Objective:To investigate the clinical and imaging characteristics of central pontine myelinolysis (CPM) without hyponatremia and explore its pathogenesis.Methods:A retrospective analysis was performed. Six CPM patients without hyponatremia, admitted to Department of Neurology, He'nan Provincial People's Hospital from March 2021 to March 2023 were chosen. Demographic information, causes, medical history, clinical presentations, and MRI features at onset, and 1 and 3 months after onset were analyzed. The prognoses were evaluated by modified Rankin Scale (mRS) scores 3 months after onset: mRS scores≤2 was classified as good prognosis, and mRS scores>2 as poor prognosis.Results:In these 6 CPM patients without hyponatremia, 4 were males and 2 females; 4 patients had dizziness, 3 headache, 4 limb weakness, 2 cognitive decline, and 2 slow reaction. Four CPM patients had a history of hypertension, 5 had a history of diabetes, and 1 had a history of alcoholic cirrhosis. Hormone therapy, nutritional support and symptomatic treatment were given; 5 patients had obvious improvement, and 1 had poor prognosis 3 months after onset. MRI showed asymmetrical abnormal signal in the basal pons and bilateral brachium pontis, with T1WI hypointensity, T2WI hyperintensity, T2-FLAIR hyperintensity, DWI hyperintensity and clear boundary, and without obvious mass effect or enhancement. DWI sequence enjoyed good diagnostic sensitivity in early stage of CPM: high signal changes could occur within 24 h of clinical symptoms, and isointensity 3 months after onset.Conclusion:Causes of CPM without hyponatremia are mostly hypokalemia, diabetes, malnutrition, and chronic alcoholism; its characteristic MRI manifestations are "pig nose sign", "bat wing sign" and "trident sign".