The Value of [18F]Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Extranodal Natural Killer/T—Cell Lymphoma

PurposeTo our knowledge, there are no published data pertinent to the use of [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) in patients with natural killer (NK)/T—cell lymphoma. The purpose of this study was to assess the value of FDG PET/CT in this aggressive type of non-Hodgkin lymphoma.Patients and MethodsAll patients with NK/T-cell lymphoma referred for FDG PET/CT at our institution from July 2001 to July 2006 were retrospectively studied. PET/CT examinations were blindly reviewed by 2 experienced readers. The results were compared with the status of the disease, which was determined after evaluation of biopsy, laboratory, clinical and conventional imaging examination, and follow-up results. PET/CT results were thereby classified as true-positive, true-negative, false-positive, or false-negative. The degree of FDG uptake in the positive lesions was semiquantified using maximum standard uptake value (SUVmax).ResultsTwenty-one PET/CT examinations were performed in 10 patients with NK/T-cell lymphoma. For nasal disease, PET/CT was true-positive in 5 cases, true-negative in 15 cases, and positive but unconfirmed in 1 case. For extranasal disease, PET/CT was true-positive in 3 cases, true-negative in 16 cases, and false-negative in 2 cases. The mean SUVmax in PET-positive lesions in nasal cavities or paranasal sinuses was 16 gm/mL (range, 5–25 gm/mL; median, 19.3 gm/mL). In extranasal disease, the mean SUVmax was 10.9 gm/mL (range, 4.6–34.1 gm/mL; median, 5.6 gm/mL).ConclusionViable NK/T-cell lymphoma is intensely FDG hypermetabolic. PET/CT appears to be sensitive for the detection of disease in the nasopharynx and, to a lesser extent, in extranasal sites.