Serial diffusion imaging in a case of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes.
OBJECTIVE
Most diffusion MRI studies of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episode stroke-like lesions report high- or normal-apparent diffusion coefficient, and this has been used to differentiate stroke-like lesion from ischemic stroke. There are, however, 3 recent reports of restricted diffusion in the acute phase of the stroke-like lesions. The purpose of our study was to investigate this apparent paradox.


METHODS
We performed 9 serial MRI covering 2 stroke-like episodes in a 36-year-old man with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episode caused by the common mitochondrial DNA mutation 3243A>G.


RESULTS
We found clear evidence of initial restricted diffusion in the stroke-like lesions, which gradually evolved to high-apparent diffusion coefficient as lesions aged. Evolution was, however, asynchronous with both high- and low-apparent diffusion coefficients temporally coexisting.


CONCLUSIONS
Our findings suggest that cytotoxic edema does occur early in the course of a stroke-like lesions and that its presence or, conversely, the absence of vasogenic edema, should not weaken the possibility of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episode in favor of ischemic stroke.
Tzoulis
Charalampos
C
Department of Neurology, Haukeland University Hospital, Bergen, Norway. chtzoulis@yahoo.com
Bindoff
Laurence A
LA
D000328:Adult; D001921:Brain / Q000473:pathology; D001929:Brain Edema / Q000473:pathology; D004247:DNA / Q000235:genetics; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D018450:Disease Progression; D006801:Humans; D007091:Image Processing, Computer-Assisted; D017241:MELAS Syndrome / Q000150:complications / Q000235:genetics / Q000473:pathology*; D008297:Male; D009154:Mutation
D004247:DNA