Cerebral metabolic rate of oxygen mapping on admission MRI may predict penumbral tissue fate in acute stroke patients treated successfully with thrombectomy.

PURPOSE: Infarct growth occurs in most patients despite successful thrombectomy. We evaluated whether a dynamic susceptibility-contrast (DSC) perfusion-MRI surrogate of the cerebral metabolic rate of oxygen (CMRO2) improves prediction of tissue fate within perfusion-diffusion mismatch regions after successful thrombectomy.

METHODS

In this retrospective analysis of the prospective HIBISCUS-STROKE registry, we included anterior-circulation stroke patients with admission DSC perfusion MRI, recanalization (mTICI ≥ 2b) after thrombectomy, and day-6T2-FLAIR MRI. Admission DSC-derived CMRO2, cerebral blood flow (CBF), cerebral blood volume (CBV), and oxygen extraction fraction (OEF) were expressed as ratios to the mirrored contralateral region (rCMRO2, rCBF, rCBV, rOEF) within mismatch subregions that infarcted (overlap with the day-6 lesion) or remained viable. All analyses accounted for within-patient clustering (generalized estimating equations, patient-level bootstrap and cross-validation).

RESULTS

Of 321 screened patients, 134 were included (median age, 71 years; 57.5 % men; median NIHSS score, 15), yielding 245 mismatch subregions (111 infarcted, 134 viable). rCMRO2, rCBF, and rCBV were lower in infarcted than in viable subregions, whereas rOEF did not differ. rCMRO2 provided the best discrimination of infarction (AUC, 0.77; 95 % CI, 0.72-0.82), higher than rCBF (0.74; P = 0.04), rCBV (0.73; P = 0.001), and rOEF (0.52; P < 0.001); the gain over rCBF was modest (integrated discrimination improvement, 0.064; 95 % CI, 0.026-0.110). rCMRO2 <0.66 was selected in all cross-validation folds and independently predicted infarction (adjusted odds ratio, 8.02; 95 % CI, 4.60-14.01).

CONCLUSIONS

A DSC-MRI surrogate of CMRO2 on admission discriminated infarct-destined from viable tissue within the perfusion-diffusion mismatch after successful thrombectomy, with a modest but consistent advantage over conventional perfusion metrics.