The Study of Brain Proton Magnetic Resonance Spectroscopy and the Volume of the Hippocampus in Mild Cognitive Impairment and Mild Alzheimer Disease

Objective To evaluate the roles of proton magnetic resonance spectroscopy(1H-MRS) and the volume of the hippocampus(HCV) measured by MRI in the diagnosis and the differential diagnosis of mild cognitive impairment (MCI) and mild Alzheimer disease (AD). Methods HCV and 1H-MRS were performed in the bilateral hippocampus and the bilateral medial temporal lobes(MTLS) in 30 cases with MCI,30 cases mild with AD and 30 healthy persons in age and sex-matched with controls by using volume analysis software and stimulates echo acquisition mode(STEAM). The ratios of NAA/Cr,Cho/Cr,MI/Cr,NAA/MI and HCV were compared among these groups.The contributions of HCV and 1H-MRS in diagnosis of MCI and AD was compared.Correlation coefficients were calculated for Mini Mental State Examination (MMSE) scores and HCV or the ratios of NAA/Cr,Cho/Cr,MI/Cr and NAA/MI in the MCI group and the mild AD group.Results Patients with mild AD showed significant reduction of HCV and NAA/Cr and NAA/MI ratios in the bilateral HCVand MTLS,and significant MI/Cr increase in the bilateral MTLS relative to control subjects. Patients with MCI demonstrates significant reduction of NAA/Cr in the left MTL , significant reduction of the bilateral HCV and NAA/MI ratio and significant MI/Cr increase in the bilateral HCV and MTLS relative to control subjects. Patients with mild AD showed statistical differences of MI/Cr and NAA/MI ratios in the left MTL relative to patients with MCI . Patients with mild AD showed no significant differences of HCV and NAA/Cr relative to patients with MCI . The Cho/Cr ratios among three groups showed no significant differences. HCV yielded the volume with the sensitivity 50% and specificity 83.33% in the diagnosis of MCI . 1H-MRS yielded the ratios with 43.33% in sensitivity and 81.25% in specificity in the di- agnosis of MCI.The combination of HCV and 1H-MRS yielded the volume and ratios with sensitivity of 73.33% and specificity of 84.62% in the diagnosis of MCI. HCV yielded the volume with sensitivity of 73.33% and specificity of 88% in the diagnosis of mild AD.1H-MRS yielded the ratios with sensitivity of 70% and specificity of 87.5% in the diagnosis of mild AD.The combination of HCV and 1H-MRS yielded the volume and ratios with sensitivity of 83.33% and specificity of 86.21% in the diagnosis of mild AD. HCV yielded the volume with the sensitivity of 50% and specificity of 62.5% in the differential diagnosis of MCI and mild AD.1H-MRS yielded the ratios with sensitivity of 56.67% and specificity of 65.38% in the differential diagnosis of MCI and mild AD.The combination of HCV and 1H-MRS yielded the volume and ratios with sensitivity of 66.67% and specificity of 64.52% in the differential diagnosis of MCI and mild AD. Patients with mild AD and MCI showed significant correlation between MMSE and the bilateral HCV ,NAA/Cr ratio. Patients with mild AD showed significant correlation between MMSE and right NAA/MI ratio . Patients with mild AD and MCI showed significant correlation between HCV and NAA/Cr ratio. Conclusion The combination of HCV and 1H-MRS are the best choice in the diagnosis and the differential diagnosis of MCI and mild AD.