Outcomes of High-Risk Breast MRI Screening in Women Without Prior History of Breast Cancer: Effectiveness Data from a Tertiary Care Center.

OBJECTIVE: To evaluate the diagnostic performance outcomes of a breast MRI screening program in high-risk women without prior history of breast cancer. METHODS: Retrospective cohort study of 1 405 consecutive screening breast MRI examinations in 681 asymptomatic women with high risk of breast cancer without prior history of breast cancer from January 1, 2015, to December 31, 2019. Outcomes (sensitivity, specificity, positive predictive value, negative predictive value, false-negative rate [FNR], cancer detection rate [CDR]) and characteristics of cancers were determined based on histopathology or 12-month follow-up. MRI examinations performed, BI-RADS assessments, pathology outcomes, and CDRs were analyzed overall and by age decade. Results in incidence screening round (MRI in last 18 months) and nonincidence round were compared. RESULTS: Breast MRI achieved CDR 20/1000, sensitivity 93.3% (28/30), and specificity 83.4% (1 147/1375). Twenty-eight (28/1 405, CDR 20/1000) screen-detected cancers were identified: 18 (64.3%, 18/28) invasive and 10 (35.7%, 10/28) ductal carcinoma in situ. Overall, 92.9% (26/28) of all cancers were stage 0 or 1 and 89.3% (25/28) were node negative. All 14 incidence screening round malignancies were stage 0 or 1 with N0 disease. Median size for invasive carcinoma was 8.0 mm and for ductal carcinoma in situ was 9.0 mm. There were two false-negative exams for an FNR 0.1% (2/1 405). CONCLUSION: High-risk screening breast MRI was effective at detecting early breast cancer and associated with favorable outcomes.

Deep learning denoising of digital breast tomosynthesis: Observer performance study of the effect on detection of microcalcifications in breast phantom images.

BACKGROUND: The noise in digital breast tomosynthesis (DBT) includes x-ray quantum noise and detector readout noise. The total radiation dose of a DBT scan is kept at about the level of a digital mammogram but the detector noise is increased due to acquisition of multiple projections. The high noise can degrade the detectability of subtle lesions, specifically microcalcifications (MCs). PURPOSE: We previously developed a deep-learning-based denoiser to improve the image quality of DBT. In the current study, we conducted an observer performance study with breast radiologists to investigate the feasibility of using deep-learning-based denoising to improve the detection of MCs in DBT. METHODS: We have a modular breast phantom set containing seven 1-cm-thick heterogeneous 50% adipose/50% fibroglandular slabs custom-made by CIRS, Inc. (Norfolk, VA). We made six 5-cm-thick breast phantoms embedded with 144 simulated MC clusters of four nominal speck sizes (0.125-0.150, 0.150-0.180, 0.180-0.212, 0.212-0.250 mm) at random locations. The phantoms were imaged with a GE Pristina DBT system using the automatic standard (STD) mode. The phantoms were also imaged with the STD+ mode that increased the average glandular dose by 54% to be used as a reference condition for comparison of radiologists' reading. Our previously trained and validated denoiser was deployed to the STD images to obtain a denoised DBT set (dnSTD). Seven breast radiologists participated as readers to detect the MCs in the DBT volumes of the six phantoms under the three conditions (STD, STD+, dnSTD), totaling 18 DBT volumes. Each radiologist read all the 18 DBT volumes sequentially, which were arranged in a different order for each reader in a counter-balanced manner to minimize any potential reading order effects. They marked the location of each detected MC cluster and provided a conspicuity rating and their confidence level for the perceived cluster. The visual grading characteristics (VGC) analysis was used to compare the conspicuity ratings and the confidence levels of the radiologists for the detection of MCs. RESULTS: The average sensitivities over all MC speck sizes were 65.3%, 73.2%, and 72.3%, respectively, for the radiologists reading the STD, dnSTD, and STD+ volumes. The sensitivity for dnSTD was significantly higher than that for STD (p < 0.005, two-tailed Wilcoxon signed rank test) and comparable to that for STD+. The average false positive rates were 3.9 ± 4.6, 2.8 ± 3.7, and 2.7 ± 3.9 marks per DBT volume, respectively, for reading the STD, dnSTD, and STD+ images but the difference between dnSTD and STD or STD+ did not reach statistical significance. The overall conspicuity ratings and confidence levels by VGC analysis for dnSTD were significantly higher than those for both STD and STD+ (p ≤ 0.001). The critical alpha value for significance was adjusted to be 0.025 with Bonferroni correction. CONCLUSIONS: This observer study using breast phantom images showed that deep-learning-based denoising has the potential to improve the detection of MCs in noisy DBT images and increase radiologists' confidence in differentiating noise from MCs without increasing radiation dose. Further studies are needed to evaluate the generalizability of these results to the wide range of DBTs from human subjects and patient populations in clinical settings.

