Key result
Repeated [15O]H2O-PET scans show reproducible resting and hyperaemic MBF but moderate variability in MFR.
Why the study?
To investigate the intra-individual variability of MBF and MFR over time in patients with angina and no obstructive coronary disease to further establish clinical and research utility.
What is the intra-individual reproducibility of myocardial blood flow and flow reserve assessed by [15O]H2O-PET in patients with angina and no obstructive coronary disease?
Observational (n=21)
What is the intra-individual reproducibility of myocardial blood flow and flow reserve assessed by [15O]H2O-PET in patients with angina and no obstructive coronary disease?
In patients with angina and no obstructive coronary disease, [15O]H2O-PET shows good reproducibility for resting and hyperaemic myocardial blood flow, but only moderate reproducibility for myocardial flow reserve, which should be considered when interpreting individual patient changes.
Reproducible MBF supports serial research use; leaves clinical MFR thresholds open due to moderate variability.
Background/Objectives: Myocardial blood flow (MBF) and myocardial flow reserve (MFR) are key measurements in myocardial perfusion imaging (MPI), with [15O]H2O-PET considered the reference standard. To further establish clinical and research utility, we investigated intra-individual variability of MBF and MFR over time in patients with angina, but no obstructive coronary disease. Methods: In a routine clinical setting, we prospectively studied 21 patients, >50 years with normal left ventricular function and no known coronary stenosis, undergoing clinically indicated PET MPI. Scan and re-scan were conducted within 30 days. Analyses were conducted by general clinical staff and re-evaluated by an expert reader. Reproducibility was assessed using paired t-tests, Bland–Altman analysis, repeatability coefficient (RC), within-subject coefficient of variation (CV) and intraclass correlation coefficient (ICC). Results: Twenty-one patients (mean age 70 ± 8.2 years; 48% female) underwent repeated scans with a median interval of 21 days. Resting MBF was 0.91 ± 0.24 vs. 0.92 ± 0.22 mL/min/g (r = 0.87; RC 0.23 mL/min/g; CV 9%; ICC 0.87). Hyperaemic MBF averaged 3.06 ± 0.9 vs. 2.97 ± 0.78 mL/min/g (r = 0.83; RC 0.98 mL/min/g; CV 11.6%; ICC 0.81). MFR showed only moderate reproducibility (3.47 ± 1.23 vs. 3.23 ± 0.92; RC 1.90; CV 21%; ICC 0.60). Neither expert re-evaluation nor rate–pressure product correction of the resting MBF improved the reproducibility. Variability was largely unaffected by atrial fibrillation and diurnal variation. Conclusions: Resting and hyperaemic MBF are reproducible, whereas MFR shows moderate variability, which should be considered when interpreting changes in individual patients.
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Seidelin et al. (2026) conducted an observational in Angina and no obstructive coronary disease (n=21). [15O]H2O-PET MPI was evaluated on Intra-individual variability of myocardial blood flow and flow reserve. Repeated [15O]H2O-PET scans showed reproducible resting (ICC 0.87) and hyperaemic (ICC 0.81) myocardial blood flow, whereas myocardial flow reserve showed moderate variability (ICC 0.60).
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