Susceptibility weighted imaging at 1.5 Tesla magnetic resonance imaging in dogs: Comparison with T2*-weighted gradient echo sequence and its clinical indications.

Susceptibility weighted imaging (SWI) is a high resolution, fully velocity-compensated, three-dimensional gradient echo (GE) MRI technique. In humans, SWI has been reported to be more sensitive than T2*-weighted GE sequences in the identification of both intracranial hemorrhage and intra-vascular deoxyhemoglobin. However, published clinical studies comparing SWI to T2*-weighted GE sequences in dogs are currently lacking. The aim of this retrospective, observational study was to compare SWI and T2*-weighted GE sequences in a group of dogs with intracranial disease. Medical records were searched for dogs that underwent a brain MRI examination that included T2*-weighted GE and SWI sequences. The presence and appearance of non-vascular and vascular signal voids observed on T2*-weighted GE and SWI were compared. Thirty-two dogs were included with the following diagnoses: presumed and confirmed intracranial neoplasia (27), cerebrovascular accidents (3), and trauma (2). Hemorrhagic lesions were significantly more conspicuous on SWI than T2*-weighted GE sequences (P < .0001). Venous structures were well defined in all SWI sequences, and poorly defined in all dogs on T2*-weighted GE. Susceptibility weighted imaging enabled identification of vascular abnormalities in 30 of 32 (93.8%) dogs, including: neovascularization in 19 of 32 (59.4%) dogs, displacement of perilesional veins in five of 32 (15.6%) dogs, and apparent dilation of perilesional veins in 10 of 32 (31.3%) dogs. Presence of neovascularization was significantly associated with T1-weighted post-contrast enhancement (P = .0184). Hemorrhagic lesions and venous structures were more conspicuous on SWI compared to T2*-weighted GE sequences. Authors recommend adding SWI to standard brain protocols in dogs for detecting hemorrhage and identifying venous abnormalities for lesion characterization.

Morte súbita causada por ruptura de aneurisma em aorta em ruminantes / Sudden death caused by aortic aneurysm rupture in ruminants

De um total de 2.088 ruminantes necropsiados no Laboratório de Patologia Animal da Universidade Federal de Campina Grande durante o período de janeiro de 2003 a dezembro de 2015, 803 (38,45%) eram bovinos, 651 (31,18%) ovinos e 634 (30,37%) caprinos. Desses, dois caprinos (0,31%), um ovino (0,15%) e um bovino (0,12%) foram diagnosticados com ruptura de artéria aorta devido à presença de aneurismas, correspondendo a 0,19% das causas de morte em ruminantes. O caso 1 ocorreu em um caprino que apresentava bom estado corporal e foi encontrado morto pelo proprietário; o caso 2, em um caprino com diagnóstico clínico presuntivo de linfadenite caseosa; o caso 3, em um ovino que foi encontrado morto pelo proprietário; e o caso 4, em um bovino com histórico de timpanismo recidivante. Em todos os casos, a morte ocorreu rapidamente por choque hipovolêmico. Os principais achados macroscópicos na necropsia foram hemotórax ou hemoperitônio e a ruptura na artéria aorta. Nos caprinos, abscessos foram visualizados microscopicamente e estavam associados à presença de bactérias, o que sugere infecção por Corynebacterium pseudotuberculosis. No ovino, não foram observadas lesões que pudessem elucidar a causa do aneurisma, por isso foi considerado de provável origem idiopática. No bovino, não foi possível estabelecer a causa, mas a presença do aneurisma dificultava a eructação dos gases da fermentação ruminal, caracterizando um quadro de timpanismo secundário. Aneurismas ocorrem de forma esporádica em caprinos, ovinos e bovinos e devem ser considerados como uma importante causa de morte súbita.(AU)

From a total of 2,088 necropsied ruminants in the Laboratory of Animal Pathology of Federal University of Campina Grande during the period from January 2003 to December 2015, 803 (38.45%) were cattle, 651 (31.18%) sheep, and 634 (30.37%) goats. Of these, two goats (0.31%), one sheep (0.15%) and one bovine (0.12%) were diagnosed with rupture of aorta due to the presence of aneurysms, corresponding to 0.19% of causes of death in ruminants. Case 1 occurred in a goat that had good body condition and was found dead by the owner, case 2 occurred in a goat that had clinical presumptive diagnosis of caseous lymphadenitis, case 3 occurred in a sheep who was found dead by the owner, and case 4 occurred in a cow with a history of recurrent bloating. In all cases, death occurred rapidly by hypovolemic shock. The macroscopic findings at necropsy were hemothorax or hemoperitoneum and the rupture in the aorta artery. In goats, abscesses were viewed microscopically and they were associated with the presence of bacteria, suggesting for Corynebacterium pseudotuberculosis infection. In the sheep, lesions that could explain the cause of the aneurysm were not observed, so we consider the aneurisma as idiopathic. In the cow, it was not possible to establish the cause, but the presence of the aneurysm hampered eructation of ruminal gases, causing secondary bloat. Aneurysms occur sporadically in goats, sheep and cattle and must be regarded as an important cause of sudden death.(AU)

Aspectos epidemiológicos, clínicos e anatomopatológicos da intoxicação por aceturato de diminazeno em cães / Epidemiological, clinical, and pathological aspects of diminazene aceturate toxicosis in dogs

