Diffusion-weighted MRI for uveal melanoma liver metastasis detection.

Abstract

We aimed to assess the sensitivity of diffusion-weighted (DW) magnetic resonance (MR) imaging for the detection of pathologically confirmed uveal melanoma liver metastases (UMLM). Twenty patients who underwent complete surgical resection of their UMLM (N = 83) were included. Pre-surgery liver MR imaging included T2-weighted, T1-weighted, DW and dynamic-gadolinium-enhanced MR sequences. Two radiologists independently reviewed three sets of images (DW / morphologic-dynamic / combined) for each patient using intraoperative and pathological findings as a standard of reference. The sensitivities of the morphologic-dynamic and DW images for UMLM detection were 63% and 59%, respectively, for reader #1 (R1) and 64% and 53%, for reader #2 (R2). Sensitivity of the combined set was higher than sensitivity in the two other sets (R1:69%, R2:67%), but was only significantly different than the sensitivity of the DW images (McNemar test). For the three sets and the two readers, the sensitivity for UMLM smaller than 5mm (37-46%) was significantly lower than that for UMLM larger than 5mm (67-90%). The sensitivity for UMLM located in the subcapsular area (41-54%) was significantly lower than that for intraparenchymal UMLM (68-86%) (Chi-square test). Our study shows that the addition of DW imaging to morphologic-dynamic images does not significantly increase MR sensitivities for UMLM detection. • The MR imaging sensitivity for uveal melanoma liver metastases (UMLM) was 69%. • Addition of DW imaging to morphologic-dynamic images does not increase sensitivity significantly. • Sensitivity for subcapsular UMLM was significantly lower than sensitivity for intraparenchymal UMLM. • The T2 shortening effect does not appear to influence lesion detection in DWI.