Discriminative Factors of Malignancy of Ipsilateral Nonmass Enhancement in Women With Newly Diagnosed Breast Cancer on Initial Staging Breast MRI.

BACKGROUND: Nonmass enhancement (NME) on breast MRI impacts surgical planning. PURPOSE: To evaluate positive predictive values (PPVs) and identify malignancy discriminators of NME ipsilateral to breast cancer on initial staging MRI. STUDY TYPE: Retrospective. SUBJECTS: Eighty-six women (median age, 48 years; range, 26-75 years) with 101 NME lesions (BI-RADS 4 and 5) ipsilateral to known cancers and confirmed histopathology. FIELD STRENGTH/SEQUENCE: 1.5 T and 3.0 T dynamic contrast-enhanced fat-suppressed T1-weighted fast spoiled gradient-echo. ASSESSMENT: Three radiologists blinded to pathology independently reviewed MRI features (distribution, internal enhancement pattern, and enhancement kinetics) of NME, locations relative to index cancers (contiguous, non-contiguous, and different quadrants), associated mammographic calcifications, lymphovascular invasion (LVI), axillary node metastasis, and radiology-pathology correlations. Clinical factors, NME features, and cancer characteristics were analyzed for associations with NME malignancy. STATISTICAL TESTS: Fisher's exact, Chi-square, Wilcoxon rank sum tests, and mixed-effect multivariable logistic regression were used. Significance threshold was set at P < 0.05. RESULTS: Overall NME malignancy rate was 48.5% (49/101). Contiguous NME had a significantly higher malignancy rate (86.7%) than non-contiguous NME (25.0%) and NME in different quadrants (10.7%), but no significant difference was observed by distance from cancer for non-contiguous NME, P = 0.68. All calcified NME lesions contiguous to the calcified index cancer were malignant. NME was significantly more likely malignant when index cancers were masses compared to NME (52.9% vs. 21.4%), had mammographic calcifications (63.2% vs. 39.7%), LVI (81.8% vs. 44.4%), and axillary node metastasis (70.8% vs. 41.6%). NME features with highest PPVs were segmental distribution (85.7%), clumped enhancement (66.7%), and nonpersistent kinetics (77.1%). On multivariable analysis, contiguous NME, segmental distribution, and nonpersistent kinetics were associated with malignancy. DATA CONCLUSION: Malignancy discriminators of ipsilateral NME on staging MRI included contiguous location to index cancers, segmental distribution, and nonpersistent kinetics. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 2.

High Peritumoral and Intratumoral T2 Signal Intensity in HER2-Positive Breast Cancers on Preneoadjuvant Breast MRI: Assessment of Associations With Histopathologic Characteristics.

BACKGROUND. Intratumoral necrosis and peritumoral edema are features of aggressive breast cancer that may present as high T2 signal intensity (T2 SI). Implications of high T2 SI in HER2-positive cancers are unclear. OBJECTIVE. The purpose of this study was to assess associations with histopathologic characteristics of high peritumoral T2 SI and intratumoral T2 SI of HER2-positive breast cancer on MRI performed before initiation of neoadjuvant therapy. METHODS. This retrospective study included 210 patients (age, 24-82 years) with 211 HER2 breast cancers who, from January 1, 2015, to July 30, 2022, underwent breast MRI before receiving neoadjuvant therapy. Two radiologists independently assessed cancers for high peritumoral T2 SI and high intratumoral T2 SI on fat-suppressed T2-weighted imaging and classified patterns of high peritumoral T2 SI (adjacent to tumor vs prepectoral extension). A third radiologist resolved discrepancies. Multivariable logistic regression analyses were performed to identify associations of high peritumoral and intratumoral T2 SI with histopathologic characteristics (associated ductal carcinoma in situ, hormone receptor status, histologic grade, lymphovascular invasion, and axillary lymph node metastasis). RESULTS. Of 211 HER2-positive cancers, 81 (38.4%) had high peritumoral T2 SI, and 95 (45.0%) had high intratumoral T2 SI. A histologic grade of 3 was independently associated with high peritumoral T2 SI (OR = 1.90; p = .04). Otherwise, none of the five assessed histopathologic characteristics were independently associated with high intratumoral T2 SI or high peritumoral T2 SI (p > .05). Cancers with high T2 SI adjacent to the tumor (n = 29) and cancers with high T2 SI with prepectoral extension (n = 52) showed no significant difference in frequency for any of the histopathologic characteristics (p > .05). Sensitivities and specificities for predicting the histopathologic characteristics ranged from 35.6% to 43.7% and from 59.7% to 70.7%, respectively, for high peritumoral T2 SI, and from 37.3% to 49.6% and from 49.3% to 62.7%, respectively, for high intratumoral T2 SI. Interreader agreement was almost perfect for high peritumoral T2 SI (Gwet agreement coefficient [AC] = 0.93), high intratumoral T2 SI (Gwet AC = 0.89), and a pattern of high peritumoral T2 SI (Gwet AC = 0.95). CONCLUSION. The only independent association between histopathologic characteristics and high T2 SI of HER2-positive breast cancer was observed between a histologic grade of 3 and high peritumoral T2 SI. CLINICAL IMPACT. In contrast with previously reported findings in broader breast cancer subtypes, peritumoral and intratumoral T2 SI had overall limited utility as prognostic markers of HER2-positive breast cancer.

