Magnetic resonance imaging features of leukoaraiosis in elderly dogs (original) (raw)
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MRI Findings in a Rottweiler with Leukoencephalomyelopathy
Journal of the American Animal Hospital Association, 2013
A 22 mo old male rottweiler presented with a 1 mo progressive history of general proprioceptive ataxia and upper motor neuron tetraparesis. Neurologic examination was consistent with a lesion affecting the first through fifth cervical spinal cord segments. MRI disclosed bilaterally symmetric hyperintensities on T2-weighted (T2W) images in the crus cerebri and pyramidal tracts of the brain and the dorsal portion of the lateral funiculi of the cervical spinal cord. Fifty days after initial presentation, the dog was euthanized due to disease progression. Pathologic examination of the central nervous system (CNS) revealed a bilaterally symmetric chronic leukoencephalomyelopathy (LEM) consistent with previous reports of LEM in rottweilers. To the authors' knowledge, this is the first report to describe the MRI characteristics of LEM in the rottweiler. The topography of the changes observed with MRI paralleled the pathologic changes, which were widespread loss of myelin, decreased axon numbers, and astroglial proliferation. Consequently, MRI of the CNS of affected rottweilers may aid in establishing a presumptive antemortem diagnosis of LEM.
BMC Veterinary Research, 2013
Background: Leukoencephalomyelopathy is an inherited neurodegenerative disorder that affects the white matter of the spinal cord and brain and is known to occur in the Rottweiler breed. Due to the lack of a genetic test for this disorder, post mortem neuropathological examinations are required to confirm the diagnosis. Leukoencephalopathy with brain stem and spinal cord involvement and elevated lactate levels is a rare, autosomal recessive disorder in humans that was recently described to have clinical features and magnetic resonance imaging (MRI) findings that are similar to the histopathologic lesions that define leukoencephalomyelopathy in Rottweilers. Leukoencephalopathy with brain stem and spinal cord involvement is caused by mutations in the DARS2 gene, which encodes a mitochondrial aspartyl-tRNA synthetase. The objective of this case report is to present the results of MRI and candidate gene analysis of a case of Rottweiler leukoencephalomyelopathy to investigate the hypothesis that leukoencephalomyelopathy in Rottweilers could serve as an animal model of human leukoencephalopathy with brain stem and spinal cord involvement. Case presentation: A two-and-a-half-year-old male purebred Rottweiler was evaluated for generalised progressive ataxia with hypermetria that was most evident in the thoracic limbs. MRI (T2-weighted) demonstrated wellcircumscribed hyperintense signals within both lateral funiculi that extended from the level of the first to the sixth cervical vertebral body. A neurodegenerative disorder was suspected based on the progressive clinical course and MRI findings, and Rottweiler leukoencephalomyelopathy was subsequently confirmed via histopathology. The DARS2 gene was investigated as a causative candidate, but a sequence analysis failed to identify any diseaseassociated variants in the DNA sequence.
2005
Longitudinal changes in cortical atrophy, ventricular enlargement, and lesion development in serial MRI scans collected from 47 healthy dogs from 1999 (8-11 years old) to 2002 (11-14 years old) were studied. The first method involved manual region of interest volumetric analysis to examine changes in cerebral and ventricular volume during the three years. No change in cerebral volume was detected but ventricular volume increased significantly each year in 2000, 2001, and 2002. Increased ventricular volume parallels early studies of agedependent ventricular enlargement in the brain of aging beagle dogs. The second method involved a visual analysis of co-registered serial MRIs for each subject. Consistent with the volumetric results, there was no visible change in cortical thickness indicating no cerebral atrophy, but a significant increase in ventricular size was noted. Visual examination also revealed a significant increase in number of dogs who developed aging lesions over the last 2 years in 2001 and 2002. Additionally, a disproportionate number of lesions were recorded in the frontal cortex and caudate nucleus compared to other brain regions. These lesion findings are consistent with other studies in the aging dog that suggest that the frontal lobes may be particularly vulnerable to age-related changes. D
The Veterinary Journal, 2010
The dog is increasingly considered as a natural animal model for the study of normal and pathological human brain aging, because it exhibits anatomical, biochemical and cognitive changes that parallel those seen in humans. This study presents a novel visual semi-quantitative rating scale of canine cerebral magnetic resonance imaging (MRI). Ninety-eight dogs of both sexes from 27 pure breeds, aged 2-15 years, were used. The results suggest that (like in humans) both hippocampal and progressive global atrophy are characteristic features that correlate with aging. When classified according to head shape, cerebral atrophy was highest in mesaticephalic and brachycephalic dogs. This is the first MRI study to characterise a simple, rapid tool for studying age-related canine brain changes that can even be applied by non-experienced observers. The results confirm the possibility of transferring innovative tools developed for human diagnosis to the veterinary field.
