ACR BI-RADS Assessment Category 4 Subdivisions in Diagnostic Mammography: Utilization and Outcomes in the National Mammography Database

Abstract

Purpose To determine the utilization and positive predictive value (PPV) of the American College of Radiology (ACR) Breast Imaging Data and Reporting System (BI-RADS) category 4 subdivisions in diagnostic mammography in the National Mammography Database (NMD). Materials and Methods This study involved retrospective review of diagnostic mammography data submitted to the NMD from January 1, 2008 to December 30, 2014. Utilization rates of BI-RADS category 4 subdivisions were compared by year, facility (type, location, census region), and examination (indication, finding type) characteristics. PPV3 (positive predictive value for biopsies performed) was calculated overall and according to category 4 subdivision. The χ test was used to test for significant associations. Results Of 1 309 950 diagnostic mammograms, 125 447 (9.6%) were category 4, of which 33.3% (41 841 of 125 447) were subdivided. Subdivision utilization rates were higher (P < .001) in practices that were community, suburban, or in the West; for examination indication of prior history of breast cancer; and for the imaging finding of architectural distortion. Of 41 841 category 4 subdivided examinations, 4A constituted 55.6% (23 258 of 41 841) of the examinations; 4B, 31.8% (13 302 of 41 841) of the examinations; and 4C, 12.6% (5281 of 41 841) of the examinations. Pathologic outcomes were available in 91 563 examinations, and overall category 4 PPV3 was 21.1% (19 285 of 91 563). There was a statistically significant difference in PPV3 according to category 4 subdivision (P < .001): The PPV of 4A was 7.6% (1274 of 16 784), that of 4B was 22% (2317 of 10 408), and that of 4C was 69.3% (2839 of 4099). Conclusion Although BI-RADS suggests their use, subdivisions were utilized in the minority (33.3% [41 841 of 125 447]) of category 4 diagnostic mammograms, with variability based on facility and examination characteristics. When subdivisions were used, PPV3s were in BI-RADS-specified malignancy ranges. This analysis supports the use of subdivisions in broad practice and, given benefits for patient care, should motivate increased utilization. RSNA, 2018 Online supplemental material is available for this article.

Evaluation of the positive predictive value (PPV3) of ACR BI-RADS category 4 and 5 based on the outcomes of Invasive Diagnostic Office in an outpatient clinic

“…BI-RADS 5 constitute 12.6% of cases, which is comparable with the 8% reported in “The Thai Journal of Surgery”, especially as this was based only on nonpalpable mammographic lesions, and those limitations did not apply to our work [20]. ACR BI-RADS 4c was observed in 15.6% of cases and 4b in 27.1%, which is similar to the 12.6% and 31.8%, respectively, published by Elezaby et al in “Radiology” in 2018 [9]. Compared with this assessment, there is clearly visible difference in the percentage of BI-RADS 4a.…”

“…Breast cancer was diagnosed in 34.8% of biopsies and in 26.2% in ACR BI-RADS 4 category. This is almost perfect pitch, as the BI-RADS 4 category reported range is from 20% to 27% and PPV for BI-RADS 5 and 4 in ultrasound-guided biopsy resume was 35% [9,20-25]. The category BI-RADS 4a is sometimes mentioned as a low cancer predictive factor, but because it is an indication for biopsy, we decided not to exclude it from our calculations for biopsy office, because it is still responsible for false positives and some true positives outcomes [26].…”

“…There is no legal implementation of BI-RADS classification for diagnostic purposes, but the scale is well known and commonly used among performers of breast diagnostics, and it is recommended [8]. According to the data from the National Mammography Database in the United States of America, about one third of BI-RADS 4 cases were reported in subcategories [9]. From our experience this does not apply to Poland, because even if there is only BI-RADS 4 in screening outcome, sustained on recall visit, it is to be subcategorised.…”

Contrast‐enhanced spectral mammography: A potential exclusion diagnosis modality in dense breast patients

“…Chaiwerawattana et al conducted a retrospective study of BI‐RADS 4 patients diagnosed in the National Cancer Institute Thailand during 2003‐2008, which showed that the malignant positive rates of 4A, 4B, and 4C patients were 7.7%, 38.7%, and 58.0%, respectively . In another study published by Elezaby et al, with 41 841 patients classified as BI‐RADS 4, the positive predictive values of 4A, 4B, and 4C patients were 7.6%, 22.0%, and 69.3%, respectively . From these results, we could infer that the malignant predictive values varied significantly among BI‐RADS four subtypes, and only BI‐RADS 4C permitted prediction of more than 50% malignant tumors.…”

<p>The Vascular Index of Superb Microvascular Imaging Can Improve the Diagnostic Accuracy for Breast Imaging Reporting and Data System Category 4 Breast Lesions</p>

“…7 Studies have shown that BI-RADS 4A lesions account for about half of BI-RADS 4 lesions, but only 7.6% of those lesions yielded malignant results. 8,9 Thus, BI-RADS 4A lesions are appropriate to be reduced in rank to surveillance by providing more information about mass in more ways. A desirable specificity, accuracy, positive predictive value for the assessment of BI-RADS 4 lesions can thus reduce unnecessary biopsies and surgeries.…”