Construction and Validation of the Modified Parietal Atrophy Index by Magnetic Resonance Imaging in Patients With
Alberto José Mimenza-Alvarado1,2, Daniel Alberto Herrera-Martínez2, Johnatan Rubalcava-Ortega3
1Department of Geriatrics, INCMNSZ, Mexico City, Mexico.
Abstract:
Magnetic resonance imaging (MRI) is pivotal to the evaluation of cerebral atrophy in Alzheimer's disease (AD). Although there are several scoring systems to identify atrophy in areas of interest, the possibility of having a simple and practical scale focused on evaluating parietal atrophy by MRI in a single axial slice in T2-Flair sequencing would be highly advantageous. We develop and validate the Mimenza-Aguilar-Herrera (MAH) visual scale to determine the degree of modified parietal atrophy by analyzing the posterior cingulate gyrus in an MRI axial slice in T2 weighted sequencing in individuals with early AD. Patients with AD, mild cognitive impairment, and other dementias were included. Interrater and intrarater concordance was analyzed with Cohen's kappa. ROC analysis was used to determine sensitivity/specificity. The relationship between medial parietal atrophy (MPA) and the MMSE and MoCA scores, age, educational level, and sex was determined by linear regression. Interrater concordance in the MPA-MAH was moderate, 0.83 (p = 0.001). The area under the curve in the mild AD group was 0.74, with a sensitivity of 71.67% and a specificity of 76.19% (p < 0.001). An association was detected between a MPA score > 1 [OR 5.1 (95% CI: 2-12.9, p < 0.001)], MMSE < 24 pts, [OR 4.5 (95% CI: 1.2-17.6, p = 0.026)], and MoCA < 24 pts, after adjusting for age and sex. The MAH scale proved useful in diagnosing early AD, with comparable performance to validated scales such as Koedam's and Scheltens'. This instrument could allow a quick and easy evaluation.
Insights
A new visual scale, the Mimenza-Aguilar-Herrera (MAH) scale, effectively evaluates parietal atrophy on MRI for early Alzheimer's disease (AD) diagnosis. This practical tool shows good accuracy and correlates with cognitive scores.
Area of Science:
- Neurology
- Radiology
- Neuroimaging
Background:
- Cerebral atrophy assessment via MRI is crucial for Alzheimer's disease (AD) diagnosis.
- Existing scoring systems can be complex; a simpler method for evaluating parietal atrophy is needed.
- Parietal lobe atrophy is an early indicator in AD, often assessed using MRI.
Purpose of the Study:
- To develop and validate the Mimenza-Aguilar-Herrera (MAH) visual scale for assessing parietal atrophy in early AD.
- To evaluate the scale's utility using a single axial T2-FLAIR MRI slice focusing on the posterior cingulate gyrus.
- To compare the MAH scale's performance against established methods and cognitive scores.
Main Methods:
- Development of the MAH visual scale for grading medial parietal atrophy (MPA) on MRI.
- Inclusion of patients with AD, mild cognitive impairment, and other dementias.
- Analysis of interrater and intrarater reliability using Cohen's kappa, and ROC analysis for sensitivity and specificity.
- Linear regression to assess the relationship between MPA, cognitive scores (MMSE, MoCA), age, education, and sex.
Main Results:
- The MAH scale demonstrated moderate interrater concordance (kappa = 0.83).
- In the mild AD group, ROC analysis yielded an area under the curve of 0.74, with 71.67% sensitivity and 76.19% specificity.
- A higher MPA score (>1) was significantly associated with lower MMSE (<24) and MoCA (<24) scores, independent of age and sex.
Conclusions:
- The MAH scale is a useful and practical tool for diagnosing early AD by evaluating parietal atrophy on MRI.
- Its performance is comparable to validated scales, offering a quick and easy evaluation method.
- The scale's findings correlate with cognitive impairment, supporting its clinical utility in AD assessment.