Journal of Veterinary Clinics, 2018
The object of this study was to compare magnetic resonance imaging (MRI) findings and neurological signs in canine brain diseases. Brain diseases can cause severe neurological deficits and may be life-threatening. The antemortem diagnosis of the brain diseases is difficult for the clinician, since definitive diagnosis is based upon histopathological confirmation. Brain diseases are often associated with specific clinical signs, signalment, progression, and location. Accurate lesion localization through neurological examination and MRI findings is helpful for developing a differential diagnosis. A retrospective study was performed to compare the neurological examination of dogs with suspected brain disease to the MRI findings. Based on this study, neurological examination is a reliable way to localize most brain lesions. Postural reaction deficits do not provide sufficient information to localize lesions. Additionally, not all brain lesions present clinical signs and inflammatory lesions may cause no detectable abnormalities on MRI. Therefore, in clinical practice, a combination of neurological examination and MRI findings recommended for accurate brain lesion localization.
PeerJ, 2020
Objective Spontaneous brain microhemorrhages in elderly people are present to some degree in Alzheimer’s disease patients but have been linked to brain atrophy in the absence of obvious cognitive decline. Brain microhemorrhages have recently been described in older dogs, but it is unclear whether these are associated with brain atrophy. Diminution of interthalamic adhesion size-as measured on MRI or CT-has been shown to be a reliable indicator of brain atrophy in dogs with canine cognitive dysfunction (CCD) in comparison with successfully aging dogs. We hypothesized that aging dogs with brain microhemorrhages presenting for neurologic dysfunction but without obvious features of cognitive decline would have small interthalamic adhesion measurements, like dogs with CCD, compared with control dogs. The objective of this study was to compare interthalamic adhesion size between three groups of aging (>9 years) dogs: (1) neurologically impaired dogs with presumptive spontaneous brain m...
MRI-leukoaraiosis thresholds and the phenotypic expression of dementia
Neurology, 2012
Objective: To examine the concept of leukoaraiosis thresholds on working memory, visuoconstruction, memory, and language in dementia. Methods: A consecutive series of 83 individuals with insidious onset/progressive dementia clinically diagnosed with Alzheimer disease (AD) or small vessel vascular dementia (VaD) completed neuropsychological measures assessing working memory, visuoconstruction, episodic memory, and language. A clinical MRI scan was used to quantify leukoaraiosis, total white matter, hippocampus, lacune, and intracranial volume. We performed analyses to detect the lowest level of leukoaraiosis associated with impairment on the neuropsychological measures. Results: Leukoaraiosis ranged from 0.63% to 23.74% of participants' white matter. Leukoaraiosis explained a significant amount of variance in working memory performance when it involved 3% or more of the white matter with curve estimations showing the relationship to be nonlinear in nature. Greater leukoaraiosis (13%) was implicated for impairment in visuoconstruction. Relationships between leukoaraiosis, episodic memory, and language measures were linear or flat. Conclusions: Leukoaraiosis involves specific threshold points for working memory and visuoconstructional tests in AD/VaD spectrum dementia. These data underscore the need to better understand the threshold at which leukoaraiosis affects and alters the phenotypic expression in insidious onset dementia syndromes. Neurology ® 2012;79:734-740 GLOSSARY AD ϭ Alzheimer disease; BET ϭ Brain Extraction Tool; CDT ϭ Clock Drawing Test; DSC ϭ dice similarity coefficient; FLAIR ϭ fluid-attenuated inversion recovery; ICV ϭ intracranial volume; LA ϭ leukoaraiosis; P(r)VLT ϭ Philadelphia (repeatable) Verbal Learning Test; UMDNJ ϭ University of Medicine and Dentistry of New Jersey; VaD ϭ vascular dementia; WM ϭ white matter.
Clinical anatomy of the canine brain using magnetic resonance imaging
Veterinary Radiology …, 2008
The purpose of this study was to produce an magnetic resonsnce (MR) image atlas of clinically relevant brain anatomy and to relate this neuroanatomy to clinical signs. The brain of a large mixed breed dog was imaged in transverse, sagittal, and dorsal planes using a 1.5 T MR unit and the following pulse sequences: Turbo (fast) spin echo (TSE) T2, T1, and T2-weighted spatial and chemical shift-encoded excitation sequence. Relevant neuroanatomic structures were identified using anatomic texts, sectioned cadaver heads, and previously published atlases. Major subdivisions of the brain were mapped and the neurologic signs of lesions in these divisions were described. TSE T2-weighted images were found to be the most useful for identifying clinically relevant neuroanatomy. Relating clinical signs to morphology as seen on MR will assist veterinarians to better understand clinically relevant neuroanatomy in MR images.