Cardiac microcalcification burden: Global assessment in high cardiovascular risk subjects with Na[¹⁸F]F PET-CT

Fluorine-18 sodium fluoride (Na[¹⁸F]F) atherosclerotic plaque uptake in positron emission tomography with computed tomography (PET-CT) identifies active microcalcification. We aim to evaluate global cardiac microcalcification activity with Na[¹⁸F]F, as a measure of unstable microcalcification burden, in high cardiovascular (CV) risk patients.

Thirty-four high CV risk individuals without previous CV events were scanned with Na[¹⁸F]F PET-CT. Cardiac Na[¹⁸F]F uptake was assessed through the global molecular calcium score (GMCS), which was calculated by summing the product of the mean standardized uptake value times the area of the cardiac regions of interest times the slice thickness for all cardiac transaxial slices, divided by the total number of slices. Mean age is 63.5 ± 7.8 years and 62% male. Median GMCS is 320.9 (240.8-402.8). Individuals with more than five CV risk factors (50%) have increased GMCS [356.7 (321.0-409.6) vs. 261.1 (225.6-342.1), P = 0.01], which is positively correlated with predicted fatal CV risk by SCORE (r_s = 0.32, P = 0.04). There is a positive correlation between GMCS and weight (r_s = 0.61), body mass index (r_s = 0.66), abdominal perimeter (r_s = 0.74), thoracic fat volume (r_s = 0.47), and epicardial adipose tissue (r_s = 0.41), all with P ≤ 0.01. There is no correlation between GMCS and coronary calcium score nor coronary artery wall Na[¹⁸F]F uptake.

In a high CV risk group, the global cardiac microcalcification burden is related to CV risk factors, metabolic syndrome variables and cardiac fat. Cardiac GMCS is a promising risk stratification tool, combining a straightforward and objective methodology with a comprehensive analysis of both coronary and valvular microcalcification.