CHICAGO - Directly scheduling biopsy is an appropriate course of action for breast lesions categorized as BI-RADS 4C and 5 on screening ultrasound, according to research presented on Tuesday at the annual RSNA meeting.
The results address the long-held question of which BI-RADS categories on screening breast ultrasound should prompt further imaging, follow-up, or biopsy, presenter Dr. Wendie Berg of the University of Pittsburgh told session attendees.
The study is part of a three-year trial that is comparing DBT and supplemental ultrasound with DBT alone; Berg presented preliminary data from two of those years. The two years of data included 5,689 asymptomatic women between the ages of 40 and 74 who underwent digital breast tomosynthesis (DBT) and technologist-performed handheld screening ultrasound at three centers -- one academic and two private practice.
"Unlike in the [American College of Radiology Imaging Network (ACRIN)] trial, in this study technologists are performing the ultrasound, which reflects the reality of clinical practice in this country," Berg said.
Two radiologists reviewed each DBT/ultrasound set independently. Whenever additional imaging was recommended before the next annual screening, the readers recorded a "final" BI-RADS assessment (categories 3, 4A, 4B, 4C, or 5).
Of 8,151 ultrasound exams over the first two years of the trial, 5.6% were recalled. The recall rate was higher in year 1, at 6.1% of 5,589 ultrasounds, than in year 2, at 4.3% of 2,462 ultrasounds. Twenty-four women were diagnosed with cancer after ultrasound recall, for a positive predictive value for recall (PPV1) rate of 5.3%.
Only 2.5% of lesions found in the two-year cohort were categorized as BI-RADS 3, a much lower percentage than the ACRIN 6666 rate, Berg noted.
| BI-RADS category results from screening ultrasound | ||||||
| BI-RADS category | Percentage of total cohort (8,151) | Directed to immediate additional targeted ultrasound | Directed to 6-month follow-up | Reassessed to BI-RADS 2 or 3 at recall | Biopsies | Cancers detected |
| 3 (209 women) | 2.6% | 55% | 45% | -- | 9.6% | 1% |
| 4A (153 women) | 1.8% | -- | -- | 42.4% | 56.2% | 1.3% |
| 4B (60 women) | 0.7% | -- | -- | 26.7% | 77.7% | 6.7% |
| 4C (11 women) | 0.1% | -- | -- | -- | 100% | 63.6% |
| 5 (9 women) | 0.1% | -- | -- | -- | 100% | 100% |
The malignancy rates were lower than expected for BI-RADS 4A (1.3%) and 4B (6.7%) categories. In contrast, lesions assessed as BI-RADS 4C or 5 were in the expected ranges for malignancy, and all were biopsied, Berg said.
These results confirm that radiologists can send women with lesions characterized as BI-RADS 4C or 5 on screening ultrasound straight to the biopsy room, according to Berg.
"BI-RADS 4A and 4B assessments merit targeted ultrasound to determine the need for biopsy, but going directly to biopsy is appropriate for a 4C or 5 assessment on screening ultrasound," she concluded.
![Examples of ultrasound findings and techniques. (A) Images in a 39-year-old male patient with a mass in the left thigh. The mass is heterogeneous on the B-mode US image (compared with the patient in D) and showed increased microvascularity (superb microvascular imaging [SMI]) and shear-wave elastography (SWE) values. Undifferentiated pleomorphic sarcoma was diagnosed at biopsy (with pleomorphic rhabdomyosarcoma in surgical specimen). (B) Images in an 18-year-old male patient with a mass in the left leg. The mass is hypoechoic on the B-mode image, with no other findings suggestive of malignancy. The lesion is in contact with the cortex of the tibia, which is slightly irregular. CT revealed a doubtful anteromedial tibial erosion. The microvascular study demonstrated high vascularization, suggestive of malignancy. Periosteal Ewing sarcoma was diagnosed with both histologic and immunohistochemical confirmation. (C) Images in a 69-year-old female patient with a lump growing on the outside of the left leg. Multiple SWE examinations were performed (please note the high values obtained in the measurements, whereas the color map highlights the stiffness relative to adjacent tissues). SMI showed areas of increased vascularization to target for sampling. Undifferentiated spindle cell sarcoma was diagnosed at biopsy, with residual leiomyosarcoma in the surgical specimen after neoadjuvant therapy. (D) Images in a 56-year-old female patient with a mass in the right thigh. The mass is heterogeneous at both B-mode ultrasound (similar to patient A) and MRI (coronal T2-weighted spectral attenuated inversion recovery [SPAIR]; T1-weighted pre-contrast and postcontrast imaging), which even shows uptake after the administration of paramagnetic contrast material, which is traditionally suggestive of malignancy. Low values at SMI and elastography are suggestive of benignity. Spindle cell lipoma was diagnosed at biopsy, with atypical spindle cell lipomatous tumor in the surgical specimen.](https://img.auntminnie.com/mindful/smg/workspaces/default/uploads/2026/08/images-radiol250278fig2.APCFLSvX6p.jpg?auto=format%2Ccompress&dpr=2&fit=crop&h=167&q=70&w=250)
