Gary J. Whitman

Change in tumor cellularity of breast carcinoma after neoadjuvant chemotherapy as a variable in the pathologic assessment of response

Complete pathologic response of breast carcinoma to neoadjuvant chemotherapy is a well defined outcome that correlates with prolonged survival. Categorization of incomplete response depends on accurate measurement of residual tumor size but is complicated by the variable histopathologic changes that occur within the tumor bed. In the current study, the authors investigated the contribution of assessing tumor cellularity in the pathologic evaluation of response to chemotherapy.

The Many Faces of Fat Necrosis in the Breast

OBJECTIVE This article describes the manifestations of fat necrosis on mammography, sonography, and MRI and correlates the imaging findings with the pathologic findings. CONCLUSION On imaging studies, the appearance of fat necrosis ranges from typically benign to worrisome for malignancy. Mammography is more specific than sonography, and emphasis should be placed on mammography in making the diagnosis of fat necrosis. In selected cases, MRI may be helpful in showing findings consistent with fat necrosis.

Atypical Ductal Hyperplasia Diagnosis by Directional Vacuum-Assisted Stereotactic Biopsy of Breast Microcalcifications

In 824 patients who underwent directional vacuum-assisted biopsies (DVABs) of breast microcalcifications, 61 (7.4%) showed atypical ductal hyperplasia (ADH). The 42 who subsequently underwent excision were the subjects of this study. Cases were evaluated for the mammographic characteristics of the lesion, the percentage of lesion removed according to mammography, and histologic findings (including number of large ducts and/or terminal duct-lobular units involved with ADH) in DVAB specimens. Pathologic findings in the surgical specimens in the area of the biopsy site also were recorded. In the DVAB specimens, ADH was confined to an average of 1.5 large ducts or lobular units and was associated with microcalcifications in all of the patients. Surgical specimens showed ADH in 15 cases, no residual lesion in 24 cases, and ductal carcinoma in situ in 3 cases. We found that microcalcifications that contain ADH in less than 3 lobules or ducts and/or that are removed completely by DVAB do not reveal higher-risk lesions on excision; thus, removal is unnecessary. When assessing microcalcifications with ADH, clinicians should consider the percentage of microcalcifications removed by DVAB and the extent of lobular involvement to better assess the need for excision.

BI-RADS-MRI: A Primer

OBJECTIVE Variations in breast MRI techniques and descriptions of morphologic findings led to the development of a breast MRI lexicon. This lexicon, the American College of Radiologys BI-RADS-MRI, includes terminology for describing lesion architecture and enhancement characteristics. We show the use of these descriptors on breast MR images obtained at our institution. CONCLUSION BI-RADS-MRI is a common language with which to report MRI findings of studies from different institutions.

Automatic segmentation of whole breast using atlas approach and deformable image registration.

PURPOSE To compare interobserver variations in delineating the whole breast for treatment planning using two contouring methods. METHODS AND MATERIALS Autosegmented contours were generated by a deformable image registration-based breast segmentation method (DEF-SEG) by mapping the whole breast clinical target volume (CTVwb) from a template case to a new patient case. Eight breast radiation oncologists modified the autosegmented contours as necessary to achieve a clinically appropriate CTVwb and then recontoured the same case from scratch for comparison. The times to complete each approach, as well as the interobserver variations, were analyzed. The template case was also mapped to 10 breast cancer patients with a body mass index of 19.1-35.9 kg/m(2). The three-dimensional surface-to-surface distances and volume overlapping analyses were computed to quantify contour variations. RESULTS The median time to edit the DEF-SEG-generated CTVwb was 12.9 min (range, 3.4-35.9) compared with 18.6 min (range, 8.9-45.2) to contour the CTVwb from scratch (30% faster, p = 0.028). The mean surface-to-surface distance was noticeably reduced from 1.6 mm among the contours generated from scratch to 1.0 mm using the DEF-SEG method (p = 0.047). The deformed contours in 10 patients achieved 94% volume overlap before correction and required editing of 5% (range, 1-10%) of the contoured volume. CONCLUSION Significant interobserver variations suggested a lack of consensus regarding the CTVwb, even among breast cancer specialists. Using the DEF-SEG method produced more consistent results and required less time. The DEF-SEG method can be successfully applied to patients with different body mass indexes.

Dedicated Cone-Beam Breast CT: Feasibility Study with Surgical Mastectomy Specimens

OBJECTIVE The purpose of this study was to investigate the feasibility of diagnostic breast imaging using a flat-panel detector-based cone-beam CT system. CONCLUSION Imaging of 12 mastectomy specimens was performed at 50-80 kVp with a voxel size of 145 or 290 microm. Our study shows that cone-beam breast CT images have exceptional tissue contrast and can potentially reduce examination time with comparable radiation dose.

