[Comparison of ¹⁸F-FDG PET/CT and large-scale DWI for evaluation of non-Hodgkin lymphoma bone marrow infiltration].

Objective: To compare the diagnostic value of ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) and large-scale diffusion weighted imaging (DWI) for evaluation of non-Hodgkin lymphoma (NHL) bone marrow (BM) infiltration.
Methods: A total of 79 patients with pathologically diagnosed NHL underwent ¹⁸F-FDG PET/CT, large scale DWI and BM pathological examination. BM examination as the "gold standard", the performance (the sensitivity, specificity, accuracy, positive and negative predictive value) of ¹⁸F-FDG PET/CT and large scale DWI for evaluation of BM infiltration was compared and the risk of BM infiltration of different subtypes and sources of NHL was analyzed.
Results: 25 of 79 cases were diagnosed as BM infiltration by pathological examination with 57 BM sites. Abnormal high BM metabolisms were identified in 22 cases with 56 BM sites by ¹⁸F-FDG PET/CT and 25 cases with 58 BM sites by large-scale DWI. The sensitivity, specificity, accuracy, positive and negative predictive value of ¹⁸F-FDG PET/CT were 80.0%, 96.3%, 91.1%, 90.9%, 91.2%, respectively. And they were 84.0%, 92.6%, 89.9%, 84.0%, and 92.6% by large-scale DWI, respectively. A receiver operating characteristic (ROC) analysis demonstrated that there was no statistical difference in ¹⁸F-FDG PET/CT and large-scale DWI (P>0.05). The area under ROC curve for ¹⁸F-FDG PET/CT and large-scale DWI were 0.911 and 0.883 respectively. The incidences of BM infiltration in aggressive NHL patients by ¹⁸F-FDG PET/CT (21/69, 30.4%) and large-scale DWI (23/69, 33.3%) were higher than those (PET/CT: 10.0%; large-scale DWI: 20.0%; P>0.05) in indolent NHL patients.
Conclusion: ¹⁸F-FDG PET/CT and large-scale DWI had important clinical value in diagnosing BM infiltration of NHL. A combination of ¹⁸F-FDG PET/CT, large-scale DWI and pathological examination could improve the positive rate of BM infiltration in NHL.