Breast Cancer Screening in High-risk Women During Pregnancy and Lactation.

Women who are at high risk of developing breast cancer warrant screening that is often initiated at younger ages than in average-risk women; this is usually with a combination of annual mammography and breast MRI. Compared to average-risk women, those at high risk are more frequently recommended to undergo screening during childbearing age and thus potentially during pregnancy and lactation. Understanding the appropriate use of screening breast imaging during pregnancy and lactation can be challenging due to limited data defining the evidence-based roles of the different imaging modalities, including mammography, US, and MRI. There have also been assumptions about the diagnostic accuracy of these modalities secondary to physiological changes. This scientific review discusses the current state of evidence- and expert-based guidelines and data for breast imaging screening of high-risk pregnant and/or lactating women, and the clinical and imaging presentations of breast cancer for these women.

Mammographic positioning in women with pectus excavatum: An anatomic challenge.

PURPOSE: To assess mammographic image quality in women with pectus excavatum (PEx) compared to women without PEx. MATERIALS & METHODS: Fifty-six women with PEx between the ages 36-80 (median, 57 years) with screening mammograms from 2006 to 2020 were identified in an IRB-approved HIPAA-compliant retrospective review. Two fellowship-trained breast radiologists independently evaluated mammographic quality of 109 individual breasts in the 56 women using Enhancing Quality Using the Inspection Program (EQUIP) positioning criteria and visual breast density assessments. The number of images per breast was documented. Comparison was made to 2:1 age-matched controls whose screening mammograms were performed in the same year. A power analysis for the difference in the number of images per breast between study groups was performed before data collection. RESULTS: Statistically significant differences with worse performance in women with PEx included: the pectoralis muscle extending to the posterior nipple line (p < 0.0001); adequacy of tissue visualized (p < 0.0001); inframammary fold included (p < 0.0001); breast free of skin folds (p = 0.003); presence of fibroglandular tissue at the CC view posterior edge (p < 0.0001); and CC and MLO within 1 cm of each other (p < 0.001). The average number of images per breast in the PEx group was greater than the control group (2.94 vs. 2.24, p < 0.0001). CONCLUSION: PEx women more often fail to meet mammographic positioning quality standards and more often require additional views for screening.

Breast Malignancies After Mastectomy With Autologous or Implant Reconstruction.

There are multiple indications for mastectomy for breast cancer, including extent of tumor, inability to achieve negative margins after re-excision, patient preference, or prevention in women with a high lifetime risk of breast cancer. Multiple types of autologous or implant reconstruction options are available for cosmesis. Although rare, breast cancers after mastectomy can occur, and it is important for both surgeons and radiologists to be aware of the associated risk factors, common locations, and classic imaging features of these malignancies. This article reviews the types of mastectomies, reconstruction options, and information about the location, presentation, and prognosis of cancers in the reconstructed breast.

Lobular neoplasia detected at MRI-guided biopsy: imaging findings and outcomes.