Effect of Dose Level on Radiologists' Detection of Microcalcifications in Digital Breast Tomosynthesis: An Observer Study with Breast Phantoms.

OBJECTIVES: To compare radiologists' sensitivity, confidence level, and reading efficiency of detecting microcalcifications in digital breast tomosynthesis (DBT) at two clinically relevant dose levels. MATERIALS AND METHODS: Six 5-cm-thick heterogeneous breast phantoms embedded with a total of 144 simulated microcalcification clusters of four speck sizes were imaged at two dose modes by a clinical DBT system. The DBT volumes at the two dose levels were read independently by six MQSA radiologists and one fellow with 1-33 years (median 12 years) of experience in a fully-crossed counter-balanced manner. The radiologist located each potential cluster and rated its conspicuity and his/her confidence that the marked location contained a cluster. The differences in the results between the two dose modes were analyzed by two-tailed paired t-test. RESULTS: Compared to the lower-dose mode, the average glandular dose in the higher-dose mode for the 5-cm phantoms increased from 1.34 to 2.07 mGy. The detection sensitivity increased for all speck sizes and significantly for the two smaller sizes (p <0.05). An average of 13.8% fewer false positive clusters was marked. The average conspicuity rating and the radiologists' confidence level were higher for all speck sizes and reached significance (p <0.05) for the three larger sizes. The average reading time per detected cluster reduced significantly (p <0.05) by an average of 13.2%. CONCLUSION: For a 5-cm-thick breast, an increase in average glandular dose from 1.34 to 2.07 mGy for DBT imaging increased the conspicuity of microcalcifications, improved the detection sensitivity by radiologists, increased their confidence levels, reduced false positive detections, and increased the reading efficiency.

Breast cancer screening in average and high-risk women.

Breast cancer is the most common cancer among females worldwide with rising incidence. In the United States, screening mammography and advances in therapy have lowered mortality by 41% since 1990. Screening mammography is supported by randomized control trials (RCT), observational studies, and computer model data. Digital breast tomosynthesis is a new technology that addresses limitations in mammography resulting from overlapping breast tissue, improving its sensitivity and specificity. Patients at high risk for breast cancer include those with a ≥20% lifetime risk, high-risk germline mutation, or history of thoracic radiation treatment between 10-30 years of age. Such patients are recommended to undergo annual screening mammography and adjunctive annual screening breast MRI. Patients unable to undergo MRI may undergo whole breast ultrasound or contrast-enhanced mammography. Pregnant and lactating patients at average risk for breast cancer are recommended to undergo age-appropriate screening mammography.

Management of Incidental Breast Lesions Detected at Nuclear Medicine Examinations.

Nuclear medicine studies are often performed in patients with breast cancer; however, incidental radiotracer uptake in the breasts can be observed in patients with nonbreast malignancies. Benign and malignant lesions can be identified on planar, SPECT, and PET scans. This review will outline the molecular and radiographic imaging appearance of benign and malignant breast lesions on sestamibi scans, bone scans, radioiodine studies, as well as PET studies using fluorine 18 (18F) fluorodeoxyglucose, gallium 68 (68Ga) tetraazacyclododecane tetraacetic acid octreotate (or DOTATATE), 68Ga prostate-specific membrane antigen, and 18F-fluciclovine radiotracers. Recognizing these lesions at molecular and anatomic imaging is important to ensure accurate diagnosis and appropriate management. Keywords: Breast, Mammography, Molecular Imaging, PET/CT, Radionuclide Studies, SPECT/CT © RSNA, 2020.

The impact of infection and inflammation in oncologic 18F-FDG PET/CT imaging.

Sites of infection and inflammation can be misleading in oncology PET/CT imaging because these areas commonly show 18F-FDG activity. Caution in the interpretation must be taken to avoid the misdiagnosis of malignancy. Utilization of both CT findings as well as patient history can help differentiate benign infectious and inflammatory processes from malignancy, although occasionally additional work-up may be required. This article discusses the mechanism of 18F-FDG uptake in infection and inflammation with illustrative examples.

