Background: Callosal angle (CA) and Evans index (EI) had been considered as imaging biomarkers to
diagnosis normal-pressure hydrocephalus as traditional MR measurement methods.
Objective: The current study was aimed to evaluate the differential diagnostic value of CA and EI in the mild cognitive
impairment (MCI) and Alzheimer’s disease (AD).
Methods: Five-hundred and two subjects were selected from the Alzheimer's Disease Neuroimaging Initiative (ADNI)
database, which included 168 normal controls (NC), 233 MCI and 101 AD patients. The structural MR images were
interactively applied with multiplanar reconstruction to measure the CA and EI.
Results: CA presented no significant difference among NC, MCI and AD groups (H value = 3.848, P value = 0.146), and
EI was demonstrated the higher in MCI and AD groups than that in NC groups (P = 0.000 and 0.001, respectively). MCI
group had significant larger EI (0.29±0.04) than that (0.27±0.03) in NC group in 70-75 years old sub-groups. ROC
showed that the area under the curve was 0.704±0.045 for NC-MCI in 70-75 years old groups. The correlation analysis
indicated that EI was significantly negatively related with MMSE scores of MCI patients (r = -0.131, P = 0.046).
Conclusion: EI might serve as a screening imaging biomarker for MCI in 70-75 years old, and show limited differential
value for the diagnosis of AD. CA could present no diagnostic value for MCI and AD in the current study.