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.