磁共振血管造影结合彩色多普勒对椎动脉狭窄的诊断

THE DIAGNOSIS OF COMBINING MRA WITH COLOR DOPPLER ULTRASOUND IN VERTEBRAL ARTERY STENOSIS

目的:探讨椎动脉狭窄导致椎基底动脉供血不足(CVBI)的定量诊断标准,为临床诊断椎动脉狭窄提供依据。方法:病人组53例,对照组13例,两组共66例病人,均作磁共振血管造影(MRA)和彩色多普勒血流成像(CDFI)检查,测量椎动脉内径及血流速度,并计算脑血流量(CBF)。结果:对照组中的患侧椎动脉与病人组中的各组患侧椎动脉内径比较均有明显差异(P<0.01);无狭窄组与对照组比较,双侧椎动脉总CBF值及患侧椎动脉平均流速Vm值无明显下降(P>0.05);而无狭窄组及轻、中、重度狭窄组各组间比较,双侧总CBF值均有明显差异(P<0.01),轻、中、重度狭窄组健患侧Vm之比分别为1∶0.88、1∶0.98、1∶0.85,三组健侧椎动脉内径均大于对照组健侧椎动脉内径,三组健侧CBF占总CBF的比例分别为73.8±6.2%、86.7±6.5%、93.1±6.1%。结论:1.椎动脉狭窄时,以一侧椎动脉狭窄,而对侧代偿性增宽为多见,VBI的发生除因患侧椎动脉血流量下降外,还与健侧椎动脉失代偿,导致总CBF值下降有关。2.通过CDFI测量Vm及MRA测量椎动脉内径并计算CBF值,能对椎动脉狭窄作出以下诊断标准:轻、中、重度狭窄各组患侧椎动脉内径分别为2.59±0.32mm、1.83±0.28mm、1.08±0.52mm;患侧椎动脉Vm值分别为0.19±0.07m/s、0.18±0.07m/s、0.11±0.06m/s;双侧椎动脉总CBF分别为161.5±25.9mL/min、142.3±18.7mL/min、117.2±21.6mL/min。

Objective：To study the quantitative criteria for diagnosis of vertebrobasilar ischemia（VBI） caused by vertebral artery（VA） stenosis.Methods：53 cases in experimontal group and 13 cases in control group were all examined by magnetic resonance angiography（MRA） and color doppler flow imaging（CDFI）.VA diameter and blood flow velocity were measured and cerebral blood flow（CBF） volume were calculated.Results：The results showed that VA diameters in control group were of different significantly with experimontal group（P〈0.01）;Total CBF volume of bilateral VA and Vm of the involved VA in no stenosis group weren＇t significantly decrease with control group（P〉0.05）;Total CBF volume of bilateral VA in no stenosis group showed significantly different with the mild,moderate,severe stenosis groups（P〈0.01）,the ratio of bilateral VA in mild,moderate,severe stenosis groups were 1∶0.88,1∶0.98,1∶0.85 respectively;the health VA diameter in these groups were all greater than that of the control group;proportions of the health VA CBF held in total CBF in these three groups were 73.8±6.2%,86.7±6.5%,93.1±6.1% respectively.Conclutions：（1）When VA stenosis occured,it was always seen that unilateral VA stenosis and contralateral VA compensatively widened,VBI caused not only by CBF volume decline in the involved VA but also by no complete compensation in the health VA resulting in total CBF decline.（2）Through measuring VA diameter and Vm by color Doppler and MRA,calculating CBF volume,a criteria for diagnosis of VA stenosis as follows：the involved VA diameter in the mild,moderate,severe stenosis groups were 2.59±0.32mm,1.83±0.28mm,1.08±0.52mm respectively;Vm value in the involved VA were 0.19±0.07m/s,0.18±0.07m/s,0.11±0.06m/s respectively;total CBF volume of bilateral VA were 161.5±25.9mL/min,142.3±18.7mL/min,117.2±21.6mL/min respectively.