Assessment of myocardial perfusion by dynamic O-15-labeled water PET imaging: Validation of a new fast factor analysis

Background  Factor analysis (FA) is an established method for separating myocardium from blood pool by use of oxygen 15-labeled water and positron emission tomography for analyzing myocardial blood flow (MBF). Conventional FA methods generating images from sinograms (sinoFA) are time-consuming, whereas FA can be performed on the reconstructed images (reconFA) in a fraction of time. We validated the MBF values obtained by reconFA versus sinoFA. Methods and Results  In 23 volunteers (mean age, 26.6±3.4 years) MBF was calculated from sinoFA and reconFA and blindly reanalyzed 1 month later by the same observer. Intraobserver agreement and reconFA-versus-sinoFA agreement were assessed according to Bland and Altman (BA). Reproducibility proved excellent for global sinoFA (r=0.968; P<.001; BA limits, −0.617 to 0.676 mL·min⁻¹·g⁻¹) and slightly superior for reconFA (r=0.979; P<.001; BA limits, −0.538 to 0.558 mL·min⁻¹·g⁻¹), with wider limits of agreement for segmental MBF from sinoFA (r=0.777; P<.001; BA limits, −1.676 to 1.656 mL·min⁻¹·g⁻¹) and reconFA (r=0.844; P<.001; BA limits, −1.999 to 1.992 mL·min⁻¹·g⁻¹). In addition, sinoFA and reconFA showed excellent correlation (r=0.975, P<.001) and agreement (BA limits, −0.528 to 0.648 mL·min⁻¹·g⁻¹) for global and segmental values (r=0.955; P<.001; BA limits, −1.371 to 1.491 mL·min⁻¹·g⁻¹). Conclusions  Use of reconFA allows rapid and reliable quantitative MBF assessment with O-15-labeled water. This study was supported by a grant from the Swiss National Science Foundation (professorship grant PP00A-114706).