OBJECTIVE: To review MRI findings of pure lobular neoplasia (LN) on MRI guided biopsy, evaluate surgical and clinical outcomes, and assess imaging findings predictive of upgrade to malignancy. METHODS: HIPAA compliant, IRB-approved retrospective review of our MRI-guided breast biopsy database from October 2008-January 2015. Biopsies yielding atypical lobular hyperplasia or lobular carcinoma in situ were included in the analysis; all biopsy slides were reviewed by a dedicated breast pathologist. Imaging indications, MRI findings, and histopathology were reviewed. Statistical analysis was performed using the two-tailed Fisher exact-test and the t-test, and 95% CIs were determined. A p < 0.05 was considered statistically significant. RESULTS: Database search yielded 943 biopsies in 785 patients of which 65/943 (6.9%) reported LN as the highest risk pathologic lesion. Of 65 cases, 32 were found to have LN as the dominant finding on pathology and constituted the study population. All 32 findings were mammographically and sonographically occult. Three of 32 (9.3%) cases of lobular neoplasia were upgraded to malignancy, all LCIS (one pleomorphic and two classical). The most common MRI finding was focal, heterogenous non-mass enhancement with low T2 signal. No clinical features or imaging findings were predictive of upgrade to malignancy. CONCLUSION: Incidence of pure lobular neoplasia on MRI guided biopsy is low, with comparatively low incidence of upgrade to malignancy. No imaging or clinical features are predictive of upgrade on surgical excision, therefore, prudent radiologic-pathologic correlation is necessary.

Lesion conspicuity on synthetic screening mammography compared to full field digital screening mammography.

OBJECTIVE: To compare lesion conspicuity on synthetic screening mammography (SM) plus digital breast tomosynthesis (DBT) versus full field digital mammography (FFDM) plus DBT. MATERIALS AND METHODS: Seven breast imagers each prospectively evaluated 107-228 screening mammograms (FFDM, DBT, and SM; total 1206 examinations) over 12 weeks in sets of 10-50 consecutive examinations. Interpretation sessions alternated as follows: SM + DBT, then FFDM, or FFDM + DBT, then SM. Lesion conspicuity on SM versus FFDM (equal/better versus less) was assessed using proportions with 95% confidence intervals. DBT-only findings were excluded. RESULTS: Overall 1082 of 1206 (89.7%) examinations were assessed BI-RADS 1/2, and 124 of 1206 (10.3%) assessed BI-RADS 0. There were 409 evaluated findings, including 134 masses, 119 calcifications, 72 asymmetries, 49 architectural distortion, and 35 focal asymmetries. SM conspicuity compared to FFDM conspicuity for lesions was rated 1) masses: 77 (57%) equal or more conspicuous, 57 (43%) less conspicuous; 2) asymmetries/focal asymmetries: 61 (57%) equal or more conspicuous, and 46 (43%) less conspicuous; 3) architectural distortion: 46 (94%) equal or more conspicuous, 3 (6%) less conspicuous; 4) calcifications: 115 (97%) equal or more conspicuous, 4 (3%) less conspicuous. SM had better conspicuity than FFDM for calcifications and architectural distortion and similar conspicuity for most masses and asymmetries. CONCLUSION: Compared to FFDM, SM has better conspicuity for calcifications and architectural distortion and similar conspicuity for most masses and asymmetries.

Optimizing Success and Avoiding Mishaps in the Most Difficult Image-guided Breast Biopsies.

Breast cancer is an increasing challenge in developed and limited resource areas of the world. Early detection of breast cancer offers the best chance for optimal care and best outcomes. A critical step in early detection is to obtain efficient and accurate tissue diagnoses. Although image-guided core needle breast biopsies are usually straightforward for experienced breast imagers, there are some not uncommon scenarios that present particular challenges. In this review article we will discuss these difficult situations and offer our tried and true methods to ensure safe and successful biopsies, while using stereotactic, ultrasound, and MRI guidance.

Computer-aided heterogeneity analysis in breast MR imaging assessment of ductal carcinoma in situ: Correlating histologic grade and receptor status.

