MRI findings of pure ductal carcinoma in situ: kinetic characteristics compared according to lesion type and histopathologic factors.

Abstract

OBJECTIVE: The purposes of this study were to analyze the morphologic and kinetic characteristics of pure ductal carcinoma in situ on MR images and to compare the kinetic characteristics according to MRI lesion type, histopathologic factors, and mammographic and sonographic findings.

MATERIALS AND METHODS: Sixty-seven patients with histologically proven pure ductal carcinoma in situ were included in this study. The MRI findings were analyzed according to the BI-RADS MRI lexicon without knowledge of the pathologic findings. The quantitative variables of the kinetic enhancement pattern calculated for each lesion were initial enhancement slope, peak enhancement, time to peak enhancement, and washout ratio. The histopathologic factors of nuclear grade, hormone receptor status, and c-erbB-2 expression status were reviewed. Mammographic and sonographic findings were reviewed independently without knowledge of the MRI findings. Kinetic characteristics were compared according to MRI lesion type, histopathologic factors, and mammographic and sonographic findings.

RESULTS: The dominant morphologic appearance was a nonmass lesion with segmental and clumped or heterogeneous enhancement. The pure ductal carcinoma in situ lesions exhibited variable enhancement patterns consisting of persistent (34.3%), plateau (52.2%), and washout (13.4%) curves. The mean initial enhancement slope (p < 0.005) and time to peak enhancement (p < 0.05) correlated with MRI lesion type, and time to peak enhancement (p < 0.05) correlated with the sonographic findings. No statistically significant correlations were observed between the kinetic characteristics and histopathologic factors or mammographic findings (p > 0.05).

CONCLUSION: Nonmass lesions and plateau curve enhancement were the dominant MRI findings of pure ductal carcinoma in situ. The lesions with mass appearance at MRI had more suspicious kinetic characteristics than did nonmass lesions.