A Non-Contrast Multi-Parametric MRI Biomarker for Assessment of MR-Guided Focused Ultrasound Thermal Therapies.

OBJECTIVE: We present the development of a non-contrast multi-parametric magnetic resonance (MPMR) imaging biomarker to assess treatment outcomes for magnetic resonance-guided focused ultrasound (MRgFUS) ablations of localized tumors. Images obtained immediately following MRgFUS ablation were inputs for voxel-wise supervised learning classifiers, trained using registered histology as a label for thermal necrosis. METHODS: VX2 tumors in New Zealand white rabbits quadriceps were thermally ablated using an MRgFUS system under 3 T MRI guidance. Animals were re-imaged three days post-ablation and euthanized. Histological necrosis labels were created by 3D registration between MR images and digitized H&E segmentations of thermal necrosis to enable voxel-wise classification of necrosis. Supervised MPMR classifier inputs included maximum temperature rise, cumulative thermal dose (CTD), post-FUS differences in T2-weighted images, and apparent diffusion coefficient, or ADC, maps. A logistic regression, support vector machine, and random forest classifier were trained in red a leave-one-out strategy in test data from four subjects. RESULTS: In the validation dataset, the MPMR classifiers achieved higher recall and Dice than a clinically adopted 240 cumulative equivalent minutes at 43 °C (CEM 43) threshold (0.43) in all subjects. The average Dice scores of overlap with the registered histological label for the logistic regression (0.63) and support vector machine (0.63) MPMR classifiers were within 6% of the acute contrast-enhanced non-perfused volume (0.67). CONCLUSIONS: Voxel-wise registration of MPMR data to histological outcomes facilitated supervised learning of an accurate non-contrast MR biomarker for MRgFUS ablations in a rabbit VX2 tumor model.

NCCN Guidelines® Insights: Breast Cancer Screening and Diagnosis, Version 1.2023.

The NCCN Guidelines for Breast Cancer Screening and Diagnosis provide health care providers with a practical, consistent framework for screening and evaluating a spectrum of clinical presentations and breast lesions. The NCCN Breast Cancer Screening and Diagnosis Panel is composed of a multidisciplinary team of experts in the field, including representation from medical oncology, gynecologic oncology, surgical oncology, internal medicine, family practice, preventive medicine, pathology, diagnostic and interventional radiology, as well as patient advocacy. The NCCN Breast Cancer Screening and Diagnosis Panel meets at least annually to review emerging data and comments from reviewers within their institutions to guide updates to existing recommendations. These NCCN Guidelines Insights summarize the panel's decision-making and discussion surrounding the most recent updates to the guideline's screening recommendations.

Comparison of Diagnostic Sensitivity and Procedure-Related Pain of Concurrent Ultrasound-guided Fine-needle Aspiration and Core-needle Biopsy of Axillary Lymph Nodes in Patients with Suspected or Known Breast Cancer.

OBJECTIVE: Conflicting data exist on the diagnostic sensitivity of core-needle biopsy (CNB) compared to fine-needle aspiration (FNA) in the evaluation of axillary lymph node metastasis from breast cancer. Our purpose was to evaluate the sensitivity of CNB and FNA using subsequent axillary surgery as the gold standard and to compare the patients' subjective pain levels for each biopsy method. METHODS: This IRB-approved prospective study enrolled 140 patients from February 2014 to May 2019 with known or suspected breast cancer. Patients underwent both US-guided FNA and 14-gauge CNB of the same node with clip placement and rated their pain level using a verbal numerical rating scale of 0 to 10. The diagnostic sensitivities were determined by pathology of the surgically excised lymph node using the McNemar test of correlated proportions. Changes in pain scores for CNB and FNA were determined using the Wilcoxon rank sum test. RESULTS: A total of 94 patients had confirmatory excision of the biopsied node with nodal metastasis detected in 71.3% (67/94). The sensitivity of CNB for detection of nodal metastasis was 95.5% (64/67), while the sensitivity of FNA was 67.2% (45/67) (P < 0.05). Overall pain score ratings for CNB increased by 0.6 from baseline on an 11-point numerical rating scale, while overall pain score rating for FNA decreased by 0.2 from baseline (P < 0.05). CONCLUSION: Our study demonstrates that 14-gauge CNB has superior sensitivity for detection of axillary nodal metastases and mildly increased pain compared with 25-gauge FNA in patients with breast cancer.

ACGME Diagnostic Radiology Milestones 2.0: the Time is Now.