PURPOSE: To identify breast MR imaging biomarkers to predict histologic grade and receptor status of ductal carcinoma in situ (DCIS). MATERIALS AND METHODS: Informed consent was waived in this Health Insurance Portability and Accountability Act-compliant Institutional Review Board-approved study. Case inclusion was conducted from 7332 consecutive breast MR studies from January 1, 2009, to December 31, 2012. Excluding studies with benign diagnoses, studies without visible abnormal enhancement, and pathology containing invasive disease yielded 55 MR-imaged pathology-proven DCIS seen on 54 studies. Twenty-eight studies (52%) were performed at 1.5 Tesla (T); 26 (48%) at 3T. Regions-of-interest representing DCIS were segmented for precontrast, first and fourth postcontrast, and subtracted first and fourth postcontrast images on the open-source three-dimensional (3D) Slicer software. Fifty-seven metrics of each DCIS were obtained, including distribution statistics, shape, morphology, Renyi dimensions, geometrical measure, and texture, using the 3D Slicer HeterogeneityCAD module. Statistical correlation of heterogeneity metrics with DCIS grade and receptor status was performed using univariate Mann-Whitney test. RESULTS: Twenty-four of the 55 DCIS (44%) were high nuclear grade (HNG); 44 (80%) were estrogen receptor (ER) positive. Human epidermal growth factor receptor-2 (HER2) was amplified in 10/55 (18%), nonamplified in 34/55 (62%), unknown/equivocal in 8/55 (15%). Surface area-to-volume ratio showed significant difference (P < 0.05) between HNG and non-HNG DCIS. No metric differentiated ER status (0.113 < p ≤ 1.000). Seventeen metrics showed significant differences between HER2-positive and HER2-negative DCIS (0.016 < P < 0.050). CONCLUSION: Quantitative heterogeneity analysis of DCIS suggests the presence of MR imaging biomarkers in classifying DCIS grade and HER2 status. Validation with larger samples and prospective studies is needed to translate these results into clinical applications. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017;46:1748-1759.

Intraoperative Supine Breast MR Imaging to Quantify Tumor Deformation and Detection of Residual Breast Cancer: Preliminary Results.

Purpose To use intraoperative supine magnetic resonance (MR) imaging to quantify breast tumor deformation and displacement secondary to the change in patient positioning from imaging (prone) to surgery (supine) and to evaluate residual tumor immediately after breast-conserving surgery (BCS). Materials and Methods Fifteen women gave informed written consent to participate in this prospective HIPAA-compliant, institutional review board-approved study between April 2012 and November 2014. Twelve patients underwent lumpectomy and postsurgical intraoperative supine MR imaging. Six of 12 patients underwent both pre- and postsurgical supine MR imaging. Geometric, structural, and heterogeneity metrics of the cancer and distances of the tumor from the nipple, chest wall, and skin were computed. Mean and standard deviations of the changes in volume, surface area, compactness, spherical disproportion, sphericity, and distances from key landmarks were computed from tumor models. Imaging duration was recorded. Results The mean differences in tumor deformation metrics between prone and supine imaging were as follows: volume, 23.8% (range, -30% to 103.95%); surface area, 6.5% (range, -13.24% to 63%); compactness, 16.2% (range, -23% to 47.3%); sphericity, 6.8% (range, -9.10% to 20.78%); and decrease in spherical disproportion, -11.3% (range, -60.81% to 76.95%). All tumors were closer to the chest wall on supine images than on prone images. No evidence of residual tumor was seen on MR images obtained after the procedures. Mean duration of pre- and postoperative supine MR imaging was 25 minutes (range, 18.4-31.6 minutes) and 19 minutes (range, 15.1-22.9 minutes), respectively. Conclusion Intraoperative supine breast MR imaging, when performed in conjunction with standard prone breast MR imaging, enables quantification of breast tumor deformation and displacement secondary to changes in patient positioning from standard imaging (prone) to surgery (supine) and may help clinicians evaluate for residual tumor immediately after BCS. © RSNA, 2016 Online supplemental material is available for this article.

Radiation-Associated Angiosarcoma of the Breast: What the Radiologist Needs to Know.

OBJECTIVE: The purpose of this article is to describe the diagnosis, treatment, and follow-up of radiation-associated angiosarcoma (RAS) of the breast. CONCLUSION: Radiologists play an important role in the diagnosis of RAS, which may initially present clinically as erythema, ecchymosis, or skin thickening. Conventional imaging with mammography and ultrasound is less sensitive than MRI for the diagnosis of RAS. Follow-up CT is important to monitor treatment response.

Magnetic Resonance Imaging-Guided Breast Interventions: Role in Biopsy Targeting and Lumpectomies.

