (e.g., potentially cancerous).

In the illustrated exemplary embodiment, the X-ray module <NUM> includes an X-ray source <NUM>, a paddle assembly <NUM> (including an upper plate <NUM> and a lower plate <NUM>), a detector <NUM>, and an actuator <NUM>. The X-ray source <NUM> is configured to emit X-rays that pass through an object (e.g., object <NUM>) and are received by the detector <NUM>. The detector is position on, mounted to, and/or forms a part of the lower plate <NUM>. Information acquired by the detector <NUM> is communicated to the control module <NUM>. The X-ray source <NUM> in the illustrated embodiment has a field of view <NUM> that projects on to the detector <NUM>.

The paddle assembly <NUM> includes an upper plate <NUM> and lower plate <NUM>. The upper plate <NUM> and lower plate <NUM> are an example of first and second opposed plates that are articulable with respect to each other. In the illustrated embodiment, the lower plate <NUM> is fixed and the upper plate <NUM> is articulable along a compression direction <NUM> by the actuator <NUM>. The upper plate <NUM> may be articulated downward (in the sense of <FIG>) toward the lower plate <NUM> to compress the breast and upward away from the lower plate <NUM> to reduce an amount of compression on the breast <NUM> and/or to release the breast <NUM> from between the upper plate <NUM> and the lower plate <NUM>. In alternate embodiments, other arrangements may be employed to provide articulation of two plates with respect to each other. In the illustrated embodiment, the upper plate <NUM> and the lower plate <NUM> are depicted as substantially flat. In alternate embodiments, plates may be employed having curved or otherwise contoured profiles. Other types or orientations of articulation may be employed as well. As one example, in some embodiments, the first and second plates may be coupled by a pivot and thus be rotatable with respect to each other. The actuator <NUM> may be controlled by the control module <NUM> and/or an operator. In various embodiments, a variety of devices or mechanisms (e.g., one or more motors, pneumatic or hydraulic cylinders, electronic linear actuators, hand-operated mechanisms, or the like) may be employed to articulate the plates. In some embodiments, one or more paddles or plates may translate and/or rotate on a gantry which may be mounted to a floor and/or a wall.

In various embodiments, the upper plate <NUM> and/or the lower plate <NUM> may be configured to reduce any potential attenuation (e.g., radiolucent) of an X-ray as the X-ray passes through the plates. Further, in various embodiments, the upper plate <NUM> and/or the lower plate <NUM> may be substantially transparent to provide an operator with visual confirmation of the positioning of the object <NUM>.

The detector <NUM> is configured to receive X-ray beams that have been emitted from the X-ray source <NUM> and have passed through the breast <NUM>, and to provide X-ray imaging information to the control module <NUM>. The control module <NUM> is configured to receive the X-ray image information from the detector <NUM> and/or to reconstruct 2D and/or 3D X-ray image(s) using the X-ray information from the detector <NUM>. In some embodiments, the detector <NUM> may include more than one detector, such as an array of detectors. In the illustrated embodiment the detector <NUM> is mounted to the lower plate <NUM>. In other embodiments, the detector <NUM> may be a part of, embedded within or otherwise associated with a plate or paddle.

In the illustrated exemplary embodiment, the 3D imaging module is constructed as an ultrasound module <NUM>, such as an automated breast ultrasound system (ABUS), that is configured to acquire ultrasound information of the object to be imaged. In the illustrated embodiment, the ultrasound module <NUM> includes an ultrasound transducer <NUM>, a dispensing module <NUM>, an actuator <NUM>, and a reservoir <NUM>. The ultrasound transducer <NUM> is configured to send an ultrasonic beam or beams through a portion of an object and to receive returned ultrasonic beams. Information acquired by the ultrasound transducer is then used to reconstruct a 3D image corresponding to the object, or portion thereof, that is scanned. For example, information from the ultrasound transducer <NUM> may be communicated to the control module <NUM> and/or the interface <NUM> for image reconstruction and/or analysis.

