Hyde Derek E, Fox Allan J, Gulka Irene, Kalapos Paul, Lee Don H, Pelz David M, Holdsworth David W
Robarts Research Institute, Imaging Research Laboratories, London, Ontario, Canada.
Stroke. 2004 Dec;35(12):2776-81. doi: 10.1161/01.STR.0000147037.12223.d5. Epub 2004 Oct 28.
Clinical trials have shown that carotid endarterectomy reduces stroke risk in symptomatic individuals with severe internal carotid artery (ICA) stenosis. As a result of these trials, digital subtraction angiography (DSA) became a standard of reference for ICA stenosis diagnosis. Newer 3D techniques provide a larger number of views than DSA, which may influence the estimated degree of stenosis. We evaluate this possibility by directly comparing stenosis grades from 3D computed rotational angiography (CRA) and DSA.
As a prospective diagnostic study, we performed CRA and DSA on 26 consecutive symptomatic patients. Only 1 angiographic procedure was performed on normal asymptomatic arteries, yielding 42 arteries for comparison. Four neuroradiologists graded the CRA maximum intensity projections (MIPs) and DSA images, according to the North American Symptomatic Carotid Endarterectomy Trial guidelines. CRA studies included a search for the narrowest view by evaluating 60 MIPs generated at 3 degrees intervals and measurement of actual artery diameters. Artery diameters and stenosis grades were analyzed graphically; statistical significance was determined using a paired t test.
The mean difference of 1.2% (CI, -18%, 21%) between CRA and DSA stenosis grades was not statistically significant (P=0.55). Agreement of the optimal CRA viewing angle was limited, with an interobserver variability of 24+/-13 degrees . The interobserver variability of DSA and CRA stenosis grades, 9.1% (CI, 0%, 21%) and 9.4% (CI, 0%, 22%), respectively, was not significantly different (P=0.79).
CRA provides stenosis grades equivalent to DSA, as well as absolute measurements, providing a comparison for newer 3D techniques.
临床试验表明，颈动脉内膜切除术可降低有症状的严重颈内动脉（ICA）狭窄患者的中风风险。基于这些试验，数字减影血管造影（DSA）成为了ICA狭窄诊断的参考标准。更新的三维技术提供的视图比DSA更多，这可能会影响狭窄程度的估计。我们通过直接比较三维计算机旋转血管造影（CRA）和DSA的狭窄分级来评估这种可能性。
作为一项前瞻性诊断研究，我们对26例连续的有症状患者进行了CRA和DSA检查。仅对正常无症状动脉进行了1次血管造影检查，共获得42条动脉用于比较。4名神经放射科医生根据北美症状性颈动脉内膜切除术试验指南对CRA最大密度投影（MIP）和DSA图像进行分级。CRA研究包括通过评估以3度间隔生成的60个MIP来寻找最窄视图，并测量实际动脉直径。以图形方式分析动脉直径和狭窄分级；使用配对t检验确定统计学意义。
CRA和DSA狭窄分级的平均差异为1.2%（CI，-18%，21%），无统计学意义（P = 0.55）。最佳CRA视角的一致性有限，观察者间变异性为24±13度。DSA和CRA狭窄分级的观察者间变异性分别为9.1%（CI，0%，21%）和9.4%（CI，0%，22%），无显著差异（P = 0.79）。
CRA提供的狭窄分级与DSA相当，同时还提供绝对测量值，可为更新的三维技术提供比较。
