冠状动脉血流储备与管腔狭窄关系的MR研究

The relation between coronary artery flow reserve and stenosis severity of lumen as revealed by MR

目的利用相位对比磁共振(PCMR)测量冠状动脉(简称冠脉)血流及血流储备(CFR),与血管造影检查作对照,分析其与管腔狭窄程度的关系。方法选取拟行冠脉造影检查的患者,利用MR测量其冠脉左前降支(LAD)和右冠脉(RCA)静息和负荷状态下的血流,从而计算出血流储备;并依据造影证实的LAD和RCA管腔狭窄程度将患者分为4组,分别为正常组(0%)、轻度狭窄组(≤50%)、中度狭窄组(50%～75%)、重度狭窄组(≥75%)。分析CFR与血管狭窄程度的关系。结果患者按上述分组,各组分别为39例、22例、13例及18例(LAD组)和43例、15例、16例及15例(RCA),各组之间CFR测量值分别为3.75±1.60、2.84±0.84、1.83±0.85、1.37±0.45(LAD)和3.30±1.42、3.16±0.79、1.78±1.08、1.21±0.22(RCA);排除其他干扰因素影响后,证实正常组、轻度狭窄组分别与中、重度狭窄组之间的CFR差异有统计学意义(P<0.01)。通过CFR与冠脉血管狭窄程度的相关性研究,建立CFR与狭窄程度的多元线性回归模型。进一步证实当CFR<2.0时,诊断血管狭窄程度大于75%的准确度分别为84.79%和79.78%(LAD和RCA)。结论利用PCMR技术测量的CFR与血管狭窄程度呈线性相关;冠脉静息血流量在轻、中度狭窄时减少并不明显,甚至还有增加,直到重度狭窄才略有降低;而负荷血流量和血流储备在管腔中度以上狭窄时就开始显著下降;当CFR<2.0时,可以作为判断冠脉血管存在重度以上狭窄的指标。

Objective To analyze the relationship between CFR and stenosis severity of coronary arteries by means of measuring the coronary flow and flow reserve (CFR) with phase contrast magnetic resonance, with comparison to conventional angiography (CAG). Methods 97 cases underwent MR examination to measure the flow of LAD and RCA in rest and stress state, then CFR was calculated. All cases were divided into four groups due to the stenosis severity in LAD and RCA with the quantitative analysis of CAG examination: normal group (0%), mild stenosis group (≤50%), moderate stenosis group (50%-75%) and severe stenosis group (≥75%). Analyzing the relationship between CFR and stenosis severity in the same coronary artery was performed. Results In CAG results, the effective cases of every group were 39,22,13,18(LAD) and 43,15,16,15(RCA). The CFR values of every group were 3.75±1.60,2.84±0.84,1.83±0.85,1.37±0.45(LAD) and 3.30±1.42,3.16±0.79,1.78±1.08,1.21±0.22(RCA). Either in LAD or RCA, the CFR between normal, mild stenosis and moderate stenosis, severe stenosis groups had significant differences (P<0.01). In the correction analysis between the CFR measured by MR and stenosis severity by CAG, multi-liner regression model was established. If the CFR<2.0, the accuracy of prediction of stenosis severity more than 75% in two vessels were 84.79%(LAD) and 79.78%(RCA). Conclusion Noninvasive measurement of CFR by PC-MR is linearly related to stenosis severity detected by quantitative angiography. No remarkable change of the rest flow is noted in moderate stenosis (intermediate) of coronary arteries, but the stress flow decrease in severe stenosis. It might be a parameter of severe stenosis if CFR measured by MR was < 2.0.