In some embodiments, the ultrasound transducer <NUM> includes an array of aligned transducers that are configured to be articulated in a substantially lateral direction, allowing for a region of interest of the breast to be ultrasonically scanned in a single pass. The ultrasound transducer <NUM> may be part of a cassette type assembly that is movable within and/or along a plate or paddle (as one example, an upper surface <NUM> of the upper plate <NUM>, or, as another example, a lower surface of the lower plate <NUM>). A liquid or gel may be employed to create or improve an acoustic contact between the ultrasound probe and a casing or surface of the plate or paddle.

The actuator <NUM> is configured to articulate the ultrasound transducer <NUM> to a desired position for scanning the object <NUM> or a region of interest of the object (e.g., a region of interest of the breast <NUM>). The actuator <NUM> may position the ultrasound transducer based on control signals or messages received from the control module <NUM>. In the illustrated embodiment, the actuator <NUM> is configured to articulate the ultrasound transducer <NUM> in an ultrasound direction <NUM> substantially laterally along an upper surface <NUM> of the upper plate <NUM>. In various embodiments, the actuator <NUM> may include one or more of a variety of devices or mechanisms (e.g., one or more motors, pneumatic or hydraulic cylinders, electronic linear actuators, or the like).

The ultrasound transducer <NUM> may be positioned outside of the field of view <NUM> of the X-ray source <NUM> while an X-ray scan is being performed. After the X-ray scan is complete and a region of interest has been selected, the actuator <NUM> may position the ultrasound transducer <NUM> to scan the object <NUM>. Thus, the ultrasound transducer <NUM> may be articulable between a position outside of the field of view <NUM> and one or more positions inside of the field of view <NUM>. In some embodiments, the ultrasound transducer may be mounted to one or more paddles and plates, and articulable across one or more surfaces, for example, via a track or guide. In some embodiments, the ultrasound transducer may be movable in a plurality of lateral directions (e.g., the actuator <NUM> may include a plurality of linear actuators or otherwise be configured to articulate the ultrasound transducer <NUM> in a plurality of directions). For example, the actuator <NUM> may be configured to move the ultrasound transducer in a raster pattern sized and configured to cover a region of interest. Further still, in some embodiments, the ultrasound transducer <NUM> may be removably mounted to a paddle or plate, and physically removed from the paddle or plate during X-ray scanning.

The dispensing module <NUM> in the illustrated exemplary embodiment illustrated in <FIG> includes a reservoir <NUM> (e.g., a sealed reservoir). The dispensing module <NUM> is configured to dispense a liquid or gel from the reservoir <NUM> to acoustically couple an ultrasound transducer with a surface of a plate or paddle. For example, in the illustrated embodiment, the dispensing module <NUM> is configured to dispense a liquid to the upper surface <NUM> of the upper plate <NUM> over which the ultrasound transducer <NUM> traverses during ultrasound scanning of one or more regions of interest. The liquid or gel is configured to improve the acoustic contact between a transducer and a plate or paddle, so that soundwaves may be transmitted between the transducer and the object via the plate or paddle (e.g., with the plate or paddle pressed against the object to be scanned as the object is compressed). In some embodiments, a portion of the dispensing module and/or a surface of a plate or paddle may be configured to improve retention of liquid or gel on the surface when the imaging system <NUM> is articulated in the rotational direction <NUM> at an angle in which gravity may urge the liquid or gel off of the surface.

The control module <NUM> includes a motion control module <NUM> that is configured to control movement and/or position of the X-ray source <NUM>, the plates <NUM>, <NUM> and/or the ultrasound transducer <NUM> to scan the object <NUM> and/or a region of interest within the object <NUM>.

The analysis module <NUM> of control module <NUM> is configured to receive information from the detector <NUM> of the X-ray module <NUM> and the ultrasound transducer <NUM>, and to reconstruct 2D and 3D images using the information using each image data set. The analysis module <NUM> may also be configured, for example, to adjust or account for compression when reconstructing an image using ultrasound information from the ultrasound transducer <NUM>. In some embodiments, reconstructed X-ray and/or ultrasound images may be provided by the control module to a practitioner or other system via the display <NUM> on the interface <NUM>.

