CLINICAL ARTICLE J Neurosurg 129:876–882, 2018 A neurysmAl subarachnoid hemorrhage (aSAH) ex- hibits diverse outcomes, with some patients suffer- ing from a devastating course after initial bleeding and others recovering completely from the acute event. Despite the availability of several clinical outcome assess- ments, early prediction of the course in patients with se- vere aSAH remains inaccurate. This is a critical issue for decision making and prognosis evaluation. 20 Currently, the best outcome predictors in patients with aSAH are thought to be those highly correlated with the initial clinical pre- sentation, such as the Hunt and Hess scale and the World Federation of Neurosurgical Societies grade. 19 The Fisher grade is another commonly used imaging grading system that predicts the possibility of delayed neurological defcits according to the results of initial CT. 3 Although up to 40 different clinical assessment tools have been proposed for this purpose, there is no universal consensus on which is most useful. 10,15 After aSAH, the increased intracranial pressure (ICP) and possible ultra-early vasospasm resulting from arterial bleeding is thought to result in compromised global per- fusion and poor clinical outcomes. 1,5 Several authors have proposed the use of a perfusion study, such as CT perfusion (CTP) or MR perfusion, to evaluate the defcit after aSAH and its correlation with clinical outcomes. 6,11,23 However, the use of perfusion studies in the emergency department (ED) ABBREVIATIONS aSAH = aneurysmal subarachnoid hemorrhage; CTA = CT angiography; CTP = CT perfusion; ED = emergency department; ICP = intracranial pressure; MIP = maximal intensity projection; MLS = midline shift; mRS = modified Rankin Scale; ROI = region of interest. SUBMITTED March 29, 2017. ACCEPTED May 23, 2017. INCLUDE WHEN CITING Published online November 24, 2017; DOI: 10.3171/2017.5.JNS17794. * Drs. Hsieh and Y. M. Wu contributed equally to this work and share first authorship. The venous delay phenomenon in computed tomography angiography: a novel imaging outcome predictor for poor cerebral perfusion after severe aneurysmal subarachnoid hemorrhage *Po-Chuan Hsieh, MD, 1 Yi-Ming Wu, MD, 2 Alvin Yi-Chou Wang, MD, 1 Ching-Chang Chen, MD, 1 Chien-Hung Chang, MD, 3 Shy-Chyi Chin, MD, 2 Tai-Wei Erich Wu, MPH, 1 Chieh-Tsai Wu, MD, 1 and Shih-Tseng Lee, MD 1 Departments of 1 Neurosurgery, 2 Medical Imaging and Intervention, and 3 Neurology, Chang Gung Memorial Hospital, Linkou, Chang Gung University and Medical College, Kweishan, Taoyuan, Taiwan OBJECTIVE Diverse treatment results are observed in patients with poor-grade aneurysmal subarachnoid hemorrhage (aSAH). Signifcant initial per fusion compromise is thought to predict a worse treatment outcome, but this has scant sup- port in the literature. In this cohort study, the authors correlate the treatment outcomes with a novel poor-outcome imag- ing predictor representing impaired cerebral perfusion on initial CT angiography (CTA). METHODS The authors reviewed the treatment results of 148 patients with poor-grade aSAH treated at a single tertiary referral center between 2007 and 2016. Patients with the “venous delay” phenomenon on initial CTA were identifed. The outcome assessments used the modifed Rankin Scale (mRS) at the 3rd month after aSAH. Factors that may have had an impact on outcome were retrospectively analyzed. RESULTS Compared with previously identifed outcome predictors, the venous delay phenomenon on initial CTA was found to have the strongest correlation with posttreatment outcomes on both univariable (p < 0.0001) and multivariable analysis (OR 4.480, 95% CI 1.565–12.826; p = 0.0052). Older age and a higher Hunt and Hess grade at presentation were other factors that were associated with poor outcome, defned as an mRS score of 3 to 6. CONCLUSIONS The venous delay phenomenon on initial CTA can serve as an imaging predictor for worse functional outcome and may aid in decision making when treating patients with poor-grade aSAH. https://thejns.org/doi/abs/10.3171/2017.5.JNS17794 KEY WORDS subarachnoid hemorrhage; cerebrovascular circulation; computed tomography angiography; vascular disorders J Neurosurg Volume 129 • October 2018 876 ©AANS 2018, except where prohibited by US copyright law