Journal of Nuclear Cardiology · Mar 9, 2026

Normal values of myocardial blood flow and flow reserve with rubidium-82 positron emission tomography in low-risk patients

By Ngo V, Harel F, Finnerty V et al.

BACKGROUND: This study aims to establish lower reference values for myocardial blood flow (MBF) and myocardial flow reserve (MFR) measured by rubidium-82 (⁸²Rb) myocardial perfusion imaging (MPI) in patients at a low risk for coronary artery disease (CAD). METHODS: This single-center study included 3320 patients with very low risk of obstructive CAD who underwent dipyridamole ⁸²Rb positron emission tomography MPI. Patients were grouped by biological sex and age (≤40, 41-50, 51-60, 61-70, 71-80, and ≥81 years). Lower reference limits were derived using the Hoffmann method. RESULTS: Rest MBF increased with age in females (r = 0.104, P < 0.001) and males (r = 0.149, P < 0.001), while stress MBF and MFR decreased with age in both females (r = -0.344, P < 0.001; r = -0.440, P < 0.001) and males (r = -0.371, P < 0.001; r = -0.479, P < 0.001). Females had significantly higher rest and stress MBF and lower MFR than males (P < 0.001). MFR lower reference limits were 2.14, 2.11, 1.94, 1.77, 1.57, and 1.38 for females and 2.05, 2.32, 1.97, 1.92, 1.56, and 1.28 for males across the six age groups. Stress MBF lower reference limits were 2.46, 2.34, 2.23, 2.04, 1.84, and 1.59 mL/min/g for females and 1.85, 1.88, 1.65, 1.56, 1.33, and 1.20 mL/g/min for males across the six age groups. CONCLUSIONS: This study establishes sex- and age-specific lower reference limits for stress MBF and MFR in low-risk CAD patients. Females exhibited higher stress MBF and MFR than males, while both values declined with age in both sexes. These findings underscore the necessity of incorporating sex- and age-adjusted reference values when interpreting MBF and MFR in clinical practice.

doi.org/10.1016/j.nuclcard.2026.102680PubMed 41812856Biomarkers