PT  - JOURNAL ARTICLE
AU  - Rodman, Dean
AU  - Tal, Ilan
AU  - Palmer, Matthew
AU  - Williams, Gethin
AU  - Cypess, Aaron
AU  - Kolodny, Gerald
TI  - Quantitative estimation of brown adipose tissue activity in adults
DP  - 2010 May 01
TA  - Journal of Nuclear Medicine
PG  - 1332--1332
VI  - 51
IP  - supplement 2
4099  - http://jnm.snmjournals.org/content/51/supplement_2/1332.short
4100  - http://jnm.snmjournals.org/content/51/supplement_2/1332.full
SO  - J Nucl Med2010 May 01; 51
AB  - 1332 Objectives Variable accumulation of FDG and other radiopharmaceuticals in brown adipose tissue (BAT) has recently been convincingly demonstrated. This activity has also been shown to correlate inversely with percent body fat, BMI and age. Pharmacological modification of brown fat metabolism has important potential clinical applications in the treatment of obesity and other metabolic disorders. Since FDG is the most readily available biomarker of BAT activity, it is important to establish a reliable and reproducible method of quantifying its uptake. We present the application of a modification of PET-CT Viewer, a shareware software package for display and analysis of PET/CT images, which allows regional quantification of tracer activity. Methods Subjects were routine patients imaged on a GE Discovery LS PET/CT system. Relevant clinical and biometric information was assessed. Fat deposits visible on CT were evaluated retrospectively using a visual scoring method. 98 subjects who demonstrated visible active BAT deposits were further evaluated using the program. The best discriminator of adipose tissue based on CT density was a window of -250 to -50 Hounsfield Units. The program mapped regions of interest (ROI) using this window. We then looked for ROI with an SUVmax of ≥2g/ml, the lowest value of visible adipose FDG activity. This was also 2 SD above the SUVmax seen in deposits of white adipose tissue. Using these criteria, we constructed user-defined ROI to quantify the volume, activity, and volume x activity of BAT, less active adipose tissue and other tissues. Results PET and CT images were well-aligned and easily manipulated. Derived maps of BAT activity correlated with visual grading in most, but not all cases, and resulted in values of greater consistency. In areas of disagreement the quantitative map was more specific for BAT activity. Conclusions Quantitative assessment of regional levels and distribution of activity is practical and will likely be essential if nuclear biomarkers are to be utilized in metabolic studies of BAT and other tissues