In the illustrated embodiments, the analysis module <NUM> may include or have access to software, such as a computer-aided detection (CAD) system, that facilitates the identification of lesions or other regions of interest in a 2D image(s) and/or the 3D images provided by the X-ray and ultrasound scans. In some embodiments, the control module <NUM> may receive an input from a practitioner, such as through the interface <NUM>, identifying one or more regions of interest. For example, in some embodiments, the analysis module <NUM> is configured to autonomously identify one or more potential lesions or other aspects of interest based on X-ray information received from the detector <NUM>. In some embodiments, the region or regions of interest may be identified by a practitioner based on an analysis of one or more of the 2D and/or 3D images on the display <NUM>.

The interface <NUM> is configured to allow information and/or commands to be communicated between the control module <NUM> and a practitioner. In the illustrated embodiments, the interface <NUM> includes a display module <NUM> and an input module <NUM>. The display module <NUM> may include, for example, a printer, a screen, a touchscreen, a speaker, or the like. The input module <NUM> may include a touchscreen (e.g., a touchscreen shared between the display module <NUM> and the input module <NUM>), a mouse, stylus, keyboard, keypad, or the like. One or more reconstructed images may be displayed via the display module <NUM>.

The input module <NUM> is configured to receive input from a practitioner to perform one or more imaging activities. For example, the input module <NUM> may receive input from a practitioner establishing one or more settings or parameters for imaging. Further, the input module <NUM> may receive input from a practitioner establishing a region of interest within the images for further evaluation or display.

In one exemplary embodiment of the system <NUM>, after the 2D and 3D imaging scans of the object <NUM> have been performed, the analysis module <NUM> will generate synthetic 2D image(s) and 3D images/volumes of the object <NUM> from the X-ray/DBT/full filed digital mammography (FFDM)/contrast-enhanced spectral mammography (CESM) scans performed by the X-ray source <NUM> and the data provided by the X-ray detector <NUM> to the analysis module <NUM>. An exemplary embodiment of a DBT/DBT-FFDM/DBT-CESM imaging process performed on the image data from the X-ray detector <NUM> is disclosed in <CIT>, entitled SYSTEM AND METHOD TO GENERATE A SELECTED VISUALIZATION OF A RADIOLOGICAL IMAGE OF AN IMAGED SUBJECT, and in US Patent Application Publication No. <CIT>, entitled METHOD AND SYSTEM FOR OBTAINING LOW DOSE TOMOSYNTHESIS AND MATERIAL DECOMPOSITION IMAGES. In addition, the analysis module <NUM> can employ the images from the ultrasound transducer <NUM> to generate a 3D volume of the object <NUM>.

In another exemplary embodiment, the system and method for acquiring and processing 2D and 3D imaging data for improving navigation through the imaging data may include the acquisition of 2D and 3D imaging data from a separate and independent DBT X-ray imaging system and a separate and independent ABUS ultrasound imaging system.

Looking now at <FIG>, in generating both the synthetic 2D image(s) and 3D volume(s) containing a number of planar views of the imaged tissue from the DBT acquisition or scan, the analysis module <NUM> maps location of any point on the synthetic 2D image <NUM> to the location of a voxel within the generated 3D DBT volume <NUM>. As such, for any synthetic 2D image <NUM> presented to the user on the display <NUM>, the analysis module <NUM> creates an associated but hidden navigation map <NUM> for the image <NUM> containing the height or z-axis information for any (x,y) pixel <NUM> on the synthetic 2D image <NUM>. The z-axis information associated with each (x,y) pixel <NUM> is correlated by the analysis module <NUM> to the corresponding z-axis plane <NUM> of the 3D DBT volume <NUM>. This process is described in <CIT> along with <CIT>.

Further, with the information on the z-axis plane <NUM> in the 3D DBT volume <NUM>, the analysis module <NUM> can correlate the (x,y,z) location in the DBT z-axis plane <NUM> to a corresponding section or plane <NUM> of the automated breast ultrasound system (ABUS) or MRI 3D or CEDBT or CT volume <NUM>. The DBT plane <NUM> to ABUS/MRI/CEDBT/CT plane or section <NUM> correspondence can require a quite straightforward transformation when the image modalities were obtained at the same time and/or with the object <NUM> in the same position and/or compression in the system <NUM>, though some resolution scaling may need to be performed.

