Relative Mean Transit Time Predicts Subsequent Stroke in Symptomatic Carotid Occlusion

• Published in: Journal of stroke and cerebrovascular diseases Vol. 25; no. 6; pp. 1421 - 1424
• Main Authors: Grubb, Robert L., MD, Derdeyn, Colin P., MD, Videen, Tom O., PhD, Carpenter, David A., MD, Powers, William J., MD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.06.2016
• Subjects: Area Under Curve; Blood Flow Velocity; Cardiovascular; Carotid Artery, Internal - diagnostic imaging; Carotid Artery, Internal - physiopathology; Carotid Stenosis - complications; Carotid Stenosis - diagnostic imaging; Carotid Stenosis - physiopathology; Cerebrovascular Circulation; Humans; internal carotid artery occlusion; Kaplan-Meier Estimate; mean transit time; Middle Cerebral Artery - diagnostic imaging; Middle Cerebral Artery - physiopathology; Missouri; Neurology; Positron emission tomography; Predictive Value of Tests; Prognosis; Proportional Hazards Models; Regional Blood Flow; Retrospective Studies; Risk Assessment; Risk Factors; ROC Curve; Stroke - diagnostic imaging; Stroke - etiology; Stroke - physiopathology; stroke risk; Time Factors; internal carotid artery occlusion; stroke risk; Positron emission tomography; mean transit time
• ISSN: 1052-3057; 1532-8511
• DOI: 10.1016/j.jstrokecerebrovasdis.2015.12.041

Background Mean transit time (MTT) measurements to assess cerebral hemodynamics are easily obtained by computed tomography and magnetic resonance imaging. We reviewed hemodynamic and clinical outcome data from the St. Louis Carotid Occlusion Study to determine if increased MTT was associated with an increased risk of stroke in patients with symptomatic complete carotid artery occlusion. Methods Positron emission tomography (PET) studies of cerebral blood volume-to-cerebral blood flow ratios were used to calculate MTTs. Mean ipsilateral (side of the occluded internal carotid artery)-to-contralateral ratios of MTTs in the middle cerebral artery territories were determined. MTT was tested as a predictor of stroke risk using Cox regression analysis. Receiver operating characteristic curves for stroke risk prediction were generated by varying the mean ispilateral-to-contralateral MTT ratio to identify an optimal cutpoint. Results Increased MTT ratio was associated with an increased risk of ipsilateral stroke ( P  < .001). The maximum combination of sensitivity (.778) and specificity (.763) was obtained at a cutpoint ratio of 1.387 or higher. Subjects with a MTT ratio of 1.387 or higher had a 29.3% 2-year risk of ipsilateral stroke compared to 4.6% for those without ( P  < .001). Conclusions PET relative MTT ratio identified patients with symptomatic complete internal artery occlusion who were at high risk for subsequent ipsilateral stroke. Confirmation using measurements of relative MTT from other imaging modalities in a patient cohort receiving contemporary medical management is needed.