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Abstract：
Background/Objectives: Digital subtraction angiography (DSA) is the gold standard in the diagnosis of cerebral vasospasm, frequently observed after subarachnoid hemorrhage (SAH). However, less-invasive methods, such as computed tomography angiography (CTA), may be equally accurate. To further clarify comparability, this study evaluated the reliability of CTA in detecting cerebral vasospasm. Methods: This retrospective study included 51 patients with SAH who underwent both CTA and DSA within 24 h. The smallest diameter of the proximal cerebral arterial segments was measured in both modalities at admission and during the vasospasm period. The mean difference in diameter, the intraclass correlation coefficient (ICC) of CTA and DSA, the difference in grade of vasospasm and sensitivity, the specificity and the positive predictive value (PPV) for CTA were calculated. Results: A total of 872 arterial segments were investigated. At time of admission, arterial diameters were significantly smaller on CTA compared to DSA in all segments (-0.26 ± 0.12 mm; p < 0.05). At time of suspected vasospasm (day 9 ± 5), these differences remained significant only for the M1 segment (-0.18 ± 0.37 mm, p = 0.02), the P1 segment (-0.13 ± 0.24 mm, p = 0.04) and the basilar artery (-0.20 ± 0.37 mm, p = 0.0.04). The ICC between CTA and DSA was good (0.5-0.8). The sensitivity of CTA for predicting angiographic vasospasm was 99%, the specificity was 50% and the PPV was 92%. Conclusions: Arterial diameters measured on CTA may underestimate the arterial caliber observed in DSA; however, these absolute differences were minor. Importantly, vessel diameter alone does not fully reflect malperfusion, requiring additional imaging techniques such as CT perfusion.
摘要：
背景/目的:数字减影血管造影(DSA)是诊断脑血管痉挛的金标准。蛛网膜下腔出血（SAH）后经常观察到。然而,侵入性较小的方法，如计算机断层扫描血管造影（CTA），可能同样准确。为了进一步澄清可比性，这项研究评估了CTA检测脑血管痉挛的可靠性。方法：这项回顾性研究包括51例SAH患者，他们在24h内同时接受了CTA和DSA。在入院时和血管痉挛期间的两种方式中都测量了近端脑动脉段的最小直径。直径的平均差异，CTA和DSA的组内相关系数(ICC)，血管痉挛的分级和敏感性的差异，计算CTA的特异性和阳性预测值(PPV).结果：共调查了872个动脉段。入院时,与所有节段的DSA相比,CTA的动脉直径均明显较小(-0.26±0.12mm;p<0.05).在怀疑血管痉挛时（第9±5天），这些差异仅在M1段(-0.18±0.37毫米，p=0.02),P1段(-0.13±0.24mm,p=0.04）和基底动脉（-0.20±0.37mm，p=0.0.04)。CTA和DSA之间的ICC良好（0.5-0.8）。CTA预测血管造影血管痉挛的敏感性为99%,特异性为50%,PPV为92%.结论：在CTA上测量的动脉直径可能低估了在DSA中观察到的动脉口径；但是，这些绝对差异很小。重要的是,血管直径不能完全反映灌注不良，需要额外的成像技术，如CT灌注。
