Background Gliomas in dogs remain poorly understood. Objectives To characterize the clinicopathologic findings, diagnostic imaging features and survival of a large sample of dogs with glioma using the Comparative Brain Tumor Consortium diagnostic classification. Animals Ninety-one dogs with histopathological diagnosis of glioma. Methods Multicentric retrospective case series. Signalment, clinicopathologic findings, diagnostic imaging characteristics, treatment, and outcome were used. Tumors were reclassified according to the new canine glioma diagnostic scheme. Results No associations were found between clinicopathologic findings or survival and tumor type or grade. However, definitive treatments provided significantly (P = .03) improved median survival time (84 days; 95% confidence interval [CI], 45-190) compared to palliative treatment (26 days; 95% CI, 11-54). On magnetic resonance imaging (MRI), oligodendrogliomas were associated with smooth margins and T1-weighted hypointensity compared to astrocytomas (odds ratio [OR], 42.5; 95% CI, 2.42-744.97; P = .04; OR, 45.5; 95% CI, 5.78-333.33; P < .001, respectively) and undefined gliomas (OR, 84; 95% CI, 3.43-999.99; P = .02; OR, 32.3; 95% CI, 2.51-500.00; P = .008, respectively) and were more commonly in contact with the ventricles than astrocytomas (OR, 7.47; 95% CI, 1.03-53.95; P = .049). Tumor spread to neighboring brain structures was associated with high-grade glioma (OR, 6.02; 95% CI, 1.06-34.48; P = .04). Conclusions and Clinical Importance Dogs with gliomas have poor outcomes, but risk factors identified in survival analysis inform prognosis and the newly identified MRI characteristics could refine diagnosis of tumor type and grade.

Background: The pathophysiology of changes in magnetic resonance imaging (MRI) detected after a seizure is not fully understood. Objective: To characterize and describe seizure-induced changes detected by MRI. Animals: Eighty-one client-owned dogs diagnosed with idiopathic epilepsy. Methods: Data collected retrospectively from medical records and included anatomical areas affected, T1-, T2-weighted and T2-FLAIR (fluid-attenuated inversion recovery) appearance, whether changes were unilateral or bilateral, symmetry, contrast enhancement, mass effect, and, gray and white matter distribution. Diffusion- and perfusion weighted maps were evaluated, if available. Results: Seizure-induced changes were T2-hyperintense with no suppression of signal on FLAIR. Lesions were T1-isointense (55/81) or hypointense (26/81), local mass effect (23/81) and contrast enhancement (12/81). The majority of changes were bilateral (71/81) and symmetrical (69/71). The most common areas affected were the hippocampus (39/81) cingulate gyrus (33/81), hippocampus and piriform lobes (32/81). Distribution analysis suggested concurrence between cingulate gyrus and pulvinar thalamic nuclei, the cingulate gyrus and parahippocampal gyrus, hippocampus and piriform lobe, and, hippocampus and parahippocampal gyrus. Diffusion (DWI) characteristics were a mixed-pattern of restricted, facilitated, and normal diffusion. Perfusion (PWI) showed either hypoperfusion (6/9) or hyperperfusion (3/9). Conclusions and Clinical Importance: More areas, than previously reported, have been identified that could incur seizure-induced changes. Similar to human literature, DWI and PWI changes have been identified that could reflect the underlying metabolic and vascular changes.

