Whole-body diffusion-weighted magnetic resonance imaging in the staging of oncological patients: comparison with positron emission tomography computed tomography (PET-CT) in a pilot study.

PURPOSE: The aim of this pilot study was to compare positron emission tomography computed tomography (PET-CT) and whole-body DWIBS in staging oncological patients to determine the staging accuracy of whole-body DWIBS.

MATERIALS AND METHODS: We initiated a prospective, blinded investigation on 29 patients affected by oncological diseases (n=14) or lymphoma (n=15), who underwent fluorodeoxyglucose (FDG)-based PET-CT and whole-body DWIBS for restaging purposes. Magnetic resonance (MR) imaging was conducted with a multistack (n=4) DWIBS pulse sequence. Images were read independently by two experienced radiologists and one nuclear physician. Statistical analysis assessed interobserver agreement and diagnostic accuracy.

RESULTS: Whole-body DWIBS had a room occupation time of 20 min. Mean postprocessing time was 15 min (range 10-17 min). Mean reading time was 20 min for reader 1 (range 15-25 min) and 18 min for reader 2 (range 13-22 min). Interobserver agreement was almost perfect (=0.93). Reader 1 had a sensitivity of 89.07%, a specificity of 98.5%, and an accuracy of 97.65%, with a positive predictive value (PPV) of 85.48% and a negative predictive value (NPV) of 98.91%. Reader 2 had a sensitivity of 87.39%, a specificity of 98.39% and a diagnostic accuracy of 97.8%, with a PPV of 88.13% and a NPV of 98.75%.

CONCLUSIONS: The whole-body DWIBS protocol provided a fast whole-body examination with high specificity and NPV. One major bias of the study was the inclusion of patients with diffuse disease and advanced disease stage and the heterogeneity of the neoplastic diseases included.