Dual-modality breast tomosynthesis

Abstract

Purpose: To evaluate the clinical performance of a hybrid scanner that uses dual-modality tomosynthesis (DMT) and technetium 99m sestamibi to provide coregistered anatomic and functional breast images in three dimensions.

Materials and methods: A prospective pilot evaluation of the scanner was performed in women scheduled to undergo breast biopsy after institutional review board approval and informed consent were obtained. All subject data were handled in compliance with the rules and regulations concerning the privacy and security of protected health information under HIPAA. The study included 17 women (mean age, 53 years; age range, 44-67 years) and 21 biopsy-sampled lesions. Results of DMT scanning were compared with histopathologic results for the 21 lesions.

Results: Of the 21 lesions, seven were malignant, and 14 were benign. Among the 13 subjects with one lesion each, three had positive biopsy results, and 10 had negative biopsy results. Among the four subjects with two lesions, the biopsy results were as follows: bilateral in one, both negative; bilateral in one, both positive; unilateral in two, one positive and one negative. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of DMT scanning were 86%, 100%, 100%, 93%, and 95%, respectively.

Conclusion: Pilot clinical evaluation of the DMT scanner suggests that it is a feasible and accurate method with which to detect and diagnose breast cancer. Systems such as the DMT scanner that are designed specifically for three-dimensional multimodality breast imaging could make possible some of the advances in tumor detection, localization, and characterization of breast cancer that are now being observed with whole-body three-dimensional hybrid systems, such as positron emission tomography/computed tomography (CT) or single photon emission computed tomography/CT.

Figure 1:

DMT breast scanner. A dedicated high-spatial-resolution gamma camera is mounted on a translation stage attached to the gantry arm. The configuration during gamma imaging is shown here. The camera is positioned anteriorly out of the x-ray beam during x-ray imaging.

Figure 2a:

(a) X-ray tomosynthesis section from the DMT scan in a 52-year-old woman who was scheduled to undergo breast biopsy because of suspicious-looking microcalcifications visible on her screening mammogram. (The microcalcifications lay at a different depth in the breast than the section shown.) The section was 1 mm thick. Mediolateral oblique breast compression was used. The overall compressed breast thickness was 6.6 cm. (b) Gamma ray tomosynthesis section located at the same depth within the breast as the section shown in a. The region of focal uptake corresponds to the location of high-grade ductal carcinoma in situ comedonecrosis. This cancer was not detected at clinical examination. Note that its location coincides with that of the radiographically dense parenchyma in a. (c) Merged sections from a and b show the location of ductal carcinoma in situ (arrow). The circle indicates the region in which biopsy was performed on the basis of the clinical examination results. Results of that biopsy were negative.

Figure 2b:

(a) X-ray tomosynthesis section from the DMT scan in a 52-year-old woman who was scheduled to undergo breast biopsy because of suspicious-looking microcalcifications visible on her screening mammogram. (The microcalcifications lay at a different depth in the breast than the section shown.) The section was 1 mm thick. Mediolateral oblique breast compression was used. The overall compressed breast thickness was 6.6 cm. (b) Gamma ray tomosynthesis section located at the same depth within the breast as the section shown in a. The region of focal uptake corresponds to the location of high-grade ductal carcinoma in situ comedonecrosis. This cancer was not detected at clinical examination. Note that its location coincides with that of the radiographically dense parenchyma in a. (c) Merged sections from a and b show the location of ductal carcinoma in situ (arrow). The circle indicates the region in which biopsy was performed on the basis of the clinical examination results. Results of that biopsy were negative.

Figure 2c:

(a) X-ray tomosynthesis section from the DMT scan in a 52-year-old woman who was scheduled to undergo breast biopsy because of suspicious-looking microcalcifications visible on her screening mammogram. (The microcalcifications lay at a different depth in the breast than the section shown.) The section was 1 mm thick. Mediolateral oblique breast compression was used. The overall compressed breast thickness was 6.6 cm. (b) Gamma ray tomosynthesis section located at the same depth within the breast as the section shown in a. The region of focal uptake corresponds to the location of high-grade ductal carcinoma in situ comedonecrosis. This cancer was not detected at clinical examination. Note that its location coincides with that of the radiographically dense parenchyma in a. (c) Merged sections from a and b show the location of ductal carcinoma in situ (arrow). The circle indicates the region in which biopsy was performed on the basis of the clinical examination results. Results of that biopsy were negative.