Nipple Discharge: Imaging Variability Among U.S. Radiologists.

OBJECTIVE: The purpose of this study was to assess radiologists' choice of imaging modality for the evaluation of clinical symptoms of physiologic nipple discharge (e.g., bilateral discharge, multiple-duct orifices, and yellow, green, or white color) and pathologic nipple discharge (e.g., unilateral discharge, single-duct orifices, spontaneous and serous discharge, and clear or bloodstained color). MATERIALS AND METHODS: An online survey was sent to lead interpreting physicians at mammography facilities accredited by the American College of Radiology (ACR). Statistical analysis was performed using chi-square tests for frequency data and multinomial logistic regression. RESULTS: A total of 849 responses to 8170 distributed surveys were received, for a response rate of 10.4%. For the workup of physiologic nipple discharge, 30% of respondents recommended screening mammography (SM); 24%, diagnostic mammography (DM) only; and 46%, both DM and targeted ultrasound (US) (DM plus US). For the workup of physiologic nipple discharge, practitioners in nonacademic settings and those who read breast images during less than 50% of their practice were significantly more likely to recommend DM (with or without US), compared with SM (the standard recommended by the ACR). Those reading breast images less than 50% of the time were also more likely to recommend MRI after conventional imaging revealed negative results. For the workup of pathologic nipple discharge, 91.0% of respondents recommended DM plus US; 8.5%, DM only; and fewer than 1.0%, SM. Nonacademic providers and those who read breast images less than 50% of the time were significantly less likely to recommend DM plus US (the standard recommended by the ACR), compared with DM only. CONCLUSION: The present study shows variability in imaging modality selection among U.S. radiologists handling the imaging workflow for benign and pathologic nipple discharge. Radiologists do not uniformly follow ACR practice guidelines, which potentially leads to unnecessary workups and extra health care costs.

Variability of Postsurgical Imaging Surveillance of Breast Cancer Patients: A Nationwide Survey Study.

OBJECTIVE: Because of observed clinical variance and the discretion of referring physicians and radiologists in patient follow-up, the purpose of this study was to conduct a survey to explore whether broad discrepancy exists in imaging protocols used for postsurgical surveillance. SUBJECTS AND METHODS: An online survey was created to assess radiologists' use of diagnostic versus screening mammography for women with a personal history of breast cancer and determine whether the choice of protocol was associated with practice characteristics (setting, region, and reader type). RESULTS: Of 8170 surveys sent, 849 (10%) completed responses were returned. Seventy-nine percent of respondents recommended initial diagnostic mammography after lumpectomy (65% at 6 months, 14% at 12 months); 49% recommended diagnostic surveillance for up to 2 years before a return to screening mammography; and 33% continued diagnostic surveillance for 2-5 years before returning to screening. For imaging after mastectomy, 57% of respondents recommended diagnostic mammography of the unaffected breast. Among the 57%, however, 37% recommended diagnostic screening for only the first postmastectomy follow-up evaluation, and the other 20% permanently designated patients for diagnostic mammography after mastectomy. CONCLUSION: The optimal surveillance mammography regimen must be better defined. This preliminary study showed variability in diagnostic versus screening surveillance mammography for women with a history of breast cancer. Future studies should evaluate why these variations occur and how to standardize recommendations to tailor personalized imaging.

Can Breast Compression Be Reduced in Digital Mammography and Breast Tomosynthesis?

OBJECTIVE: The objective of this study was to investigate the impact of decreasing breast compression during digital mammography and breast tomosynthesis (DBT) on perceived pain and image quality. MATERIALS AND METHODS: In this two-part study, two groups of women with prior mammograms were recruited. In part 1, subjects were positioned for craniocaudal (CC) and mediolateral oblique (MLO) views, and four levels of compression force were applied to evaluate changes in breast thickness, perceived pain, and relative tissue coverage. No imaging was performed. In part 2, two MLO DBT images of one breast of each patient were acquired at standard and reduced compression. Blurring artifacts and tissue coverage were judged by three breast imaging radiologists, and compression force, breast thickness, relative tissue coverage, and perceived pain were recorded. RESULTS: Only the first reduction in force was feasible because further reduction resulted in inadequate breast immobilization. Mean force reductions of 48% and 47% for the CC and MLO views, respectively, resulted in a significantly reduced perceived pain level, whereas the thickness of the compressed breast increased by 0.02 cm (CC view) and 0.09 (MLO view, part 1 of the study) and 0.38 cm (MLO view, part 2 of the study), respectively, with no change in tissue coverage or increase in motion blurring. CONCLUSION: Mammography and DBT acquisitions may be possible using half of the compression force used currently, with a significant and substantial reduction in perceived pain with no clinically significant change in breast thickness and tissue coverage.

