Mild cognitive impairment: baseline and longitudinal structural MR imaging measures improve predictive prognosis

Area of Science:

• Neuroimaging
• Neurology
• Radiology

Background:

• Mild cognitive impairment (MCI) is a transitional stage between normal aging and Alzheimer's disease (AD).
• Accurate prediction of conversion from MCI to AD is crucial for clinical trial enrollment and therapeutic intervention.
• Volumetric magnetic resonance (MR) imaging offers a non-invasive method to assess brain structure changes.

Purpose of the Study:

• To evaluate the prognostic value of single-time-point and longitudinal volumetric MR imaging measures in predicting AD conversion in amnestic MCI patients.
• To determine if combining baseline and 1-year change MR imaging data enhances risk prediction accuracy.

Main Methods:

• Cross-validated discriminant analyses were used to differentiate AD cases from healthy controls using volumetric MR imaging data.
• Discriminant functions derived from control/AD data were applied to MCI cases to generate individual risk scores.
• Risk of AD conversion was analyzed using Kaplan-Meier curves and odds ratios (ORs) across risk score quartiles.

Main Results:

• Baseline MR imaging provided individualized 1-year AD conversion risk estimates (3%-40%, OR 7.2).
• Incorporating 1-year volumetric changes significantly improved risk prediction (P = .001), with estimated 1-year conversion risk ranging from 3% to 69% (OR 12.0).

Conclusions:

• Volumetric MR imaging measures provide more informative patient-specific risk estimates for AD conversion than clinical diagnosis alone.
• Longitudinal MR imaging data substantially enhance the predictive accuracy of AD conversion risk in MCI.
• These predictive capabilities are vital for the development and application of future disease-modifying therapies for AD.