Diffusion tensor imaging tractography and reliability analysis for limbic and paralimbic white matter tracts

Area of Science:

• Neuroimaging
• White Matter Tractography
• Diffusion Tensor Imaging

Background:

• Diffusion tensor imaging (DTI) enables in vivo study of white matter tracts.
• Limbic and paralimbic white matter are critical for cognitive and emotional processing.
• Disruptions in these tracts are implicated in various psychiatric disorders.

Purpose of the Study:

• To assess the reliability of DTI tractography for analyzing limbic and paralimbic white matter.
• To establish normative data and evaluate inter- and intra-rater reliability.

Main Methods:

• Acquired DTI data from 24 healthy subjects and reliability data from 8 subjects (4 healthy, 4 depressed) at 1.5 Tesla.
• Utilized twice-refocused spin-echo, echoplanar DTI, and FLAIR DTI sequences.
• Performed fiber tracking with the Fiber Assignment by Continuous Tracking algorithm and calculated Fractional Anisotropy (FA), trace Apparent Diffusion Coefficient, and tract volumes.

Main Results:

• High inter-rater and intra-rater intraclass correlation coefficients (ICCs) for FA values were observed across multiple tracts.
• Specific ICCs for FA included: rostral cingulum 0.89 (0.87), dorsal cingulum 0.85 (0.90), parahippocampal cingulum 0.85 (0.95), uncinate fasciculus 0.85 (0.87), medial prefrontal white matter 0.97 (0.99), ventromedial prefrontal white matter 0.92 (0.93), and crus of fornix 0.80 (0.81).
• These results indicate robust reliability for DTI tractography in these regions.

Conclusions:

• The described DTI protocol offers a reliable method for analyzing limbic and paralimbic white matter.
• This reliability is essential for accurate investigation of white matter abnormalities in psychiatric disorders.
• DTI tractography is a valuable tool for clinical research in neuroscience and psychiatry.