LAMINAR CORTICAL NECROSIS IN MELAS SYNDROME - MR AND NEUROPATHOLOGICAL OBSERVATIONS

Laminar cortical necrosis has been described in many conditions of cel lular energy depletion, such as hypoxia and hypoglycemia. In MELAS, a genetic defect in mitochondrial protein synthesis leads to impairment of oxidative phosphorylation, with subsequent insufficient energy prod uction within the cell. Neurons are more vulnerable to energy depletio n than glial cells and vascular elements, and among the layers of the cerebral cortex the lower laminae are more vulnerable than the superfi cial layers. We studied a child with severe MELAS syndrome two months before death with MR and compared the images to autopsy findings, incl uding macroscopic specimens and light and electron microscopy. The MR images showed an excellent correlation with the neuropathological resu lts and displayed the various degrees of damage to the brain tissue ca used by deficient energy production. Acute laminar cortical necrosis w as seen as swelling of the cortex with intracortical hyperintense band s in T-2-weighted images. The subacute stage with focal cortical hemor rhage was displayed as hyperintensity of the gyral surface in T-1-weig hted and hypointensity in T-2-weighted images, with T-2-hyperintensity and swelling of the rest of the cortex and underlying white matter. S evere cortical atrophy represented the chronic stage.