Reliability of velocity pulsatility in small vessels on 3Tesla MRI in the basal ganglia: a test–retest study

Abstract

ObjectiveRecent work showed the feasibility of measuring velocity pulsatility in the perforating arteries at the level of the BG using 3T MRI. However, test–retest measurements have not been performed, yet. This study assessed the test–retest reliability of 3T MRI blood flow velocity measurements in perforating arteries in the BG.Materials and methodsTwo-dimensional phase-contrast cardiac gated (2D-PC) images were acquired for 35 healthy controls and repeated with and without repositioning. 2D-PC images were processed and analyzed, to assess the number of detected perforating arteries (Ndetected), mean blood flow velocity (Vmean), and velocity pulsatility index (vPI). Paired t-tests and Bland–Altman plots were used to compare variance in outcome parameters with and without repositioning, and limits of agreement (LoA) were calculated.ResultsThe LoA was smallest for Vmean (35%) and highest for vPI (79%). Test–retest reliability was similar with and without repositioning of the subject.DiscussionWe found similar LoA with and without repositioning indicating that the measurement uncertainty is dominated by scanner and physiological noise, rather than by planning. This enables to study hemodynamic parameters in perforating arteries at clinically available scanners, provided sufficiently large sample sizes are used to mitigate the contribution of scanner- and physiological noise.