Putative Cerebral Microbleeds in Dogs Undergoing Magnetic Resonance Imaging of the Head: A Retrospective Study of Demographics, Clinical Associations, and Relationship to Case Outcome

Abstract

BackgroundCerebral microbleeds (CMBs) are focal intraparenchymal signal voids on gradient‐echo magnetic resonance imaging (MRI), corresponding to regions of chronic hemorrhage. In humans, they are associated with systemic disease and shorter survival times. Although similar findings have been identified in dogs, their epidemiology and clinical correlations have not been investigated.ObjectiveTo determine epidemiological features, clinical associations, and associations with outcome for putative CMB‐like foci (putative microbleeds [pMBs]) identified by T2*‐weighted MRI in dogs.AnimalsFive hundred and eighty‐two dogs undergoing 3T brain MRI between 2011 and 2016.MethodsRetrospective case–control study. Demographic, diagnostic, and clinicopathological data were obtained from medical records and phone follow‐up. Demographic variables were compared between dogs with and without evidence of pMBs. For dogs with such evidence, and a subset of matched controls, associations with clinical presentation, concurrent disease, and survival times were evaluated.ResultsDogs with pMBs were older (P < .001) and smaller (P = .004) than unaffected dogs. Compared to matched controls, they presented more frequently for vestibular signs (P = .030). Cortical atrophy occurred concurrently with pMBs in 26% (14/54) of dogs. Diagnosed renal disease was not significantly associated with pMBs, but proteinuria was more common in dogs with pMBs than in matched controls (odds ratio = 3.01, P = .005). Dogs with pMBs had a shorter median survival time than did matched controls (P = .011).Conclusions and Clinical ImportancePutative microbleeds occurred in 54 of 582 (9.3%) of dogs undergoing brain MRI, but may not be a normal consequence of aging. They were associated with shorter survival time and proteinuria in the study population.

Vestibular disease in dogs: association between neurological examination, MRI lesion localisation and outcome

“…, Kerwin et al . ). Lesions in the brain with other aetiologies such as congenital malformation, abiotrophy or hydrocephalus were also differentiated as precisely as possible (De Lahunta & Glass , Bernardino et al .…”

“…For the confirmed or presumed diagnosis of neoplasia the results of blood tests, tumour staging investigation and lesion characteristics on MRI were considered (Thomas et al 1996, Kraft et al 1997, Rodenas et al 2011, Bentley 2015. For the identification of inflammatory lesions the characteristics of the MRI lesion, its behaviour concerning contrast enhancement, the results of CSF analysis and blood results were considered (Tipold 1995, Kitagawa et al 2004, Platt & Olby 2004, Talarico & Schatzberg 2010, Coates & Jeffery 2014, Cardy & Cornelis 2018.Presumed infarcts and bleeding caused by traumatic brain injury or presumed microbleeds were differentiated using MRI characteristics, case history and other diagnostic tests (Platt & Olby 2004, Garosi et al 2006, Garosi 2010, Thomsen et al 2016, Kerwin et al 2017. Lesions in the brain with other aetiologies such as congenital malformation, abiotrophy or hydrocephalus were also differentiated as precisely as possible (De Lahunta & Glass 2009, Bernardino et al 2015, Bertalan et al 2014, Kwiatkowska et al 2013, Laubner et al 2015.…”

Interthalamic adhesion size in aging dogs with presumptive spontaneous brain microhemorrhages: a comparative retrospective MRI study of dogs with and without evidence of canine cognitive dysfunction

“…or associated intracranial reason (e.g., tumor, inflammatory brain disease, etc.) for intracranial bleeding (Sharma et al, 2018;Yamada, 2015;Boulouis, Charidimou & Greenberg, 2016;Kerwin et al, 2017).…”

“…Although there is some variability in the literature concerning what constitutes a microhemorrhage, most reports include lesions that are less than 5.0 mm in diameter (Jouvent, Puy & Chabriat, 2016;Ungvari et al, 2017;Murao, Rossi & Cordonnier, 2013;Bos et al, 2018;Sharma et al, 2018). Pathologists have identified both cerebral amyloid angiopathy and cerebral microbleeds in geriatric dogs (Uchida, Nakayama & Goto, 1991;Shimada et al, 1992;Wegiel et al, 1995;Yoshino et al, 1996;Colle et al, 2000;Jakel et al, 2017;Rodrigues et al, 2018), and clinicians have described putative microhemorrhages in geriatric dogs undergoing MRI (Fulkerson et al, 2012;Hodshon, Hecht & Thomas, 2014;Kerwin et al, 2017).…”

“…As with human patients with spontaneous brain microhemorrhages, veterinary neurologists often fail to identify any metabolic cause for microhemorrhages in geriatric dogs. In one study of putative microhemorrhages in dogs, an association was found between systemic hypertension and the presence of brain microhemorrhages (Kerwin et al, 2017); however, systemic hypertension can be a result of brain pathology as well as causing brain pathology, as the control center for systemic blood pressure is located in the medulla and is responsive to changes in cerebral oxygen levels (Reis et al, 1994).…”