Dynamic Gd-DOTA-enhanced MR imaging of hepatic metastases from pancreatic neuroendocrine tumors.

The aim of this study was to determine the MR imaging features of hepatic metastases from pancreatic neuroendocrine tumors (HMPNT), and to assess their enhancement characteristics on dynamic gadolinium-chelate-enhanced MR imaging. Twelve consecutive patients with pathologically proven HMPNT underwent spin-echo (SE) and dynamic gradient-recalled echo (GRE) MR imaging before and after intravenous administration of a gadolinium-chelate (gadolinium tetraazacyclododecanetetraacetic acid; Gd-DOTA). MR examinations were performed prospectively and interpreted retrospectively in consensus by two radiologists. Fifty-five HMPNT were identified in matching anatomic sections on the different MR sequences and included in the study. On T1-weighted SE images, 45 HMPNT (82%) were hypointense and 10 HMPNT (18%) were isointense. On T2-weighted SE images 55 HMPNT (100%) were hyperintense. On GRE images obtained 20 s after Gd-DOTA injection, 41 HMPNT (75%) showed slight peripheral enhancement, and 14 HMPNT (25%) showed internal enhancement. Forty-four HMPNT (80%) were heterogeneous. On GRE images obtained 4 min after Gd-DOTA injection, 37 HMPNT (67%) showed peripheral enhancement, and 18 HMPNT (33%) showed a global and almost complete enhancement. Heterogeneity of enhancement was seen in all 55 HMPNT (100%). Although HMPNT exhibit a large spectrum of MR features, early enhancement and heterogeneity on dynamic GRE MR images are suggestive features of HMPNT.