Frameless Stereotaxy in Sheep - Neurosurgical and Imaging Techniques for Translational Stroke Research

Dreyer, Antje; Stroh, Albrecht; Pösel, Claudia; Findeisen, Matthias; Geymüller, Teresa von; Lobsien, Donald; Nitzsche, Björn; Boltze, Johannes

doi:10.5772/32367

Cited by 6 publications

(6 citation statements)

References 47 publications

(39 reference statements)

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“…First, it is useful to allocate coordinates of distinct anatomical structures to experimental findings, for example for electrophysiological (Gierthmuehlen et al, 2014 ) or functional MRI data. Second, it offers a more objective and highly standardized reference system for stereotaxic targeting of anatomical structures (Dreyer et al, 2012 ; Staudacher et al, 2014 ) due to the normalization of the created template. Third, the template provides the ground for subsequent creation of a highly precise ovine brain atlas based on a higher sample population.…”

Section: Discussionmentioning

confidence: 99%

“…Of note, all MR imaging (MRI) data sets were obtained from studies conducted for different purposes (animal license numbers TVV33/09, TVV09/11, TVV33/12, and W04/19). For those studies, sheep were subjected to stereotactic surgery using a frameless stereotactic device (Rogue Research Ltd., Canada, Dreyer et al, 2012 ). The procedures required structural/anatomical MRI data sets for neuronavigation which were used for the herein presented study.…”

Section: Methodsmentioning

confidence: 99%

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A stereotaxic, population-averaged T1w ovine brain atlas including cerebral morphology and tissue volumes

et al. 2015

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Standard stereotaxic reference systems play a key role in human brain studies. Stereotaxic coordinate systems have also been developed for experimental animals including non-human primates, dogs, and rodents. However, they are lacking for other species being relevant in experimental neuroscience including sheep. Here, we present a spatial, unbiased ovine brain template with tissue probability maps (TPM) that offer a detailed stereotaxic reference frame for anatomical features and localization of brain areas, thereby enabling inter-individual and cross-study comparability. Three-dimensional data sets from healthy adult Merino sheep (Ovis orientalis aries, 12 ewes and 26 neutered rams) were acquired on a 1.5 T Philips MRI using a T1w sequence. Data were averaged by linear and non-linear registration algorithms. Moreover, animals were subjected to detailed brain volume analysis including examinations with respect to body weight (BW), age, and sex. The created T1w brain template provides an appropriate population-averaged ovine brain anatomy in a spatial standard coordinate system. Additionally, TPM for gray (GM) and white (WM) matter as well as cerebrospinal fluid (CSF) classification enabled automatic prior-based tissue segmentation using statistical parametric mapping (SPM). Overall, a positive correlation of GM volume and BW explained about 15% of the variance of GM while a positive correlation between WM and age was found. Absolute tissue volume differences were not detected, indeed ewes showed significantly more GM per bodyweight as compared to neutered rams. The created framework including spatial brain template and TPM represent a useful tool for unbiased automatic image preprocessing and morphological characterization in sheep. Therefore, the reported results may serve as a starting point for further experimental and/or translational research aiming at in vivo analysis in this species.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

A stereotaxic, population-averaged T1w ovine brain atlas including cerebral morphology and tissue volumes

et al. 2015

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“…Experimental ruminants (sheep, goats) are predominantly used to simulate acute cerebrovascular pathologies such as ischaemic stroke [32–34] and cerebral haemorrhage [35]. In domestic dogs, hypercaloric or unbalanced diet, lack of physical exercise and dyslipidemia are prevalent [36].…”

Section: Introductionmentioning

confidence: 99%

Translational models for vascular cognitive impairment: a review including larger species

Hainsworth

Allan

Boltze

et al. 2017

BMC Med

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BackgroundDisease models are useful for prospective studies of pathology, identification of molecular and cellular mechanisms, pre-clinical testing of interventions, and validation of clinical biomarkers. Here, we review animal models relevant to vascular cognitive impairment (VCI). A synopsis of each model was initially presented by expert practitioners. Synopses were refined by the authors, and subsequently by the scientific committee of a recent conference (International Conference on Vascular Dementia 2015). Only peer-reviewed sources were cited.MethodsWe included models that mimic VCI-related brain lesions (white matter hypoperfusion injury, focal ischaemia, cerebral amyloid angiopathy) or reproduce VCI risk factors (old age, hypertension, hyperhomocysteinemia, high-salt/high-fat diet) or reproduce genetic causes of VCI (CADASIL-causing Notch3 mutations).ConclusionsWe concluded that (1) translational models may reflect a VCI-relevant pathological process, while not fully replicating a human disease spectrum; (2) rodent models of VCI are limited by paucity of white matter; and (3) further translational models, and improved cognitive testing instruments, are required.

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“…Baseline MR imaging (1.5T Phillips MRI, Gyroscan Intera; Philips, Koninklijke, The Netherlands) was performed prior to experimentation in each animal to prepare stereotaxic neurosurgery using a frameless device. 13 An array of three MR-sensitive fiducial markers defining individual positions of the scanned head were installed just prior to imaging. The arrays were adopted on an individualized tooth bar (Rogue Research Inc., Canada) and mounted to the individual maxillary dent profiles using hydroplastic (TAK Systems, US).…”

Section: Methodsmentioning

confidence: 99%

Lesional and perilesional tissue characterization by automated image processing in a novel gyrencephalic animal model of peracute intracerebral hemorrhage

Boltze

Ferrara

Hainsworth

et al. 2018

J Cereb Blood Flow Metab

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Intracerebral hemorrhage (ICH) is an important stroke subtype, but preclinical research is limited by a lack of translational animal models. Large animal models are useful to comparatively investigate key pathophysiological parameters in human ICH. To (i) establish an acute model of moderate ICH in adult sheep and (ii) an advanced neuroimage processing pipeline for automatic brain tissue and hemorrhagic lesion determination; 14 adult sheep were assigned for stereotactically induced ICH into cerebral white matter under physiological monitoring. Six hours after ICH neuroimaging using 1.5T MRI including structural as well as perfusion and diffusion, weighted imaging was performed before scarification and subsequent neuropathological investigation including immunohistological staining. Controlled, stereotactic application of autologous blood caused a space-occupying intracerebral hematoma of moderate severity, predominantly affecting white matter at 5 h post-injection. Neuroimage post-processing including lesion probability maps enabled automatic quantification of structural alterations including perilesional diffusion and perfusion restrictions. Neuropathological and immunohistological investigation confirmed perilesional vacuolation, axonal damage, and perivascular blood as seen after human ICH. The model and imaging platform reflects key aspects of human ICH and enables future translational research on hematoma expansion/evacuation, white matter changes, hematoma evacuation, and other aspects.

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Frameless Stereotaxy in Sheep - Neurosurgical and Imaging Techniques for Translational Stroke Research

Cited by 6 publications

References 47 publications

A stereotaxic, population-averaged T1w ovine brain atlas including cerebral morphology and tissue volumes

A stereotaxic, population-averaged T1w ovine brain atlas including cerebral morphology and tissue volumes

Translational models for vascular cognitive impairment: a review including larger species

Lesional and perilesional tissue characterization by automated image processing in a novel gyrencephalic animal model of peracute intracerebral hemorrhage

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