Dual-time-point F-18 FDG PET/CT for evaluation in patients with malignant lymphoma.

Objective: The aim of this study was to evaluate the usefulness of F-18 fluorodeoxyglucose (FDG) dual-time-point (DTP) positron emission tomography (PET)/computed tomography (CT) with semiquantitative analyses for the initial staging in patients with malignant lymphoma.

Methods: Forty-three patients had DTP PET/CT, with 60-min and 2-h scan [n = 8, Hodgkin's lymphoma (HL); n = 12, indolent non-Hodgkin lymphoma (NHL); n = 23, aggressive NHL].

Results: A total of 524 lesions were evaluated (406 lymph nodes and 118 extra-nodal lesions). The maximum standardized uptake value (SUV(max)) on 2-h delayed scan (SUV(2)) was significantly higher than those on 1-h early scan (SUV(1)) for all groups (P < 0.0001 for HL; P < 0.0001 for indolent NHL; P < 0.0001 for aggressive NHL). Significant differences were detected between HL and indolent NHL, between indolent NHL and the aggressive NHL for both SUV(1) and SUV(2) (each P < 0.0001). No significant differences were detected between HL and aggressive NHL for both SUV(1) and SUV(2) (P = 0.6891 for SUV(1); P = 0.8828 for SUV(2)); however, significant differences were detected for the retention index of SUV(max) between these groups (P = 0.0238).

Conclusions: DTP F-18 FDG PET/CT with a semiquantitative technique may have the potential to provide the more accurate diagnoses for the staging of malignant lymphoma and the more important role in predicting the histological grades of malignancy compared with single-time-point F-18 FDG-PET scan.