Prevalence, distribution, and clinical associations of suspected postictal changes on brain magnetic resonance imaging in epileptic dogs.

OBJECTIVE: To determine the prevalence of presumed postictal changes (PC) on brain MRI in epileptic dogs, describe their distribution, and recognize possible correlations with different epilepsy features. ANIMALS: 540 client-owned dogs with epilepsy and a complete medical record that underwent brain MRI at 4 veterinary referral hospitals between 2016 and 2019. PROCEDURES: Data were collected regarding signalment, seizure type, seizure severity, time between last seizure and MRI, and etiological classification of epilepsy. Postictal changes were considered when solitary or multiple intraparenchymal hyperintense lesions were observed on T2-weighted and fluid-attenuated inversion recovery images and were hypointense or isointense on T1-weighted sequences, which were not confined to a vascular territory and showed no to mild mass effect and no to mild contrast enhancement. RESULTS: Sixty-seven dogs (12.4%) showed MRI features consistent with PC. The most common brain sites affected were the piriform lobe, hippocampus, temporal neocortex, and cingulate gyrus. Dogs having suffered cluster seizures or status epilepticus were associated with a higher probability of occurrence of PC, compared to dogs with self-limiting seizures (OR 2.39; 95% confidence interval, 1.33 to 4.30). Suspected PC were detected both in dogs with idiopathic epilepsy and in those with structural epilepsy. Dogs with unknown-origin epilepsy were more likely to have presumed PC than were dogs with structural (OR 0.15; 95% confidence interval, 0.06 to 0.33) or idiopathic epilepsy (OR 0.42; 95% confidence interval, 0.20 to 0.87). Time between last seizure and MRI was significantly shorter in dogs with PC. CLINICAL RELEVANCE: MRI lesions consistent with PC were common in epileptic dogs, and the brain distribution of these lesions varied. Occurrence of cluster seizures or status epilepticus, diagnosis of unknown origin epilepsy, and lower time from last seizure to MRI are predictors of suspected PC.

Surgical outcomes of six bulldogs with spinal lumbosacral meningomyelocele or meningocele.

OBJECTIVE: To report the surgical treatment and outcome of six bulldogs with spina bifida (SB) and meningocele (MC) or meningomyelocele (MMC). STUDY DESIGN: Case series. ANIMALS: Five French bulldogs and one English bulldog with MC or MMC. METHODS: Medical records of dogs with spinal MC or MMC diagnosed by MRI at two institutions between 2013 and 2016 were reviewed for surgical treatment and outcomes. RESULTS: Meningocele was diagnosed in two dogs, and MMC was diagnosed in four dogs. A lumbosacral dimple was noted in all dogs along with neurological deficits most commonly consisting of urinary and fecal incontinence (n = 6) and mild/moderate paraparesis (n = 3). Dorsal laminectomy was performed in all dogs to allow dissection of the meningeal sac to the vertebral column defect. In dogs with MMC, nerves were repositioned and protruded meninges were removed prior to suturing remaining meninges. Adhesions and filum terminale were resected in two dogs with suspected tethered cord syndrome. Urinary and fecal incontinence improved in two dogs and remained unchanged in four. Paraparesis improved in two dogs. CONCLUSION: Surgical treatment resulted in partial improvement of the urinary and fecal incontinence (2/6 dogs) and paraparesis (2/3 dogs) or stable neurological condition (3/6 dogs), with only minor temporary complications. CLINICAL SIGNIFICANCE: In the absence of published data comparing surgical and conservative treatment of puppies affected by SB and MC or MMC, early surgical treatment can be considered to prevent deterioration of neurological signs and, eventually, facilitate improvement of neurological signs.

Myelographic and low-field magnetic resonance imaging findings in dogs with presumptive acute hydrated non-compressive nucleus pulposus extrusion.

