藉由[氟-18]去氧葡萄糖正子電腦斷層掃描影像探討腹部脂肪體積與身體質量指數和腰圍之相關性

Abstract

Aim Abdominal fat, especially visceral adipose tissue (VAT), is proven to relate with metabolic syndrome and coronary artery disease. Using FDG to estimate VAT and subcutaneous adipose tissue (SAT) glucose metabolism had been recently reported (J Am Coll Cardiol Img 2010;3:843-851). The analysis of SAT and VAT volume by applying imaging segmentation on attenuation low dose CT images from PET/CT and correlated with the mean standard uptake values (SUV) of liver, fat and muscle were studied. The formula was derived from BMI and waist circumference to estimate the volume of abdominal fat. Materials and Methods In a 4-year period, 100 negative FDG PET/CT findings subjects who had blood sugar, serum cholesterol and triglycerol tests within two weeks were recruited for the study. After reconstruction, the CT image was display in Philips Syntegrar software for CT segmentation by setting the binary Hounsfield unit (HU) between -30 and -190 for fat tissue. The SAT and VAT volume measurement was applied between L4 and L5 spine level for 2 cm thickness. Intra- and inter-observer measurements of the SAT and VAT from CT were tested. The means of FDG SUVs of the liver, spleen, psoas muscle, VAT and SAT were measured from PET imaging. The correlation between total abdominal fat, SAT, and VAT volume, mean FDG SUVs of above mentioned tissue, body mass index (BMI), waist circumference, and serum biochemical analysis were tested. Results The correlation between intra- and inter-observer measurements of the abdominal fat were all excellent (r = 0.99). The correlation between total abdominal fat (TAF), VAT, and SAT to BMI were (r = 0.79, 0.69, and 0.62), and those to the waist circumference were (r = 0.78, 0.76, and 0.57), respectively. The correlation between all the fat measurements to the blood biochemical tests and SUVs of above mentioned tissue were all low (r < 0.5). To estimate the abdominal fat from BMI, we could take the advantage of the formula y = 6.538x + 426.53. We could also estimate the abdominal fat from waist circumference through the formula y = 6.029x + 452.21. Conclusions The abdominal adipose tissue measurement was feasible and reproducible by using the attenuation CT imaging of the FDG PET/CT. The results of the measurements correlated well with the BMI and waist circumference but not with the blood biochemical tests and mean SUVs of liver, fat and muscle. The abdominal fat formula obtained from the BMI and waist circumference, it could provide for clinical to estimate the volume of fat.