[Evaluation of the extent of ductal carcinoma in situ: comparison of MDCT and high-spatial-resolution MR imaging].

Abstract

Purpose: To compare dual-phase contrast-enhanced multidetector-row CT (MDCT) with high-spatial-resolution MRI using a three-dimensional volumetric interpolated breath-hold examination (VIBE) sequence for evaluation of the extent of ductal carcinoma in situ (DCIS).

Materials and methods: A retrospective review was conducted in 17 consecutive patients with DCIS in which both MDCT and MRI had been performed. The early phase of MDCT and MRI was started 60 sec after commencing contrast injection. The late phase was started 4 min after the injection. The size of the lesion on MDCT and MRI was measured in coronal images obtained during the early and late phases. Histological evaluation of the size was considered the gold standard, and the deviation in tumor size as measured in the early- and late-phase images from the histologically determined tumor size was calculated.

Results: The sensitivity rates of MDCT and MRI for the detection of DCIS were 88.2% (15/17)and 100%, respectively, and no lesions were detected in the late-phase images alone. The accuracy of detection of tumor diameters with a deviation of less than 2 cm was 76.5% (13/17) with MDCT and 94.1% (16/17) with MRI. The tumor diameter was overestimated by more than 2 cm in 2 lesions (11.8%) on MDCT and one lesion (5.9%)on MRI, in both early- and late-phase scans. Tumor diameter was underestimated in early- as compared to late-phase scans in 3 cases on MDCT and one case on MRI.

Conclusion: High-spatial-resolution MRI using the VIBE sequence is more accurate for the detection and evaluation of the extent of DCIS than MDCT. In dynamic studies, more accurate evaluation of the extent of DCIS is possible in late-phase images.