MR imaging in comatose survivors of cardiac resuscitation

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.

We studied fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted (DW) imaging in 10 patients comatose after cardiac arrest.

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.

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.