Magnetic resonance imaging features of cervical stenotic myelopathy in 21 dogs.

The cervical spine of 21 dogs with clinical signs of cervical stenotic myelopathy was evaluated using magnetic resonance (MR) imaging. Spin echo T1, T2 and gradient echo T2 weighted images were obtained with a 1.5 Tesla magnet in 12 dogs and a 1.0 Tesla magnet in 9 dogs. Sagittal or parasagittal T1W and T2W images were helpful in determining the presence of spinal cord compression or degenerative disease of the articular processes. Transverse T1W and T2W images were the most useful for the identification of dorsolateral spinal cord compression secondary to soft tissue and ligament hypertrophy, as well as synovial cysts, associated with the articular processes. The MR imaging findings were consistent with the surgical findings in all 14 dogs that underwent surgery. Magnetic resonance imaging provided a safe, non-invasive method of evaluating the cervical spine in dogs suspected of having cervical stenotic myelopathy. Veterinary

Vertebrectomy, bone allograft fusion, and antitumor vaccination for the treatment of vertebral fibrosarcoma in a dog.

OBJECTIVE: To describe the surgical technique of vertebrectomy with bone allograft fusion and the use of antitumor vaccine for the treatment of a primary vertebral neoplasm in a dog. STUDY DESIGN: Case Report. ANIMALS OR SAMPLE POPULATION: A 3 year old 32 kg female spayed mixed breed dog with progressive paraplegia. METHODS: Myelography was performed to identify an L5 lytic lesion with spinal cord compression. A dorsal laminectomy was performed to decompress the spinal cord and obtain biopsies. Pathologic fracture of the vertebral body two days later was treated with L5 vertebrectomy, cortical allograft implantation, and bilateral plating from L4 to L6. Tumor samples were used to create an autologous cytokine-gene-engineered tumor cell vaccine. Recheck radiographs and neurologic examinations were obtained 1, 2, 7, and 13 months after surgery. RESULTS: The histopathologic diagnosis was fibrosarcoma. Although slight osteopenia of the allograft was noted thirteen months after surgery, the allograft and plate fixation remained stable. The patient tolerated the antitumor vaccination protocol well. Two years after the procedures the dog was able to ambulate normally but remained urinary and fecal incontinent. CONCLUSIONS AND CLINICAL RELEVANCE: Vertebrectomy and cortical allograft implantation with plating permitted this patient to return to a functional lifestyle with its owners.

Magnetic resonance imaging of a choroid plexus carcinoma and meningeal carcinomatosis in a dog.

A 6-year-old neutered female Boston Terrier had a slow onset of blindness and behavior changes. Neurologic abnormalities included bilateral visual loss with absent menace responses and visual tracking, mydriatic pupils, slow pupillary light responses and papilledema. On magnetic resonance imaging (MRI) there were multiple cyst-like structures found in the parenchyma of the cerebrum, cerebellum and brainstem. Histopathologically the diagnosis was a choroid plexus carcinoma with meningeal carcinomatosis. The findings differ from previous descriptions of the MRI characteristics of choroid plexus tumors.

Magnetic resonance imaging of the cervical spine in 27 dogs.

The cervical spine of 27 dogs with cervical pain or cervical myelopathy was evaluated using magnetic resonance imaging (MRI). Spin echo T1, T2, and post-contrast T1 weighted imaging sequences were obtained with a 0.5 Tesla magnet in 5 dogs and a 1.5 Tesla magnet in the remaining 22 dogs. MRI provided for visualization of the entire cervical spine including the vertebral bodies, intervertebral discs, vertebral canal, and spinal cord. Disorders noted included intervertebral disc degeneration and/or protrusion (12 dogs), intradural extramedullary mass lesions (3 dogs), intradural and extradural nerve root tumors (3 dogs), hydromyelia/syringomyelia (1 dog), intramedullary ring enhancing lesions (1 dog), extradural synovial cysts (1 dog), and extradural compressive lesions (3 dogs). The MRI findings were consistent with surgical findings in 18 dogs that underwent surgery. Magnetic resonance imaging provided a safe, useful non-invasive method of evaluating the cervical spinal cord.

Cervical myelopathy associated with extradural synovial cysts in 4 dogs.

Three Mastiffs and 1 Great Dane were presented to the University of Wisconsin Veterinary Medical Teaching Hospital for cervical myelopathy based on history and neurologic examination. All dogs were males and had progressive ataxia and tetraparesis. Degenerative arthritis of the articular facet joints was noted on survey spinal radiographs. Myelography disclosed lateral axial compression of the cervical spinal cord medial to the articular facets. Extradural compressive cystic structures adjacent to articular facets were identified on magnetic resonance imaging (1 dog). High protein concentration was the most important finding on cerebrospinal fluid analysis. Dorsal laminectomies were performed in all dogs for spinal cord decompression and cyst removal. Findings on cytologic examination of the cystic fluid were consistent with synovial fluid, and histopathologic results supported the diagnosis of synovial cysts. All dogs are ambulatory and 3 are asymptomatic after surgery with a follow-up time ranging from 1 to 8 months. This is the 1st report of extradural synovial cysts in dogs, and synovial cysts should be a differential diagnosis for young giant breed dogs with cervical myelopathy.

