To correlate the anatomical variants of the circle of Willis with their effects on the hemodynamic and geometrical parameters responsible for the pathogenesis of neurological diseases. The circle of Willis and the proximal segments of the main arteries were dissected and measured on ten formalin-fixed human brains. The anatomical variants were systematized using descriptive statistics. The mathematical models for brain perfusion and wall shear stress were developed by optimally approximating resistance to flow, vascular conductance, and branching. Eighty percent of the brains presented asymmetries, especially in the posterior communicating (70%) and anterior cerebral (40%) arteries. The posterior circulation had more variations (65.21%). Nine hypoplastic vessels were found in 7 brains. Atypical origins were observed in eight specimens. According to the mathematical models, which integrated each anatomical change in the global circle of Willis anatomy, the circle of Willis' geometry could represent a risk factor for intracranial aneurysms and atherosclerosis, mostly when hypoplastic arteries are present, due to high resistance to flow and imbalanced bifurcation geometry. Accessory vessels are less associated with cerebrovascular risk. We described anatomical variants of both the anterior and posterior circulations and their specific effects on the hemodynamic balance of cerebral blood flow.

The cat brain is a useful model for neuroscientific research and with the increasing use of advanced neuroimaging techniques there is a need for an open-source stereotaxic white matter brain atlas to accompany the cortical gray matter atlas, currently available. A stereotaxic white matter atlas would facilitate anatomic registration and segmentation of the white matter to aid in lesion localization or standardized regional analysis of specific regions of the white matter. In this article, we document the creation of a stereotaxic feline white matter atlas from diffusion tensor imaging (DTI) data obtained from a population of eight mesaticephalic felines. Deterministic tractography reconstructions were performed to create tract priors for the major white matter projections of Corpus callosum (CC), fornix, cingulum, uncinate, Corona Radiata (CR), Corticospinal tract (CST), inferior longitudinal fasciculus (ILF), Superior Longitudinal Fasciculus (SLF), and the cerebellar tracts. T1-weighted, fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AD) population maps were generated. The volume, mean tract length and mean FA, MD, AD and RD values for each tract prior were documented. A structural connectome was then created using previously published cortical priors and the connectivity metrics for all cortical regions documented. The provided white matter atlas, diffusivity maps, tract priors and connectome will be a valuable resource for anatomical, pathological and translational neuroimaging research in the feline model. Multi-atlas population maps and segmentation priors are available at Cornell’s digital repository: https://ecommons.cornell.edu/handle/1813/58775.2.

AIM: To present the particularities of the intraorbital foreign bodies from a neurosurgical perspective by summarizing the findings of a case series. MATERIAL and METHODS: A retrospective study was conducted including a consecutive series of 30 patients with intraorbital foreign bodies treated between 1999 and 2017. Statistical analysis was performed in order to characterize the factors that influence the location of the foreign bodies and the clinical signs. RESULTS: The orbital trauma occurred mostly in working accidents. Multiple intraorbital foreign bodies were found in 23.3% of the patients. Metallic foreign bodies were seen in 66.6%, and 30% had wooden foreign bodies. Nonmetallic foreign bodies were significantly associated with displacement of the eyeball, palpebral oedema and upper lid ptosis. Posterior orbit location was associated with displacement of the eyeball and conjunctival hemorrhage. Intraconal location was associated with mydriasis and conjunctival hemorrhage. The posterior orbit was occupied by foreign bodies in 63% of the patients. The foreign bodies were in the extraconal compartment in 55.55% of the cases. Small foreign bodies tend to be retained in the anterior orbit while large ones tend to be retained in the posterior orbit. CONCLUSION: The diagnosis and management of intraorbital foreign bodies must be tailored according to their type and location and to the clinical aspect of the patient.