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systemic weakness was not consistently seen, making a neuromuscular condition less likely. Collapse could also occur due to a loss of balance from vestibular or cerebellar disease and may coincide with leaning, falling, or a wide-based stance. In this case
of clinical signs by an attending veterinarian. Definitive diagnosis can only be made after death via histologic examination of cerebellar tissue. Cerebellar abiotrophy was first described in the veterinary medical literature in the late 1960s. 1
Abstract
Objective—To evaluate related and unrelated Old English Sheepdogs (OESD) by clinical examination, histologic evaluation, and pedigree analysis to determine whether cerebellar degeneration develops in this breed and whether there are genetic implications.
Design—Case study and pedigree analysis.
Animals—24 clinically normal or affected OESD; brain tissue specimens from 25 unaffected or affected OESD.
Procedure—Twenty-four OESD that were chosen because of a family history of gait abnormalities were given physical and neurologic examinations to determine whether they had clinical signs of cerebellar degeneration. Tissue specimens from 25 brains of OESD were examined histologically. Nine OESD that were determined to have cerebellar degeneration histologically as well as 2 clinically affected littermates of the histologically confirmed affected OESD were included in the pedigree analysis. Standard statistical evaluation of pedigrees for hereditary conclusions was used.
Results—Twelve of the 24 OESD evaluated by neurologic examination had a progressive gait abnormality. Clinical signs of cerebellar degeneration typically started later in life in OESD, compared with description for other dog breeds, and progressed ore slowly. Results of pedigree analysis revealed that 11 of 49 dogs were affected in 9 litters, providing an affected-to-total ratio of 22.49%.
Conclusions and Clinical Relevance—Results of our study indicate that a slowly progressing late-onset form of cerebellar degeneration develops in OESD, and the mode of inheritance is by an autosomal recessive gene. (J Am Vet Med Assoc 2000;217:1162–1165)
of this branch at the bifurcation remains caudal to the typical branch. In both horses, the caudal branch anastomoses with the caudal cerebellar artery (white arrows) and continues toward the cranium. All images are oriented with rostral to the left
head, vertebral column, or appendicular muscles. Given these findings, a cerebellar lesion was suspected. No neurologic abnormalities were detected in the remaining 3 puppies. Six and 10 years previously, 2 other related female Norwegian Buhunds (one 16
, with tremors, ataxia, and dysmetria 8,9,11 resulting from cerebellar damage; these signs progress to paresis. The pathological features of GLD in affected terrier breeds consist of extensive demyelination in the white matter tracts and appearance of
(large arrow) and cerebellar nuclei (small arrow) are visible bilaterally. C—Image obtained at a level through the medulla oblongata at a location caudal to the image level in panel B. Areas of hyperintensity (arrow) in the region of the vestibular nuclei
. Cerebellar compression was defined as an indentation of the cerebellum. The CC index was calculated by dividing CL, determined by measuring the distance from the outer limit of the subarachnoid space to the point of greatest neural compression, by the
(RCA, MCA, CCA, RCEA, and caudal cerebellar artery). 7 The RCA, MCA, CCA, and RCEA arise from an elongated vascular ring at the base of the brain called the circle of Willis, which is formed by the ICA and BA. The CCOA forms the lateral and caudal
Abstract
OBJECTIVE To acquire MRI diffusion data (apparent diffusion coefficient [ADC] and fractional anisotropy [FA] values, including separate measures for gray and white matter) at 3.0 T for multiple locations of the brain of neurologically normal dogs.
ANIMALS: 13 neurologically normal dogs recruited from a group of patients undergoing tibial plateau leveling osteotomy.
PROCEDURES: MRI duration ranged from 20 to 30 minutes, including obtaining preliminary images to exclude pathological changes (T2-weighted fluid-attenuated inversion recovery transverse and dorsal images) and diffusion-weighted images.,
RESULTS: Globally, there were significant differences between mean values for gray and white matter in the cerebral lobes and cerebellum for ADC (range of means for gray matter, 0.8349 × 10−3 s/mm2 to 0.9273 × 10−3 s/mm2; range of means for white matter, 0.6897 × 10−3 s/mm2 to 0.7332 × 10−3 s/mm2) and FA (range of means for gray matter, 0.1978 to 0.2364; range of means for white matter, 0.5136 to 0.6144). These values also differed among cerebral lobes. In most areas, a positive correlation was detected between ADC values and patient age but not between FA values and patient age.
CONCLUSIONS AND CLINICAL RELEVANCE: Cerebral interlobar and cerebellar diffusion values differed significantly, especially in the gray matter. Information about diffusion values in neurologically normal dogs may be used to diagnose and monitor abnormalities and was the first step in determining the clinical use of diffusion imaging. This information provided an important starting point for the clinical application of diffusion imaging of the canine brain.