Selective intraarterial gene delivery into a canine meningioma.

OBJECT: The goal of this study was to evaluate gene delivery to a benign brain tumor. METHODS: A recombinant adenovirus vector bearing the Escherichia coli beta-galactosidase reporter gene was selectively injected into the vascular supply of a spontaneously occurring canine olfactory groove meningioma. The tumor and a small amount of peritumoral brain tissue were removed 5 days after viral injection and stained with X-Gal to assess gene delivery. The authors noted significant beta-galactosidase gene expression by the tumor, but not by surrounding brain tissue. No obvious viral-related cytotoxicity was noted. CONCLUSIONS: The authors found that meningiomas can be successfully transduced by adenovirus vectors by using endovascular techniques.

Evaluation of fibular head transposition, lateral fabellar suture, and conservative treatment of cranial cruciate ligament rupture in large dogs: a retrospective study.

Sixty-one large dogs (weighing 22.7 kg or more) with cranial cruciate ligament ruptures (CCLRs) were treated with either fibular head transpositions (FHTs; n = 22 stifles), lateral fabellar sutures (LFSs; n = 39 stifles), or conservatively (CT; n = 11 stifles) with rest and aspirin. Based on owner evaluation, dogs treated with FHTs or CT did not perform as well as dogs treated with LFSs (p less than 0.05). There was no difference in owner evaluation scores for the dogs treated with FHTs or CT. Thirty dogs were reevaluated by investigators. No differences between treatment groups regarding age, sex, or time until diagnosis were noted. No differences in scores for lameness, stifle instability, or forceplate analysis among the treatment groups were observed. Degenerative joint disease progressed or remained severe regardless of treatment, based upon radiographic evidence.

Effects of phenobarbital administration on results of serum biochemical analyses and adrenocortical function tests in epileptic dogs.

OBJECTIVE: To determine what effects long-term phenobarbital administration to dogs with epilepsy would have on serum biochemical factors and adrenocortical function. DESIGN: Prospective, uncontrolled study. ANIMALS: Five dogs with idiopathic epilepsy. PROCEDURE: Serum total protein, albumin, total bilirubin, and cholesterol concentrations and serum alkaline phosphatase and alanine aminotransferase activities were measured before and 2 weeks, 6 months, and 12 months after initiation of phenobarbital administration. Endogenous ACTH concentration was measured, and ACTH stimulation and low-dose dexamethasone suppression tests were performed at the same time. RESULTS: Serum albumin concentration decreased in 4 of 5 dogs, and serum cholesterol concentrations decreased in all 5 dogs over the course of the study. Serum alkaline phosphatase concentration and alanine aminotransferase activities increased over time, and were greater than the upper reference limits in 4 of the 5 dogs by the end of the study. Endogenous ACTH concentration increased in all dogs but remained within reference limits. Plasma ACTH-stimulated aldosterone concentration increased over the course of the study. Plasma cortisol concentration did not suppress, after administration of dexamethasone in 1 dog after 6 and 12 months of phenobarbital administration. CLINICAL IMPLICATIONS: Although endogenous ACTH concentration should be normal in dogs receiving phenobarbital, results of ACTH stimulation and dexamethasone suppression tests may be altered. Serum albumin and cholesterol concentrations, and serum alkaline phosphatase and alanine aminotransferase activities may also be abnormal.

Congenital Neospora infection in calves born from cows that had previously aborted Neospora-infected fetuses: four cases (1990-1992).

Four dairy cows that had been successfully rebred following fetal Neospora infection and abortion were identified from 2 drylot dairies. All 4 cows had uncomplicated pregnancies with the birth of 5 full-term calves. The calves all had high precolostral serum IgG antibodies. The precolostral antibodies to Neospora sp as determined by indirect fluorescent antibody test ranged from 5,120 to 20,480, compared with maternal serum and colostral antibody titers from 320 to 1,280. Two calves had mild neurologic limb deficits. Three calves had mild nonsuppurative encephalomyelitis and Neospora organisms were found in the CNS of 3 calves. Findings indicate that repeat transplacental Neospora infections occur in cows. Additionally, calves born from cows with a history of Neospora fetal infection and abortion may have congenital Neospora infections and/or neurologic dysfunctions at birth. The Neospora indirect fluorescent antibody test appears to be a useful antemortem test for detection of calves exposed in utero to Neospora organisms.