Os aspectos epidemiológicos, clínicos e anatomopatológicos da intoxicação espontânea por aceturato de diminazeno foram estudados em 10 cães. Em todos os casos, os cães afetados demonstraram sinais de síndrome tálamo-cortical, principalmente alteração do nível de consciência, tetraparesia, rigidez extensora e crise convulsiva. Em alguns casos, os cães acometidos apresentaram sinais de síndrome cerebelar, como tremores musculares generalizados de alta frequência e baixa amplitude, e/ou de síndrome vestibular, como ataxia, inclinação de cabeça e quedas. Esses sinais ocorreram entre 24 e 48 horas após o uso do fármaco injetável por via intramuscular e se mantiveram até a morte ou eutanásia dos cães (entre 1 e 7 dias). Tais sinais clínicos refletiam encefalomalacia hemorrágica focal simétrica, que afetava a medula oblonga, a ponte, a medular do cerebelo, o tálamo, o mesencéfalo, os pedúnculos cerebelares e os núcleos da base. Esse artigo: 1) descreve e discute essa forma de intoxicação medicamentosa tão pouco citada na literatura internacional e desconhecida da maior parte dos clínicos e patologistas veterinários brasileiros, 2) estabelece critérios clínicos e anatomopatológicos para o seu diagnóstico e, principalmente, 3) atenta para os riscos da utilização desse princípio ativo na terapêutica canina.

The epidemiological, clinical, and pathological aspects of diminazene aceturate (DA) spontaneous toxicosis were evaluated in 10 dogs. All affected dogs developed signs of thalamic-cortical syndrome, characterized mainly by neurological changes in the conscience levels, tetraparesis, extensor stiffness, and seizures. In some cases there was also evidence of cerebellar syndrome, characterized by generalized muscle tremors (high-frequency and low-amplitude) and/or vestibular syndrome, characterized by or ataxia, head tilt, and falling. These clinical signs occurred between 24 and 48 hours following intramuscular administration of DA and persisted until spontaneous death or euthanasia occurred between 1 and 7 days after the onset of clinical signs. The mentioned clinical signs reflected lesions that consisted of focal symmetrical hemorrhagic encephalomalacia affecting medulla oblongata, pons, cerebellar medulla, thalamus, midbrain, cerebellar peduncles, and basal nuclei. This article (1) describes and discusses DA toxicosis in dogs, a poorly-described clinical entity that is unknown by most clinicians and pathologists in Brazil; (2) establishes the clinical and pathological criteria for the diagnosis of DA toxicosis in dogs; and (3) calls up the attention for the risks of using DA in dogs in clinical settings.

Revisão anatômica do seio venoso sagital dorsal no crânio de cães braquicéfalos / Anatomic features of the dorsal venous sinus in skull of brachycephalous dogs

Os seios venosos do crânio realizam a drenagem do cérebro e da medula espinhal, a fim de manter a homeostasia e o perfeito funcionamento do sistema nervoso central. Lesões na rede venosa cerebral podem causar déficits severos tais como hemiplegia, hemorragia, coma e morte. Os seios venosos são importantes pontos de referência para a realização de técnicas cirúrgicas de acesso ao cérebro. Este estudo visou analisar o trajeto do seio venoso sagital dorsal no crânio de cães braquicéfalos. Os animais braquicéfalos possuem crânios curtos e com características biométricas específicas. Foram utilizados 8 crânios de cães da raça Boxer, que foram submetidos à injeção de látex com pigmento corado e sulfato de bário. Após a perfusão, foram feitas radiografias contrastadas e imagens de tomografia computadorizada para relacionar o seio venoso com a estrutura óssea e dimensões relativas da calota craniana. Os crânios apresentaram índice cefálico (IC) médio de 91,24±8,34mm e índice crânio-facial (ICF) médio de 2,89±0,23mm. As mensurações do seio venoso sagital dorsal, relativas à calota craniana, apresentaram os seguintes valores médios: Area = 10,18±4,69mm²; D1 = 11,84±2,35mm; D2 = 19,57±2,61mm; D3 = 17,88±2,31mm; D4 = 25,32±5,68mm; e D5= 24,84±4,40mm.

The dorsal venous sinuses of the Dura mater perform the cerebral and spinal cord drainage to keep homeostasis of the Central Nervous System. Injuries in the cerebral venous network may cause severe deficits, including hemiplegia, hemorrhage, coma and death. The main landmark for neurologic surgery is the Dura mater venous sinus. The aim of this study is to analyse the pathway of the Sinus sagittalis dorsalis in the brachycephalous skull, as the brachycephalous dogs have specific characteristics. The skulls were taken from 8 Boxer dogs and venous perfusion with latex and barium sulfate solution was performed. After the perfusion, radiographies and tomographies were obtained to relate the dorsal sagittal sinus and the skull averages. The cephalic index showed mean values of 91.24±8.34cm, and the cranio-facial index was 2.89±0.23cm. The venous sinus mensuration interface to the skull was: Area = 10.18±4.69mm²; D1 = 11.84±2.35mm; D2 = 19.57±2.61mm; D3 = 17.88±2.31mm; D4 = 25.32±5.68mm e D5 = 24.84±4.40mm.