MRI-gebaseerde morfometrische analyse gerelateerd aan chiari-achtige malformatie bij brachycefale hondenrassen

Abstract

The aim of this study was to investigate potential differences and correlations between brain and skull morphology and the clinical signs of brachycephalic dogs with and without Chiari-like malformation (CLM). Various measurements were derived from magnetic resonance images of the brain and craniocervical junction of thirty brachycephalic dogs in a flexed-neck position. Each dog was assigned a clinical grade. The distance from the planum of the foramen magnum to the pons was significantly reduced, providing evidence of craniocephalic disproportion similar to human patients with Chiari malformation type I. Cerebral length relative to cranial length was significantly increased in dogs with CLM compared with control dogs, supporting the hypothesis that CLM is governed by a global overcrowding of the brain, dissimilar to the human condition. Significant correlations were identified between these measurements and the extent of cerebellar herniation. No significant differences or correlations were identified with clinical grade. This is the first described morphometric analysis to use a strictly brachycephalic study population inclusive of a control group free from CLM.

Epidemiology of periodontal disease in dogs in the UK primary‐care veterinary setting

“…However, all three could be accepted to represent a skull shape with a more moderate conformation compared to the elongated skull of a Borzoi or the flattened brachycephalic faces of breeds such as Pugs and French Bulldogs (The Kennel Club 2021b). To date, much of the research on the effects of skull shape on the health of brachycephalic dog breeds has focused on respiratory disorders, neurological disease and ocular disease (Koch et al 2003, O'Neill et al 2015, Packer et al 2015, Gordon et al 2017, Liu et al 2017, Knowler et al 2019. However, there is also some evidence that brachycephalic breeds may also be predisposed to incisor overcrowding and that smaller breeds of dog are more susceptible to periodontal disease (Lund 2008, Burns 2016, Bellows et al 2019.…”

Utility of a flexed neck sagittal magentic resonance imaging sequence for the assessment of cerebellomedullary cistern in dogs

“…A possible explanation for this discrepancy is that there appeared to be a bias in our population with brachycephalic dogs being over‐represented, both based on the breeds and on cranial index. As previously mentioned, cranial index has been used to assess conformation and divide dog breeds into brachycephalic, mesaticephalic and dolicocephalic in several studies, with brachycephaly defined as a cranial index of more or equal to 80 (Gordon et al, 2017 ; Harcourt‐Brown et al, 2015 ; Knowler et al, 2018 ; Mansour et al, 2018 ; Schmidt et al, 2011 ; Sokołowski et al, 2018 ; Stockard, 1941 ). This appears to be extrapolated from human studies; however, there are no veterinary studies validating it in dogs (Harcourt‐Brown et al, 2015 ).…”

“…For the flexed‐neck studies, the patients had their neck flexed at 90° angle based on visual assessment, to simulate the positioning for a cisternal spinal puncture (Sturges, 2015 ). This was achieved using a previously described technique by placing a 45° foam wedge behind the head, held secure with the use of sandbags (Gordon et al, 2017 ; Upchurch et al, 2011 ). Cases were excluded from the study if the angle between the basioccipital bone and the dorsal body of the axis was exceeding 140°, either due to the patient’s conformation, body condition score (BCS), or suspected discomfort manifested by an increase in heart and/or respiratory rate.…”

“…Measurement H represents the height of the skull, measured on a line perpendicular to the basioccipital bone at the level of the clivus to the external aspect of the parietal bone, in millimeters. Measurement I represents the degree of cerebellar herniation in millimeters using a previously described technique (Freeman et al, 2014 ; Gordon et al, 2017 )…”

“…For the flexed-neck studies, the patients had their neck flexed at 90° angle based on visual assessment, to simulate the positioning for a cisternal spinal puncture (Sturges, 2015). This was achieved using a previously described technique by placing a 45° foam wedge behind the head, held secure with the use of sandbags (Gordon et al, 2017;Upchurch et al, 2011).…”