Eliasziw M, Rankin R N, Fox A J, Haynes R B, Barnett H J
Department of Epidemiology and Biostatistics, University of Western Ontario, Hamilton, Canada.
Stroke. 1995 Oct;26(10):1747-52. doi: 10.1161/01.str.26.10.1747.
The accuracy of routine ultrasonography in detecting severe carotid artery stenosis was evaluated in comparison with cerebral angiography. The precision of ultrasonographic criteria in predicting the risk of stroke was also assessed.
A total of 1011 symptomatic carotid bifurcations were studied in patients from the North American Symptomatic Carotid Endarterectomy Trial (NASCET). Given that all patients were considered for entry into the trial, the chance of a verification bias affecting the analyses was minimized. The ultrasonographic data consisted of peak systolic velocities and frequency changes from both the internal and common carotid arteries. Angiographic stenosis was calculated as in NASCET. Receiver operating characteristic (ROC) curves were constructed from the ultrasonographic data for the detection of 70% or greater stenosis on the basis of an angiographic assessment. Kaplan-Meier stroke-free survival curves were used to predict the risk of stroke.
The areas under the ROC curves ranged from 0.74 to 0.75 (95% confidence interval [CI], 0.69 to 0.79). The sensitivities and specificities ranged from 0.65 to 0.71. The risk of stroke at 18 months declined sharply as the degree of angiographically defined stenosis declined from 99% to 70%. No pattern of decline was apparent on the basis of the ultrasonographic data.
The results indicate that the accuracy of ultrasonography is moderate when flow parameters are used to assess the degree of stenosis. Ultrasonography should be used as a screening tool to exclude patients with no carotid artery disease from further testing. Conventional angiography remains an essential investigation before assigning the risk of stroke and deciding appropriate treatment for extracranial carotid artery disease.
将常规超声检查与脑血管造影术进行比较，评估其检测重度颈动脉狭窄的准确性。同时评估超声诊断标准预测中风风险的精确性。
对北美症状性颈动脉内膜切除术试验（NASCET）中的患者共1011个有症状的颈动脉分叉处进行研究。鉴于所有患者均被考虑纳入试验，因此将影响分析的验证偏倚的可能性降至最低。超声检查数据包括颈内动脉和颈总动脉的收缩期峰值流速及频率变化。血管造影狭窄程度的计算方法同NASCET。根据血管造影评估结果，利用超声检查数据绘制受试者操作特征（ROC）曲线，以检测狭窄程度达70%或更高的情况。采用Kaplan-Meier无卒中生存曲线预测中风风险。
ROC曲线下面积在0.74至0.75之间（95%置信区间[CI]，0.69至0.79）。敏感性和特异性在0.65至0.71之间。随着血管造影定义的狭窄程度从99%降至70%，18个月时的中风风险急剧下降。根据超声检查数据未发现明显的下降模式。
结果表明，当使用血流参数评估狭窄程度时，超声检查的准确性中等。超声检查应用作筛查工具，以排除无颈动脉疾病的患者进行进一步检查。在评估中风风险和决定颅外颈动脉疾病的适当治疗之前，传统血管造影仍然是一项必不可少的检查。
