The value of semiquantitative analysis in identifying diffuse bone marrow involvement in follicular lymphoma

AimThe aim of the study was to investigate the value of fluorine-18-fluorodeoxyglucose (F-18-FDG)-PET/computed tomography (CT) in identifying diffuse bone marrow (BM) involvement in follicular lymphoma using semiquantitative assessment.MethodsThis is a retrospective analysis of 41 patients with grade 1-3a follicular lymphoma who underwent F-18-FDG-PET/CT, contrast-enhanced CT and bone marrow trephine biopsy (BMB) as part of staging. BM involvement on PET/CT was assessed by visual and semiquantitative analysis. Standardized uptake values (SUVmax) were measured at the sternum, at both iliac blades and at the T-12 vertebra. An average of these four measurements was recorded as SUVav. The single highest overall SUVmax for the four bone sites, the SUVav and the ratios SUVav/mediastinal blood pool (MBP) and SUVav/liver were compared with the BMB result.ResultsFocal bone uptake was identified on F-18-FDG-PET/CT by visual analysis in six patients, including two cases in which the BMB was negative. Assessment of diffuse BM involvement on F-18-FDG-PET/CT by visual analysis had a sensitivity and specificity of 31 and 92%, respectively. Semiquantitative analysis resulted in an improved sensitivity and specificity of 58 and 96%, respectively, when using SUVav greater than or equal to 2 as the cutoff. Using the ratio SUVav/MBP greater than or equal to 1 the sensitivity of F-18-FDG-PET/CT to detect BM involvement improved to 83%.ConclusionVisual analysis is useful in determining focal bone involvement, whereas semiquantitative analysis using SUVav/MBP has a high sensitivity and specificity for predicting BM involvement in patients lacking focal bone lesions. (C) 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins.