Neuroanatomy of the equine brain as revealed by high-field (3Tesla) magnetic-resonance-imaging

Abstract

In this study, the morphology of the horse brain ( Equus caballus ) is decribed in detail using high field MRI. The study includes sagittal, dorsal, and transverse T2-weighted images at 0.25 mm resolution at 3 Tesla and 3D models of the brain presenting the external morphology of the brain. Representative gallocyanin stained histological slides of the same brain are presented. The images represent a useful tool for MR image interpretation in horses and may serve as a starting point for further research aiming at in vivo analysis in this species.

Diffusion Tensor Imaging Tractography of White Matter Tracts in the Equine Brain

“…The use of advanced MRI techniques in clinical practice offers the opportunity to better understand the mechanisms of neurological diseases of the horse and to improve their diagnosis. In the research setting, the implementation of such advanced MRI techniques often use postmortem samples, as exemplified by the two most recent MRI studies of the normal equine brain (15,16). Indeed, in addition to the constraints related to the adaptation of facilities for equine neuroimaging, the development of MRI tools in neurologically healthy horses poses the ethical problem of performing a general anesthesia for an MRI examination which is not medically warranted.…”

“…For each tract, ROIs were delineated manually, and sometimes one or several ROAs were additionally placed in order to specifically segregate fibers of interest. Regions were placed using anatomical descriptions of T1- and T2-weighted images of the equine brain ( 14 , 15 ), dissection of major white matter tracts in the equine brain ( 35 ), and a human tractography atlas ( 2 ). Color-coded FA maps and down-sampled SWI were used to place ROI and ROA.…”

“…As DTI tractography assesses the structural integrity of white matter, it has been widely used for prognostic and/or diagnostic purposes in various brain pathologies such as stroke (3)(4)(5)(6), neurodegenerative diseases (7)(8)(9)(10)(11), and brain tumors (12). With the increasing availability of high-field-strength MRI (1.5 and 3 T) in veterinary facilities (13)(14)(15)(16)(17), the use of this technique is now gradually growing for the description of white matter anatomy and structural connectivity of domestic mammals (dog, cat, ferret, and sheep) (18)(19)(20)(21)(22)(23)(24)(25)(26)(27). These collected anatomical data are of particular interest as they might have applications in both veterinary medicine and experimental research.…”

A Systematic Approach to Dissection of the Equine Brain–Evaluation of a Species-Adapted Protocol for Beginners and Experts

“…With the implementation of advanced neuroimaging methodologies, neuroanatomy in the field of equine neurology has become relevant for clinicians again, and our functional understanding has steadily increased (Manso-Diaz et al, 2015;Pease et al, 2017). Therefore, imaging has already enabled and supported important clinical-diagnostic (Audigie et al, 2004;Cavalleri et al, 2013;Holmes, 2014), neuroanatomical (Chaffin et al, 1997;Johnson et al, 2019;Schmidt et al, 2019) and neurodevelopmental (Scola et al, 2018) studies in this species. As in other generic groups, magnetic resonance imaging (MRI) scans in particular have proven to be the most sensitive intravital imaging modality (Hecht and Adams, 2010;Holmes, 2014).…”

“…Brain imaging templates and atlases rendered via MRI, including diffusion-weighted-imaging (DWI) and fluidattenuated-inversion-recovery (FLAIR) sequences, have enabled unprecedented mapping and measurement of white matter (WM), gray matter (GM), CSF, and subcortical brain structures (Stuckenschneider et al, 2014;Johnson et al, 2019). The neuroanatomical resemblance has been nicely demonstrated in comparison to tissue studies (Stuckenschneider et al, 2014;Kimberlin et al, 2016;Johnson et al, 2019;Schmidt et al, 2019).…”