The Accreditation Council for Graduate Medical Education oversees graduate medical education in the United States. Designed to provide broad based training in all aspects of imaging, the diagnostic radiology residency program must provide educational experiences that not only provide technical, professional, and patient centered training, but also meet accreditation standards. With the breadth of material to cover during training, carefully orchestrated educational experiences must be planned. This manuscript offers residency program leaders resources to meet the challenges of the new Accreditation Council for Graduate Medical Education Diagnostic Radiology Milestones 2.0 and highlights potential opportunities for future educational endeavors.

Perceptions Regarding Optimal Breast Imaging Education for Radiology Residents: Results of a National Survey.

OBJECTIVES: To assess perceptions among breast radiologists regarding optimal breast imaging rotation organization and educational activities for radiology residents. METHODS: An IRB-exempt anonymous questionnaire was developed in REDCap and distributed as a member survey email by the Society of Breast imaging to 2188 members June 2019. A form with 33 questions asked questions about opinions related to resident rotation composition, read-out strategies, study/procedure volume, simulation and educational materials specific to breast imaging. RESULTS: A total of 109/2,188 (4.98%) complete survey responses were received. Of the responders, 69/109 (62%) work in academic practice, 16/109 (15%) work in private practice with residents, and 24/109 (22%) work in private practice without residents. There was no significant variation in opinion between those who have >10 years of experience teaching breast imaging 49/109(42.2%) to those with less <10 years' experience 60/109 (55%). A range of opinions is demonstrated regarding the multiple questions asked with more support for diagnostics and procedures on the second and thirds rotations compared to first rotations. There was strong support of in-person staffing, checklists, simulation for ultrasound-guided procedures (91%) and formal training on delivering bad news (90%). Radiology-pathology conferences and faculty-developed teaching files were highest-rated for effective educational tools. CONCLUSIONS: The results from this survey show varied opinions regarding perceived best practices for resident breast radiology rotations . Further research is needed to determine training outcomes related to rotation organization. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Autologous Fat Grafting to the Breast: An Educational Review.

Autologous fat grafting (AFG) is a technique that is increasingly utilized in breast cosmetic and reconstructive surgery. In this procedure, fat is aspirated by liposuction from one area of the body and injected into the breast. The procedure and process of AFG has evolved over the last few decades, leading to more widespread use, though there is no standard method. Autologous fat grafting is generally considered a safe procedure but may result in higher utilization of diagnostic imaging due to development of palpable lumps related to fat necrosis. Imaging findings depend on surgical technique but typically include bilateral, symmetric, retromammary oil cysts and scattered dystrophic and/or coarse calcifications when AFG is used for primary breast augmentation. More focal findings occur when AFG is used to improve specific areas of cosmetic deformity, scarring, or pain following breast cancer surgery. As with any cause of fat necrosis, imaging features tend to appear more benign over time, with development of rim calcifications associated with oil cysts and a shift in echogenicity of oil cyst contents on ultrasound towards anechoic in some cases. This article reviews the AFG procedure, uses, complications, and imaging findings.

Ultrasound Guided Core Breast Biopsies.

Core needle biopsies are common procedures performed in breast imaging centers. Utilizing ultrasound guidance for biopsy of suspicious findings within the breast and axilla is the standard of care when lesions are visible on ultrasound. Most ultrasound guided breast biopsies are performed by radiologists interpreting breast imaging who correlate findings across modalities including mammography, ultrasound and breast MRI, however interventional radiologists may perform in some practice settings. Appropriate knowledge of complete breast imaging is important not only for localization, but for determining radiologic-pathologic concordance. Proper localization, technique, and post biopsy management are essential to the success of the procedure and providing proper care for patients. This article discusses indications, strategies for accurate targeting, how-to biopsy techniques, post biopsy considerations and radiologic-pathologic concordance incorporating recommendations from the American College of Radiology Practice Parameter for the Performance of Ultrasound-guided Percutaneous Breast Interventional procedures.

Learning Multiparametric Biomarkers for Assessing MR-Guided Focused Ultrasound Treatment of Malignant Tumors.

