Whole-body diffusion-weighted imaging compared with FDG-PET/CT in staging of lymphoma patients

Background: Diffusion-weighted imaging (DWI) has become increasingly valuable in lymph node imaging, yet the clinical utility of this technique in the staging of lymphoma has not been established. Purpose: To compare whole-body DWI with FDG-PET/CT in the staging of lymphoma patients. Material and Methods: Thirty-one patients, eight with Hodgkin lymphoma (HL) and 23 with non-Hodgkin's lymphoma (18 aggressive and five indolent) underwent both whole-body DWI, whole-body MRI (T1W and T2W-STIR) and FDG-PET/CT. Lesions on whole-body DWI were only considered positive if they correlated with lesions on T1W and T2W-STIR images. The staging given by each technique was compared, according to the Ann Arbor staging system. Differences in staging were solved using biopsy results, and clinical and CT follow-ups as standard of reference. Results: The staging was the same for DWI and FDG-PET/CT in 28 (90.3%) patients and different in three (9.7%). Of the 28 patients with the same staging, 11 had stage IV in both techniques and 17 had stages 0-III. No HL or aggressive non-Hodgkin's lymphoma patients had different staging. Three indolent small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL) lymphoma had higher staging with DWI when compared with FDG-PET/CT. One small subcutaneous breast lymphoma was not seen but all other extranodal sites were detected by both techniques. Conclusion: Whole-body DWI is a promising technique for staging of both (aggressive and indolent) non-Hodgkin's lymphoma and HL.