The value of ~(18)F-FDG PET/CT on the detection and staging of natural killer/T cell lymphomas

Objective To investigate the value of ~(18)F-fluorodeoxyglucose (FDG) PET/CT on the detection and staging of natural killer (NK)/T cell lymphomas.Methods Thirteen new and 2 recurrent csses of NK/T cell lymphoma were inchded in this study and they all underwent wllole-body ~(18)F-FDG PET/CT scans.A lesion with intense ~(18)F-FDG uptake was taken as positive for disease involvement and semiquantitative metabolic assessment was performed with the maximum standardized uptake value(SUV_(max)).All patients were followed for more than 6 months.The t-test was used to analyze the semi-quantitative data statistics.Results (1) ~(18)F-FDG PET/CT had 100%positive detection rate for NK/T cell lymphom.Of 11 cases with disease involvement of the nasal region.PET/CT detected 10.either in the nasal cavity or in the nasopharynx,6 with extra-nasal infiltration,and 7 with regional nodal metastasis.There were 4 non-nasal cases and PET/CT detected one or multiple extra-nasal lymphoma lesions.The SUV_(max) of nasal and extra-nasal lesions was 12.42±9.25,9.54±7.12,respectively,with no significant difference(t=1.120,P＞0.05).(2)Two cases(2/15)diagnosed of this disease by PET/CT were initially referred as investigation of fever of unknown origin.For the remaining 13/15 known cases,PET/CT detected more unsuspected lymphoma lesions in 7 cases and affected the staging in 6 patients.The ~(18)F-FDG uptake (SUV_(max))of Ⅰ-Ⅱ stage patients was mildly lower than that of Ⅲ-Ⅳ stage patients,but no significant difference was observed (t=0.757,P＞0.05).Conclusions NK/T cell lymphoma is an intensely ~(18)F-FDG-avid tumor.~(18)F-FDG PET/CT is an effective imaging tool for detection and staging of this disease. Key words: Lymphoma,non-Hodgkin's; Tomography,emission-computed; Tomography,X-ray computed; Deoxyglucose