Abstract 226: Acute Abnormalities on Magnetic Resonance Imaging Do Not Rule Out Good Neurologic Outcome Following Cardiac Arrest
Objective: Magnetic resonance imaging (MRI) has been used to assist prediction of neurological recovery in patients remaining comatose after cardiac arrest. This study tested associations between initial neurologic examination on hospital arrival, MRI findings, and neurological outcome after cardiac arrest.
Methods: We conducted a retrospective review of subjects treated between 1/1/2005 and 12/31/2008 who underwent clinical brain MRI within 7 days after cardiac arrest. Age, sex, initial motor GCS, Cardiac Arrest Score, full outline of unresponsiveness (FOUR) subscores, initial rhythm, in-hospital vs. out-of-hospital cardiac arrest (OHCA), use of hypothermia, and time from arrest to MRI were abstracted from charts. The attending neuroradiologist MRI interpretation was classified as normal (N-MRI) or abnormal (A-MRI). Abnormal interpretations were subdivided into acute (AA-MRI) or old (AO-MRI) findings. Good neurologic outcome was defined as discharge to home or acute rehabilitation facility. Fisher's exact test was used to compare survival and good neurological outcome between groups.
Results: Of 371 post cardiac arrest subjects, 47 met inclusion criteria. Mean age was 59 (SD 15) years, 28(60%) were male, 32 (68%) had OHCA, and 22 (47%) had an initial ventricular dysrhythmia. The median time to MRI was 61 (IQR 34–97) hours. Overall, 28 (60%) survived and 15 (32%) experienced good neurologic outcome. A higher FOUR brainstem subscore was associated with N-MRI and AO-MRI while a lower FOUR brainstem subscore was associated with AA-MRI findings (p=0.03). Among 10 N-MRI subjects, 8 (80%) survived and 6 (60%) had good outcome. Among 17 AO-MRI subjects (old infarcts and/or small vessel ischemic disease), 12 (71%) survived and 4 (24%) had good outcome. Among 20 AA-MRI subjects (acute infarcts or diffuse anoxic injury), 8 (40%) survived and 5 (25%) had good outcome. Survival (p=0.034) but not good outcome (p=0.529) differed between MRI findings.
Conclusions: A low FOUR brainstem subscore is associated with acute MRI abnormality. Although both acute and old abnormalities are commonly found on MRI after cardiac arrest, the rate of good outcome does not differ in this cohort, and no MRI category completely precludes good outcome.
- © 2010 by American Heart Association, Inc.