Amanda M. Laslo, Abstract Co-Author: Nothing to Disclose

James David Eastwood MD, Presenter: Nothing to Disclose

Anargyros Xenocostas MD, Abstract Co-Author: Nothing to Disclose

Ting-Yim Lee PhD, Abstract Co-Author: Nothing to Disclose

Increases in cerebral circulation time are associated with poor outcome after subarachnoid hemorrhage (SAH) and may be a reliable indicator of early asymptomatic ischemia related to vasospasm. We examined mean transit time (MTT), cerebral blood flow (CBF) and cerebral blood volume (CBV) with and without vasospasm in a rabbit model of SAH.

SAH was induced in 25 New Zealand White rabbits by a single injection of autologous arterial blood (1.5 cc/kg) into the cisterna magna. CT Perfusion and CT angiography (CTA) were performed on day 0 (baseline, 10, 30, 45 and 60 minutes after SAH), and once each on day 3,5,7,9, and 16. CBF, CBV and MTT were measured in the brainstem, cerebellum, parieto-occipital cerebrum and thalamus. Animals were divided into 2 groups based on the presence or absence of basilar artery vasospasm on CTA and analyzed for differences in CBF, CBV, and MTT.

Ten animals (40%) died within 48 hours of SAH. Of the 15 animals that remained, 8 (53%) exhibited vasospasm (37 ± 13.1%) between day 3 and day 7. Vasospasm was evident on day 5 in 6 of these animals, and on day 3 in the other 2. Overall, MTT was greater in animals with vasospasm (2.9 ± 0.7 s) than in animals without vasospasm (2.0 ± 0.4 s). This difference was statistically significant (p0.05). CBV did not differ significantly between the two groups.

MTT increases in the presence of vasospasm after SAH. MTT may be a better indicator than CBF or CBV for demonstrating risk of vasospasm and associated ischemic deficits after SAH. (Project supported in part by American Society of Neuroradiology)

T.L.: TY Lee is a consultant to General Electric Healthcare on CT Perfusion

Laslo, A, Eastwood, J, Xenocostas, A, Lee, T, Mean Transit Time as an Indicator for Cerebral Vasospasm after Subarachnoid Hemorrhage.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4408889.html