Imaging Findings and Therapy Response Monitoring in Chronic Sclerodermatous Graft-Versus-Host Disease: Preliminary Data of a Simultaneous PET/MRI Approach

Purpose: Our objective was a multifunctional imaging approach of chronic sclerodermatous graft-versus-host disease (ScGVHD) and its course during therapy using PET/MRI. Methods: We performed partial-body PET/CT and PET/MRI of the calf in 6 consecutively recruited patients presenting with severe ScGVHD. The patients were treated with different immunosuppressive regimens and supportive therapies. PET/CT scanning started 60.5 T 3.3 minutes, PET/MRI imaging 139.5 T 16.7 minutes after F-FDG application. MRI acquisition included T1(precontrast and postcontrast) and T2-weighted sequences. SUVmean, T1 contrast enhancement, and T2 signal intensity from region-of-interest analysis were calculated for different fascial and muscular compartments. In addition, musculoskeletal MRI findings and the modified Rodnan skin score were assessed. All patients underwent imaging follow-up. Results: At baseline PET/MRI, ScGVHD-related musculoskeletal abnormalities consisted of increased signal and/or thickening of involved anatomical structures on T2-weighted and T1 postcontrast images as well as an increased FDG uptake. At follow-up, ScGVHD-related imaging findings decreased (SUVmean n = 4, mean T1 contrast enhancement n = 5, mean T2 signal intensity n = 3) or progressed (SUVmean n = 3, mean T1 contrast enhancement n = 2, mean T2 signal intensity n = 4). Clinically modified Rodnan skin score improved for 5 follow-ups and progressed for 2. SUVmean values correlated between PET/CTand PET/MRI acquisition (r = 0.660, P = 0.014), T1 contrast enhancement, and T2 signal (r = 0.668, P = 0.012), but not between the SUVmean values and the MRI parameters. Conclusions: PET/MRI as a combined morphological and functional technique seems to assess the inflammatory processes from different points of view and provides therefore in part complementary information.