Purpose: To explore the value of proton magnetic resonance spectroscopy imaging ((1)H-MRSI) in patients with stenosis or occlusion of the internal carotid artery (ICA) / middle cerebral artery (MCA). Materials and Methods: Fifty noninfarcted patients with stenosis or occlusion of unilateral ICA/MCA were included in our study. In the meantime, 25 patients with cerebral infarction and 25 healthy control subjects were enrolled. All patients and healthy control subjects underwent (1)H-MRSI. Cerebral metabolic changes were studied in the noninfarcted patients and compared with the infarcted patients as well as healthy control subjects. Results: In 50 noninfarcted patients N-acetylaspartate (NAA) decreased and choline increased in the ischemic hemisphere compared with the contralateral side and control subjects. Lactate peaks were observed in 12 patients. The metabolic changes were relatively slight but were associated with metabolic disruption in infarcted patients. There were relationships between metabolic abnormalities and neurological status of the noninfarcted patients. Conclusion: (1)H-MRSI can demonstrate abnormal metabolic changes in cerebral tissues with no infarction, while with ICA/MCA may show stenosis or occlusion at an early stage, which may help guide treatment decisions and preoperative evaluation.