Non-Invasive Estimation of Subcutaneous and Visceral Adipose Tissue Blood Flow by Using [15O]H2O PET with Image Derived Input Functions

Abstract

Subcutaneous adipose tissue blood flow is finely regulated, and tuned with fat metabolism; little is known about visceral fat, which is less accessible in humans. In estimating blood flow with positron emission tomography (PET) and oxygen-15-labelled water ([ 15 (FBP). Location, diameter, and inner radioactivity levels of the abdominal aorta were automatically determined. Image derived arterial curves (IDI) were compared to measured arterial blood data, as obtained by an online blood sampler (OSI). Blood flow in three adipose tissue depots was estimated using the autoradiographic method with OSI vs the FBP image derived input (F-IDI) function. Correlations between blood flow results obtained with OSI and IDI were significant (r 0.87, p<0.0001) in all regions. Estimates of the aortic diameter ranged between 10.7-17.2 mm. A good agreement was found between area under the curve (AUC) values of F-IDI and OSI curves; the AUC F-IDI /AUC OSI ratio was 0.97±0.10. Our results support the implementation of the current method for the non-invasive detection of the abdominal aorta input function from a dynamic [15 O]H 2 O PET image in the quantification of regional blood flow in low flow tissues. This method allows simultaneously examine subcutaneous and intraabdominal fat depots.