Visibility of microcalcification in cone beam breast CT: Effects of x-ray tube voltage and radiation dose

Mammography is the only technique currently used for detecting microcalcification (MC) clusters, an early indicator of breast cancer. However, mammographic images superimpose a three-dimensional compressed breast image onto two-dimensional projection views, resulting in overlapped anatomical breast structures that may obscure the detection and visualization of MCs. One possible solution to this problem is the use of cone beam computed tomography (CBCT) with a flat-panel (FP) digital detector. Although feasibility studies of CBCT techniques for breast imaging have yielded promising results, they have not shown how radiation dose and x-ray tube voltage affect the accuracy with which MCs are detected by CBCT experimentally. We therefore conducted a phantom study using a FP-based CBCT system with various mean glandular doses and kVp values. An experimental CBCT scanner was constructed with a data acquisition rate of 7.5 frames/s. 10.5 and 14.5 cm diameter breast phantoms made of gelatin were used to simulate uncompressed breasts consisting of 100% glandular tissue. Eight different MC sizes of calcium carbonate grains, ranging from 180-200 microm to 355-425 microm, were used to simulate MCs. MCs of the same size were arranged to form a 5 x 5 MC cluster and embedded in the breast phantoms. These MC clusters were positioned at 2.8 cm away from the center of the breast phantoms. The phantoms were imaged at 60, 80, and 100 kVp. With a single scan (360 degrees), 300 projection images were acquired with 0.5 x, 1x, and 2x mean glandular dose limit for 10.5 cm phantom and with 1x, 2x, and 4x for 14.5 cm phantom. A Feldkamp algorithm with a pure ramp filter was used for image reconstruction. The normalized noise level was calculated for each x-ray tube voltage and dose level. The image quality of the CBCT images was evaluated by counting the number of visible MCs for each MC cluster for various conditions. The average percentage of the visible MCs was computed and plotted as a function of the MGD, the kVp, and the average MC size. The results showed that the MC visibility increased with the MGD significantly but decreased with the breast size. The results also showed that the x-ray tube voltage affects the detection of MCs under different circumstances. With a 50% threshold, the minimum detectable MC sizes for the 10.5 cm phantom were 348(+/-2), 288(+/-7), 257(+/-2) microm at 3, 6, and 12 mGy, respectively. Those for the 14.5 cm phantom were 355 (+/-1), 307 (+/-7), 275 (+/-5) microm at 6, 12, and 24 mGy, respectively. With a 75% threshold, the minimum detectable MC sizes for the 10.5 cm phantom were 367 (+/-1), 316 (+/-7), 265 (+/-3) microm at 3, 6, and 12 mGy, respectively. Those for the 14.5 cm phantom were 377 (+/-3), 334 (+/-5), 300 (+/-2) microm at 6, 12, and 24 mGy, respectively.

Effectiveness of alternating mammography and magnetic resonance imaging for screening women with deleterious BRCA mutations at high risk of breast cancer.

Magnetic resonance imaging (MRI) has been used to supplement screening mammography and clinical breast examination (CBE) in women who are at high risk of developing breast cancer. In this study, the authors investigated the efficacy of alternating screening mammography and breast MRI every 6 months in women who had a genetically high risk of developing breast cancer.

Placement of radiopaque clips for tumor localization in patients undergoing neoadjuvant chemotherapy and breast conservation therapy

The objective of this study was to determine whether patients with breast cancer who received breast‐conservation therapy after neoadjuvant chemotherapy had improved outcomes if radiopaque clips were placed to mark the primary tumor.

Role of specimen radiography in patients treated with skin-sparing mastectomy for ductal carcinoma in situ of the breast.

Background: Specimen radiography is an important part of breast conservation surgery for ductal carcinoma in situ (DCIS). The objective of this study was to determine whether mastectomy specimen radiography could help in obtaining negative resection margins in patients with DCIS undergoing skin-sparing mastectomy (SSM) with immediate breast reconstruction (IBR).Methods: Of 95 patients treated at our institution with SSM and IBR for DCIS, 35 had specimen radiography. The mastectomy specimen was first examined grossly and then inked, serially sectioned, and sent for radiographic assessment. Tissue slices containing calcifications were identified for pathologic evaluation. Additional tissue was excised if tumor was found near the inked margins or if calcifications were found near the radiographic margins.Results: Of the 35 patients who had specimen radiography, the radiographic margins were free of calcifications in 30 patients (86%); of these patients, the margins on the final histologic examination were free of tumor in 27 and within 1 mm in 3. The other five patients (14%) had calcifications close to the radiographic margin; four underwent an intraoperative re-excision, but the margin for one of those four patients was still positive on final histologic examination. Margins were found to be negative by both mastectomy specimen radiography and histology in 77% of the patients. Of the 95 patients with DCIS, three patients (3%), none of whom had specimen radiography, developed local recurrences. One of these was successfully re-treated, one died as a result of synchronous distant metastases, and one was lost to follow-up. At a median follow-up time of 3.7 years, 93 patients (98%) were alive and free of disease.Conclusions: Intraoperative radiography of mastectomy specimens may be useful for assessing margin status and for identifying the location of microcalcifications within tissue slices.