Grant E G, Duerinckx A J, El Saden S, Melany M L, Hathout G, Zimmerman P, Cohen S N, Singh R, Baker J D
Department of Radiology, West Los Angeles Veterans Affairs Medical Center and Department of Radiological Sciences, UCLA School of Medicine, CA 90073, USA.
AJR Am J Roentgenol. 1999 Apr;172(4):1123-9. doi: 10.2214/ajr.172.4.10587159.
A wide range of Doppler threshold values for carotid stenosis is found in the literature. We undertook this study to compare methods of derivation and to determine if an optimum strategy of threshold selection exists for a high-risk population.
From the sonograms of all patent internal carotid arteries, peak systolic velocity in the internal carotid artery (ICA(PSV)) and the ratio of peak systolic velocity in the internal carotid artery to that of the common carotid artery (ICA(PSV)/ CCA(PSV)) were compared with the percentage of angiographically determined stenosis. Receiver operating characteristic curves were generated for levels of stenosis > or =60% and > or =70%. Doppler thresholds were chosen on the basis of maximum accuracy and on the basis of > or =90% sensitivity and specificity. Patients were then segregated into symptomatic and asymptomatic cohorts, and the above process was repeated. An effectiveness analysis was also conducted using various Doppler thresholds. Thresholds derived using these three methods were compared and optimal values chosen. RESULTS. Of 333 carotid arteries that fit inclusion criteria, 132 were found in asymptomatic patients and 201 in symptomatic patients. Maximum accuracy, > or =90% sensitivity and specificity, and effectiveness analysis each produced different ranges of thresholds. We chose final thresholds that maintained patient outcome profiles. For asymptomatic patients at the > or =60% stenosis level, thresholds were ICA(PSV) = 200 cm/sec and ICA(PSV)/CCA(PSV) = 3.0. For symptomatic patients with stenosis > or =70%, thresholds were ICA(PSV) = 175 cm/sec and ICA(PSV)/CCA(PSV) = 2.5.
Considerable latitude exists in the choice of carotid Doppler thresholds. We propose a rational strategy for threshold selection based on a combination of three commonly used methods. Our observations indicate that it appears advisable to consider symptomatic and asymptomatic patients separately and to apply appropriately derived thresholds.
文献中发现了多种用于颈动脉狭窄的多普勒阈值。我们开展本研究以比较推导方法，并确定对于高危人群是否存在最佳的阈值选择策略。
从所有通畅的颈内动脉超声图像中，将颈内动脉的收缩期峰值流速（ICA(PSV)）以及颈内动脉与颈总动脉收缩期峰值流速之比（ICA(PSV)/CCA(PSV)）与血管造影确定的狭窄百分比进行比较。针对狭窄程度≥60%和≥70%生成受试者操作特征曲线。基于最大准确性以及≥90%的敏感性和特异性来选择多普勒阈值。然后将患者分为有症状和无症状队列，并重复上述过程。还使用各种多普勒阈值进行了有效性分析。比较使用这三种方法得出的阈值并选择最佳值。结果：在符合纳入标准的333条颈动脉中，132条在无症状患者中发现，201条在有症状患者中发现。最大准确性、≥90%的敏感性和特异性以及有效性分析各自产生了不同范围的阈值。我们选择了维持患者预后特征的最终阈值。对于狭窄程度≥60%的无症状患者，阈值为ICA(PSV)=200 cm/秒和ICA(PSV)/CCA(PSV)=3.0。对于狭窄程度≥70%的有症状患者，阈值为ICA(PSV)=175 cm/秒和ICA(PSV)/CCA(PSV)=2.5。
在选择颈动脉多普勒阈值方面存在相当大的灵活性。我们基于三种常用方法的组合提出了一种合理的阈值选择策略。我们的观察表明，分别考虑有症状和无症状患者并应用适当推导的阈值似乎是可取的。
