[Preliminary evaluation of PET-CT and DWI for the detection of lymphoma bone marrow infiltration]

Objective: To evaluate the clinical value of PET-CT and DWI for the detection of bone marrow infiltration of lymphoma. Methods: The bone marrow samples of 93 untreated patients with pathologically diagnosed lymphoma were retrospectively analyzed. 61 patients underwent PET-CT examination, and other 32 underwent DWI examination. With bone marrow biopsy results as "gold standard" , the rates and sites of bone marrow infiltration of various lymphoma subtypes were analyzed, and the detection rates of the two imaging techniques were compared according to different lymphoma subtypes. Results: 39 patients were diagnosed as bone marrow infiltration based on pathological examination of bone marrow biopsies from routine sampling sites and bone marrow pathological examination of biopsies guided by PET-CT and DWI. The sensitivity, specificity, accuracy, positive and negative predictive values of PET-CT for lymphoma bone marrow infiltration were 80.8%, 88.6%, 85.3%, 84.0% and 86.1%, respectively; for DWI examination, these rates were 84.6%, 89.5%, 87.5%, 84.6% and 89.5%, respectively. The detection rates of the two imaging techniques for aggressive lymphoma were 37.5% (18/48) and 38.1% (8/21), respectively, which were slightly higher than those for the indolent lymphoma [23.1% (3/13) and 27.3% (3/11)], although the differences were not statistically significant (P=0.521, P=0.660). For both aggressive lymphoma and indolent lymphoma, the detection rates of DWI were numerically slightly higher than those of PET-CT(P=0.963, P=1.000). Conclusions: PET-CT and DWI have important and similar diagnostic value for bone marrow infiltration of lymphoma. None of PET-CT and DWI can replace bone marrow biopsy (BMB). However, image-guided bone marrow biopsies can improve the detection rate of bone marrow infiltration of lymphoma.