Noninvasive MR-guided focused ultrasound (MRgFUS) treatments are promising alternatives to the surgical removal of malignant tumors. A significant challenge is assessing the viability of treated tissue during and immediately after MRgFUS procedures. Current clinical assessment uses the nonperfused volume (NPV) biomarker immediately after treatment from contrast-enhanced MRI. The NPV has variable accuracy, and the use of contrast agent prevents continuing MRgFUS treatment if tumor coverage is inadequate. This work presents a novel, noncontrast, learned multiparametric MR biomarker that can be used during treatment for intratreatment assessment, validated in a VX2 rabbit tumor model. A deep convolutional neural network was trained on noncontrast multiparametric MR images using the NPV biomarker from follow-up MR imaging (3-5 days after MRgFUS treatment) as the accurate label of nonviable tissue. A novel volume-conserving registration algorithm yielded a voxel-wise correlation between treatment and follow-up NPV, providing a rigorous validation of the biomarker. The learned noncontrast multiparametric MR biomarker predicted the follow-up NPV with an average DICE coefficient of 0.71, substantially outperforming the current clinical standard (DICE coefficient = 0.53). Noncontrast multiparametric MR imaging integrated with a deep convolutional neural network provides a more accurate prediction of MRgFUS treatment outcome than current contrast-based techniques.

Breast Fibromatosis: Radiologic-Pathologic Correlation.

Fibromatosis of the breast is a rare, benign locally infiltrative tumor without metastatic potential. Patients typically present with a painless, palpable, firm breast mass, which may be mobile or fixed to the pectoralis muscle. While some cases are related to familial mutations in the adenomatous polyposis coli (APC) gene, the majority are sporadic due to somatic mutations or prior injury to the breast tissue. On mammography, fibromatosis is typically seen as an irregular, dense, spiculated mass. US demonstrates a hypoechoic, irregular mass with indistinct margins. Fibromatosis is indistinguishable from breast cancer on imaging, and core biopsy is required for definitive diagnosis. Wide local excision is the historical standard for treatment; however, recurrence rates are high, and other emerging therapies are being explored. This article reviews the clinical features, imaging and histopathologic findings, along with brief overview of management.

Impact of Immediate Interpretation of Screening Tomosynthesis Mammography on Performance Metrics.

RATIONALE AND OBJECTIVES: This study aimed to compare performance metrics for immediate and delayed batch interpretation of screening tomosynthesis mammograms. MATERIALS AND METHODS: This HIPAA compliant study was approved by institutional review board with a waiver of consent. A retrospective analysis of screening performance metrics for tomosynthesis mammograms interpreted in 2015 when mammograms were read immediately was compared to historical controls from 2013 to 2014 when mammograms were batch interpreted after the patient had departed. A total of 5518 screening tomosynthesis mammograms (n = 1212 for batch interpretation and n = 4306 for immediate interpretation) were evaluated. The larger sample size for the latter group reflects a group practice shift to performing tomosynthesis for the majority of patients. Age, breast density, comparison examinations, and high-risk status were compared. An asymptotic proportion test and multivariable analysis were used to compare performance metrics. RESULTS: There was no statistically significant difference in recall or cancer detection rates for the batch interpretation group compared to immediate interpretation group with respective recall rate of 6.5% vs 5.3% = +1.2% (95% confidence interval -0.3 to 2.7%; P = .101) and cancer detection rate of 6.6 vs 7.2 per thousand = -0.6 (95% confidence interval -5.9 to 4.6; P = .825). There was no statistically significant difference in positive predictive values (PPVs) including PPV1 (screening recall), PPV2 (biopsy recommendation), or PPV 3 (biopsy performed) with batch interpretation (10.1%, 42.1%, and 40.0%, respectively) and immediate interpretation (13.6%, 39.2%, and 39.7%, respectively). After adjusting for age, breast density, high-risk status, and comparison mammogram, there was no difference in the odds of being recalled or cancer detection between the two groups. CONCLUSIONS: There is no statistically significant difference in interpretation performance metrics for screening tomosynthesis mammograms interpreted immediately compared to those interpreted in a delayed fashion.

Impaired brain response to odors in patients with varied severity of olfactory loss after traumatic brain injury.

Traumatic brain injury (TBI) as a major public health problem may lead to olfactory dysfunction. However, little is known about brain responses to odors in TBI olfactory loss patients. Nineteen healthy controls and forty TBI olfactory dysfunctional patients (19 with hyposmia and 21 with anosmia) underwent a functional magnetic resonance imaging scan when two odors (peach and coffee) were presented intranasally using a computerized olfactometer. Olfactory performance was measured using the "Sniffin' Sticks" test. TBI patients with hyposmia or anosmia showed decreased odor-induced brain activations in the primary olfactory area and insular cortex as compared to healthy controls (FWE-corrected peak p < 0.05). In addition, negative correlations were found between the time since injury (in month) and odor-induced brain responses in the right primary olfactory area for patients with hyposmia. Similar correlations were seen in the insula and orbitofrontal cortex for patients with anosmia. In conclusion, results from the current study are evidences for the impairment of central nervous processing of odor perception at all levels of the olfactory system among TBI patients with olfactory loss. In addition, the duration after the initial injury may have an impact on the severity of olfactory dysfunction.

