18F-FDG uptake in patients with hypercholesterolemia using a standard compartmental modeling approach

Hypercholesterolemia is a major risk factor of atherosclerotic cardiovascular disease. However, current risk stratification models lack consideration of calcium burden. This study aimed to examine the association between calcium burden and inflammatory response in hypercholesterolemia patients. Eighteen participants were prospectively scheduled for 18F-fluorodeoxyglucose (18F-FDG) PET/CT examination. They were classified into a control group (CL, n=4), a hypercholesteremia group (HC, n=8), and a stable angina group (SA, n=6). Arterial calcium was defined at attenuation ≥130 Hounsfield units in arterial regions of interest (ROIs), and calcium density was divided into four groups based on the Agatston strategy. Calcium area was defined by at least two adjoining pixels and normalized to artery area, forming two groups based on the mean area. The metabolic rate of glucose (MRGlu) was estimated using a two-tissue compartment model. For all ROIs, MRGlu was significantly higher in both HC and SA groups compared to CL (p<0.05). Among no-calcium groups (CL, HC, and SA), no statistical significance was observed (p>0.05). In with-calcium groups, MRGlu in HC was significantly higher than in CL and SA (p<0.05). At the highest calcium density cluster, the difference between CL and HC was also significant (p<0.05). CL and SA showed a similar pattern of decreasing MRGlu with increasing calcium area (p<0.05 when compared with no-calcium), while the HC group showed a marked increase in MRGlu with higher calcium area (p<0.05) compared to CL and AS. Hypercholesterolemia is associated with increased glucose metabolism. Higher calcium area and density in hypercholesterolemia patients appear metabolically active. The results suggest that incorporating calcium burden in hypercholesterolemia risk stratification models may enhance risk assessment.