Alternatively, the DBT plane <NUM> to ABUS/MRI/CEDBT/CT section <NUM> correspondence can require their positions in the respective 3D volumes <NUM>,<NUM> to be correlated using a suitable transformation to accommodate for the changes in position of the object/tissue <NUM> (e.g., compression of the object/tissue <NUM>) between imaging modalities. The registration process could rely on matching findings detected in the DBT volume <NUM> and ABUS/MRI/CEDBT/CT volume <NUM>, such as for example, by utilizing finite element model in a known manner, and/or by employing a linear affine transformation-MLO translation utilizing the compression angle from the dicom header from the ABUS images. For registration or translation of the DBT volume <NUM> to an MRI/CT volume <NUM>, the lack of compression performed in the MRI/CT scan enables finite element modeling to be effectively utilized to transform the MRI/CT scan volume <NUM> to register it to the DBT volume <NUM>.

With this mapping of the pixels <NUM> in the synthetic 2D DBT image <NUM> to the DBT volume <NUM>, and the corresponding correlation and/or registration of the DBT volume <NUM> to the 3D imaging (ABUS or MRI or CEDBT or CT) volume <NUM>, in the review of the synthetic 2D image <NUM> on the display <NUM> by the radiologist, the selection of an (x,y) pixel <NUM> corresponding to a potential region of interest within the synthetic 2D image <NUM> being reviewed allows the analysis module <NUM> to access and read the navigation map <NUM> to determine the z-axis information for that pixel <NUM>. In a particular embodiment, the analysis module <NUM> can then automatically utilize the z-axis information for the pixel <NUM> selected to locate the corresponding DBT plane <NUM> and the ABUS/MRI/CEDBT/CT section <NUM> registered with that DBT plane <NUM>, which, e.g., can be an axial or coronal plane/view of the ABUS volume <NUM> created in a process disclosed in US Patent Application Publication No. <CIT>, entitled THICK SLICE PROCESSING AND DISPLAY OF INFORMATION FROM A VOLUMETRIC ULTRASOUND SCAN OF A CHESTWARDLY COMPRESSED BREAST. The analysis module <NUM> can then present the ABUS/MRI section <NUM>, and optionally the DBT plane <NUM>, on the display <NUM> in conjunction with the synthetic 2D image <NUM> with a cross or cursor <NUM> on each image <NUM>,<NUM>,<NUM> indicating the corresponding precise position of the pixel <NUM> selected in the image <NUM>. As a result the speed of navigation between the DBT and ABUS/MRI/CEDBT/CT image data sets/volumes is greatly enhanced, consequently speeding up the overall workflow when reading DBT and ABUS/MRI/CEDBT/CT volumes <NUM>, <NUM> obtained in a combined image acquisition.

Referring now to <FIG>, in another exemplary embodiment of the disclosure the analysis module <NUM> can be utilized to identify volumes of interest (VOIs) or regions of interest (ROIs) <NUM> in the ABUS/MRI/CEDBT/CT volume <NUM>. This identification of the VOIs/ROIs <NUM> can be performed manually by the user through the interface input <NUM> during a review of the ABUS/MRI/CEDBT/CT volume <NUM>, or can be performed automatically using a computer aided detection (CAD) system <NUM> associated with the analysis module <NUM>. As certain ROIs <NUM> are more readily detectable/visible in the ABUS volume <NUM> than in the DBT volume <NUM>, the identification of the ROIs <NUM> in the ABUS/MRI/CEDBT/CT volume <NUM> can be used to mitigate both the omission of the ROIs <NUM> in the DBT volume <NUM> and the rate of false positives where the ROI <NUM> is present in the ABUS/MRI/CEDBT/CT volume <NUM> but not in the DBT volume <NUM>.

