Cerebral vasospasm is a common complication of aneurysmal SAH and remains a risk factor for delayed cerebral ischemia and poor outcome. The interrater reliability of CTA in combination with CTP has not been sufficiently studied. We aimed to investigate the reliability of CTA alone and in combination with CTP in the detection of cerebral vasospasm and the decision to initiate endovascular treatment.

This is a retrospective single-center study including patients treated for aneurysmal SAH. Inclusion criteria were a baseline CTA and follow-up imaging including CTP due to suspected vasospasm. Three neuroradiologists were asked to grade 15 intracranial arterial segments in 71 cases using a tripartite scale (no, mild <50%, or severe >50% vasospasm). Raters further evaluated whether endovascular treatment should be indicated. The ratings were performed in 2 stages with a minimum interval of 6 weeks. The first rating included only CTA images, whereas the second rating additionally encompassed CTP images. All raters were blinded to any clinical information of the patients.

Interrater reliability for per-segment analysis of vessels was highly variable ( = 0.16–0.61). We observed a tendency toward higher interrater reliability in proximal vessel segments, except for the ICA. CTP did not improve the reliability for the per-segment analysis. When focusing on senior raters, the addition of CTP images resulted in higher interrater reliability for severe vasospasm ( = 0.28; 95% CI, 0.10–0.46 versus = 0.46; 95% CI, 0.26–0.66) and subsequently higher concordance ( = 0.23; 95% CI, –0.01–0.46 versus = 0.73; 95% CI, 0.55–0.91) for the decision of whether endovascular treatment was indicated.

CTA alone offers only low interrater reliability in the graduation of cerebral vasospasm. However, using CTA in combination with CTP might help, especially senior neuroradiologists, to increase the interrater reliability to identify severe vasospasm following aneurysmal SAH and to increase the reliability regarding endovascular treatment decisions.

脑血管痉挛是动脉瘤性蛛网膜下腔出血的常见并发症，并且仍然是迟发性脑缺血和预后不良的危险因素。CTA 与 CTP 结合的人间可靠性尚未得到充分研究。我们的目的是研究单独使用 CTA 以及与 CTP 联合使用来检测脑血管痉挛和决定开始血管内治疗的可靠性。

这是一项回顾性单中心研究，包括接受动脉瘤性蛛网膜下腔出血治疗的患者。纳入标准是基线 CTA 和后续影像学检查，包括因疑似血管痉挛而进行的 CTP。三位神经放射科医生被要求使用三重量表（无、轻度 <50% 或严重 >50% 血管痉挛）对 71 例病例的 15 个颅内动脉段进行分级。评估者进一步评估是否应进行血管内治疗。评级分两个阶段进行，最短间隔为 6 周。第一个评级仅包括 CTA 图像，而第二个评级还包括 CTP 图像。所有评估者都不了解患者的任何临床信息。

血管每节段分析的评估者间可靠性差异很大 (= 0.16–0.61)。我们观察到除 ICA 之外的近端血管段有更高的受试者间可靠性的趋势。CTP 没有提高每个段分析的可靠性。当关注高级评估者时，CTP 图像的添加导致严重血管痉挛的评估者间可靠性更高（= 0.28；95% CI，0.10–0.46 对比 = 0.46；95% CI，0.26–0.66），并随后获得更高的一致性（= 0.23；95% CI，0.10–0.46）。 95% CI，–0.01–0.46 vs = 0.73；95% CI，0.55–0.91）用于决定是否需要血管内治疗。

单独使用 CTA 在脑血管痉挛分级方面只能提供较低的受试者间可靠性。然而，结合使用 CTA 和 CTP 可能有助于提高诊断者间的可靠性，以识别动脉瘤性 SAH 后的严重血管痉挛，并提高血管内治疗决策的可靠性，尤其是高级神经放射科医生。