Harms of Restrictive Risk-Based Mammographic Breast Cancer Screening.

OBJECTIVE: The objective of this study was to determine if restrictive risk-based mammographic screening could miss breast cancers that population-based screening could detect. MATERIALS AND METHODS: Through a retrospective search of records at a single institution, we identified 552 screen-detected breast cancers in 533 patients. All in situ and invasive breast cancers detected at screening between January 1, 2011, and December 31, 2014, were included. Medical records were reviewed for history, pathology, cancer size, nodal status, breast density, and mammographic findings. Mammograms were interpreted by one of 14 breast imaging radiologists with 3-30 years of experience, all of whom were certified according to the Mammography Quality Standards Act. Patient ages ranged from 36 to 88 years (mean, 61 years). The breast cancer risks evaluated were family history of breast cancer and dense breast tissue. Positive family history was defined as a first-degree relative with breast cancer. Dense breast parenchyma was either heterogeneously or extremely dense. RESULTS: Group 1 consisted of the 76.7% (409/533) of patients who had no personal history of breast cancer. Of these patients, 75.6% (309/409) had no family history of breast cancer, and 56% (229/409) had nondense breasts. Group 2 consisted of the 16.7% (89/533) of patients who were 40-49 years old. Of these patients, 79.8% (71/89) had no family history of breast cancer, and 30.3% (27/89) had nondense breasts. Ductal carcinoma in situ made up 34.6% (191/552) of the cancers; 65.4% (361/552) were invasive. The median size of the invasive cancers was 11 mm. Of the screen-detected breast cancers, 63.8% (352/552) were minimal cancers. CONCLUSION: Many screen-detected breast cancers occurred in women without dense tissue or a family history of breast cancer. Exclusive use of restrictive risk-based screening could result in delayed cancer detection for many women.

Neurovascular emergencies: imaging diagnosis and neurointerventional treatment.

Neurovascular emergencies, consisting of acute ischemic stroke, non-traumatic aneurysmal subarachnoid hemorrhage, arteriovenous malformation, dural arteriovenous fistula, and carotid- cavernous fistula, can have an acute presentation to the emergency department. Radiologists should have an understanding of these processes and their imaging findings in order to provide a prompt and accurate diagnosis. Neurointerventional radiology plays a critical role in providing additional diagnostic information and potentially curative treatment. Understanding the grading scales used to evaluate and prognosticate these neurovascular emergencies can help expedite management for best possible patient outcomes.

Reinterpretation of Outside Hospital MRI Abdomen Examinations in Patients With Cirrhosis: Is the OPTN Mandate Necessary?

OBJECTIVE: The objective of our study was to determine the relevance of a policy mandating reinterpretation of outside abdominal MRI examinations in patients with cirrhosis at risk for hepatocellular carcinoma (HCC). MATERIALS AND METHODS: A random subset (n = 125) of consecutive outside-hospital MRI abdomen examinations (n = 473) performed in subjects with cirrhosis and reinterpreted at a tertiary care center by one of 11 fellowship-trained radiologists was included. The original and reinterpreted reports were compared in consensus by two hepatobiliary imaging experts; one hepatologist determined the clinical impact. Each was blinded to outcome. The primary outcome was discrepancies relevant to the Organ Procurement and Transplantation Network (OPTN), including diagnosis of HCC and exceeding the Milan criteria for transplantation. Rates were compared with the McNemar test. RESULTS: HCC was diagnosed in 34% (43/125) of reinterpretations; of these, 44% (19/43) were concordant, 42% (18/43) originally were considered suspicious but not diagnostic of HCC, and 14% (6/43) were discordant. The Milan criteria were exceeded in 21% (26/125) of reinterpretations; of these, 73% (19/26) were concordant and 27% (7/26) were discordant. Overall, 10% (12/125) of subjects had a discrepant diagnosis of HCC, and 10% (12/125) of subjects had discrepant Milan status; 26% (11/43) of masses diagnosed to be HCC had been biopsied at the original institution. Original reports were significantly more likely to be missing major details (26% [32/125] vs 0.8% [1/125], p < 0.001) or difficult to understand (18% [23/125] vs 0.8% [1/125], p < 0.001). Predicted clinical management differed in 50% (62/125) of reinterpretations. CONCLUSION: The OPTN mandate for expert interpretation of liver MRI in patients with cirrhosis appears justified.