Related Experiment Video
Updated: May 28, 2026
Multi-Tracer Studies of Brain Oxygen and Glucose Metabolism Using a Time-of-Flight Positron Emission Tomography-Computed Tomography Scanner
Published on: June 7, 2024
Failure of cerebral hemodynamic selection in general or of specific positron emission tomography methodology?:
Andrew P Carlson1, Howard Yonas, Yue-Fang Chang
1Department of Neurosurgery, University of New Mexico, MSC 10 5615, Albuquerque, NM 87131, USA.
Background And Purpose:
The Carotid Occlusion Surgery Study (COSS) was an improvement over the Extracranial-Intracranial Bypass Study, which did not utilize physiological selection. To assess possible reasons for early closure of the COSS trial, we reviewed COSS methods used to identify high-risk patients and compared results with separate quantitative data.
Methods:
Increased oxygen extraction fraction (OEF) by positron emission tomography is a gold standard for ischemia, but the specific thresholds and equivalency of the semiquantitative OEF ratio utilized in COSS and quantitative OEF are at issue.
Results:
The semiquantitative hemispheric OEF ratio used in COSS did not identify the same group of patients as did quantitative OEF using a threshold of 50%.
Conclusions:
The failure of COSS is likely caused by a failure of the semiquantitative, hemispheric OEF ratio method rather than by the selection for bypass based on hemodynamic compromise.
