Quantification of Infarct Core Volume in Patients with Acute Ischemic Stroke Using Cerebral Metabolic Rate of Oxygen in CT Perfusion.

Background and Purpose: The cerebral metabolic rate of oxygen (CMRO ₂ ) is considered a robust marker of the infarct core in ¹⁵ O-tracer-based PET. We aimed to delineate the infarct core in patients with acute ischemic stroke by using commonly used relative CBF (rCBF) < 30% and oxygen metabolism parameter of CMRO ₂ on CT perfusion in comparison with pretreatment DWI-derived infarct core volume.
Materials and Methods: Patients with acute ischemic stroke who met the inclusion criteria were recruited. The CMRO ₂ and CBF maps in CT perfusion were automatically generated by using postprocessing software. The infarct core volume was quantified with relative cerebral metabolic rate of oxygen (rCMRO ₂ ) <20% -30% and rCBF <30%. The optimal threshold was defined as those that demonstrated the smallest mean absolute error, lowest mean infarct core volume difference, narrowest 95% limit of agreement, and largest intraclass correlation coefficient (ICC) against the DWI.
Results: This study included 76 patients (mean age ± standard deviation, 69.97 ± 12.15 years, 43 men). The optimal thresholds of rCMRO ₂ <26% resulted in the lowest mean infarct core volume difference, narrowest 95% limit of agreement, and largest ICC among different thresholds. Bland-Altman analysis demonstrated a volumetric bias of 1.96 mL between DWI and rCMRO ₂ <26%, whereas in cases of DWI and rCBF <30%, the bias was notably larger at 14.10 mL. The highest correlation was observed for rCMRO ₂ <26% (ICC = 0.936), whereas rCBF <30% showed a slightly lower ICC of 0.934.
Conclusions: CT perfusion-derived CMRO ₂ is a promising parameter for estimating the infarct core volume in patients with acute ischemic stroke.
(© 2024 by American Journal of Neuroradiology.)