Inflammation and microcalcification in atherosclerotic plaques: a dual-tracer PET study in post-MI patients

Background Atherosclerosis progresses through intertwined inflammatory and microcalcific processes that contribute to plaque instability. Circulating inflammatory biomarkers lack spatial specificity for detecting active arterial disease. Dual-tracer PET/CT with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) and ¹⁸F-sodium fluoride (¹⁸F-NaF) enables in vivo assessment of vascular inflammation and microcalcification, but their interrelationship and association with systemic biomarkers remain unclear. Purpose To examine the relationship between ¹⁸F-FDG and ¹⁸F-NaF uptake in arterial territories (abdominal aorta) in healthy individuals and post–myocardial infarction (post-MI) patients, and to compare imaging findings with systemic inflammatory biomarkers. Methods Ten healthy participants and 12 post-MI patients underwent dual-tracer PET/CT imaging. Regional arterial uptake of both tracers was quantified in segments of the abdominal aorta. Associations between tracer uptake and circulating biomarkers (CRP, fibrinogen) were analyzed. Results In healthy individuals, metabolic and microcalcific activities were partially dissociated. In post-MI patients, ¹⁸F-FDG and ¹⁸F-NaF uptake were significantly correlated (r = 0.546, p < 0.0001), indicating pathological coupling of inflammation and mineral deposition in the abdominal aorta. Post-MI patients showed a higher proportion of metabolically active calcified segments than controls (95% vs. 67.8%, p < 0.0001). Systemic biomarkers showed weak associations with imaging measures. Conclusion Dual-tracer PET/CT demonstrates disease-state-dependent coupling of inflammation and microcalcification in the abdominal aorta and potentially in other vascular beds not adequately reflected by circulating biomarkers, underscoring the value of molecular imaging for assessing plaque activity after MI.