Can diffusion weighted magnetic resonance imaging help differentiate stroke from stroke-like events in MELAS?
- aDepartment of Neuroradiology, Groupe Hospitalier Pitié-Salpêtrière, Paris VI University, 47 Boulevard de l'Hôpital, 75651 Paris, Cedex 13, France, bUrgences cérébro-vasculaires, cDepartment of Internal Medicine
- Dr Catherine Oppenheimcatherine.oppenheim{at}psl.ap-hop-paris.fr
- Received 22 November 1999
- Revised 26 January 2000
- Accepted 23 March 2000
Abstract
The precise mechanism of neurological symptoms in patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is still controversial. The diffusion weighted MR findings at the acute phase of a neurological event in MELAS are described and the pathophysiology of stroke-like lesion in the light of diffusion changes is discussed.
Brain MRI was performed 2 days after the sudden onset of cortical blindness in a 25 year old patient with MELAS. Fluid attenuated inversion recovery (FLAIR) images showed multifocal cortical and subcortical hyperintensities located bilaterally in the frontobasal and the temporo-occipital lobes. Diffusion weighted images showed normal to increased apparent diffusion coefficient values in the acute left temporooccipital lesion and increased values in the older stroke-like lesions.
These diffusion weighted findings support the metabolic rather than the ischaemic pathophysiological hypothesis for stroke-like episodes occurring in MELAS. Normal or increased apparent diffusion coefficient values within 48 hours of a neurological deficit of abrupt onset should raise the possibility of MELAS, especially if conventional MR images show infarct-like lesions.
Footnotes
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↵* These authors contributed equally to this work
