ABSTRACT
Objective: To describe the clinical and imaging findings of 33 dogs with Brucella canis discospondylitis (BDS). Animals: 33 client owned dogs from four veterinary specialty hospitals within Colorado and Arizona with at least one positive B. canis test and spinal diagnostic imaging. Procedures: Retrospective review of signalment, physical and neurological examination findings, laboratory results, B. canis serology, and diagnostic imaging of 33 dogs with BDS. All imaging was reviewed by a board-certified veterinary neurologist. Radiographs were reviewed by a board-certified veterinary radiologist blinded to MRI and CT findings. Results: 31/33 (94%) dogs were <5 years old (median = 2.5 years, mean = 2.9 years, range 0.5-10 years). 21/29 (72%) dogs had signs of nonspecific pain, spinal pain, or lameness for >3 months (median = 6 months, mean = 8.2 months, range 5 days-4 years). Fever was seen in only 4/28 (14%) dogs. Multifocal lesions were evident on radiographs in 21/29 (72%) dogs and MRI in 12/18 (67%) dogs. Smooth, round, central end-plate lysis, defined as "hole punch" lesions, were identified radiographically in 25/29 (86%) dogs. Vertebral physitis or spondylitis without discitis was evident on MRI in 7/18 (39%) dogs. Clinical relevance: Dogs with BDS typically present at a young age with a long duration of clinical signs. Identification of radiographic "hole punch" lesions and MRI evidence of vertebral physitis, spondylitis, and paravertebral inflammation without discitis should increase suspicion for BDS. BDS may be increasing in frequency in the southwestern United States, and dogs with signs of chronic spinal pain and/or lameness should be screened for B. canis.
ABSTRACT
In humans, high-grade gliomas may infiltrate across the corpus callosum resulting in bihemispheric lesions that may have symmetrical, winged-like appearances. This particular tumor manifestation has been coined a "butterfly" glioma (BG). While canine and human gliomas share many neuroradiological and pathological features, the BG morphology has not been previously reported in dogs. Here, we describe the magnetic resonance imaging (MRI) characteristics of BG in three dogs and review the potential differential diagnoses based on neuroimaging findings. All dogs presented for generalized seizures and interictal neurological deficits referable to multifocal or diffuse forebrain disease. MRI examinations revealed asymmetrical (2/3) or symmetrical (1/3), bihemispheric intra-axial mass lesions that predominantly affected the frontoparietal lobes that were associated with extensive perilesional edema, and involvement of the corpus callosum. The masses displayed heterogeneous T1, T2, and fluid-attenuated inversion recovery signal intensities, variable contrast enhancement (2/3), and mass effect. All tumors demonstrated classical histopathological features of glioblastoma multiforme (GBM), including glial cell pseudopalisading, serpentine necrosis, microvascular proliferation as well as invasion of the corpus callosum by neoplastic astrocytes. Although rare, GBM should be considered a differential diagnosis in dogs with an MRI evidence of asymmetric or symmetric bilateral, intra-axial cerebral mass lesions with signal characteristics compatible with glioma.
ABSTRACT
BACKGROUND AND OBJECTIVES: A fiberoptic microneedle device (FMD) was designed and fabricated for the purpose of enhancing the volumetric dispersal of macromolecules delivered to the brain through convection-enhanced delivery (CED) by concurrent delivery of sub-lethal photothermal hyperthermia. This study's objective was to demonstrate enhanced dispersal of fluid tracer molecules through co-delivery of 1,064 nm laser energy in an in vivo rodent model. MATERIALS AND METHODS: FMDs capable of co-delivering fluids and laser energy through a single light-guiding capillary tube were fabricated. FMDs were stereotactically inserted symmetrically into both cerebral hemispheres of 16 anesthetized rats to a depth of 1.5 mm. Laser irradiation (1,064 nm) at 0 (control), 100, and 200 mW was administered concurrently with CED infusions of liposomal rhodamine (LR) or gadolinium-Evans blue-serum albumin conjugated complex (Gd-EBA) at a flow rate of 0.1 µl/min for 1 hour. Line pressures were monitored during the infusions. Rodents were sacrificed immediately following infusion and their brains were harvested, frozen, and serially cryosectioned for histopathologic and volumetric analyses. RESULTS: Analysis by ANOVA methods demonstrated that co-delivery enhanced volumetric dispersal significantly, with measured volumes of 15.8 ± 0.6 mm(3) for 100 mW compared to 10.0 ± 0.4 mm(3) for its fluid only control and 18.0 ± 0.3 mm(3) for 200 mW compared to 10.3 ± 0.7 mm(3) for its fluid only control. Brains treated with 200 mW co-delivery exhibited thermal lesions, while 100 mW co-deliveries were associated with preservation of brain cytoarchitecture. CONCLUSION: Both lethal and sub-lethal photothermal hyperthermia substantially increase the rate of volumetric dispersal in a 1 hour CED infusion. This suggests that the FMD co-delivery method could reduce infusion times and the number of catheter insertions into the brain during CED procedures.
