Callosal Angle and Evans Index predict beta amyloid and tau protein in patients with dementia

Aβ and tau protein have been widely investigated for the diagnosis of dementia entities, most commonly Alzheimer's disease (AD). However, their measurement is an interventional, time-consuming procedure, while it requires specialized personnel, unlike the evaluation of radiological markers, such as Evans index (EI) and Callosal angle (CA). This study aims to investigate the correlation between EI, CA, Aβ and total tau in order to outline a basis of diagnostic evaluation for the patient's CSF biomarker profile.

Sixty-two (62) patients who presented with dementia symptoms participated in this study. Aβ and total tau levels in their CSF as well as CA and EI values from their MRIs were measured. Multiple regression was employed to predict Aβ and total tau values from EI and CA. From the Durbin-Watson analysis (d1=2.057, d2=1.881) we can assume that there is no first order linear auto-correlation in our multiple linear regression data.

The variables statistically significantly predicted both Aβ and total tau (F1=8.720, R1=0.484, p1=0.001 and F2=4.110, R2=0.355, p2=0.022). Out of all the variables, it was shown that CA, EI (p<0.05) and CA (p<0.05) added statistically significantly to the prediction of Aβ and total tau.

Collectively, these results support a significant correlation between EI and Aβ and CA, Aβ and total tau. This highlights the potential role of radiological markers as rough estimates of biomarker levels in everyday clinical practice, assisting to a robust and inexpensive diagnosis.