Background and Purpose- Symptomatic vasospasm is an important factor that affects the outcomes of aneurysmal subarachnoid hemorrhage. Subarachnoid blood volume can predict symptomatic vasospasm, and we postulated that the blood clot density would also be an important factor involved in such events. The present study aimed to determine the relationship between the incidence of symptomatic vasospasm and the Hounsfield unit (HU) value of the interpeduncular cistern that reflects the density of hematomas. Methods- Data from 323 patients admitted and treated at a single center between 2008 and 2017 within 24 hours of subarachnoid hemorrhage onset were retrospectively analyzed. Initial HU values of the interpeduncular cistern were measured using CT, then correlations with the incidence of symptomatic vasospasm and HU values as well as other variables were assessed. Results- Symptomatic vasospasm developed in 54 (16.7%) of the 323 patients. The incidence of symptomatic vasospasm was low (1.8%, 2/166) for HU <50, but this incidence increased greatly when the HU value exceeded 50 (23.7%, 22/93 for HU >50 to ≤60, and 45.3%, 29/64 for HU >60). The odds ratio for symptomatic vasospasm was 2.0 (95% CI, 1.6-2.4) per 5 HU increase. Symptomatic vasospasm correlated significantly with intraventricular hemorrhage (P=0.05) and with intracerebral hematoma (P=0.046) but even more significantly with the HU value of the interpeduncular cistern (P<0.0001). Conclusions- The HU value of the interpeduncular cistern on initial CT is an accurate and reliable predictor of symptomatic vasospasm.

中文翻译：

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椎间盘池血肿的Hounsfield单位值可以预测症状性血管痉挛。

背景和目的-有症状的血管痉挛是影响动脉瘤性蛛网膜下腔出血结果的重要因素。蛛网膜下腔的血容量可以预测症状性血管痉挛，我们推测血凝块密度也将是此类事件的重要因素。本研究旨在确定症状性血管痉挛的发生率与反映血肿密度的椎间盘水箱的Hounsfield单位（HU）值之间的关系。方法-回顾性分析2008年至2017年在蛛网膜下腔出血发作24小时内在一个中心收治的323例患者的数据。使用CT测量椎弓根间水箱的初始HU值，然后评估与症状性血管痉挛，HU值以及其他变量发生率的相关性。结果-323例患者中有54例（16.7％）出现了症状性血管痉挛。HU <50时症状性血管痉挛的发生率较低（1.8％，2/166），但是当HU值超过50（23.7％，HU> 50至≤60时为22/93）时，这种发生率大大增加， HU> 60时为29/64）。每增加5 HU，症状性血管痉挛的优势比为2.0（95％CI，1.6-2.4）。有症状的血管痉挛与脑室内出血（P = 0.05）和脑内血肿（P = 0.046）显着相关，但与椎间盘水箱的HU值显着相关（P <0.0001）。结论-椎弓根间水箱在初次CT上的HU值是对症状性血管痉挛的准确可靠的预测指标。