Sue Peacock

BI-RADS Lesion Characteristics Predict Likelihood of Malignancy in Breast MRI for Masses But Not for Nonmasslike Enhancement

OBJECTIVE The purpose of our study was to evaluate the predictive features of BI-RADS lesion characteristics and the risk of malignancy for mammographically and clinically occult lesions detected initially on breast MRI. MATERIALS AND METHODS We reviewed 1,523 consecutive breast MRI examinations performed from January 1, 2003, to June 30, 2005, to identify all lesions initially detected on MRI and assessed as BI-RADS 4 or 5 for which the patient underwent subsequent imaging-guided needle or excisional biopsy. BI-RADS lesion features were recorded for each case, and the risk of malignancy was assessed using generalized estimating equations. Separate multivariate models were constructed for lesions classified as masses. RESULTS Included in the analysis were 258 suspicious lesions in 196 women. Among all lesions, those of 1 cm or greater were significantly more often malignant (50/147, 34%) than lesions of less than 1 cm (22/111, 20%; odds ratio, 2.09; 95% CI, 1.13-3.83). For masses, size, BI-RADS margin, and enhancement pattern predicted malignancy. In multivariate analysis of combinations of features, masses of 1 cm or greater with heterogeneous enhancement and irregular margins had a 68% probability of malignancy. Masses of 1 cm or greater with smooth margins and homogeneous enhancement had the lowest predicted probability of malignancy of 3%. BI-RADS descriptors and size were not significant predictors of malignancy for nonmasslike enhancement (NMLE). CONCLUSION Combinations of BI-RADS lesion descriptors can predict the probability of malignancy for breast MRI masses but not for NMLE. If our model is validated, masses with a low probability of malignancy may be eligible for short-interval follow-up rather than biopsy. Further research focused on predictive features of NMLE is needed.

Utility of Targeted Sonography for Breast Lesions That Were Suspicious on MRI

OBJECTIVE Data remain sparse to guide the use of targeted sonography for suspicious breast lesions found with MRI. The purpose of our study was to determine the usefulness of sonography in this setting. MATERIALS AND METHODS Retrospective review of our breast MRI database was performed to identify all nonpalpable, mammographically occult MRI-detected suspicious lesions from January 1, 2003, to December 30, 2004, that underwent targeted sonography followed by imaging-guided biopsy. Frequency of sonography detection was determined, and MRI features (BI-RADS lesion type and size), histopathology outcomes, and positive biopsy rates of sonographically detected and occult findings were compared using chi-square analysis. RESULTS Targeted sonography was performed for 167 of 201 MRI lesions. Outcomes were benign in 120 (72%) and malignant in 47 (28%) findings. Lesions assessed on sonography were 84 (50%) masses, 53 (32%) nonmasslike enhancements, and 30 (18%) foci, with mean size of 16 mm. Overall, 76 of 167 (46%) lesions were detected with sonography. Depiction was significantly more frequent for masses (58%) than for nonmasslike enhancement (30%) or foci (37%) (p = 0.003). Lesion size did not affect the frequency of detection. Sonographically depicted findings had a significantly higher positive biopsy rate (36%) than sonographically occult lesions (22%) (p = 0.05). CONCLUSION Targeted sonography detected nearly half (46%) of MRI lesions evaluated, with depiction being most frequent for masses. Sonographically occult lesions had a probability of malignancy (22%), which warrants biopsy despite lack of sonographic detection.

Diffusion tensor MRI: preliminary anisotropy measures and mapping of breast tumors.

To investigate whether diffusion tensor imaging (DTI) measures of anisotropy in breast tumors are different from normal breast tissue and can improve the discrimination between benign and malignant lesions.

Background Parenchymal Enhancement on Breast MRI: Impact on Diagnostic Performance

