Terence Hong, Presenter: Nothing to Disclose

Ruth Lim MD, Abstract Co-Author: Nothing to Disclose

Rahim Moineddin, Abstract Co-Author: Nothing to Disclose

Hyun Soo Ko MD, Abstract Co-Author: Nothing to Disclose

Martin Charron MD, Abstract Co-Author: Nothing to Disclose

Amer Shammas MD, Abstract Co-Author: Nothing to Disclose

Adult literature reports that prevalence of 18F-fluorodeoxyglucose (FDG) uptake in brown adipose tissue (BAT) is inversely correlated with outdoor temperature and suggests that prevalence may be relatively greater in females and in children. The purpose of this study was to investigate prevalence and anatomic distribution of FDG uptake in BAT of children in relation to outdoor temperature and body surface area (BSA).

We retrospectively reviewed all whole-body FDG PET/CT scans in oncology patients from Feb 2007 through Feb 2009: 341 scans in 157 patients (M=87, F=70, mean age = 12 y, age range = 1 to 18 y). All scans were independently reviewed by an experienced nuclear medicine physician blinded to information from previous reporting and date of each examination. FDG uptake was assessed in the following anatomic regions associated with BAT deposition in children: cervical, supraclavicular and axillar, costovertebral and intercostal, upper mediastinal, internal mammary and pericardial, periaortic and periazygous, perirenal, and anterior abdominal wall. Degree of FDG uptake in each region was graded visually on a 3-point scale based on uptake intensity relative to liver: 1 – less than liver, 2 – equal to liver, 3 – greater than liver. Spearman rank correlation was used to analyze relationships between variables.

105/341 (31%) scans contained at least one region with BAT-FDG uptake: 90/230 (39%) scans in patients over 10 y, and 15/111 (14%) scans in patients under 10 y. In females, there was an inverse relationship between the number of anatomic regions with BAT-FDG uptake and outdoor temperature (rs = -0.15025, p = 0.0207). Furthermore, in females, there was a positive relationship between BAT-FDG uptake and BSA independent of outdoor temperature (rs = 0.24827, p = 0.0001). No such relationships were observed in males.

BAT-FDG uptake is more prevalent among children than adults, especially in patients over 10 y. However, an inverse correlation with outdoor temperature was only observed in females. A positive correlation between BAT-FDG uptake and BSA was observed in females independent of changes in outdoor temperature.

Cold temperatures, high BSA, and female sex may increase BAT-FDG uptake in children, thereby potentially increasing false positives in FDG-PET/CT scans of oncology patients.

Hong, T, Lim, R, Moineddin, R, Ko, H, Charron, M, Shammas, A, Relationship between FDG Uptake in Brown Adipose Tissue, Outdoor Temperature, and Body Surface Area in Children.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9007130.html