The Differential Diagnostic Value of the Callosal Angle and Evans Index in Mild Cognitive Impairment and Alzheimer's Disease

Abstract

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.

Application of Evans Index in Normal Pressure Hydrocephalus Patients: A Mini Review

“…On the other hand, for NPH patients, EI measurement is a fast and highly reproducible indirect method for assessing VV (Bao et al, 2016 ; Liu et al, 2020 ). VV measurement methods can be direct and indirect (Ambarki et al, 2010 ).…”

“…The EI is used as an imaging biomarker of NPH to indirectly assess the VV (Liu et al, 2020 ). A study including 23 definite iNPH patients and 62 healthy elderly volunteers, showed that the correlation between EI and VV and relative VV (RVV) was 0.843 and 0.840, respectively.…”