Changes of Magnetic Resonance Imaging on the Brain in Beagle Dogs with Aging

Abstract

ABSTRACT. Age-associated changes of magnetic resonance imaging (MRI) on the brain were evaluated in 19 beagle dogs aged from 8-month-to 16-year-old. A significant correlation of the volume of lateral ventricle space was observed in the dogs with age advanced, however, no correlation was found between hippocampus size and the aging. The hypo-intensity areas on T2-weighted MRI were detected in globus pallidus and substantia nigra with a significant correlation of both intensity ratios to lateral ventricle with age advanced. These areas were coincided with the accumulation of iron in the slice of the brain with Perls' staining. In addition, hyperintensity area, suggesting perivascular demyelination with fluid-filled space, was also observed in white matter surrounding the lateral ventricle on T2-weighted MRI. These results suggested that age-associated changes of T2-weighted MRI were developed in the dog brain, especially in globus pallidus, substantia nigra, and white matter surrounding lateral ventricle, like as those reported in the human brain KEY WORDS: age-associated change, brain, canine, hypo-and hyper-intensity, MRI.J. Vet. Med. Sci. 67(10): 961-967, 2005 Magnetic resonance imaging (MRI) has been used as a noninvasive and useful diagnostic technique for evaluating age related brain disorders, such as Alzheimer's disease, Parkinson's disease, and dementia, indicating severe atrophy of the brain, hippocampus, amygdala, and temporal lobe, gray matter, and dilatation of ventricle space, and cortical sulci, [9,17,26,28,34]. However, age-associated similar changes of MRI was also observed in the clinically healthy human brain, indicating brain atrophy, dilatation of ventricle space and cortical sulci, hypo-intensity area in globus pallidus and substantia nigra, and hyper-intensity area in white matter [7,16,20,31]. In addition, age-associated pathological changes of the brain, including developments of senile plaque, decrease number of neuronal cell, deposit of lipofuscin, and activation of astrocyte, have also been well documented [8,12,23,38]. Therefore, it is necessary for diagnose of age related degenerative diseases to evaluate age-associated changes in the brain. Various age-associated changes were detected in aged dogs with occasionally abnormal behaviors [4,6,10,27,30], like as those reported in human [13]. Although MRI has been applied in veterinary clinics and experimental medicine, several reports were on clinical cases and few reports on age-associated changes in the dog brain [5,37]. This study deals with ageassociated changes in MRI on the brain, especially lateral ventricle space, hippocampus size, and hypo-and hyperintensity area, in beagle dogs with age advanced. MATERIALS AND METHODS Animals:Clinically healthy 19 beagle dogs (8 male and 11 female), aged from 8-month-to 16-year-old, were used. All the dogs were bred, reared, and kept in Medicinal Safety Research Laboratories, Sankyo Co., Ltd. under the condition of circumstance temperature at 22 ± 2°C. The air extraction was designed to be 10...

Age-Associated Changes of Flash Visual Evoked Potentials in Dogs

“…The flash VEP recorded in dogs showed 3 positive (P1, P2 and P3) and 2 negative (N1 and N2) components by 150 msec after the flash stimuli, like as those reported in human [11,17,19]. In addition, various age-associated pathological and/or physiological changes were commonly observed in aged dogs as well as aged human [5,10]. Since there are few diagnostic techniques for dementia in dogs, age-associated changes of the flash VEP were evaluated using various aged beagle dogs.…”

Most commonly used sequences and clinical protocols for brain and spine magnetic resonance imaging allowing better identification of pathological changes in dogs

“…There are different reports that have distinguished the MR signs in dogs with hydrocephalus, cerebellar degeneration, necrotizing encephalitis, granulomatous meningoencephalitis, infarcts, age-related degeneration, spinal cord hernias, wobbler syndrome, arachnoid cysts, syringohydromyelia associated with Chiari-like malformation in the Cavalier King Charles spaniel (Fig. 1), discospondylitis, atlantoaxial instability, meningeal calcification, hydromyelia, mechanical damage, and brain and spinal tumors (Vullo et al 1997, Gonzalo-Orden et al 2000, Kimotsuki et al 2005, Besalti et al 2006, Garosi et al 2006, Okada et al 2006, Matiasek et al 2007, Couturier J et al 2008, Sturges et al 2008, Carrera et al 2009, Cerda-Gonzalez S et al 2009, Young et al 2009, Gavin PR 2011.…”

Dogs with Cognitive Dysfunction Syndrome: A Natural Model of Alzheimer’s Disease

“…However, they are not commonly used for the prediction, diagnosis or follow-up of canine aging with cognitive dysfunction. The relationship between progressive canine brain atrophy and aging has been evidenced in several post-mortem studies [40][41][42] and recently confirmed in housed dogs, frequently beagles, using a variety of MRI techniques [43,44]. To determine whether progressive global cerebral atrophy is a marker of aging in dogs as well as in humans, an MRI study in companion dogs was performed with an adapted version of a simple human visual rating assessment (Fig.2).…”