Comparison of Breast Density Between Synthesized Versus Standard Digital Mammography.

PURPOSE: To evaluate perceptual difference in breast density classification using synthesized mammography (SM) compared with standard or full-field digital mammography (FFDM) for screening. MATERIALS AND METHODS: This institutional review board-approved, retrospective, multireader study evaluated breast density on 200 patients who underwent baseline screening mammogram during which both SM and FFDM were obtained contemporaneously from June 1, 2016, through November 30, 2016. Qualitative breast density was independently assigned by seven readers initially evaluating FFDM alone. Then, in a separate session, these same readers assigned breast density using synthetic views alone on the same 200 patients. The readers were again blinded to each other's assignment. Qualitative density assessment was based on BI-RADS fifth edition. Interreader agreement was evaluated with κ statistic using 95% confidence intervals. Testing for homogeneity in paired proportions was performed using McNemar's test with a level of significance of .05. RESULTS: For patients across the SM and standard 2-D data set, diagnostic testing with McNemar's test with P = 0.32 demonstrates that the minimal density transitions across FFDM and SM are not statistically significant density shifts. Taking clinical significance into account, only 8 of 200 (4%) patients had clinically significant transition (dense versus not dense). There was substantial interreader agreement with overall κ in FFDM of 0.71 (minimum 0.53, maximum 0.81) and overall SM κ average of 0.63 (minimum 0.56, maximum 0.87). CONCLUSION: Overall subjective breast density assignment by radiologists on SM is similar to density assignment on standard 2-D mammogram.

An AAST-MITC analysis of pancreatic trauma: Staple or sew? Resect or drain?

INTRODUCTION: Pancreatic trauma results in high morbidity and mortality, in part caused by the delay in diagnosis and subsequent organ dysfunction. Optimal operative management strategies remain unclear. We therefore sought to determine CT accuracy in diagnosing pancreatic injury and the morbidity and mortality associated with varying operative strategies. METHODS: We created a multicenter, pancreatic trauma registry from 18 Level 1 and 2 trauma centers. Adult, blunt or penetrating injured patients from 2005 to 2012 were analyzed. Sensitivity and specificity of CT scan identification of main pancreatic duct injury was calculated against operative findings. Independent predictors for mortality, adult respiratory distress syndrome (ARDS), and pancreatic fistula and/or pseudocyst were identified through multivariate regression analysis. The association between outcomes and operative management was measured. RESULTS: We identified 704 pancreatic injury patients of whom 584 (83%) underwent a pancreas-related procedure. CT grade modestly correlated with OR grade (r 0.39) missing 10 ductal injuries (9 grade III, 1 grade IV) providing 78.7% sensitivity and 61.6% specificity. Independent predictors of mortality were age, Injury Severity Score (ISS), lactate, and number of packed red blood cells transfused. Independent predictors of ARDS were ISS, Glasgow Coma Scale score, and pancreatic fistula (OR 5.2, 2.6-10.1). Among grade III injuries (n = 158, 22.4%), the risk of pancreatic fistula/pseudocyst was reduced when the end of the pancreas was stapled (OR 0.21, 95% CI 0.05-0.9) compared with sewn and was not affected by duct stitch placement. Drainage alone in grades IV (n = 25) and V (n = 24) injuries carried increased risk of pancreatic fistula/pseudocyst (OR 8.3, 95% CI 2.2-32.9). CONCLUSION: CT is insufficiently sensitive to reliably identify pancreatic duct injury. Patients with grade III injuries should have their resection site stapled instead of sewn and a duct stitch is unnecessary. Further study is needed to determine if drainage alone should be employed in grades IV and V injuries. LEVEL OF EVIDENCE: Epidemiologic/Diagnostic study, level III.

Alterations of Brain Gray Matter Density and Olfactory Bulb Volume in Patients with Olfactory Loss after Traumatic Brain Injury.