OBJECTIVE Breast density is documented to reduce sensitivity and specificity of mammography. However, little is known regarding the effect of normal background parenchymal enhancement on accuracy of breast MRI. The purpose of this study was to evaluate the effect of background parenchymal enhancement on MRI diagnostic performance. MATERIALS AND METHODS A review of our established MRI data identified all women undergoing breast MRI from March 1, 2006, through June 30, 2007. Prospectively reported background parenchymal enhancement categories of minimal, mild, moderate, or marked (anticipated BI-RADS MRI lexicon definitions) and assessments were extracted from the database for each patient. Outcomes were determined by pathologic analysis, imaging, and linkage with the regional tumor registry with a minimum of 24 months of follow-up. Patients were dichotomized into categories of minimal or mild versus moderate or marked background parenchymal enhancement. Associations with patient age, abnormal interpretation rate, positive biopsy rate, cancer yield, sensitivity, and specificity were compared using chi-square and z score tests. RESULTS The study cohort included 736 women. Moderate or marked background parenchymal enhancement was significantly more frequent among patients younger than 50 years compared with those 50 years old and older (39.7% vs 18.9%; p < 0.0001). Moderate or marked background parenchymal enhancement was also associated with a higher abnormal interpretation rate compared with minimal or mild background parenchymal enhancement (30.5% vs 23.3%; p = 0.046). Positive biopsy rate, cancer yield, sensitivity, and specificity were not significantly different according to background parenchymal enhancement category. CONCLUSION Increased background parenchymal enhancement on breast MRI is associated with younger patient age and higher abnormal interpretation rate. However, it is not related to significant differences in positive biopsy rate, cancer yield, sensitivity, or specificity of MRI.

BI-RADS MRI Enhancement Characteristics of Ductal Carcinoma In Situ

Abstract:  To identify the Breast Imaging Reporting and Data System magnetic resonance imaging (MRI) enhancement characteristics of ductal carcinoma in situ (DCIS). A retrospective review of consecutive patients who underwent breast MRI for newly diagnosed breast carcinoma prior to surgery was conducted. This yielded 381 lesions in 361 patients with pathologic confirmation of either DCIS alone, invasive carcinoma alone, or mixed invasive and in‐situ disease. Presence or absence of a MRI lesion at the site of the documented carcinoma was recorded, and for all identified MRI lesions the Breast Imaging Reporting and Data System morphology patterns were recorded. MRI features of the different malignancy types were compared utilizing Fisher’s exact tests; 64/381 (16.8%) lesions had DCIS, 101/381 (26.5%) had invasive carcinoma, and 216/381 (56.7%) had mixed invasive/in situ carcinoma. A MRI lesion corresponding to the known cancer was identified in 55/64 (85.9%) cases of DCIS, 98/101 (97.0%) cases of invasive carcinoma, and 212/216 (98.1%) cases of mixed invasive and in‐situ carcinoma. For pure DCIS lesions, 38/64 (59.4%) exhibited nonmass‐like enhancement (NMLE), 9/64 (14.1%) were masses, and 8/64 (12.5%) were a focus. For pure invasive carcinomas 79/101(78.2%) were masses, 16/101 (15.8%) were NMLE, and 3/101 (3.0%) were a focus. For mixed lesions 163/216 (75.5%) were masses, 44/216 (20.4%) demonstrated NMLE, and 5/216 (2.3%) were a focus. The most common NMLE patterns of pure DCIS were segmental distribution and clumped internal enhancement. Although there is overlap in the MRI morphology and enhancement pattern of in situ and invasive breast carcinoma, DCIS more frequently manifests as NMLE than does invasive carcinoma.

Risk of Upgrade of Atypical Ductal Hyperplasia after Stereotactic Breast Biopsy: Effects of Number of Foci and Complete Removal of Calcifications

PURPOSE To determine if patients with fewer than three foci of atypical ductal hyperplasia (ADH) who have all of their calcifications removed after stereotactic 9- or 11-gauge vacuum-assisted breast biopsy (VABB) have a rate of upgrade to malignancy that is sufficiently low to obviate surgical excision. MATERIALS AND METHODS An institutional review board-approved, HIPAA-compliant retrospective review of 991 cases of consecutive 9- or 11-gauge stereotactic VABB performed during a 65-month period revealed 147 cases of atypia. One pathologist performed a blinded review of the results of procedures performed to assess for calcifications and confirmed ADH in 101 cases with subsequent surgical excision. Each large duct or terminal duct-lobular unit containing ADH was considered a focus and counted. Postbiopsy mammograms were reviewed to determine whether all calcifications were removed. Upgrade to malignancy was determined from excisional biopsy pathology reports. Upgrade rates as a function of both number of foci and presence or absence of residual calcifications were calculated and compared by using chi(2) tests. RESULTS Upgrade to malignancy occurred in 20 (19.8%) of the 101 cases. The upgrade rate was significantly higher in cases of three or more foci of ADH (15 [28%] of 53 cases) than in cases of fewer than three foci (five [10%] of 48 cases) (P = .02). Upgrade rates were similar, regardless of whether all mammographic calcifications were removed (seven [17%] of 41 cases) or all were not removed (nine [20%] of 45 cases) (P = .77). Upgrade occurred in two (12%) of 17 cases in which there were fewer than three ADH foci and all calcifications were removed. CONCLUSION The upgrade rate is significantly higher when ADH involves at least three foci. Surgical excision is recommended even when ADH involves fewer than three foci and all mammographic calcifications have been removed, because the upgrade rate is 12%.