Does Preoperative MRI Workup Affect Mastectomy Rates and/or Re-excision Rates in Patients with Newly Diagnosed Breast Carcinoma? A Retrospective Review.

The purpose of this study is to determine whether including breast magnetic resonance imaging (MRI) in the preoperative workup of patients with known breast cancer has an impact on mastectomy and/or re-excision rates. This is an Institutional Review Board approved HIPAA compliant retrospective study reviewing the impact MRI has on mastectomy and re-excision rates in patients with newly diagnosed breast cancer. Our study compares two groups: (i) 154 patients who did not receive preoperative MRIs and served as a control group and (ii) 96 patients who received preoperative breast MRIs. Patient race and age between the two populations were not statistically different. The difference in mastectomy rates between the two populations was 10.7%; although not statistically different, the p value of 0.10 suggests a trend toward significance. The re-excision rates between the two populations, however, were significantly different (p < 0.001), with women in the control group having a higher re-excision rate than those in the study group. The difference between involved and clear margins was significant as well (p = 0.002), with patients undergoing preoperative MRI more likely to have negative margins. Preoperative breast MRI significantly decreases the likelihood of involved margins as well as the need for surgical re-excision. Preoperative breast MRI does not result in a statistically significant difference in mastectomy rates, although further investigation is required to determine whether there is a trend towards statistical significance.

Determining the impact of US mammography screening guidelines on patient survival in a predominantly African American population treated in a public hospital during 2008.

BACKGROUND: In November 2009, the US Preventive Service Task Force (USPSTF) published updated breast cancer screening guidelines. This marked a change from the 2002 recommendations and a significant divergence from the American Cancer Society (ACS) guidelines. In the current study, the potential effect of using the revised 2009 USPSTF guidelines on patient disease stage and survival were evaluated and compared with those actually observed and to predicted under ACS recommendations. METHODS: A retrospective chart review was performed for 84 patients who were diagnosed with stage I through III breast cancer at Grady Memorial Hospital during 2008. Previously published tumor volume doubling times were used to model an equation that would estimate tumor sizes. For each patient, a disease stage at diagnosis was predicted, and outcomes were modeled as though the patient had been screened according to the recommended versions of the ACS and USPSTF guidelines. Patient survival rates were then estimated based on prognostic data according to disease stage. RESULTS: The average age of patients in the study was 55 years, and 85% were African American. The USPSTF guidelines predicted later stages at diagnosis (14% stage I, 73% stage II), whereas the ACS guidelines predicted earlier stages (47% stage I, 53% stage II). CONCLUSIONS: A large stage migration was predicted, indicating significantly earlier diagnosis, when the ACS-recommended screening guidelines were followed. The authors concluded that practitioners should understand how race and/or socioeconomic factors increase the risk of breast cancer and should be encouraged to prioritize discussions regarding the benefits and risks of annual mammographic screening, especially among women who have a potentially greater risk of developing breast cancer at a younger age.

Stereoscopic digital mammography: improved specificity and reduced rate of recall in a prospective clinical trial.

PURPOSE: To compare stereoscopic digital mammography (DM) with standard DM for the rate of patient recall and the detection of cancer in a screening population at elevated risk for breast cancer. MATERIALS AND METHODS: Starting in September 2004 and ending in December 2007, this prospective HIPAA-compliant, institutional review board-approved screening trial, with written informed consent, recruited female patients at elevated risk for breast cancer (eg, personal history of breast cancer or breast cancer in a close relative). A total of 1298 examinations from 779 patients (mean age, 58.6 years; range, 32-91 years) comprised the analyzable data set. A paired study design was used, with each enrolled patient serving as her own control. Patients underwent both DM and stereoscopic DM examinations in a single visit, findings of which were interpreted independently by two experienced radiologists, each using a Breast Imaging Reporting and Data System (BI-RADS) assessment (BI-RADS category 0, 1, or 2). All patients determined to have one or more findings with either or both modalities were recalled for standard diagnostic evaluation. The results of 1-year follow-up or biopsy were used to determine case truth. RESULTS: Compared with DM, stereoscopic DM showed significantly higher specificity (91.2% [1167 of 1279] vs 87.8% [1123 of 1279]; P = .0024) and accuracy (90.9% [1180 of 1298] vs 87.4% [1135 of 1298]; P = .0023) for detection of cancer. Sensitivity for detection of cancer was not significantly different for stereoscopic DM (68.4% [13 of 19]) compared with DM (63.2% [12 of 19], P .99). The recall rate for stereoscopic DM was 9.6% (125 of 1298) and that for DM was 12.9% (168 of 1298) (P = .0018). CONCLUSION: Compared with DM, stereoscopic DM significantly improved specificity for detection of cancer, while maintaining comparable sensitivity. The recall rate was significantly reduced with stereoscopic DM compared with DM. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12120382/-/DC1.