Contrast-enhanced breast MR imaging is increasingly being used to diagnose breast cancer and to perform biopsy procedures. The American Cancer Society has advised women at high risk for breast cancer to have breast MR imaging screening as an adjunct to screening mammography. This article places special emphasis on biopsy and operative planning involving MR imaging and reviews use of breast MR imaging in monitoring response to neoadjuvant chemotherapy. Described are peer-reviewed data on currently accepted MR imaging-guided procedures for addressing benign and malignant breast diseases, including intraoperative imaging.

MRI kinetics with volumetric analysis in correlation with hormonal receptor subtypes and histologic grade of invasive breast cancers.

OBJECTIVE. The aim of this study was to assess whether computer-assisted detection-processed MRI kinetics data can provide further information on the biologic aggressiveness of breast tumors. MATERIALS AND METHODS. We identified 194 newly diagnosed invasive breast cancers presenting as masses on contrast-enhanced MRI by a HIPAA-compliant pathology database search. Computer-assisted detection-derived data for the mean and median peak signal intensity percentage increase, most suspicious kinetic curve patterns, and volumetric analysis of the different kinetic patterns by mean percentage tumor volume were compared against the different hormonal receptor (estrogen-receptor [ER], progesterone-receptor [PR], ERRB2 (HER2/neu), and triple-receptor expressivity) and histologic grade subgroups, which were used as indicators of tumor aggressiveness. RESULTS. The means and medians of the peak signal intensity percentage increase were higher in ER-negative, PR-negative, and triple-negative (all p ≤ 0.001), and grade 3 tumors (p = 0.011). Volumetric analysis showed higher mean percentage volume of rapid initial enhancement in biologically more aggressive ER-negative, PR-negative, and triple-negative tumors compared with ER-positive (64% vs 53.6%, p = 0.013), PR-positive (65.4% vs 52.5%, p = 0.001), and nontriple-negative tumors (65.3% vs 54.6%, p = 0.028), respectively. A higher mean percentage volume of rapid washout component was seen in ERRB2-positive tumors compared with ERRB2-negative tumors (27.5% vs 17.9%, p = 0.020). CONCLUSION. Peak signal intensity percentage increase and volume analysis of the different kinetic patterns of breast tumors showed correlation with hormonal receptor and histologic grade indicators of cancer aggressiveness. Computer-assisted detection-derived MRI kinetics data have the potential to further characterize the aggressiveness of an invasive cancer.

MRI findings of radiation-associated angiosarcoma of the breast (RAS).

PURPOSE: To describe the magnetic resonance imaging (MRI) characteristics of radiation-associated breast angiosarcomas (RAS). MATERIALS AND METHODS: In this Institutional Review board (IRB)-approved retrospective study, 57 women were diagnosed with pathologically confirmed RAS during the study period (January 1999 to May 2013). Seventeen women underwent pretreatment breast MRI (prior to surgical resection or chemotherapy), of which 16 studies were available for review. Imaging features, including all available mammograms, ultrasounds, and breast MRIs, of these patients were evaluated by two radiologists independently and correlated with clinical management and outcomes. RESULTS: The median age of patients at original breast cancer diagnosis was 69.3 years (range 42-84 years), with average time from initial radiation therapy to diagnosis of RAS of 7.3 years (range 5.1-9.5 years). Nine women had mammograms (9/16, 56%) and six had breast ultrasound (US) (6/16, 38%) prior to MRI, which demonstrated nonsuspicious findings in 5/9 mammograms and 3/6 ultrasounds. Four patients had distinct intraparenchymal masses on mammogram and MRI. MRI findings included diffuse T2 high signal skin thickening (16/16, 100%). Nearly half (7/16, 44%) of patients had T2 low signal intensity lesions; all lesions rapidly enhanced on postcontrast T1 -weighted imaging. All women underwent surgical resection, with 8/16 (50%) receiving neoadjuvant chemotherapy. Four women died during the study period. CONCLUSION: Clinical, mammographic, and sonographic findings of RAS are nonspecific and may be occult on conventional breast imaging; MRI findings of RAS include rapidly enhancing dermal and intraparenchymal lesions, some of which are low signal on T2 weighted imaging.

Patient compliance and diagnostic yield of 18-month unilateral follow-up in surveillance of probably benign mammographic lesions.

