Flat-Detector CT to Quantify Response to Intra-Arterial Spasmolytic Therapy for Cerebral Vasospasm

Cerebral vasospasm in the setting of subarachnoid hemorrhage causes morbidity and mortality due to delayed cerebral ischemia and permanent neurological deficits. Vasospasm treatment includes intra-arterial injection of a spasmolytic during cerebral angiography. To evaluate effectiveness, neurointerventionalists subjectively examine a posttreatment cerebral angiogram to determine change in vessel diameter or increase in microvascular perfusion. Flat-detector computed tomography (FDCT) scanner has the ability to quantitatively measure cerebral blood volume (CBV) within the parenchyma and detect a quantitative change following treatment.

This is a prospective study at a single institution between October 5, 2017 and June 3, 2019 that examines CBV studies from the Artis Q biplane (Siemens). Regions of interest were made in various territories to measure the CBV within the parenchyma before and after treatment with the spasmolytic verapamil. All instances of vasospasm involved vasculature within the left middle cerebral artery or internal carotid artery. The Wilcoxon signed-rank test was used to determine significance before and after treatment.

Our cohort consists of 6 patients who underwent Digital Subtraction Angiography (DSA) and FDCT scans for cerebral vasospasm within the left hemisphere. After intra-arterial injection of 20 mg of verapamil, average increases in blood volume were 59%, 22%, and 24% for the temporal, frontal, and parietal lobes, respectively. P-values associated were .03. We also observed decrease in the mean arterial blood pressure and transcranial Doppler values after treatment.

In conclusion, FDCT could measure the effectiveness of a change in CBV from infusion of verapamil in the setting of cerebral vasospasm. The authors believe quantifying the change allows for reassurance of improvement of cerebral vasospasm.