Using Ct Perfusion Distinguishs Between Reversible Ischemia And Ischemia Progressing To Infarction During Delayed Cerebral Ischemia After Subarachnoid Hemorrhage

Objective To study cerebral perfusion in surrounding brain parenchyma and follow-up imaging within delay cerebral ischemia(DCI) after aneurismal subarachnoid hemorrhage, we explore whether CT perfusion(CTP) can distinguish between reversible ischemia and ischemia progressing to cerebral infarction.Methods Imaging data of 38 DCI after aSAH patients by interventional therapy or surgical treatment or drug treatment during September 2013 to October 2015 in Tianjin Medical University General Hospital were retrospectively reviewed. All patients with subarachnoid hemorrhage use non-contrast CT and CT perfusion and CT angiography at the time of subarachnoid hemorrhage and clinical deterioration. We select the aneurismal subarachnoid hemorrhage patients. And during clinical deterioration we follow up by CT or MRI with 3 weeks. We record the Hunt-Hess classification, aneurysm location and treatment of all aneurismal subarachnoid hemorrhage patients and CT perfusion imaging and perfusion value(Cerebral Blood Flow, Mean Transit Time, Time Peak, Cerebral blood volume). In qualitative CTP analyses(visual assessment), we calcultated positive predictive value and negative predictive value with 95% confidence intervals(95% CI) of perfusion deficit for infraction on follow-up imaging. In quanlitative CTP analyses, we compared perfusion values of the least perfusion area between patients with infraction and without infraction by ROC curves. In quantitative CTP analyses, we calutated athershold value in the highest area under the ROC cure. And we caluteted the positive predictive value and the nagetive value. We compared perfusion values of the least perfusion brain tissue between patients with cerebral infraction and without cerebral infraction. Result The trial included 38 patients : 17 patients with cerebral infraction(45%) and 21 patients without cerebral infraction. 14 of 17 patients(82%) with cerebral infraction and 7 of 21 patients(33%) without cerebral infraction on follow-up had a perfusion deficit during clinical deterioration(P<0.05). A perfusion deficit had a PPV of 67%(95%CI:)and a NPV of 82%(95%CI:) for infraction on follow-up. In quanlitative CTP analyses, an absolute CBF threshold of 17.63 ml/100g/min had a PPV of 65% and a NPV of 76%. Conclusion Using CT perfusion distinguished between reversible ischemia and ischemia progressing to infarction during delayed cerebral ischemia after subarachnoid hemorrhage. In addition, qualitative analysis may perform better than quanlitative analysis.