Characteristics of probably benign breast MRI lesions.

OBJECTIVE The purpose of our study was to describe the characteristics of probably benign breast MRI lesions and determine how these characteristics could be used to define the MRI BI-RADS 3 category. MATERIALS AND METHODS We prospectively collected morphology and kinetic data on lesions assessed as BI-RADS 3 in 2,569 consecutive breast MRI examinations from January 2003 through November 2006. The clinical indications for MRI, follow-up assessments, and pathology findings through May 2008 were collected from clinical records. Data were linked to the regional tumor registry to identify cases of malignancy in patients who did not follow-up at our institution. Frequency of BI-RADS 3 and cancer yield were calculated. Characteristics of probably benign lesions were analyzed for predictors of malignancy. RESULTS Three hundred sixty-two lesions were assessed as BI-RADS 3 in 260 (10.1%) of 2,569 examinations in 236 patients. The 362 lesions included 168 (46%) foci, 132 (36%) nonmasslike enhancements, and 62 (17%) masses. Delayed kinetic information was available in 275 lesions. The most suspicious delayed kinetic enhancement was persistent in 164 (60%) of 275, plateau in 47 (17%) of 275, and washout in 64 (23%) of 275. The cancer yield in patients with a BI-RADS 3 assessment was two (0.85%) of 236; both were ductal carcinoma in situ lesions. There were no malignancies in the 69 foci with 100% persistent enhancement. CONCLUSION The characteristics of BI-RADS 3 lesions were highly variable in our population, and the risk of malignancy was low (0.85%). Assigning foci with 100% persistent enhancement to the BI-RADS 2 category can decrease the frequency of BI-RADS 3 assessment and maintain a likelihood of malignancy in less than 2% of cases.

Frequency and Upgrade Rates of Atypical Ductal Hyperplasia Diagnosed at Stereotactic Vacuum-Assisted Breast Biopsy: 9-Versus 11-Gauge

OBJECTIVE Our goals were to determine the frequency and upgrade rate for atypical ductal hyperplasia (ADH) diagnosed with stereotactic 9-gauge vacuum-assisted breast biopsy and to compare the frequencies and upgrade rates of ADH between 9- and 11-gauge vacuum-assisted breast biopsy. MATERIALS AND METHODS We retrospectively reviewed the pathology results of 991 consecutive 9- or 11-gauge stereotactic vacuum-assisted breast biopsy procedures from February 2001 through June 2006 and identified lesions diagnosed as ADH. The final diagnosis after surgical excision was determined from medical records. The frequencies and upgrade rates to carcinoma were calculated for all ADH lesions and compared between 9- and 11-gauge procedures. The number of core samples was recorded and compared. RESULTS One hundred forty-one of 991 (14.2%) lesions yielded a diagnosis of ADH at 9- or 11-gauge stereotactic vacuum-assisted breast biopsy. Upgrade to ductal carcinoma in situ or invasive carcinoma occurred in 26 of 123 (21.1%) patients. The frequency of ADH was 83 of 600 (13.8%) lesions for 9-gauge and 58 of 391 (14.8%) lesions for 11-gauge vacuum-assisted breast biopsy. The 9-gauge upgrade rate was 16 of 74 (21.6%) lesions compared with 10 of 49 (20.4%) lesions for 11-gauge vacuum-assisted breast biopsy. There was no significant difference between the number of core samples obtained with each device (p=0.40). Neither the frequency of ADH (p=0.66) nor the upgrade rates (p=0.87) were significantly different between 9- and 11-gauge vacuum-assisted breast biopsy. CONCLUSION Compared with an 11-gauge vacuum-assisted breast biopsy device, the use of a larger 9-gauge vacuum-assisted breast biopsy needle does not decrease the upgrade rate of ADH. Our frequency of ADH at vacuum-assisted breast biopsy is higher than any previously reported and may reflect regional differences in the incidence of breast cancer or practice patterns of the pathologist.

