Georgia Institute of Technology, Atlanta, Georgia, USA.
Magn Reson Med. 2010 Apr;63(4):940-50. doi: 10.1002/mrm.22278.
This study evaluates reliability of current technology for measurement of renal arterial blood flow by breath-held velocity-encoded MRI. Overall accuracy was determined by comparing MRI measurements with known flow in controlled-flow-loop phantom studies. Measurements using prospective and retrospective gating methods were compared in phantom studies with pulsatile flow, not revealing significant differences. Phantom study results showed good accuracy, with deviations from true flow consistently below 13% for vessel diameters 3mm and above. Reproducibility in human subjects was evaluated by repeated studies in six healthy control subjects, comparing immediate repetition of the scan, repetition of the scan plane scouting, and week-to-week variation in repeated studies. The standard deviation in the 4-week protocol of repeated in vivo measurements of single-kidney renal flow in normal subjects was 59.7 mL/min, corresponding with an average coefficient of variation of 10.55%. Comparison of renal arterial blood flow reproducibility with and without gadolinium contrast showed no significant differences in mean or standard deviation. A breakdown among error components showed corresponding marginal standard deviations (coefficients of variation) 23.8 mL/min (4.21%) for immediate repetition of the breath-held flow scan, 39.13 mL/min (6.90%) for repeated plane scouting, and 40.76 mL/min (7.20%) for weekly fluctuations in renal blood flow.
本研究评估了目前通过屏气流速编码 MRI 测量肾动脉血流的技术的可靠性。通过将 MRI 测量值与在受控流量环体模研究中已知的流量进行比较,确定了整体准确性。在具有脉动流的体模研究中比较了前瞻性和回顾性门控方法的测量值,结果未显示出显著差异。体模研究结果表明,准确性良好,对于直径为 3mm 及以上的血管,测量值与真实流量的偏差始终低于 13%。通过对 6 名健康对照者进行重复研究,比较了扫描的即时重复、扫描平面搜索的重复以及重复研究中的每周变化,评估了人体的可重复性。在正常受试者的单肾肾血流的 4 周重复活体测量中,标准偏差为 59.7mL/min,对应的平均变异系数为 10.55%。比较有无钆对比剂的肾动脉血流可重复性,平均值和标准差均无显著差异。对误差成分的细分显示,即时重复屏气流量扫描的相应边际标准差(变异系数)为 23.8mL/min(4.21%),重复平面搜索为 39.13mL/min(6.90%),每周肾血流量波动为 40.76mL/min(7.20%)。