Excerpt

Positron emission tomography (PET) is increasingly applied to assess myocardial perfusion in conjunction with global and regional myocardial blood flow (MBF) quantitation in mL·g·min in patients with suspected and/or known CAD.1,2 While the stress-related regional myocardial perfusion defects commonly identify the “culprit” or the most-advanced CAD lesion in multivessel disease, the hemodynamic significance of less-severe, intermediate CAD lesions with still homogenous radiotracer uptake may be identified by corresponding regional reductions in hyperemic MBF and/or myocardial flow reserve (MFR = MBF-stress/MBF-rest).2,3 In this respect, the concurrent assessment of PET-determined MFR has been appreciated to provide not only the additional diagnostic value, but it carries also important prognostic information in patients with subclinical and clinically manifest CAD.4,5 The reproducibility of such MBF quantitation with PET has been performed mainly in healthy volunteers with and without cardiovascular risk factors.6 These data have convincingly demonstrated that PET-determined serial MBFs during pharmacologic-stimulated hyperemia and at rest can be employed reliably and are reproducible for quantitation of effects of preventive medical intervention, gastric-bypass-induced weight loss, and/or behavioral interventions related to weight, diet, and physical activity on coronary circulatory dysfunction.1,7 Subsequently, the reproducibility of PET-flow studies among different software tools was investigated.8‐11 For example, Slomka et al.8 compared MBF values obtained from three software tools such as QPET, syngo MBF, and PMOD in individuals with or without obstructive CAD. And indeed, the global and regional MBF and MFR values did closely correlate between the three software packages (correlation coefficient r² for global values ranging from 0.88 to 0.92 and for regional values from 0.78 to 0.94, respectively), which was reflected by similar mean MFR values (QPET: 3.39 ± 1.22, Syngo MBF: 3.41 ± 0.76, and PMOD: 3.66 ± 1.19, respectively). …