Increased hepatic FDG uptake on PET/CT in hepatic sinusoidal obstructive syndrome

PURPOSE: Imaging features of sinusoidal obstruction syndrome (SOS), an increasingly common drawback of chemotherapy, were evaluated via 18F-fluorodeoxyglucose (FDG) positron emission tomography computed tomography (PET/CT). EXPERIMENTAL DESIGN: This retrospective study was approved by our Institutional Review Board, with a waiver of informed consent. FDG PET/CT studies of 35 patients (male, 24; female, 11; median age, 53.2 years) obtained between January, 2005 and December, 2012 were analyzed before and after systemic chemotherapy. Diagnosis of SOS was based on histologic (n=13) or gadoxetic acid-enhanced MRI (n=22) findings. On PET/CT images, ROIs drawn on non-tumorous liver generated mean standardized uptake value (SUV(liver)). Total lesion glycolysis of liver (TLG(liver)) was calculated as: SUV(liver) × CT-derived hepatic volume. Paired t-test was applied to compare changes before and after SOS. RESULTS: Mean (±standard error [SE]) values of hepatic volume (baseline, 1307.7±46.2 cm(3); SOS, 1395.4±41.3 cm(3); p=0.004), SUV(liver) (baseline, 2.08±0.06; SOS, 2.27±0.07; p=0.02), and TLG(liver) (baseline, 2697.5±114.5; SOS, 3170.2±134.2; p=0.001) significantly increased with development of SOS. In contrast, mean SUV(aorta) was unchanged (baseline, 1.53±0.04; SOS, 1.50±0.04; p=0.52). CONCLUSIONS: Hepatic FDG uptake on PET/CT intensified after onset of SOS and thus may be an inappropriate reference in this setting, potentially skewing chemotherapeutic responses gauged by lesion-to-liver SUV ratio.