Congenital vertebral malformations (CVM) are common in brachycephalic ‘screw‐tailed’ dogs; they can be associated with neurological deficits and a genetic predisposition has been suggested. The purpose of this study was to evaluate radiography as a screening method for congenital thoracic vertebral malformations in brachycephalic ‘screw‐tailed’ dogs by comparing it with CT. Forty‐nine dogs that had both radiographic and CT evaluations of the thoracic vertebral column were included. Three observers retrospectively reviewed the images independently to detect CVMs. When identified, they were classified according to a previously published radiographic classification scheme. A CT consensus was then reached. All observers identified significantly more affected vertebrae when evaluating orthogonal radiographic views compared with lateral views alone; and more affected vertebrae with the CT consensus compared with orthogonal radiographic views. Given the high number of CVMs per dog, the number of dogs classified as being CVM free was not significantly different between CT and radiography. Significantly more midline closure defects were also identified with CT compared with radiography. Malformations classified as symmetrical or ventral hypoplasias on radiography were frequently classified as ventral and medial aplasias on CT images. Our results support that CT is better than radiography for the classification of CVMs and this will be important when further evidence of which are the most clinically relevant CVMs is identified. These findings are of particular importance for designing screening schemes of CVMs that could help selective breeding programmes based on phenotype and future studies.

Background Although the presence of seizures in dogs with meningoencephalitis of unknown origin (MUO) has been associated with shorter survival times, data regarding the prevalence and risk factors for postencephalitic epilepsy (PEE) is lacking. Objectives To describe the clinical features, prevalence, risk factors, and long‐term outcome of PEE in dogs with MUO. Animals Sixty‐one dogs with presumptive diagnosis of MUO based on the clinicopathological and diagnostic imaging findings. Methods Retrospective study. Cases were identified by search of hospital medical records for dogs with suspected or confirmed MUO. Medical records of dogs meeting inclusion criteria were reviewed. Signalment, seizure history, clinicopathologic, and magnetic resonance imaging (MRI) findings were recorded. Results Among 61 dogs at risk of PEE, 14 (23%) dogs developed PEE. Three of 14 dogs with PEE (21%) developed drug‐resistant epilepsy. Dogs with PEE were younger (P = .03; OR_adjusted = 0.75; 95% confidence interval [CI], 0.58‐0.98) and had significantly shorter survival times (log‐rank test P = .04) when compared to dogs that did not develop epilepsy. The risk factors associated with the development of PEE were the presence of acute symptomatic seizures (ASS; P = .04; OR_adjusted = 4.76; 95% CI, 1.11‐20.4) and MRI lesions in the hippocampus (P = .04; OR_adjusted = 4.75; 95% CI, 1.07‐21.0). Conclusions and Clinical Importance Dogs with MUO and seizures at the early stage of the disease (ASS) seem to be at a higher risk of developing PEE.

Case Description—A 9-year-old male Miniature Poodle was evaluated because of progressive severe right hemiparesis, right forelimb lameness, and signs of cervical pain. Clinical Findings—A low body condition score (2/9) and popliteal lymphadenopathy were detected. Results of a CBC, serum biochemical analyses, urinalysis, cytologic examination of bone marrow and popliteal lymph node aspirates, and serum ELISA were consistent with systemic leishmaniasis. Magnetic resonance imaging of the cervical spinal cord revealed an intramedullary mass extending from the caudal aspect of the C5 vertebral body to the C5–6 intervertebral disk space with a contrast medium–enhanced pattern that had 3 zones (central contrast medium–enhanced core, intermediate isointense zone, and peripheral contrast medium–enhanced ring). Surgical biopsy of the mass was performed by means of a right C5–6 dorsal hemilaminectomy. Results of PCR assays for detection of Leishmania DNA in CSF and tissue biopsy samples were positive. Treatment and Outcome—Treatment for systemic leishmaniasis was initiated. Two months later, body condition, neurologic signs, and gait of the dog had substantially improved; the dog had mild right forelimb paresis at that time. Results of follow-up MRI indicated resolution of the cervical spinal cord lesion. Four months after diagnosis, the dog's neurologic condition was stable. Clinical Relevance—To the authors’ knowledge, this report is the first in which clinical findings, clinicopathologic data, and MRI characteristics of an intramedullary inflammatory spinal cord lesion presumptively attributable to leishmaniasis in a dog have been reported, and the first report of CNS leishmaniasis in a dog with MRI resolution and a successful clinical response to treatment.