Delineating In Vivo T1‐Weighted Intensity Profiles Within the Human Insula Cortex Using 7‐Tesla MRI

TL;DR

Using 7-Tesla MRI, the study identifies distinct intensity patterns in the human insula cortex, offering new insights into its structure and potential clinical applications.

Contribution

The study introduces a novel in vivo parcellation of the insula cortex using 7-Tesla MRI, revealing distinct intensity clusters across different regions.

Findings

Two clusters of high and low T1-weighted signal intensity were identified in the posterior and anterior-inferior insula.

Reliable in vivo parcellation was achieved across two separate cohorts in different locations.

Findings align with ex vivo studies and highlight the impact of brain atlas choice on detecting intensity clusters.

Abstract

The integral role of the insula cortex in sensory and cognitive function has been well documented in humans, and fine anatomical details characterizing the insula have been extensively investigated ex vivo in both human and non‐human primates. However, in vivo studies of insula anatomy in humans (in general) and within‐insula parcellation (in particular) have been limited. The current study leverages 7 Tesla magnetic resonance imaging to delineate cortical depth intensity profiles within the human cortex. Our analysis revealed two separate clusters of relatively high and low signal intensity across the insula cortex located in three distinct compartments within the posterior, anterior‐inferior, and middle insula. The posterior and anterior‐inferior compartments are characterized by elevated T1‐weighted signal intensities, contrasting with lower intensity observed in the middle insular compartment, compatible with ex vivo studies. Importantly, the detection of the high T1‐weighted anterior cluster is determined by the choice of brain atlas employed to define the insular region of interest. We obtain reliable in vivo within‐insula parcellation at the individual and group levels, across two separate cohorts acquired in two separate sites (n1 = 21, Glasgow, UK; n2 = 101, Amsterdam, NL). Results are further confirmed by deriving cortical depth dependent profiles from T1Map and R1Map images. These results reflect new insights into the insula anatomical structure, in vivo, while highlighting the use of 7 Tesla in neuroimaging with potential implications for individualized medicine approaches.

Using 7‐Tesla MRI, this research delineates cortical depth dependent intensity profiles within the human insula cortex, identifying distinct clusters in the posterior–anterior and anterior‐inferior portions of the human insula. These findings offer insights into the structural underpinnings of the insula, supporting individualized approaches potentially useful in clinical research.

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