XTR-004

This study aimed to evaluate image quality, myocardial perfusion, and diagnostic performance of a novel [¹⁸F]F-labeled PET tracer, XTR004 PET, myocardial perfusion imaging (MPI) compared with [¹³N]Ammonia (NH₃) PET MPI.

Forty-seven patients with suspected or known coronary artery disease (CAD) were prospectively enrolled to undergo one-day rest/ATP-stress XTR004 and NH₃ electrocardiograph-gated PET imaging within 2 weeks. Among them, twenty-six patients underwent invasive coronary angiography (ICA), and nineteen were identified with flow-limited CAD (stenosis ≥ 70%). Image quality (excellent/good/average) and certainty of interpretation were evaluated by two independent, blinded readers. Despite a higher liver uptake, XTR004 achieved good to excellent image quality in 83% of cases, comparable to 95.7% of NH₃(P = 0.091). Additionally, the diagnostic certainty, measured as the percentage of cases with definitely abnormal or normal interpretations, was similar between XTR004 and NH₃, with results of 87.2% and 89.2%, respectively. The sensitivity and specificity levels of XTR004 and NH₃ MPI were similar (79% vs. 79%, 86% vs. 71%, P = 1.00). Linear regression of rest/stress myocardial perfusion in 17 segments revealed the linear slope close to unity with excellent R² value (rest: slope = 0.954-1.074, R² = 0.990-0.997; stress: slope = 0.951-1.082, R² = 0.971-0.996). XTR004 was tolerated well by all patients. No adverse events were reported.

XTR004 PET MPI demonstrated promising image quality, diagnostic certainty and myocardial perfusion characteristics comparable to NH₃ PET MPI. Future research should concentrate on the quantitative analysis of myocardial blood flow to explore the clinical implications of XTR004 PET MPI.