Ability of a Composite Brain Magnetic Resonance Imaging Score to Predict Neurologic Outcomes in Survivors of Out-Of-Hospital Cardiac Arrest

Abstract

Background: Brain magnetic resonance imaging (MRI) has been investigated as a neuroprognostication (NP) test after out-of-hospital cardiac arrest (OHCA); however, most studies have focused on predicting poor neurologic outcomes or death.

Methods: We examined the ability of a composite brain MRI score ("NP score") to predict neurologic outcomes in an OHCA cohort (2017-2023) who underwent brain MRI within 2-7 days post arrest and survived to hospital discharge. NP scores (range 0-214) were calculated from diffusion weighted imaging and fluid attenuated inversion recovery signals in prespecified neuroanatomical regions. We categorized neurologic outcomes as "independent" (Cerebral Performance Categories [CPC] 1-2), "dependent" (CPC 3), and "vegetative state" (CPC 4). We conducted correlation analyses and used computational modeling for probabilities to identify transition points between the outcome categories.

Results: Forty-two OHCA survivors were included (median age 47 years; 74% male, 43% shockable rhythm; 88% underwent targeted temperature management). At hospital discharge, 50% (n = 21) had recovered to independent, 24% (n = 10) were dependent, and 26% (n = 11) remained in a vegetative state. MRIs were obtained at a median of 4 days post arrest, (interquartile range 3-5). NP scores (range 0-136, median 11.5, interquartile range 0-41.5, intraclass correlation coefficient 0.89) strongly correlated with CPC (r_s = 0.69, p < 0.001) and were significantly different between CPC groups (p < 0.001); thresholds of 15 and 54 were identified as transition points between independent-dependent and dependent-vegetative state, respectively. Among survivors with bilaterally intact somatosensory evoked potentials, median NP scores were 0, 29, 68.5 for independent, dependent, and vegetative state patients, respectively.

Conclusions: Quantitative brain MRI-based scoring may predict neurologic outcomes at discharge among OHCA survivors. External validation in larger prospective multicenter cohorts, assessment of long-term outcomes, and examination of the score in deceased patients are needed to establish the prognostic value and address concerns about generalizability.

Keywords: Cardiac arrest; Cerebral Performance Category; Computational modeling; Magnetic resonance imaging; Neuroprognostication; Predictive modeling.