A Structural Connectivity Approach to Validate a Model-based Technique for the Segmentation of the Pulvinar Complex

Area of Science:

• Neuroimaging
• Neuroanatomy
• Computational Neuroscience

Background:

• The pulvinar, a higher-order thalamic nucleus, plays a crucial role in information gating to the cortex.
• Dysfunction of the pulvinar is implicated in various neurological disorders, necessitating accurate segmentation in clinical imaging.
• Previous segmentation models were based on limited healthy subject data and high-resolution scans.

Purpose of the Study:

• To validate a previously proposed active shape model for pulvinar segmentation on clinically acquired MRI data.
• To assess the reliability of the segmentation method in a larger cohort of healthy volunteers.
• To leverage the known strong white matter connections between the pulvinar and hippocampus for validation.

Main Methods:

• Acquired T1-weighted and diffusion MRI data from 43 healthy volunteers using a clinical 3T scanner.
• Applied an active shape model segmentation to T1-weighted images to delineate intrathalamic nuclei.
• Calculated hippocampal-thalamic connectivity maps from diffusion MRI data.

Main Results:

• The active shape model segmentation consistently localized the pulvinar within regions of high hippocampal structural connectivity.
• The method demonstrated reliability in segmenting the pulvinar on clinically acquired MRI data.
• Results support the use of hippocampal connectivity as a validation metric for pulvinar segmentation.

Conclusions:

• The proposed active shape model segmentation method is reliable for identifying the pulvinar in clinical MRI scans.
• Leveraging structural connectivity, particularly with the hippocampus, provides a robust validation strategy for thalamic nuclei segmentation.
• This validated method can be extended to other thalamic nuclei and applied to broader clinical populations.