Yonsei Med J.  2001 Feb;42(1):128-133. 10.3349/ymj.2001.42.1.128.

Diffusion-weighted image and MR spectroscopic analysis of a case of MELAS with repeated attacks

• Kim HS
• Kim DI
• Lee BI
• Jeong EK
• Choi C
• Lee JD
• Yoon PH
• Kim EJ
• Kim SH
• Yoon YK

• KMID: 720596
• DOI: http://doi.org/10.3349/ymj.2001.42.1.128

Abstract

We report the clinical and MR manifestations of an 18 year-old girl with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome. Recurrent status epilepticus caused reversible cytotoxic edema on diffusion-weighted images (DWI). Initial and one month follow-up MR spectroscopy, after seizure control, showed some discrepancies in the ratio of metabolites. N-acetylaspartate (NAA) partially recovered (NAA/creatine (Cr) ratio: 1.27-->1.84). This was because of a normalization of decreased NAA due to cellular dysfunction as a result of status epilepticus. A low ratio of NAA/Cr due to abnormal mitochondria remained in the decreased state. Reversible NAA/Cr ratios in the acute lesion suggested that NAA reflects the neuronal function as well as the level of neuronal structural damage. The altered NAA/Cr ratio better correlated with the abnormal signal intensity area of T2-weighted images (T2WI) and DWI than the lactate (Lac)/Cr ratio. With conservative treatment with anti-epileptics not accompanied by coenzyme Q or sodium dichloroacetate, lactate persistently increased (Lac/Cr ratio: 1.01-->1.21) because of the continued production of lactate in cells with respiratory deficiency, which is the main pathology of MELAS.

Keyword

Magnetic resonance imaging; diffusion study; spectroscopy; MELAS; brain metabolism

MeSH Terms

Adolescence
Aspartic Acid/metabolism
Aspartic Acid/analogs & derivatives*
Brain/metabolism
Case Report
Creatine/metabolism
Diffusion
Female
Human
MELAS Syndrome/metabolism
MELAS Syndrome/diagnosis*
Magnetic Resonance Imaging
Magnetic Resonance Spectroscopy