Influence of computer-aided detection on performance of screening mammography.

BACKGROUND: Computer-aided detection identifies suspicious findings on mammograms to assist radiologists. Since the Food and Drug Administration approved the technology in 1998, it has been disseminated into practice, but its effect on the accuracy of interpretation is unclear. METHODS: We determined the association between the use of computer-aided detection at mammography facilities and the performance of screening mammography from 1998 through 2002 at 43 facilities in three states. We had complete data for 222,135 women (a total of 429,345 mammograms), including 2351 women who received a diagnosis of breast cancer within 1 year after screening. We calculated the specificity, sensitivity, and positive predictive value of screening mammography with and without computer-aided detection, as well as the rates of biopsy and breast-cancer detection and the overall accuracy, measured as the area under the receiver-operating-characteristic (ROC) curve. RESULTS: Seven facilities (16%) implemented computer-aided detection during the study period. Diagnostic specificity decreased from 90.2% before implementation to 87.2% after implementation (P<0.001), the positive predictive value decreased from 4.1% to 3.2% (P=0.01), and the rate of biopsy increased by 19.7% (P<0.001). The increase in sensitivity from 80.4% before implementation of computer-aided detection to 84.0% after implementation was not significant (P=0.32). The change in the cancer-detection rate (including invasive breast cancers and ductal carcinomas in situ) was not significant (4.15 cases per 1000 screening mammograms before implementation and 4.20 cases after implementation, P=0.90). Analyses of data from all 43 facilities showed that the use of computer-aided detection was associated with significantly lower overall accuracy than was nonuse (area under the ROC curve, 0.871 vs. 0.919; P=0.005). CONCLUSIONS: The use of computer-aided detection is associated with reduced accuracy of interpretation of screening mammograms. The increased rate of biopsy with the use of computer-aided detection is not clearly associated with improved detection of invasive breast cancer.

Dosimetric characterization of a dedicated breast computed tomography clinical prototype.

PURPOSE: To investigate the glandular dose magnitudes and characteristics resulting from image acquisition using a dedicated breast computed tomography (BCT) clinical prototype imaging system. METHODS: The x-ray spectrum and output characteristics of a BCT clinical prototype (Koning Corporation, West Henrietta, NY) were determined using empirical measurements, breast phantoms, and an established spectrum model. The geometry of the BCT system was replicated in a Monte Carlo-based computer simulation using the GEANT4 toolkit and was validated by comparing the simulated results for exposure distribution in a standard 16 cm CT head phantom with those empirically determined using a 10 cm CT pencil ionization chamber and dosimeter. The computer simulation was further validated by replicating the results of a previous BCT dosimetry study. Upon validation, the computer simulation was modified to include breasts of varying sizes and homogeneous compositions spanning those encountered clinically, and the normalized mean glandular dose resulting from BCT was determined. Using the system's measured exposure output determined automatically for breasts of different size and density, the mean glandular dose for these breasts was computed and compared to the glandular dose resulting from mammography. Finally, additional Monte Carlo simulations were performed to study how the glandular dose values vary within the breast tissue during acquisition with both this BCT prototype and a typical craniocaudal (CC) mammographic acquisition. RESULTS: This BCT prototype uses an x-ray spectrum with a first half-value layer of 1.39 mm Al and a mean x-ray energy of 30.3 keV. The normalized mean glandular dose for breasts of varying size and composition during BCT acquisition with this system ranges from 0.278 to 0.582 mGy/mGy air kerma with the reference air kerma measured in air at the center of rotation. Using the measured exposure outputs for the tube currents automatically selected by the system for the breasts of different sizes and densities, the mean glandular dose for a BCT acquisition with this prototype system varies from 5.6 to 17.5 mGy, with the value for a breast of mean size and composition being 17.06 mGy. The glandular dose throughout the breast tissue of this mean breast varies by up to +/- 50% of the mean value. During a typical CC view mammographic acquisition of an equivalent mean breast, which typically results in a mean glandular dose of 2.0-2.5 mGy, the glandular dose throughout the breast tissue varies from approximately 15% to approximately 400% of the mean value. CONCLUSIONS: Acquisition of a BCT image with the automated tube output settings for a mean breast with the Koning Corp. clinical prototype results in mean glandular dose values approximately equivalent to three to five two-view mammographic examinations for a similar breast. For all breast sizes and compositions studied, this glandular dose ratio between acquisition with this BCT prototype and two-view mammography ranges from 1.4 to 7.2. In mammography, portions of the mean-sized breast receive a considerably higher dose than the mean value for the whole breast. However, only a small portion of a breast undergoing mammography would receive a glandular dose similar to that from BCT.

