Oxygen extraction fraction and stroke risk in patients with carotid stenosis or occlusion: a systematic review and meta-analysis.
OBJECTIVE
Increased oxygen extraction fraction on PET has been considered a risk factor for stroke in patients with carotid stenosis or occlusion, though the strength of this association has recently been questioned. We performed a systematic review and meta-analysis to summarize the association between increased oxygen extraction fraction and ipsilateral stroke risk.


METHODS
A comprehensive literature search was performed. We included studies with baseline PET oxygen extraction fraction testing, ipsilateral stroke as the primary outcome, and at least 1 year of follow-up. A meta-analysis was performed by use of a random-effects model.


RESULTS
After screening 2158 studies, 7 studies with 430 total patients with mean 30-month follow-up met inclusion criteria. We found that 6 of 7 studies were amenable to meta-analysis. Although 4 of the 6 studies independently did not reach statistical significance, meta-analysis revealed a significant positive relationship between abnormal oxygen extraction fraction and future ipsilateral stroke, with a pooled OR of 6.04 (95% CI, 2.58-14.12). There was no statistically significant difference in OR in the subgroup analyses according to testing method or disease site.


CONCLUSIONS
Abnormal oxygen extraction fraction remains a powerful predictor of stroke in carotid stenosis or occlusion and is a valuable reference standard to compare and validate MR imaging-based measures of brain oxygen metabolism. However, there is a need for further evaluation of oxygen extraction fraction testing in patients with high-grade but asymptomatic carotid disease.
From the Departments of Radiology (A.G., H.B., A.D.S., Y.W., P.C.S.).
A
A
Gupta
H
H
Baradaran
A D
AD
Schweitzer
H
H
Kamel
A
A
Pandya
D
D
Delgado
D
D
Wright
S
S
Hurtado-Rua
Y
Y
Wang
P C
PC
Sanelli
D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D016893:Carotid Stenosis / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000378:metabolism*; D015984:Causality; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism*; D010104:Oxygen Radioisotopes / Q000493:pharmacokinetics; D049268:Positron-Emission Tomography / Q000379:methods; D015995:Prevalence; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity; D020521:Stroke / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000378:metabolism*
D015415:Biomarkers; D010104:Oxygen Radioisotopes; D019275:Radiopharmaceuticals; D010100:Oxygen