OBJECTIVE: The purpose of this study is to determine the patient compliance with and diagnostic yield of 18-month unilateral mammography in surveillance of probably benign (BI-RADS category 3) lesions. MATERIALS AND METHODS: This retrospective study identified lesions prospectively classified BI-RADS 3 in asymptomatic women from January 1, 2004, to December 31, 2008. Surveillance protocol for BI-RADS 3 lesions included 6-month (unilateral), 12-month (bilateral), 18-month (unilateral), and 24-month (bilateral) imaging, with subsequent annual screening. Demographics, surveillance data, BI-RADS upgrades and downgrades, and biopsy results were abstracted from the longitudinal medical record. RESULTS: One thousand one hundred eighty-eight lesions in 1077 patients (mean age, 51.5 years; age range, 26-89 years) had BI-RADS 3 assessment, representing 1.07% of all screening examinations. The compliance rates for follow-up at 6, 12, 18, and 24 months were 83.3%, 75.9%, 54.8%, and 53.9%, respectively. Sixty lesions were upgraded to BI-RADS 4 or 5 during surveillance. Biopsy revealed 15 cancers (cancer yield of 1.47%) from 1017 lesions with either 24-month imaging stability or tissue diagnosis available. Five, six, one, and three cancers were detected at 6, 12, 18, and 24 months, respectively. Cancers were all stage 0 or 1 except for one stage 2A cancer. Seven hundred forty-four of 1188 (62.6%) BI-RADS 3 lesions were downgraded before completing 2-year surveillance. CONCLUSION: Most (11/15 [73%]) breast cancers initially assessed as BI-RADS 3 are diagnosed at up to 12 months' surveillance. Eighteen-month unilateral mammography performed as BI-RADS 3 surveillance contributes minimally to cancer detection and has poor patient compliance.

MR imaging assessment of the breast after breast conservation therapy: distinguishing benign from malignant lesions.

Dynamic contrast material-enhanced magnetic resonance (MR) imaging has emerged as a valuable tool in evaluation of women who have undergone lumpectomy and whole-breast radiation therapy for breast cancer. Early diagnosis of local recurrence by means of close clinical and imaging follow-up is an important component of a breast-conserving strategy, as it may improve survival. In the post-breast conservation therapy (BCT) breast, resolving edema, fat necrosis, a small focal area of non-masslike enhancement (NMLE), and thin linear NMLE at the lumpectomy site can all be expected findings. In contrast, masslike enhancement or NMLE of ductal or segmental distribution can indicate recurrence. Therefore, at MR imaging of the post-BCT breast, it is important to identify lesions that are benign or appropriate for short-interval imaging surveillance to minimize unnecessary intervention, as well as to discern suspicious lesions and optimize the diagnosis of recurrence.

Factors that impact the duration of MRI-guided core needle biopsy.

OBJECTIVE: The purpose of our study was to determine which patient-related, target lesion-related, or procedure-related variables impact the duration of MRI-guided core needle breast biopsy. MATERIALS AND METHODS: Between July 11, 2006, and September 26, 2007, data were collected for 75 single-target MRI-guided 9-gauge vacuum-assisted core needle biopsy procedures using a grid-guidance technique and performed at a single institution. The following variables were studied: MRI suite occupation time, number of operators, patient age and breast size, target morphology and location, approach to target, equipment used, number of image acquisitions and times the patient was moved in and out of the closed magnet, and occurrence of complications. Statistical analysis was performed using the Student's t test, analysis of variance, and Pearson's correlation, with p values < 0.05 considered significant. RESULTS: The mean duration was 57.9 minutes (SD, 17.2 minutes; range, 30-109 minutes). None of the patient- or target-related variables significantly impacted the duration, although lesions located in the anterior third of the breast showed a trend to prolong the procedure (p = 0.059). The time to complete a procedure was reduced when the operating radiologist was assisted by a breast imaging fellow-in-training (p = 0.01). Increasing numbers of image acquisitions and times the patient was moved in and out of the magnet significantly lengthened the procedure duration (p = 0.0001 for both). No major complications occurred. Biopsies yielded 16% (12/75) malignant and 84% (63/75) benign diagnoses. CONCLUSION: Variables that minimized procedure duration were number of image acquisitions, number of patient insertions or removals from the magnet, and assistance of a breast imaging fellow-in-training. No patient-related or target-related variables impacted procedure time.

Breast MRI in the evaluation of eligibility for accelerated partial breast irradiation.

