Breast MR imaging: computer-aided evaluation program for discriminating benign from malignant lesions

Abstract

Purpose: To retrospectively determine the sensitivity of kinetic features measured with computer-aided evaluation at breast magnetic resonance (MR) imaging in discriminating benign from malignant lesions, with histopathologic findings used as the reference standard.

Materials and methods: Institutional review board approval was obtained for this HIPAA-compliant study. Informed consent was waived. Suspicious breast lesions visible only at MR imaging and in which biopsy had been performed with MR imaging guidance were retrospectively evaluated with a computer-aided evaluation program. Computer-generated kinetic features for each lesion were recorded, and those of benign and malignant lesions were compared. Features analyzed included the presence or absence of computer-aided evaluation "threshold enhancement" at 50% and 100% minimum thresholds; degree of initial peak enhancement; and enhancement profiles composed of lesion percentages of washout, plateau, and persistent enhancement. The Fisher exact test and Student t test were used to assess differences in these analyses.

Results: One hundred fifty-four consecutive lesions (41 malignant, 113 benign) in 125 women (age range, 27-86 years; mean age, 52 years) were evaluated. The presence of threshold enhancement at computer-aided evaluation was sensitive for malignancy, with 38 of 41 (93%) malignant lesions demonstrating enhancement at both the 50% and 100% thresholds. Absence of threshold enhancement at computer-aided evaluation helped improve the discrimination between benign and malignant lesions when compared with that at initial interpretation by the radiologists. False-positive rates were reduced by 8.8% at the 50% enhancement threshold (not significant) and by 23.0% at the 100% enhancement threshold (P=.02) when compared with that at initial interpretation. Analyses of initial peak enhancement values and enhancement profiles did not demonstrate further improvements in lesion discrimination.

Conclusion: The use of computer-aided evaluation for breast MR imaging significantly helped improve the discrimination of benign from malignant lesions when compared with that at initial interpretations by radiologists.