Central washout sign in computer-aided evaluation of breast MRI: preliminary results

Although computer-aided evaluation (CAE) programs were introduced to help differentiate benign tumors from malignant ones, the set of CAE-measured parameters that best predict malignancy have not yet been established.

To assess the value of the central washout sign on CAE color overlay images of breast MRI.

We evaluated the frequency of the central washout sign using CAE. The central washout sign was determined so that thin, rim-like, persistent kinetics were seen in the periphery of the tumor. Then, sequentially, plateau and washout kinetics appeared. Two additional CAE-delayed kinetic variables were compared with the central washout sign for assessment of diagnostic utility: the predominant enhancement type (washout, plateau, or persistent) and the most suspicious enhancement type (any washout > any plateau > any persistent kinetics).

One hundred and forty-nine pathologically proven breast lesions (130 malignant, 19 benign) were evaluated. A central washout sign was associated with 87% of malignant lesions but only 11% of benign lesions. Significant differences were found when delayed-phase kinetics were categorized by the most suspicious enhancement type (P < 0.001) and the presence of the central washout sign (P < 0.001). Under the criteria of the most suspicious kinetics, 68% of benign lesions were assigned as plateau or washout pattern.

The central washout sign is a reliable indicator of malignancy on CAE color overlay images of breast MRI.