Olfactory loss and traumatic brain injury (TBI) both lead to anatomical brain alterations in humans. Little research has been done on the structural brain changes for TBI patients with olfactory loss. Using voxel-based morphometry, the gray matter (GM) density was examined for 22 TBI patients with hyposmia, 24 TBI patients with anosmia, and 22 age-matched controls. Olfactory bulb (OB) volumes were measured by manual segmentation of acquired T2-weighted coronal slices using a standardized protocol. Brain lesions in the olfactory-relevant areas also were examined for TBI patients. Results showed that patients with anosmia have more frequent lesions in the OB, orbitofrontal cortex (OFC), and the temporal lobe pole, compared with patients with hyposmia. GM density in the primary olfactory area was decreased in both groups of patients. In addition, compared with controls, patients with anosmia showed GM density reduction in several secondary olfactory eloquent regions, including the gyrus rectus, medial OFC, anterior cingulate cortex, insula, and cerebellum. However, patients with hyposmia showed a lesser degree of GM reduction, compared with healthy controls. Smaller OB volumes were found for patients with olfactory loss, compared with controls. TBI patients with anosmia had the smallest OB volumes, which were caused by the lesions for OB. In addition, post-TBI duration was negatively correlated with GM density in the secondary olfactory areas in patients with hyposmia, but was positively correlated with GM density in the frontal and temporal gyrus in patients with anosmia. The GM density and OB volume reduction among TBI patients with olfactory loss was largely dependent on the location and severity of brain lesions in olfactory-relevant regions. Longer post-TBI duration had an impact on brain GM density changes, which indicate a decreased olfactory function in patients with hyposmia and possible compensatory mechanisms in patients with anosmia.

Ditching the Disc: The Effects of Cloud-Based Image Sharing on Department Efficiency and Report Turnaround Times in Mammography.

In screening mammography, accessing prior examination images is crucial for accurate diagnosis and avoiding false-positives. When women visit multiple institutions for their screens, these "outside" examinations must be retrieved for comparison. Traditionally, prior images are obtained by faxing requests to other institutions and waiting for standard mail (film or CD-ROM), which can greatly delay report turnaround times. Recently, advancements in cloud-based image transfer technology have opened up more efficient options for examination transfer between institutions. The objective of this study was to evaluate the effect of cloud-based image transfer on mammography department workflow, time required to obtain prior images, and report turnaround times. Sixty screening examinations requiring prior images were placed into two groups (30 each). The control group used the standard institutional protocol for requesting prior images: faxing requests and waiting for mailed examinations. The experimental group used a cloud-based transfer for both requesting and receiving examinations. The mean number of days between examination request and examination receipt was measured for both groups and compared. The mean number of days from examination request to receipt was 6.08 days (SD 3.50) in the control group compared with 3.16 days (SD 3.95) in the experimental group. Using a cloud-based image transfer to obtain prior mammograms resulted in an average reduction of 2.92 days (P = .0361; 95% confidence interval 0.20-5.65) between examination request and receipt. This improvement in system efficiency is relevant for interpreting radiologists working to improve reporting times and for patients anxious to receive their mammography results.

Clinical implementation of synthesized mammography with digital breast tomosynthesis in a routine clinical practice.

BACKGROUND: Most published studies evaluating digital breast tomosynthesis (DBT) included a separate 2-dimensional full-field digital mammogram (FFDM) for DBT screening protocols, increasing radiation from screening mammography. Synthesized mammography (SM) creates a 2-dimensional image from the DBT source data, and if used in place of FFDM, it reduces radiation of DBT screening. This study evaluated the implementation of SM + DBT in routine screening practice in terms of recall rates, cancer detection rates (CDR), % of minimal cancers, % of node-positive cancers, and positive predictive values (PPV). MATERIALS AND METHODS: A multivariate retrospective institutional analysis was performed on 31,979 women who obtained screening mammography (10/2013-12/2015) with cohorts divided by modality (SM + DBT, FFDM + DBT, and FFDM). We adjusted for comparison mammograms, age, breast density, and the interpreting radiologist. Recall type was analyzed for differences (focal asymmetry, asymmetry, masses, calcifications, architectural distortion). RESULTS: SM + DBT significantly decreased the recall rate compared to FFDM (5.52 vs. 7.83%, p < 0.001) with no differences in overall CDR (p = 0.66), invasive and/or in situ CDR, or percentages of minimal and node-negative cancers. PPV1 significantly increased with SM + DBT relative to FFDM (9.1 vs. 6.2%, p = 0.02). SM + DBT did not differ significantly in recall rate or overall CDR compared to FFDM + DBT. There were statistically significant differences in certain findings recalled by screening modality (e.g., focal asymmetries). CONCLUSIONS: SM + DBT reduces false positives compared to FFDM, while maintaining the CDR and other desirable audit outcome data. SM + DBT is more accurate than FFDM alone, and is a desirable alternative to FFDM + DBT, given the added benefit of radiation reduction.

