Atypical thoracic and supraclavicular FDG-uptake in patients with Hodgkin's and non-Hodgkin's lymphoma.

Abstract

In FDG-PET imaging abnormal supraclavicular and paravertebral FDG uptake is a frequent finding which recently could be demonstrated to partly represent brown fat tissue. This study was carried out to further investigate causes for this phenomenon. Patients variables such as age, gender, body mass index (BMI) and the value of sedation and delayed imaging were compared with the presence of atypical uptake in 2 distinct groups of diseases, Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL). PET images of 81 patients (53 HD and 28 NHL) were evaluated for atypical uptake. In 5 patients additional delayed images were acquired. Sedatives were used in anxious patients (n=45). Twelve out of 53 patients with HD and 2 out of 28 patients with NHL showed an atypical uptake. The BMI of patients with atypical uptake (median, 21 kg/m2 versus 24 kg/m2; p<0.05) and the age (median, 25 y versus 44 y; p<0.05) were significantly lower compared with patients without atypical uptake. In nearly 50% of all women with HD= or <30 y and 20% of all male patients with HD= or <30 y an atypical uptake was observed. Delayed images showed a SUVmax decrease in 4 patients and an increase in 1 patient. All patients with atypical uptake received sedatives which had an anxiolytic effect in all patients, but did not prevent atypical uptake. Abnormal supraclavicular and paravertebral FDG accumulation occurs particularly in younger patients and those with lower BMI values. The use of sedatives or delayed acquisition does not increase the diagnostic information in these cases.