Anderson G B, Ashforth R, Steinke D E, Ferdinandy R, Findlay J M
Division of Neurosurgery, University of Alberta, Edmonton, Alberta, Canada.
Stroke. 2000 Sep;31(9):2168-74. doi: 10.1161/01.str.31.9.2168.
Computed tomographic angiography (CTA) is a relatively new and minimally invasive method of imaging intracranial and extracranial blood vessels. The main purpose of this study was to compare CTA to the current gold standard of arterial imaging, digital subtraction angiography (DSA), for the detection and quantification of carotid artery bifurcation stenosis. We also compared Doppler ultrasound (US) with these 2 techniques.
In a prospective study, 40 patients (80 carotid arteries) underwent CTA, US, and DSA. Patients chosen for inclusion were symptomatic with TIAs or stroke and had initial US screening that indicated >50% carotid stenosis on the side appropriate for the symptoms. Source axial, maximum intensity projection (MIP), and shaded-surface display (SSD) images were produced for each CTA study. The US, CTA, and DSA images were reviewed, with the degree of stenosis quantified and presence of ulcers determined; each type of imaging was reviewed by a separate investigator blinded to the results of the other 2 modalities. The results of CTA and US imaging were compared with the DSA images for degrees of carotid stenosis.
CTA source axial images correlated with DSA more closely than MIP or SSD images for all degrees of stenosis. The correlation between US and DSA (0.808) was poorer than that between CTA and DSA (0.892 to 0.922). CTA performed well in the detection of mild (0% to 29%) carotid stenosis, as well as carotid occlusion, with values for sensitivity, specificity, and accuracy near 100%. In determining that a stenosis was >50% by DSA measurement, CTA was again useful, with a sensitivity, specificity, and accuracy of 89%, 91%, and 90%, respectively. While CTA was quite specific and accurate in identifying degrees of stenoses in either the 50% to 69% or the 70% to 99% ranges, in this task it was much less sensitive: 65% for 50%-69% stenosis and 73% for 70%-99% stenosis. These results did not change significantly when only the data from the most clinically relevant symptomatic arteries were analyzed. CTA was found to correlate quite well with DSA in the detection of ulcers associated with the carotid stenosis.
CTA was found to be an excellent examination for the detection of carotid occlusion and categorization of stenosis in either the 0%-29% or >50% ranges. However, CTA was unable to reliably distinguish between moderate (50%-69%) and severe (70%-99%) stenosis, which is an important limitation in the investigation and treatment of carotid stenosis.
计算机断层血管造影（CTA）是一种相对较新的用于颅内和颅外血管成像的微创方法。本研究的主要目的是将CTA与当前动脉成像的金标准——数字减影血管造影（DSA）进行比较，以检测和量化颈动脉分叉处狭窄。我们还将多普勒超声（US）与这两种技术进行了比较。
在一项前瞻性研究中，40例患者（80条颈动脉）接受了CTA、US和DSA检查。入选患者有短暂性脑缺血发作（TIA）或中风症状，且初始US筛查显示症状侧颈动脉狭窄>50%。为每项CTA研究生成源轴位、最大密度投影（MIP）和表面阴影显示（SSD）图像。对US、CTA和DSA图像进行评估，量化狭窄程度并确定溃疡的存在；每种成像类型由一名对其他两种检查结果不知情的独立研究人员进行评估。将CTA和US成像结果与DSA图像的颈动脉狭窄程度进行比较。
对于所有狭窄程度，CTA源轴位图像与DSA的相关性比MIP或SSD图像更紧密。US与DSA之间的相关性（0.808）低于CTA与DSA之间的相关性（0.892至0.922）。CTA在检测轻度（0%至29%）颈动脉狭窄以及颈动脉闭塞方面表现良好，其敏感性、特异性和准确性接近100%。通过DSA测量确定狭窄>50%时，CTA同样有用，其敏感性、特异性和准确性分别为89%、91%和90%。虽然CTA在识别50%至69%或70%至99%范围内的狭窄程度时非常特异和准确，但在这项任务中其敏感性较低：50% - 69%狭窄时为65%，70% - 99%狭窄时为73%。仅分析最具临床相关性的症状性动脉的数据时，这些结果没有显著变化。发现CTA在检测与颈动脉狭窄相关的溃疡方面与DSA相关性良好。
发现CTA是检测颈动脉闭塞以及对0% - 29%或>50%范围内的狭窄进行分类的优秀检查方法。然而，CTA无法可靠地区分中度（50% - 69%）和重度（70% - 99%）狭窄，这是颈动脉狭窄研究和治疗中的一个重要局限性。
