Stroke volume measurements with first-pass dynamic positron emission tomography: Comparison with cardiovascular magnetic resonance

Background  The assessment of forward stroke volume (SV) using dynamic, first-pass cardiac positron emission tomography (PET) was shown to be feasible in a limited number of studies with small numbers of subjects. The aim of this study was to compare first-pass derived SV with cardiovascular magnetic resonance imaging (CMR)-obtained values in a larger population of subjects. Methods and Results  Fifty-nine subjects with varying degrees of cardiac function were studied. Stroke volume was assessed using oxygen-15-labeled water (H₂ ¹⁵O) dynamic first-pass PET for both the right ventricle (RV) and left ventricle (LV), and compared with the findings of aorta velocity-encoded phase-contrast CMR. The PET-estimated SV was higher for the RV than for the LV (133±34 vs 116±31 mL, P<.01, ±SD), and both were higher compared with values obtained by CMR (81±20 mL, both P<.01,±SD). Although significant, the correlations between PET and CMR were moderate for both the RV (r=0.37, P<.01) and the LV (r=0.40, P<.01,±SD). Bland-Altman analysis revealed a progressive overestimation with increasing SV measured in either ventricle. Conclusions  First-pass dynamic H₂ ¹⁵O PET for the assessment of forward SV is feasible, although values are progressively overestimated with increasing SV, particularly when the RV is used, and correlations with aorta velocity-encoded phase-contrast CMR are moderate. These findings are probably protocol-dependent and warrant further study before the use of first-pass dynamic H₂ ¹⁵O PET in clinical or research settings can be advocated.