Absolute Stenosis Measures of Renal Artery Independently Influence Kidney Perfusion in Contrast-Enhanced Multidetector Computed Tomography

<b>Background:</b> A renal artery lumen reduction of ≥60% indicates hemodynamically significant stenosis and is one of the main criteria for invasive revascularization. We hypothesize that direct parameters describing renal artery stenosis (RAS) could better correlate with renal blood flow and improve the criterion for revascularization. This study aimed to investigate RAS parameters independently associated with renal blood flow estimated in contrast-enhanced multidetector computed tomography (CE-MDCT). <b>Methods:</b> Ultrasound Doppler dynamic renal cortical perfusion (dRCP), CE-MDCT with cortical blood flow (CBF), and RAS assessment in the form of cross-sectional area reduction (CSAR), maximal diameter reduction (MaxDR), mean diameter (MeD), and minimal diameter (MinD) were investigated. <b>Results:</b> CBF correlated with CSAR (r = -0.422, <i>p</i> = 0.003), MeD (r = 0.344, <i>p</i> = 0.005) and MinD (r = 0.348, <i>p</i>= 0.005), whereas RCP correlated only with MeD (r = 0.357, <i>p</i> = 0.005) and MinD (r = 0.427, <i>p</i>< 0.001). In multivariable regression, only MeD was independently associated with CBF (R² = 0.179; <i>p</i> < 0.001), and MeD < 3.5 mm substantially indicated CBF < 175 mL/100 g/min in ROC analysis. <b>Conclusions:</b> The directly measured mean diameter of RAS is independently associated with renal cortex blood flow and is probably a more appropriate parameter for the invasive RAS treatment criterion.