The positive predictive value of BI-RADS microcalcification descriptors and final assessment categories.

OBJECTIVE: The purpose of this article is to retrospectively assess the likelihood of malignancy of microcalcifications according to the BI-RADS descriptors in a digital mammography environment. MATERIALS AND METHODS: The study included 146 women with calcifications who underwent imaging-guided biopsy between April 2005 and July 2006. Digital mammograms procured before biopsy were analyzed independently by two breast imaging subspecialists blinded to biopsy results. Lesions described discordantly were settled by consensus. One of the radiologists provided a BI-RADS final assessment score. RESULTS: The overall positive predictive value of biopsies was 28.8%. The individual morphologic descriptors predicted the risk of malignancy as follows: fine linear/branching, 16 (70%) of 23 cases; fine pleomorphic, 14 (28%) of 50 cases; coarse heterogeneous, two (20%) of 10 cases; amorphous, 10 (20%) of 51 cases; and typically benign, zero (0%) of 12 cases. Fisher-Freeman-Halton exact testing showed statistical significance among morphology descriptors (p < 0.001) and distribution descriptors (p < 0.001). The positive predictive value for malignancy according to BI-RADS assessment categories were as follows: category 2, 0%; category 3, 0%; category 4A, 13%; category 4B, 36%; category 4C, 79%; and category 5, 100%. CONCLUSION: BI-RADS morphology and distribution descriptors can aid in assessing the risk of malignancy of microcalcifications detected on full-field digital mammography. The positive predictive value increased in successive BI-RADS categories (4A, 4B, and 4C), verifying that subdivision provides an improved assessment of suspicious microcalcifications in terms of likelihood of malignancy.

The Clinically Relevant Breast Imaging Audit.

An audit of a breast imaging practice must be based on data with accepted definitions and rules so that the comparisons between breast imaging facilities and interpretive staff are comparable. The four basic data points for calculating these metrics are true positive (TP), true negative (TN), false positive (FP), and false negative (FN). For mammography, the definition of "true" is the presence of a proven malignancy within a year of the exam. The presence or absence of breast cancer within a year of the exam and an increase in patient mobility between different facilities may render the calculation of sensitivity and specificity difficult for most facilities unless a regional cancer registry is available.Thus, the metrics that can be easily calculated within a facility are recall rate (all the positive interpretations divided by all the exams read), positive predictive value (PPV) 1 = percentage of abnormal screening exams that result in a diagnosis of cancer within a year, PPV2 = percentage of all diagnostic exams recommended for biopsy and cancer discovered within a year, PPV3 = benign tissue diagnosis and no cancer within a year, and the cancer detection rate (the true positive exams per one thousand exams). Intuitively, one may assume that accuracy (TP + TN/TP + FP + TN + FN) is the best metric for an interpreter. However, this can produce spurious results. The most accurate method to determine a reader's skills is the use of the receiver operating characteristic (ROC) curve, which clearly presents, in graphic form, the relationship between the four basic data points.

Comparison of soft-copy and hard-copy reading for full-field digital mammography.

