Evaluation of mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes with magnetic resonance imaging and proton magnetic resonance spectroscopy.

Objective: To study the characteristics of spectra on proton magnetic resonance spectroscopy (1H-MRS) and its value in patients with mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS).

Methods: Seven clinically diagnosed patients with MELAS underwent magnetic resonance imaging (MRI) and 1H-MRS examinations. The 1H-MRS techniques, characteristics of the spectra, and its correlation with the laboratory tests were analyzed.

Results: Cerebral abnormalities were revealed in all 7 patients on conventional MR images, and most abnormal signals were observed in bilateral occipital, parietal, and temporal lobes. We found 4 cases with basal ganglia involvement, 2 cases with mild frontal lobe lesions, and 1 case with involvement of lateral cerebral peduncles and thalami. Additionally, 1 patient was involved with left insular lobe. Spectra from prominent lesions in brain parenchyma showed lactate doublet peak in 6 patients, 3 of whom were also noted lactate peak in ventricular cerebrospinal fluid (CSF).

Conclusions: 1H-MRS may provide more direct information about the metabolism changes, which aids to affirm the diagnosis, and may replace the conventional invasive method of quantifying lactate in CSF.