Once identified in the ABUS/MRI/CEDBT/CT volume <NUM>, the correlation of the ABUS/MRI/CEDBT/CT volume <NUM> to the DBT volume <NUM> allows for the locations of the ROIs <NUM> to be translated into the DBT volume <NUM> where the ROIs <NUM> can be represented in the synthetic 2D image <NUM> generated by the analysis module <NUM> using a reprojection operation. Additionally, in other exemplary embodiments the representation of the VOI/ROI <NUM> in the synthetic 2D image <NUM> can include a boundary for the VOI/ROI <NUM> overlaid within the synthetic 2D image <NUM>. Optionally, the ROI/VOI <NUM> as obtained from the DBT volume <NUM> can also be blended onto the existing synthetic 2D image <NUM>. Alternatively, the synthetic image DBT images <NUM> are enhanced/enriched during the generation process for the synthetic 2D image <NUM>, such as that disclosed in <CIT>, entitled METHOD FOR PROCESSING TOMOSYNTHESIS ACQUISITIONS IN ORDER TO OBTAIN A REPRESENTATION OF THE CONTENTS OF AN ORGAN, and/or in US Patent Application Publication No. <CIT>, entitled METHOD AND SYSTEM FOR TOMOSYNTHESIS PROJECTION IMAGES ENHANCEMENT, to take the ROIs <NUM> position into account and avoid non-relevant overlapping tissues within the presented image <NUM>.

In addition, the navigation map <NUM> can be modified accordingly to direct the user upon the selection of pixels <NUM> within the modified area <NUM> of the map <NUM> to the corresponding ABUS/MRI/CEDBT/CT section <NUM> including the VOI/ROI <NUM>, thereby providing more efficient synthetic 2D to DBT/ABUS/MRI/CEDBT/CT navigation. In particular, with reference to the exemplary embodiment illustrated in <FIG>, with the ability to represent the VOIs/ROIs <NUM> overlaid in the synthetic 2D image <NUM> that are manually identified or identified using the CAD system <NUM> in the ABUS/MRI/CEDBT/CT volume <NUM>. The selection of a VOI/ROI <NUM> represented on the synthetic 2D image <NUM> instructs the analysis module <NUM> to present the corresponding DBT plane <NUM> and/or ABUS/MRI/CEDBT/CT plane/section <NUM> on the display <NUM> for a side-by-side comparison of the planes of interest carrying the multi-modality information on the selected VOI/ROI <NUM>.

Looking now at <FIG>, in addition to the ROIs <NUM> that are identified in the ABUS/MRI volume <NUM> and correlated into the synthetic 2D image <NUM> and DBT volume <NUM>, the position of the nipple <NUM> is represented in the ABUS/MRI volume <NUM> with high precision, but is not readily apparent in the synthetic 2D image <NUM> or 3D volume <NUM>. Thus, with the correlation or registration of the ABUS/MRI volume <NUM> to the DBT volume <NUM> and synthetic 2D image <NUM>, the position of the nipple <NUM> can be represented/reprojected onto the synthetic 2D image <NUM> and the 3D volume <NUM>. When a pixel <NUM> representing an ROI <NUM> on the synthetic 2D image <NUM> is selected on the display <NUM> by the user, the nipple position <NUM> can be presented on the synthetic 2D image(s) <NUM>, the DBT plane <NUM> (if presented) and optionally on the ABUS/MRI section <NUM> corresponding to the information contained within the navigation map <NUM> associated with the pixel <NUM>. In addition, the images <NUM>, <NUM> and <NUM> can include the distance of the VOI/ROI <NUM> to the nipple <NUM>, a clockwise position of the VOI/ROI <NUM> with respect to the nipple <NUM> and the distance of the VOI/ROI <NUM> from the skin line <NUM>. This information is reported for further treatment wherein VOI/ROI <NUM> localization in the anatomy is required as biopsy.

Claim 1:
A method of navigating between images of an object obtained in different imaging modalities of the object, the method comprising:
obtaining a number of x-ray images of the object at varying angles relative to the object in a digital breast tomosynthesis (DBT) acquisition;
obtaining a three-dimensional (3D) volumetric image (<NUM>) of the object in a 3D imaging acquisition;
forming a DBT volume (<NUM>) of the object from the x-ray images;
forming a synthetic two-dimensional (2D) image (<NUM>) of the object from the x-ray images and/or the DBT volume;
forming a navigation map (<NUM>) correlating locations of pixels (<NUM>) of the synthetic 2D image within associated planes in the DBT volume;
registering the 3D volumetric image from the 3D imaging acquisition with the DBT volume from the DBT acquisition;
displaying the synthetic 2D image; and
displaying a section of the 3D volumetric image corresponding to a location of a pixel in the synthetic 2D image in response to a selection of the pixel in the displayed synthetic 2D image.