Utility of quantitative FDG-PET/CT for the detection of bone marrow involvement in follicular lymphoma: a histopathological correlation study

To determine the value of visual and quantitative (18) F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) for the detection of bone marrow involvement in follicular lymphoma, using direct histopathological examination at the right posterior iliac crest as reference standard. This retrospective study included 22 patients with newly diagnosed follicular lymphoma who had undergone FDG-PET/CT before BMB of the right posterior iliac crest. FDG-PET/CT images were visually evaluated for bone marrow involvement in the right posterior iliac crest. Volumes of interest were placed in the right posterior iliac crest to calculate the 3D partial volume corrected mean standardized uptake value (cSUV(mean)), maximum standardized uptake value (SUVmax) and peak standardized uptake value (SUVpeak). Sensitivity and specificity of visual FDG-PET/CT analysis for the detection of bone marrow involvement in the right posterior iliac crest were 0.0 % (95 % confidence interval (CI): 0-32.4 %) and 100 % (95 % CI: 78.5-100 %), respectively. Areas under the receiver-operating characteristic curve of cSUV(mean), SUVmax and SUVpeak for the detection of bone marrow involvement in the right posterior iliac crest were 0.85 (95 % CI: 0.63-0.96), 0.89 (95 % CI: 0.68-0.98) and 0.87 (95 % CI: 0.65-0.97), respectively. Optimal cutoff values for cSUV(mean), SUVmax and SUVpeak were 1.3, 2.1 and 1.7, and yielded sensitivity and specificity combinations of 75.0 % and 85.7 %, 87.5 % and 85.7 % and 87.5 % and 85.7 %, respectively. This histopathological correlation study shows that, unlike visual interpretation of FDG-PET/CT images, quantitative FDG-PET/CT analysis may be beneficial in diagnosing bone marrow involvement by follicular lymphoma.