Computer-aided evaluation as an adjunct to revised BI-RADS Atlas: improvement in positive predictive value at screening breast MRI.

OBJECTIVES: To investigate whether kinetic features via magnetic resonance (MR)-computer-aided evaluation (CAE) can improve the positive predictive value (PPV) of morphological descriptors for suspicious lesions at screening breast MRI.
METHODS: One hundred and sixteen consecutive, suspiciously enhancing lesions detected at contralateral breast MRI screening in 116 women with newly-diagnosed breast cancers were included. Morphological descriptors according to the revised BI-RADS Atlas and kinetic features from MR-CAE were analysed. The PPV of each descriptor was analysed to identify subgroups in which PPV could be improved by the addition of MR-CAE.
RESULTS: When biopsy recommendations were downgraded to follow-up in cases where there were both the absence of enhancement at a 50% threshold and the absence of delayed washout, PPV increased from 0.328 (95% CI, 0.249-0.417) to 0.500 (95% CI, 0.387- 0.613). Two ductal carcinoma in situ (DCIS) non-mass enhancement (NME) lesions were missed. Application of downgrading criteria to foci or masses led to increased PPV from 0.310 (95% CI, 0.216-0.419) to 0.437 (95% CI, 0.331-0.547) without missing cancers.
CONCLUSIONS: MR-CAE has the potential to improve the PPV of breast MR imaging by reducing the number of false positives. When suspicious mass lesions do not show enhancement at a 50% threshold nor delayed washout, follow-up rather than biopsy can be considered. KEY POINTS: • MR-CAE has the potential to increase PPV at breast MRI screening. • Lesions without enhancement at 50% threshold and washout might be downgraded. • DCIS non-mass lesions might be false-negative cases at MR-CAE.