Establishing normal myocardial blood flow and myocardial flow reserve values: a rubidium-82 positron emission tomography study.

Abstract

Quantitative Rubidium-82 (⁸²Rb) PET allows assessment of myocardial blood flow (MBF) and flow reserve (MFR), yet clinically applicable normal reference ranges remain incompletely defined across age and sex. This study aims to establish age- and sex-specific reference ranges for resting MBF (rMBF), stress MBF (sMBF), and MFR using ⁸²Rb PET in healthy adults. Data from four cohorts of 277 carefully screened healthy adults (143 women, 134 men) aged 19-79 years were examined with an identical ⁸²Rb PET protocol on the same scanner. Global rMBF, sMBF, and MFR were quantified with a 1-tissue compartment model. Age- and sex-specific percentiles were derived using natural spline regressions. Median [IQR] rMBF was 1.00 [0.82; 1.18] mL/g/min, sMBF was 3.25 [2.82; 3.58] mL/g/min, and MFR was 3.18 [2.77; 3.86]. The rMBF increased with age (~ 1% per year), while sMBF and MFR decreased with age (sMBF ~-0.1%, MFR ~ -0.6% per year). Women had higher rMBF and sMBF, but lower MFR than men. Age- and sex-specific percentile curves (5-95%) demonstrated substantial physiologic variation in rMBF, sMBF, and MFR across the adult lifespan. This study establishes reference percentiles for rMBF, sMBF, and MFR derived from a uniform multicohort dataset of healthy adults, aged 19-79 years. These values may aid clinical interpretation of quantitative perfusion PET. These reference percentiles are intended to complement - rather than replace - validated prognostic thresholds for sMBF and MFR. As the population was almost exclusively Euro-Caucasian with body mass index in the normal to moderately overweight range, validation in more diverse cohorts is warranted.