Measurement Variability of Liver Metastases From Neuroendocrine Tumors on Different Magnetic Resonance Imaging Sequences

The aim of our study is to assess variability of measurements of liver metastases from neuroendocrine tumors (NET) on different magnetic resonance imaging (MRI) sequences.

In this institutional review board-approved retrospective study from January 2011 to December 2012, all liver MRIs performed at our department in patients with proven liver metastases from NETs and with at least one measurable lesion according to Response evaluation criteria in solid tumors (RECIST 1.1) were included. Up to two lesions were selected by an independent radiologist on T2-weighted images and marked by an arrow. Three reviewers (attending radiologist R1, fellow R2, senior R3) independently obtained long axis measurements of 135 metastases in 30 patients, on T2, diffusion-weighted imaging (DWI) with three b values (50, 400, 800), arterial, portal and late phases after gadolinium ), and during two distant separate sessions. Intraclass correlation coefficients and Bland-Altman plots were used to assess intra-and interobserver variability.