Multi-atlas thalamic nuclei segmentation on standard T1-weighed MRI with application to normal aging

Area of Science:

• Neuroimaging
• Human Brain Anatomy
• Aging Research

Background:

• Thalamic nuclei are crucial in aging and neurodegeneration, but automated segmentation methods are limited.
• Accurate segmentation is needed to study age-related changes and their functional impact.

Purpose of the Study:

• To validate a modified THalamus Optimized Multi-Atlas Segmentation (THOMAS) method for thalamic nuclei segmentation using standard T1 MRI.
• To quantify age-related volume changes in thalamic nuclei.
• To assess the functional relevance of thalamic nuclei volumes by correlating them with motor test performance.

Main Methods:

• A modified THOMAS algorithm was used to segment 22 unilateral thalamic nuclei from T1 MRI data.
• Validation involved comparing THOMAS segmentations from T1 MRI with white-matter-nulled (WMn) MRI data.
• Age- and sex-related volume changes were analyzed in a large cohort (N=238, ages 20-86), and correlations with Grooved Pegboard test scores were computed.

Main Results:

• THOMAS segmentation on standard T1 MRI showed strong agreement with WMn MRI data, particularly for larger nuclei.
• Significant age-related volume declines were observed in 20 of 22 unilateral thalamic nuclei and the whole thalamus, after adjusting for supratentorial intracranial volume (sICV).
• Specific thalamic regions (Posterior, Ventral) and nuclei (Ventral Anterior/Pulvinar) correlated with better eye-hand coordination performance.

Conclusions:

• The modified THOMAS method is robust for segmenting thalamic nuclei using standard T1 MRI data.
• This method enables reliable quantification of age-related thalamic volume changes.
• Thalamic nuclei volumes are functionally relevant, showing associations with motor task performance.