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 （~ 1 H-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 ~ 1 H-MRS examinations. The ~ 1 H-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）. Conclusion ~ 1 H-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.