MRI is considered gold standard for the diagnosis of presumptive acute hydrated non-compressive nucleus pulposus extrusions (AHNCNPE). This retrospective study describes the myelographic findings in dogs with AHNCNPE diagnosed by low-field MRI and their association with neurological grade, need of surgical decompression and outcome. Forty-two myelographies (21 dogs with presumptive AHNCNPE, 21 dogs with Hansen type I disc disease herniation) were blindly evaluated. Site of herniation, compression pattern, ratio of length of the lesion to length of the second lumbar vertebra (LL:L2) and degree of spinal cord compression (SCC) were measured on the myelographies of dogs with presumptive AHNCNPE and were compared with the corresponding MRI features. Percentage of extruded volume of nucleus pulposus (VNP) was calculated on MR images. Myelographic interobserver agreement for presumptive diagnosis of AHNCNPE was almost perfect (κ=0.8). Accuracy of myelography to detect site of herniation was 80.9 per cent and to identify extradural compression was 57.1 per cent. Mean SCC was 5.8±2.6 per cent for myelography and 6.6±3 per cent for MRI. Mean LL:L2 ratio was 1.7±0.9 for myelography and 1.2±0.8 for MRI. Mean percentage of extruded VNP was 40±14 per cent, and it was positively associated with neurological grade.

Dural tear and myelomalacia caused by an airgun pellet in a cat.

An 8-year-old cat was presented with severe neurological deficits secondary to a traumatic cervical spinal cord injury caused by an airgun pellet. This report describes, for the first time, the myelographic findings of a dural rupture in a cat and also describes a bilateral Horner's syndrome in a cat.

Déchirure durale et myélomalacie causées par le plomb d'un pistolet pneumatique chez un chat. Un chat âgé de 8 ans a été présenté avec des déficits neurologiques graves secondaires à une blessure traumatique de la moelle épinière cervicale causée par le plomb d'un pistolet pneumatique. Ce rapport décrit, pour la première fois, les résultats myélographiques d'une rupture durale chez un chat et aussi un syndrome de Horner chez un chat.(Traduit par Isabelle Vallières).

Cerebellar granuloprival degeneration in an Australian kelpie and a Labrador retriever dog.

A 7-month-old Australian kelpie dog and a 14-month-old Labrador retriever dog were diagnosed with an uncommon form of cerebellar abiotrophy called cerebellar granuloprival degeneration. This was characterized by a loss of the granular neurons with relative sparing of the Purkinje neurons.

Dégénérescence cérébelleuse granuloprive chez un chien Kelpie australien et un chien Labrador retriever. Un chien Kelpie australien âgé de 7 mois et un chien Labrador retriever âgé de 14 mois ont été diagnostiqués avec une forme rare d'abiotrophie cérébelleuse appelée dégénérescence cérébelleuse granuloprive. Elle a été caractérisée par la perte de neurones granulaires en épargnant en grande partie les neurones de Purkinje.(Traduit par Isabelle Vallières).

Chronic hypertrophic ganglioneuritis mimicking spinal nerve neoplasia: clinical, imaging, pathologic findings, and outcome after surgical treatment.

OBJECTIVE: To report the clinical, imaging, pathologic findings, surgical planning, and long-term outcome after surgery in a dog with neurologic deficits because of a hypertrophic ganglioneuritis that compressed the spinal cord. STUDY DESIGN: Clinical report. ANIMAL: An 8-year-old male intact Yorkshire terrier. METHODS: The dog had ambulatory tetraparesis and neurologic examination was consistent with a C1-C5 myelopathy. Magnetic resonance imaging (MRI) revealed enlargement of the left C2 spinal nerve causing compression of the spinal cord. The main differential diagnosis was spinal nerve neoplasia with compression and possibly spinal cord invasion. On ultrasonography, there was enlargement of the spinal nerve and fine needle aspiration did not show evidence of neoplasia. Fascicular biopsy of the spinal nerve was consistent with enlargement because of chronic inflammation (hypertrophic neuritis). RESULTS: Hemilaminectomy followed by durotomy and rhizotomy allowed resection of an intradural-extramedullary mass that was the enlarged left C2 spinal nerve. Histopathology was consistent with a hypertrophic ganglioneuritis. Thirteen months later the dog remained free of clinical signs. CONCLUSION: Hypertrophic neuritis affecting the spinal nerves may be misdiagnosed as spinal nerve neoplasia that in dogs is usually malignant with a poor prognosis. Focal spinal nerve lesions with compression of the spinal cord evident on MRI may be inflammatory and are not necessarily a neoplastic condition.

Imaging diagnosis-magnetic resonance imaging findings of an intracranial epidural tuberculoma in a dog.