OBJECTIVE: Eligibility for accelerated partial breast irradiation is generally determined by physical examination in conjunction with conventional imaging techniques such as mammography and breast sonography. MRI is recognized as a significant imaging tool in diagnosing breast cancer and has shown the ability to identify mammographically occult carcinoma. Our purpose was to retrospectively assess preoperative breast MRI examinations in women with early-stage breast cancer who were theoretically eligible for accelerated partial breast irradiation and to explore the use of MRI in selecting patients for this treatment. MATERIALS AND METHODS: Seventy-nine patients with core needle biopsy-proven breast cancer, who were eligible candidates for breast-conserving surgery and accelerated partial breast irradiation, underwent bilateral breast MRI examinations. At review, the presence and location of occult tumor sites (detected on MRI only) were documented and subsequently correlated with pathology findings. RESULTS: From 79 patients, a total of 126 suspicious areas, including the index tumors, were detected by MRI. Additional sites of cancer other than the index tumor were observed in 30 patients (38%). Of these, eight (10%) had an additional cancer in a different quadrant from the index tumor. CONCLUSION: The treatment effect of whole-breast irradiation on microscopic tumor cells and on additional occult foci in other quadrants of the breast is lost with partial breast irradiation. Our results suggest that MRI before accelerated partial breast irradiation may be of benefit to patients to ensure they do not have multifocal or multicentric disease, remote from the lumpectomy bed.

MRI-directed, wire-localized breast excisions: incidence of malignancy and recommendations for pathologic evaluation.

Magnetic resonance imaging (MRI) has an evolving role in the evaluation of breast lesions and is currently being used for the screening of high-risk patients (eg, women with a personal or family history of breast cancer), for the evaluation of extent of disease in patients with a current diagnosis of cancer, and for patients with suspicious, but indeterminate, findings by other imaging modalities. If a suspicious lesion detected by MRI is not well visualized by another method, an MRI-directed core biopsy or breast excision may be performed. MRI cannot be used to verify the lesion in the specimen because MRI lesion detection is dependent on uptake of gadolinium after intravenous injection. Accordingly, these breast excisions present unique challenges to pathologists. The purpose of this report is to define the surgical pathology issues involved in processing MRI-localized excisions. Retrospective review of 85 consecutive MRI-directed breast excisions from 77 patients was performed. Malignant lesions were present in 20 (24%) of 85 excisions, including 10 cases of invasive carcinoma (median size, 0.4 cm), 9 cases of ductal carcinoma in situ, and 1 case of lymphoma. Most of the malignancies (85% or 17/20) had no associated gross finding and only 5 (25%) of 20 of these malignancies were associated with a definite finding on the specimen radiograph. This study demonstrates that gross examination and specimen radiography do not identify most of the malignancies in MRI-localized biopsies and, therefore, optimal processing requires complete microscopic examination of these specimens.

Imaging findings after breast brachytherapy.

OBJECTIVE: The purpose of this study was to determine whether there are imaging changes specific to partial breast radiation therapy with interstitial catheters or a single balloon. MATERIALS AND METHODS: The records of 43 of 83 patients treated with partial breast irradiation at our institution from June 1996 to October 2003 were retrospectively reviewed. The images of 27 patients who had received radiation by interstitial catheters and 16 who had received radiation by a single balloon were reviewed. Patients were examined for the presence of skin thickening, diffuse and focal increased density, mass, lucency, and calcifications. Fifteen initial sonograms were ordered to evaluate pain or focal findings on mammograms. In addition, two patients underwent one and one patient underwent three follow-up sonographic examinations. RESULTS: Mild to moderate skin thickening was present in 26 (60%) and no skin thickening in 17 (40%) of the 43 patients. Forty-one (95%) of the 43 patients had focal increased density. Diffuse increased density was seen in only one (2%) of the patients. There was no change in overall density in 2 (5%) of the patients. Fifteen (35%) of the 43 patients had mass or seroma at the first follow-up examination. Central lucency was present in 35 (81%) of 43 patients on at least one follow-up study. Calcification was present in 8 (19%) of 43 cases. CONCLUSION: Imaging findings after breast brachytherapy include the spectrum of findings seen with external beam radiation but are more focal. The focal findings may be alarming both clinically and radiographically, but biopsy can be avoided in most instances if information from the history is correlated with findings from continued follow-up of the patient's case.