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

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. 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). Use of reconFA allows rapid and reliable quantitative MBF assessment with O-15–labeled water.