Whole-body MRI with diffusion-weighted imaging: a valuable alternative to contrast-enhanced CT for initial staging of aggressive lymphoma

AIM: To compare the accuracy of whole-body magnetic resonance imaging (Wb-MRI) with diffusion-weighted imaging (DWI) to that of contrast-enhanced computed tomography (CE-CT) and 2-[F-18]-fluoro-2-deoxy-D-glucose (F-18-FDG) positron-emission tomography co-registered with low dose-CT (PET-CT) in defining lymphoma disease stage. MATERIALS AND METHODS: From February 2010 to May 2014, 41 lymphoma patients underwent Wb-MRI-DWI, CE-CT, and F-18-FDG PET-CT. Histological subtypes included aggressive B-cell (n = 11), follicular (n = 13), mantle cell (n = 3), and Hodgkin's (n = 14) lymphoma. To compare the procedures, the reference standard (RS) assessment was defined by combining the results from F-18-FDG PET-CT, CE-CT, and bone marrow (BM) histology, modifications after therapy, and histological re-assessments of uncertain lesions. RESULTS: Among 1025 nodal sites, 217 had disease involvement according to the RS. CE-CT yielded 23 false-negative and 11 false-positive errors. Wb-MRI-DWI failed to recognise 17 localisations and had six false-positive errors; F-18-FDG PET-CT had no errors. Among 458 extranodal sites, 37 were positive according to the RS. F-18-FDG PET-CT yielded four false-negative and two false-positive results. CE-CT yielded 17 false-negative errors. Wb-MRI-DWI yielded a single false-negative error. Wb-MRI-DWI was the most reliable imaging technique for BM evaluation. Considering each procedure alone, the final stage would have been missed in four cases using F-18-FDG PET-CT, 12 cases using CE-CT, and none using Wb-MRI-DWI. CONCLUSION: The present data support Wb-MRI-DWI as a sensitive and specific imaging technique for lymphoma evaluation, supporting its use in place of CE-CT for staging. (C) 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.