A head-to-head comparison of breast lesion's conspicuity at contrast-enhanced mammography and contrast-enhanced MRI

Lesion conspicuity, the relative enhancement of a lesion compared to surrounding tissue, is a new descriptor in the ACR BI-RADS 2022 CEM supplement. We compared lesion conspicuity in contrast-enhanced mammography (CEM) and contrast-enhanced MRI (CE-MRI) in patients with suspicious breast lesions.

IRB-approved retrospective study; three blinded readers rated 462 indeterminate or suspicious breast lesions in 388 patients (54.2 ± 11 years; range 30-90) who underwent CEM and CE-MRI from 2018 to 2022. Each lesion's conspicuity was scored from 1 to 5, with 5 indicating excellent conspicuity. Visual grading characteristics (VGC) analysis and area under the curve (AUC) were used for comparison, with sub-analyses for benign and malignant lesions.

VGC analysis showed a significant AUC of 0.670 to 0.723 (p < 0.001) favouring CE-MRI. No lesion enhancement (score 1) was observed in 16.2% of CE-MRI and 44.7% of CEM. Excellent conspicuity was seen in 29.6% of CE-MRI and 11.9% of CEM. Sub-analysis showed higher conspicuity on CE-MRI for both malignant (AUC 0.665 to 0.732, p < 0.001) and benign lesions (AUC 0.734 to 0.798, p < 0.001). CE-MRI showed higher lesion conspicuity compared to CEM both for non-mass lesions (0.656) and for mass lesions 0.605.

CE-MRI shows significantly higher conspicuity for benign and malignant breast lesions compared to CEM, especially for benign lesions. The low conspicuity of benign lesions on CEM may help reduce false positives in clinical practice.

Question Lesion conspicuity is a new descriptor for lesion enhancement according to the new CEM lexicon. Data correlating lesion conspicuity with malignancy likelihood are limited. Findings Lesion conspicuity is higher for contrast-enhanced-MRI than for contrast-enhanced mammography (CEM) for all lesions but significantly better for benign lesions. Clinical relevance The low conspicuity of benign lesions on CEM may reduce false-positive results, making it a valuable tool in breast cancer screening.