Molecular imaging in hypertrophic cardiomyopathy: an exploratory study with 2-[¹⁸F]FDG and [¹³N]NH₃

Area of Science:

• Cardiology
• Nuclear Medicine
• Medical Imaging

Background:

• Hypertrophic Cardiomyopathy (HCM) is a genetic heart disorder with varied presentations, increasing risks of heart failure and sudden cardiac death.
• Pathological pathways in HCM include inflammation, increased workload, myocyte disarray, apoptosis, and fibrosis.
• The utility of molecular imaging, specifically PET-CT, in assessing these pathways in HCM remains largely unexplored.

Purpose of the Study:

• To investigate the relationship between myocardial metabolism and perfusion in patients with non-obstructive HCM (NOHCM) using PET-CT.
• To explore the association of metabolic and perfusion abnormalities with clinical parameters and risk scores in NOHCM.

Main Methods:

• PET-CT imaging was performed on 30 NOHCM patients using 13N-ammonia for perfusion and 2-18F-FDG for metabolism assessment.
• Key clinical parameters measured included maximal myocardial wall thickness (MMWT), left atrial volume (LAV), NT-proBNP levels, and the sudden cardiac death (SCD) risk score.
• Analysis focused on 2-18F-FDG uptake (inflammatory pattern) and areas of fibrosis (scar pattern) within the left ventricle (LV).

Main Results:

• Increased 2-18F-FDG uptake, indicative of inflammation, was observed in 53% of patients.
• The extent of inflammatory patterns correlated significantly with MMWT, LAV, and NT-proBNP levels.
• Fibrotic patterns (scar) were also identified and correlated with the SCD risk score.
• Higher metabolic activity (TBR) was associated with greater MMWT, elevated NT-proBNP, and increased SCD risk.

Conclusions:

• PET-CT imaging offers valuable insights into myocardial metabolic activity and fibrosis in NOHCM patients.
• These imaging findings are closely linked to myocardial hypertrophy, left ventricular dysfunction, and elevated risk of sudden cardiac death.