无对比增强MR血管成像与CT血管成像对肾动脉狭窄评价的对照研究

目的探讨结合时间-空间双重标记反翻转恢复脉冲（Time-SLIP）序列的无对比增强（non-contrast-enhanced）MR血管造影（MRA）技术在评价肾动脉狭窄（RAS）中的应用,并与CT血管造影（CTA）比较。材料与方法对22例怀疑RAS的患者同期进行MRA和CTA检查。在1.5 T MR扫描仪上,运用结合Time-SLIP技术的冠状面和轴面采集真实稳态自由进动序列（true SSFP）进行肾动脉MRA成像。评价肾动脉MRA图像质量和狭窄程度,并与CTA进行比较。结果共46支肾动脉列入统计,MRA图像质量优秀29例（63%）,良好13例（28%）,一般4例（9%）。无对比增强MRA与CTA对诊断肾动脉狭窄程度分级结果具有相关性（r=0.991,（P〈0.01）。以CTA为参照标准,MRA诊断明显RAS（狭窄程度≥50%）的敏感度为100%,特异度为97.1%。结论结合Time-SLIP的无对比增强MRA技术可有效用于评价肾动脉狭窄。

Non-contrast-enhanced MR angiography for evaluation renal artery stenosis:comparison with CT angiography

Objective： To explore the application of non-contrast-enhanced magnetic resonance angiography（MRA） with time-spatial labeling inversion pulse（Time-SLIP） for assessment of renal artery stenosis（RAS） comparing with computer tomography angiography（CTA）.Materials and Methods： Twenty-two patients [12 men and 10 women,mean age：（47.4±9.2） years] in the suspicion of RAS were evaluated with MRA and CTA in the same period.Coronal and axial true steady-state free-precession（SSFP） sequences with Time-SLIP technique were performed on a 1.5 T MRI system for MRA imaging.Image quality and grade of RAS were evaluated.The UnenhancedMRA images were compared against CTA results.Results： Forty-six renal arteries were included in the statistical analysis.Image quality of MRA was excellent in 63%（29 of 46）,good in 28%（13 of 46） and moderate in 9%（four of 46） of patients.The agreement between Time-SLIP MRA and CTA assessments for RAS grading was excellent,with a Spearman rank-order correlation coefficient（r） of 0.991（P0.01）.The sensitivity and specificity of non-enhanced-MRA for the detection of significant RAS（≥50%） were 100% and 97.1% using CTA as the gold standard.Conclusion： Non-contrast-enhanced MRA with Time-SLIP is an appropriate method for assessment of renal artery stenosis.