Synthesized Digital Mammography Imaging.

Synthesized mammography (SM) is a new imaging technique similar to digital mammography constructed from an acquired digital breast tomosynthesis (DBT) examination. SM allows for widespread screening using DBT, maintaining the benefits of DBT while decreasing the radiation of DBT by nearly half. This article reviews studies evaluating SM, most of which suggest that SM may be appropriate to use clinically to replace an actual acquired conventional 2-dimensional full-field digital mammogram (FFDM) when using DBT for breast cancer screening. These results should be interpreted with caution because there are inherent differences between SM and FFDM image quality and lesion visibility and larger, more robust studies still need to be performed.

Spectrum of Pregnancy- and Lactation-related Benign Breast Findings.

INTRODUCTION: Extensive physiologic changes occur in the breasts during pregnancy and lactation. Additionally, several specific benign lesions are also common in pregnant and lactating patients. These changes and lesions have characteristic imaging appearances and findings. OBJECTIVE: This article provides an image-rich educational review of typical and atypical benign imaging findings in pregnant and lactating patients. The discussion also includes basic imaging protocol considerations and explores management options. CONCLUSION: An understanding of the typical and atypical imaging appearance of physiological changes and specific benign lesions occurring in pregnancy and lactation is essential for appropriate patient care and management.

Developing Asymmetries at Mammography: A Multimodality Approach to Assessment and Management.

A developing asymmetry is a focal asymmetry that is new or increased in conspicuity compared with the previous mammogram. It is challenging to evaluate, as it often looks similar to fibroglandular tissue at mammography. A developing asymmetry should be viewed with suspicion because it is an uncommon manifestation of breast cancer. Diagnostic mammography forms the foundation of diagnostic evaluation of a developing asymmetry and begins with additional spot compression, lateral, and/or rolled views to evaluate and localize it in three-dimensional space. Digital breast tomosynthesis can aid in evaluation by improving radiologists' sensitivity and specificity, as well as allowing localization of the lesion. Once the developing asymmetry has been fully characterized and localized with diagnostic mammography, targeted ultrasonography (US) should be performed to identify potentially benign causes of the developing asymmetry or identify a target for biopsy. However, lack of a US correlate should not preclude biopsy of a developing asymmetry. Diagnostic breast magnetic resonance imaging can be used in a minority of cases for problem solving or biopsy planning if no US correlate is identified and stereotactic biopsy is not feasible. The purpose of this article is to review the definition of developing asymmetry, describe the multimodality diagnostic tools available to the radiologist for evaluation of this challenging entity, and review the various causes, both benign and malignant.

Effect of Training on Qualitative Mammographic Density Assessment.

PURPOSE: The aim of this study was to evaluate the accuracy of visual mammographic breast density assessment and determine if training can improve this assessment, to compare the accuracy of qualitative density assessment before and after training with a quantitative assessment tool, and to evaluate agreement between qualitative and quantitative density assessment methods. METHODS: Consecutive screening mammograms performed over a 4-month period were visually assessed by two study breast radiologists (the leads), who selected 200 cases equally distributed among the four BI-RADS density categories. These 200 cases were shown to 20 other breast radiologists (the readers) before and after viewing a training module on visual density assessment. Agreement between reader assessment and lead radiologist assessment was calculated for both reading sessions. Quantitative volumetric density of the 200 mammograms, determined using a commercially available tool, was compared with both sets of reader assessment and with lead radiologist assessment. RESULTS: Compared with lead radiologist assessment, reader accuracy of breast density assessment increased from 65% before training to 72% after training (odds ratio, 1.41; P < .0001). Training specifically improved assignment to BI-RADS categories 1 (P < .0001) and 4 (P < .10). Compared with quantitative assessment, reader accuracy showed statistically nonsignificant improvement with training (odds ratio, 1.1; P = .26). Substantial agreement between qualitative and quantitative breast density assessment was demonstrated (κ = 0.78). CONCLUSIONS: Training may improve the accuracy of mammographic breast density assessment. Substantial agreement between qualitative and quantitative breast density assessment exists.