Are Qualitative Assessments of Background Parenchymal Enhancement, Amount of Fibroglandular Tissue on MR Images, and Mammographic Density Associated with Breast Cancer Risk?

PURPOSE To investigate whether qualitative magnetic resonance (MR) imaging assessments of background parenchymal enhancement (BPE), amount of fibroglandular tissue (FGT), and mammographic density are associated with risk of developing breast cancer in women who are at high risk. MATERIALS AND METHODS In this institutional review board-approved HIPAA-compliant retrospective study, all screening breast MR images obtained from January 2006 to December 2011 in women aged 18 years or older and at high risk for but without a history of breast cancer were identified. Women in whom breast cancer was diagnosed after index MR imaging comprised the cancer cohort, and one-to-one matching (age and BRCA status) of each woman with breast cancer to a control subject was performed by using MR images obtained in women who did not develop breast cancer with follow-up time maximized. Amount of BPE, BPE pattern (peripheral vs central), amount of FGT at MR imaging, and mammographic density were assessed on index images. Imaging features were compared between cancer and control cohorts by using conditional logistic regression. RESULTS Twenty-three women at high risk (mean age, 47 years ± 10 [standard deviation]; six women had BRCA mutations) with no history of breast cancer underwent screening breast MR imaging; in these women, a diagnosis of breast cancer (invasive, n = 12; in situ, n = 11) was made during the follow-up interval. Women with mild, moderate, or marked BPE were nine times more likely to receive a diagnosis of breast cancer during the follow-up interval than were those with minimal BPE (P = .007; odds ratio = 9.0; 95% confidence interval: 1.1, 71.0). BPE pattern, MR imaging amount of FGT, and mammographic density were not significantly different between the cohorts (P = .5, P = .5, and P = .4, respectively). CONCLUSION Greater BPE was associated with a higher probability of developing breast cancer in women at high risk for cancer and warrants further study.

In Vivo Assessment of Ductal Carcinoma in Situ Grade: A Model Incorporating Dynamic Contrast-enhanced and Diffusion-weighted Breast MR Imaging Parameters

PURPOSE To develop a model incorporating dynamic contrast material-enhanced (DCE) and diffusion-weighted (DW) magnetic resonance (MR) imaging features to differentiate high-nuclear-grade (HNG) from non-HNG ductal carcinoma in situ (DCIS) in vivo. MATERIALS AND METHODS This HIPAA-compliant study was approved by the institutional review board and requirement for informed consent was waived. A total of 55 pure DCIS lesions (19 HNG, 36 non-HNG) in 52 women who underwent breast MR imaging at 1.5 T with both DCE and DW imaging (b = 0 and 600 sec/mm(2)) were retrospectively reviewed. The following lesion characteristics were recorded or measured: DCE morphology, DCE maximum lesion size, peak initial enhancement at 90 seconds, worst-curve delayed enhancement kinetics, apparent diffusion coefficient (ADC), contrast-to-noise ratio (CNR) at DW imaging with b values of 0 and 600 sec/mm(2), and T2 signal effects (measured with CNR at b = 0 sec/mm(2)). Univariate and stepwise multivariate logistic regression modeling was performed to identify MR imaging features that optimally discriminated HNG from non-HNG DCIS. Discriminative abilities of models were compared by using the area under the receiver operating characteristic curve (AUC). RESULTS HNG lesions exhibited larger mean maximum lesion size (P = .02) and lower mean CNR for images with b value of 600 sec/mm(2) (P = .004), allowing discrimination of HNG from non-HNG DCIS (AUC = 0.71 for maximum lesion size, AUC = 0.70 for CNR at b = 600 sec/mm(2)). Differences in CNR for images with b value of 0 sec/mm(2) (P = .025) without corresponding differences in ADC values were observed between HNG and non-HNG lesions. Peak initial enhancement was the only kinetic variable to approach significance (P = .05). No differences in lesion morphology (P = .11) or worst-curve delayed enhancement kinetics (P = .97) were observed. A multivariate model combining CNR for images with b value of 600 sec/mm(2) and maximum lesion size most significantly discriminated HNG from non-HNG (AUC = 0.81). CONCLUSION The preliminary findings suggest that DCE and DW MR imaging features may aid in identifying patients with high-risk DCIS. Further study may yield a model combining MR characteristics with histopathologic data to facilitate lesion-specific targeted therapies.