⁸²Rb positron emission tomography myocardial blood flow quantification: Influence of arterial input curve quality on diagnostic accuracy

Background: We investigated whether the shape of arterial blood input curves affects the diagnostic performance of myocardial blood flow (MBF) on rubidium-82 (⁸²Rb) positron emission tomography (PET) myocardial perfusion imaging (MPI) for obstructive coronary artery disease (CAD). Methods and results: We retrospectively enrolled 386 patients without prior CAD who underwent ⁸²Rb PET-MPI and invasive coronary angiography within 6 months, from 2010 to 2018. Abnormal shapes of stress left atrial blood pool (BP) time activity curve were characterized into five categories based on visual/quantitative assessment: (1) low stress/rest peak ratio (SRPR), (2) slow activity rise, (3) slow activity decline, (4) broad peak and (5) multiple peaks. The SRPR was defined as the ratio of peak count value on the stress BP activity by rest BP activity. A low SRPR was defined as one below the median value (0.82). We compared the diagnostic performance of stress MBF and myocardial flow reserve for detecting obstructive CAD (≥70% stenosis) using area under the curve (AUC) analysis. Results: Among the five abnormal categories, the AUC of stress MBF in the low SRPR group (n = 193) was lower than in the normal SRPR group (n = 193) in per-patient (.67 [.59-.74] vs. .78 [.70-.84], P = .0499, respectively) and per-vessel analyses (.68 [.63-0.73] vs. .75 [.71-.79], P = .0352, respectively). The AUC in slow activity rise group (n = 167) for stress MBF was lower than in others in per-vessel analysis (n = 219) (.68 [.62-.72] vs. .75 [.70-.79], P = .0270). Other abnormal profiles showed no significant differences (all P > .05). Conclusions: Low SRPR and slow activity rise were associated with reduced diagnostic performance of stress MBF.