Determining the extent and stage of disease in patients with newly diagnosed non-Hodgkin's lymphoma using 18F-FDG-PET/CT.

ABSTRACT

Positron emission tomography (PET) using 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (18F-FDG) combined with computed tomography (CT) represents a three-dimensional imaging method suitable for staging in patients with non-Hodgkin's lymphomas (NHLs). The aim of our prospective multicenter study was to assess the value of initial PET/CT as compared with CT and PET alone for determining the stage and extent of the disease. A total of 122 patients with newly diagnosed NHL were examined using PET/CT. Four patients with resected lymphoma lesion and negative PET/CT were therefore excluded from the study. Of the remaining 118 cases, a total of 117 (99%) were described as 18F-FDG-avid. When compared with PET/CT, CT and PET showed very good sensitivity of lymph node imaging (97% and 100%, respectively); the specificity, however, was significantly lower (66.7% and 94.4%, respectively; p=0.0001). When detecting organ lesions, the sensitivity of CT and PET was lower than that of PET/CT (92.5% and 96.3%, respectively; p=0.0001); specificity was significantly decreased in CT and a little lower in PET (59.5% and 91.9%; p=0.0001). When compared with CT alone, PET/CT changed staging of the disease in 11 patients (9%) and was able to detect a total of 82 discrepancies in 67 of the 117 patients (57%). In conclusion, PET/CT is a new standard in imaging the involvement of lymph nodes and extranodal organs in NHL patients regardless of their histopathological types. Both sensitivity and specificity of the examination are higher than those of CT as well as PET alone.