Association of baseline subject characteristics with changes in coronary calcification assessed by 18F-sodium fluoride PET/CT.

Abstract

The goal of this study was to test if changes in coronary microcalcification over a two year period assessed by fluorine-18-sodium fluoride (18F-NaF) positron emission tomography/computed tomography (PET/CT) are associated with baseline subject characteristics. This prospective study included healthy female (N=8, age 52±10 years, body mass index(BMI) 24±1.7kg/m2) and male (N=15, age 50±10 years, BMI 27±2.9kg/m2) participants who had 18F-NaF PET/CT scans taken two years apart. Imaging was performed 90 minutes after intravenous injection of 2.2MBq of 18F-NaF per kilogram of body weight. The analysis regions were selected on CT images by drawing volumes of interest around the entire heart using a semi-automatic segmentation method.Mean standardize uptake value (SUVmean) and maximum SUV (SUVmax) were calculated in the same regions of the registered PET images. Percent change in SUV between the two time points were correlated against baseline age, BMI, cardiovascular risk factors, and blood chemistry. In males, percent change in SUVmean over the two year period was positively correlated with baseline BMI (r=0.85, P<0.0001) and systolic blood pressure (r=0.65, P=0.0082). These baseline values were not significantly correlated with SUVmax in either gender. High BMI is a known risk factor for atherosclerosis. Our data showed that rate of increase in coronary microcalcification over time measured by 18F-NaF PET/CT is associated with baseline BMI and some clinical risk factors in males. Lack of such associations in females could be due to low sample size (N=8). Further prospective studies are needed to determine if baseline BMI and clinical factors could be used to predict rate of increase in coronary microcalcification which could provide the basis for managing the progression of atherosclerosis in patient-specific manner.