PURPOSE: To compare radiologists' performance in detecting breast cancer when reading full-field digital mammographic (FFDM) images either displayed on monitors or printed on film. MATERIALS AND METHODS: This study received investigational review board approval and was HIPAA compliant, with waiver of informed consent. A reader study was conducted in which 26 radiologists read screening FFDM images displayed on high-resolution monitors (soft-copy digital) and printed on film (hard-copy digital). Three hundred thirty-three cases were selected from the Digital Mammography Image Screening Trial screening study (n = 49,528). Of these, 117 were from patients who received a diagnosis of breast cancer within 15 months of undergoing screening mammography. The digital mammograms were displayed on mammographic workstations and printed on film according to the manufacturer's specifications. Readers read both hard-copy and soft-copy images 6 weeks apart. Each radiologist read a subset of the total images. Twenty-two readers were assigned to evaluate images from one of three FFDM systems, and four readers were assigned to evaluate images from two mammographic systems. Each radiologist assigned a malignancy score on the basis of overall impression by using a seven-point scale, where 1 = definitely not malignant and 7 = definitely malignant. RESULTS: There were no significant differences in the areas under the receiver operating characteristic curves (AUCs) for the primary comparison. The AUCs for soft-copy and hard-copy were 0.75 and 0.76, respectively (95% confidence interval: -0.04, 0.01; P = .36). Secondary analyses showed no significant differences in AUCs on the basis of manufacturer type, lesion type, or breast density. CONCLUSION: Soft-copy reading does not provide an advantage in the interpretation of digital mammograms. However, the display formats were not optimized and display software remains an evolving process, particularly for soft-copy reading.

Diagnostic performance of digital versus film mammography for breast-cancer screening.

BACKGROUND: Film mammography has limited sensitivity for the detection of breast cancer in women with radiographically dense breasts. We assessed whether the use of digital mammography would avoid some of these limitations. METHODS: A total of 49,528 asymptomatic women presenting for screening mammography at 33 sites in the United States and Canada underwent both digital and film mammography. All relevant information was available for 42,760 of these women (86.3 percent). Mammograms were interpreted independently by two radiologists. Breast-cancer status was ascertained on the basis of a breast biopsy done within 15 months after study entry or a follow-up mammogram obtained at least 10 months after study entry. Receiver-operating-characteristic (ROC) analysis was used to evaluate the results. RESULTS: In the entire population, the diagnostic accuracy of digital and film mammography was similar (difference between methods in the area under the ROC curve, 0.03; 95 percent confidence interval, -0.02 to 0.08; P=0.18). However, the accuracy of digital mammography was significantly higher than that of film mammography among women under the age of 50 years (difference in the area under the curve, 0.15; 95 percent confidence interval, 0.05 to 0.25; P=0.002), women with heterogeneously dense or extremely dense breasts on mammography (difference, 0.11; 95 percent confidence interval, 0.04 to 0.18; P=0.003), and premenopausal or perimenopausal women (difference, 0.15; 95 percent confidence interval, 0.05 to 0.24; P=0.002). CONCLUSIONS: The overall diagnostic accuracy of digital and film mammography as a means of screening for breast cancer is similar, but digital mammography is more accurate in women under the age of 50 years, women with radiographically dense breasts, and premenopausal or perimenopausal women. (ClinicalTrials.gov number, NCT00008346.)

Monte Carlo and phantom study of the radiation dose to the body from dedicated CT of the breast.

PURPOSE: To prospectively determine the radiation dose absorbed by the organs and tissues of the body during a dedicated breast computed tomography (CT) study by using Monte Carlo methods and a phantom. MATERIALS AND METHODS: By using the Geant4 Monte Carlo tool kit, the Cristy anthropomorphic phantom and the geometry of a dedicated breast CT prototype were simulated. The simulation was used to track x-rays emitted from the source until their complete absorption or exit from the simulation limits. The interactions of the x-rays with the 65 different volumes representing organs, bones, and other tissues of the phantom that resulted in energy deposition were recorded. These data were used to compute the radiation dose to the organs and tissues during a complete dedicated breast CT scan relative to the average glandular dose to the imaged breast (relative organ dose [ROD]), by using the x-ray spectra proposed for dedicated breast CT imaging. The effectiveness of a lead shield for reducing the dose to the organs was investigated. RESULTS: The maximum ROD among the organs was for the ipsilateral lung with a maximum ROD of 3.25%, followed by ROD for the heart and the thymus. Of the skeletal tissues, the sternum received the highest dose with a maximum ROD to the bone marrow of 2.24% and to the bone surface of 7.74%. The maximum ROD to the uterus, representative of that of an early-stage fetus, was 0.026%. These maxima occurred for the highest-energy x-ray spectrum (80 kVp) that was analyzed. A lead shield does not substantially protect the organs that receive the highest dose from dedicated breast CT. CONCLUSION: Although the dose to the organs from dedicated breast CT is substantially higher than that from planar mammography, it is comparable to or considerably lower than that reached by other radiographic procedures and much lower than that of other CT examinations.