In vivo diffusion tensor imaging of the human optic chiasm at sub-millimeter resolution

Abstract Objective: The ultimate anatomy of the Meyer’s loop continues to elude us. Diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) may be able to demonstrate, in vivo, the anatomy of the complex network of white matter fibers surrounding the Meyer’s loop and the optic radiations. This study aims at exploring the anatomy of the Meyer’s loop by using DTI and fiber tractography. Methods: Ten healthy subjects underwent magnetic resonance imaging (MRI) with DTI at 3 T. Using a region-of-interest (ROI) based diffusion tensor imaging and fiber tracking software (Release 2.6, Achieva, Philips), sequential ROI were placed to reconstruct visual fibers and neighboring projection fibers involved in the formation of Meyer’s loop. The 3-dimensional (3D) reconstructed fibers were visualized by superimposition on 3-planar MRI brain images to enhance their precise anatomical localization and relationship with other anatomical structures. Results: Several projection fiber including the optic radiation, occipitopontine/parietopontine fibers and posterior thalamic peduncle participated in the formation of Meyer’s loop. Two patterns of angulation of the Meyer’s loop were found. Conclusions: DTI with DTT provides a complimentary, in vivo, method to study the details of the anatomy of the Meyer’s loop.

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PB 1 In vivo assessment of neurodegeneration in the brain by serial longitudinal diffusion tensor imaging – an application to amyotrophic lateral sclerosis

Clinical Neurophysiology ◽

10.1016/j.clinph.2017.06.060 ◽

2017 ◽

Vol 128 (10) ◽

pp. e315

Author(s):

H.P. Müller ◽

I. Kobor ◽

U. Bogdahn ◽

A.C. Ludolph ◽

A. Khomenko ◽

...

Keyword(s):

Amyotrophic Lateral Sclerosis ◽

Diffusion Tensor Imaging ◽

Diffusion Tensor ◽

Longitudinal Diffusion ◽

The Brain ◽

Lateral Sclerosis ◽

In Vivo Assessment

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Quantifying nerve decussation abnormalities in the optic chiasm

10.1101/633347 ◽

2019 ◽

Author(s):

Robert J. Puzniak ◽

Khazar Ahmadi ◽

Jörn Kaufmann ◽

Andre Gouws ◽

Antony B. Morland ◽

...

Keyword(s):

Diffusion Mri ◽

Diffusion Tensor ◽

Area Under The Curve ◽

Optic Chiasm ◽

List Type ◽

Test Model ◽

Discriminative Power ◽

Significant Group ◽

Structural Abnormalities

AbstractObjectiveThe human optic chiasm comprises partially crossing optic nerve fibres. Here we used diffusion MRI (dMRI) for the in-vivo identification of the abnormally high proportion of crossing fibres found in the optic chiasm of people with albinism.MethodsIn 9 individuals with albinism and 8 controls high-resolution 3T dMRI data was acquired and analyzed with a set of methods for signal modeling [Diffusion Tensor (DT) and Constrained Spherical Deconvolution (CSD)], tractography, and streamline filtering (LiFE, COMMIT, and SIFT2). The number of crossing and non-crossing streamlines and their weights after filtering entered ROC-analyses to compare the discriminative power of the methods based on the area under the curve (AUC). The dMRI results were cross-validated with fMRI estimates of misrouting in a subset of 6 albinotic individuals.ResultsWe detected significant group differences in chiasmal crossing for both unfiltered DT (p=0.014) and CSD tractograms (p=0.0009) also reflected by AUC measures (for DT and CSD: 0.61 and 0.75, respectively), underlining the discriminative power of the approach. Estimates of crossing strengths obtained with dMRI and fMRI were significantly correlated for CSD (R2=0.83, p=0.012). The results show that streamline filtering methods in combination with probabilistic tracking, both optimized for the data at hand, can improve the detection of crossing in the human optic chiasm.ConclusionsEspecially CSD-based tractography provides an efficient approach to detect structural abnormalities in the optic chiasm. The most realistic results were obtained with filtering methods with parameters optimized for the data at hand.SignificanceOur findings demonstrate a novel anatomy-driven approach for the individualized diagnostics of optic chiasm abnormalities.HighlightsDiffusion MRI is capable of detecting structural abnormalities of the optic chiasm.Quantification of crossing strength in optic chiasm is of promise for albinism diagnostics.Optic chiasm is a powerful test model for neuroimaging methods resolving crossing fibers.

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