Background and purpose: The prognosis of comatose survivors is determined by clinical examination. Early laboratory indicators of poor prognosis (such as evoked potentials) have low sensitivity. The role of MR imaging as a confirmatory study was investigated.
Methods: We studied fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted (DW) imaging in 10 patients comatose after cardiac arrest.
Results: None of the 10 comatose patients had myoclonus status epilepticus or fixed, dilated pupils on neurologic examination, and none had abnormal somatosensory-evoked potentials. Eight patients showed diffuse signal abnormalities, predominantly in the cerebellum (n = 5), the thalamus (n = 8), the frontal and parietal cortices (n = 8), and the hippocampus (n = 9). One patient showed normal MR imaging results, and one patient had abnormalities in the thalamus and cerebellum and minimal abnormality on DW images; both later awakened. None of the patients with abnormal cortical structures on FLAIR MR images recovered beyond a severely disabled state.
Conclusion: MR imaging in comatose survivors may parallel the pathologic findings in severe anoxic-ischemic injury, and extensive abnormalities may indicate little to no prospects for recovery. If confirmed, MR imaging may have a role as a prognosticating test in anoxic-ischemic coma.