Magnetic resonance (MR) imaging is highly sensitive for detecting tuberculomas in human patients but the specificity of the MR imaging features is low. Misdiagnosis with intracranial neoplasia is common, especially with dural-based lesions or lesions located in the epidural space. We describe the MR imaging characteristics of an intracranial epidural tuberculoma caused by Mycobacterium tuberculosis infection in a dog. The intracranial mass and skull flat bone lysis and erosion are similar to those described in human caseating tuberculomas and can mimic intracranial neoplastic disease.

Magnetic resonance imaging findings in 40 dogs with histologically confirmed intracranial tumours.

Magnetic resonance (MR) images of 40 dogs with histologically confirmed primary and secondary intracranial tumours were reviewed. Forty-one tumours were diagnosed by means of MR imaging (MRI). MRI findings allowed diagnosis of a neoplastic lesion in 37/41 cases. Based on MRI features, differentiation between neoplastic and non-neoplastic lesions was possible in 24/27 (89%) primary brain tumours and in 13/14 (92%) secondary brain tumours. Diagnosis of tumour type based on MRI features was correct in 19/27 (70%) primary tumours and in 13/14 secondary tumours. The results of this study show that MRI is a good diagnostic imaging modality to detect neoplastic lesions and to diagnose tumour type in dogs. However, as some neoplasms show equivocal MRI features the technique has limitations in the detection of some intracranial tumours and in predicting tumour type.

Acute postretinal blindness: ophthalmologic, neurologic, and magnetic resonance imaging findings in dogs and cats (seven cases).

OBJECTIVE: To describe the ophthalmologic, neurologic, and magnetic resonance imaging (MRI) findings of seven animals with acute postretinal blindness as sole neurologic deficit. METHODS: Medical records were reviewed to identify dogs and cats with postretinal blindness of acute presentation, that had a cranial MRI performed as part of the diagnostic workup. Only animals lacking other neurologic signs at presentation were included. Complete physical, ophthalmic, and neurologic examinations, routine laboratory evaluations, thoracic radiographs, abdominal ultrasound, electroretinography, and brain MRI were performed in all animals. Cerebrospinal fluid analysis and postmortem histopathologic results were recorded when available. RESULTS: Four dogs and three cats met the inclusion criteria. Lesions affecting the visual pathways were observed on magnetic resonance (MR) images in six cases. Location, extension, and MRI features were described. Neuroanatomic localization included: olfactory region with involvement of the optic chiasm (n = 4), pituitary fossa with involvement of the optic chiasm and optic tracts (n = 1), and optic nerves (n = 1). Of all lesions detected, five were consistent with intracranial tumors (two meningiomas, one pituitary tumor, two nasal tumors with intracranial extension), and one with bilateral optic neuritis that was confirmed by cerebrospinal fluid analysis. Histologic diagnosis was obtained in four cases and included one meningioma, one pituitary carcinoma, one nasal osteosarcoma, and one nasal carcinoma. CONCLUSIONS: Central nervous system (CNS) disease should be considered in dogs and cats with acute blindness, even when other neurologic deficits are absent. This study emphasizes the relevance of MRI as a diagnostic tool for detection and characterization of CNS lesions affecting the visual pathways.

Imaging diagnosis--cervical spine chondroma in a dog.

An extradural chondroma originating in the cervical spine was diagnosed in an 8-year-old, intact male Chow-Chow that presented acute cervical pain and chronic right thoracic limb lameness. Myelographic images were within normal limits. With magnetic resonance (MR) imaging, an extradural mass was identified at the level of the C4-C5 vertebrae. This mass was excised, and the histologic diagnosis was chondroma. Fifteen months after surgery, the dog was clinically normal, and no regrowth of the mass was identified on follow-up MR images. Spinal chondromas are rare tumors in the dog, but should be considered as a rule out for contrast-enhancing extradural vertebral masses.

Combined use of surgery and radiation in the treatment of an intradural myxoid liposarcoma in a dog.

An intradural-extramedullary myxoid liposarcoma of the high cervical spine was diagnosed in a 9-year-old, spayed female Cavalier King Charles spaniel that was presented for a 2-month history of cervical pain and tetraparesis. Radiation therapy applied after surgery resulted in complete remission of the neurological deficits. The tumor recurred 18 months after surgical excision. A second surgery and another course of radiotherapy again resulted in complete remission of the clinical signs. The dog was euthanized 11 months after the second surgery because of tumor recurrence.