Gerediaga G D, Elizagaray E, Canto-Morereira N, Albuquerque C, Branco R, Beirão I, Grande T
Unidad de Neurorradiología, Hospital São Teotónio, Viseu, Portugal.
Rev Neurol. 2009;48(8):406-11.
The degree of stenosis measured by Doppler ultrasonography in patients with contralateral occlusion of the internal carotid artery (ICA) is assumed to be overestimated. We propose to measure the extent to which this phenomenon affects the capacity of Doppler ultrasonography to classify stenoses.
A retrospective study of 47 patients was conducted using Doppler ultrasonography and digital subtraction angiography; all subjects had confirmed unilateral occlusion of the ICA and stenoses of the contralateral ICA. Curves were traced plotting the degree of stenosis against the peak systolic velocity (PSV) and its ratio in the ICA and in the common carotid artery (VICA/VCCA). The curves were compared with their equivalents with no contralateral occlusion found in the literature. Later, the cases of stenosis were classified into groups of less than 50, 50-69 and more than 70%, and the main statistical values were calculated.
The PSV in the stenoses between 40-50% presents more than 1 standard deviation (SD) above the mean. There were no significant deviations in other degrees of stenosis (p > 0.4). The VICA/VCCA showed a similar parallelism, but with deviations lower than 1 SD (p = 0.56). Seventeen per cent of the stenoses were over-classified, and this conditioned a sensitivity of 84, 71 and 100%, and a specificity of 100, 94 and 88% for the groups of less than 50, 50-69 and over 70%, respectively. The VICA/VCCA over-classified 41% of the stenoses; sensitivity was seen to be 56, 43 and 100% and specificity was 90, 64 and 87%. Diagnostic accuracy of the PSV and VICA/VCCA stands at 83 and 57%, respectively.
Contralateral occlusion leads to over-classification of the PSV. There is a tendency to over-classify, although this does not affect the overall diagnostic accuracy. The VICA/VCCA does not offer greater diagnostic accuracy in classifying stenoses with contralateral occlusion.
通过多普勒超声测量颈内动脉（ICA）对侧闭塞患者的狭窄程度被认为存在高估情况。我们旨在评估这种现象对多普勒超声对狭窄进行分类能力的影响程度。
对47例患者进行回顾性研究，采用多普勒超声和数字减影血管造影术；所有受试者均确诊为单侧ICA闭塞及对侧ICA狭窄。绘制狭窄程度与ICA及颈总动脉（VICA/VCCA）收缩期峰值速度（PSV）及其比值的曲线。将这些曲线与文献中未发现对侧闭塞情况的等效曲线进行比较。随后，将狭窄病例分为狭窄程度小于50%、50 - 69%和大于70%的组，并计算主要统计值。
狭窄程度在40 - 50%之间的PSV比平均值高出1个标准差（SD）以上。其他狭窄程度无显著偏差（p > 0.4）。VICA/VCCA显示出类似的平行关系，但偏差低于1个SD（p = 0.56）。17%的狭窄被过度分类，这使得狭窄程度小于50%、50 - 69%和大于70%的组的敏感性分别为84%、71%和100%，特异性分别为100%、94%和88%。VICA/VCCA对41%的狭窄进行了过度分类；敏感性分别为56%、43%和100%，特异性分别为90%、64%和87%。PSV和VICA/VCCA的诊断准确性分别为83%和57%。
对侧闭塞导致PSV过度分类。存在过度分类的倾向，尽管这并不影响总体诊断准确性。VICA/VCCA在对侧闭塞的狭窄分类中并未提供更高的诊断准确性。
