Normative distribution of posterior circulation tissue time-to-maximum: Effects of anatomic variation, tracer kinetics, and implications for patient selection in posterior circulation ischemic stroke
- 14 January 2021
- journal article
- research article
- Published by SAGE Publications in Journal of Cerebral Blood Flow & Metabolism
- Vol. 41 (8), 1912-1923
- https://doi.org/10.1177/0271678x20982395
Abstract
The generalization of perfusion-based, anterior circulation large vessel occlusion selection criteria to posterior circulation stroke is not straightforward due to physiologic delay, which we posit produces physiologic prolongation of the posterior circulation perfusion time-to-maximum (Tmax). To assess normative Tmax distributions, patients undergoing CTA/CTP for suspected ischemic stroke between 1/2018-3/2019 were retrospectively identified. Subjects with any cerebrovascular stenoses, or with follow-up MRI or final clinical diagnosis of stroke were excluded. Posterior circulation anatomic variations were identified. CTP were processed in RAPID and segmented in a custom pipeline permitting manually-enforced arterial input function (AIF) and perfusion estimations constrained to pre-specified vascular territories. Seventy-one subjects (mean 64 ± 19 years) met inclusion. Median Tmax was significantly greater in the cerebellar hemispheres (right: 3.0 s, left: 2.9 s) and PCA territories (right: 2.9 s; left: 3.3 s) than in the anterior circulation (right: 2.4 s; left: 2.3 s, p < 0.001). Fetal PCA disposition eliminated ipsilateral PCA Tmax delays (p = 0.012). Median territorial Tmax was significantly lower with basilar versus any anterior circulation AIF for all vascular territories (p < 0.001). Significant baseline delays in posterior circulation Tmax are observed even without steno-occlusive disease and vary with anatomic variation and AIF selection. The potential for overestimation of at-risk volumes in the posterior circulation merits caution in future trials.Keywords
This publication has 39 references indexed in Scilit:
- Thrombolysis Guided by Perfusion Imaging up to 9 Hours after Onset of StrokeThe New England Journal of Medicine, 2019
- 2018 Guidelines for the Early Management of Patients With Acute Ischemic Stroke: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke AssociationStroke, 2018
- Perfusion computed tomography in posterior circulation stroke: predictors and prognostic implications of focal hypoperfusionEuropean Journal of Neurology, 2018
- Thrombectomy 6 to 24 Hours after Stroke with a Mismatch between Deficit and InfarctThe New England Journal of Medicine, 2018
- European Cooperative Acute Stroke Study-4: Extending the time for thrombolysis in emergency neurological deficits ECASS-4: ExTENDInternational Journal of Stroke, 2016
- Stent-Retriever Thrombectomy after Intravenous t-PA vs. t-PA Alone in StrokeThe New England Journal of Medicine, 2015
- Endovascular Therapy for Ischemic Stroke with Perfusion-Imaging SelectionThe New England Journal of Medicine, 2015
- Ischemic Posterior Circulation Stroke: A Review of Anatomy, Clinical Presentations, Diagnosis, and Current ManagementFrontiers in Neurology, 2014
- Posterior circulation ischaemic stroke and transient ischaemic attack: diagnosis, investigation, and secondary preventionThe Lancet Neurology, 2013
- Distribution of Cerebral Blood Flow in the Circle of WillisRadiology, 2005