The Role of Whole- Body Diffusion Imaging with Background Signal Suppression (DWBS) in comparison with PET/CT in assessment of lymphoma patients

Abstract

Abstract Background Malignant lymphomas [Hodgkin lymphomas (HL) and non-Hodgkin lymphoma (NHL)] rank third in incidence, of all childhood cancers, Moreover, in adolescents (aged 15-19 years) the malignant lymphomas are the leading cause of cancer. Furthermore, as with many other cancers, the likelihood of an individual being diagnosed with lymphoma increases markedly with age, with the median age at diagnosis being 67 years. Aim of the Work To compare between F-18-FDG PET-CT and whole-body diffusion-weighted imaging MR protocol (DWIBS) for initial staging and post chemotherapy evaluation in patients with pathologically proven lymphoma (Hodgkin and Non-Hodgkin). Patients and Methods The study is conducted on 32 patients with pathologically proven lymphoma to perform 18-F-FDG PET/CT either for pre-treatment initial staging or for evaluation of response to chemotherapy. A total of 22 had HD (69%) and 10 had NHL (31%). Staging PET/CT and WB-MRI/DWIBS were done at time of diagnosis in 19 of the 32 patients (59.4%), where immediate post-therapy PET/CT and WB-MRI-DWIBS were performed 13 patients (40.6%). Accuracy measures were calculated for PET CT and DWIBS. Results Accuracy measures confirm the higher sensitivity and specificity of PET-CT over DWIBS. Results for F-18 FDG PET/CT were clearly superior with statistically higher sensitivity, specificity, accuracy, PPV & NPV (96.3%, 99.16%, 98.43%, 97.5% and 98.75%) compared to (83.95%, 97.91%, 94.38%, 93.15% and 94.74%) for DWIBS results respectively. Conclusion F-18-FDG PET-CT remains a cornerstone in the evaluation of malignant lymphoma patients; it has significant higher sensitivity, specificity and overall accuracy compared to WB-MRI/DWIBS in HL and NHL patients, either in initial staging or in post therapy evaluation. WB-MRI/DWIBS in HL and NHL patients, either in initial staging or in post therapy evaluation. WB-MRI/DWIBS despite of its relatively longer acquisition time may provide a complementary tool for FDG PET CT.