Nine dogs with Chiari malformation and syringomyelia, which were subjected to low-field magnetic resonance imaging (MRI) test, were described. The results of MRI examinations were presented. The outcomes of pharmacological therapy involving two dogs and surgical treatment of one dog were also described. The applied treatments produced positive short-term outcomes, and they eliminated the clinical symptoms of the disease.

Syringobulbia is a rare neurological disorder characterized by a fluid-filled cavity in the brainstem. In this study, clinical signs, features on magnetic resonance imaging (MRI), and the diseases present concurrently with syringobulbia were investigated in 33 small breed dogs. Most dogs (97%) had concurrent syringomyelia, and some dogs (24%) presented with vestibular or cranial nerve symptoms associated with the medulla oblongata. MRIs revealed slit-like, bulbous, and vertical linear shapes of the cavities on T2-weighted hyperintense and T1-weighted hypointense signals similar to the cerebrospinal fluid. Chiari-like malformations were identified in all dogs. This study highlights the association of syringobulbia with syringomyelia and Chiari-like malformations in small breed dogs with or without brainstem-associated clinical signs.

The present study aimed to describe the normal cross sectional anatomy and magnetic resonance imaging of pastern and coffin joints in dromedary camel. This study was conducted on twelve distal limbs (fore and hind) of fresh cadavers from three adult camels of both sexes. The specimens appeared normal without orthopedic disorders. Twelve distal limbs were scanned using a 1 Tesla MRI scanner and then injected with colored latex to be sectioned into sagittal, dorsal and transverse slices. Cross anatomical sections were matched with their corresponding MR images for identification and evaluation of the clinically relevant anatomical structures that appeared with different signal intensities on MRI scans. The present study showed that all major soft tissues in pastern and coffin joints of camel were clearly depicted on MR images, however, the palmar/plantar ligaments of pastern joint and ligaments of navicular cartilage could not be identified on MR images. The annotated cross anatomical sections with the corresponding MR images could be used as a normal reference for interpretation of some clinical diseases in pastern and coffin joints of camel.

OBJECTIVE To characterize the MRI and histologic features of the supraspinatus tendon in nonlame dogs. ANIMALS 7 cadavers (14 shoulder joints) of nonlame 2-year-old sexually intact male Beagles. PROCEDURES Multiple MRI fluid-sensitive pulse sequences were obtained for both shoulder joints of each cadaver, and the thickness, volume, and signal intensity of each supraspinatus tendon were assessed. After MRI scanning was complete, the shoulder joints were processed for histologic examination. Tissue specimens were stained with various stains to determine tendon morphology and composition. Histologic and MRI findings were correlated and described. RESULTS All supraspinatus tendons had a trilaminar appearance on sagittal and transverse MRI images, which was characterized by a thick, hyperintense center layer (central substance) sandwiched between thin hypointense superficial and deep margins. The mean ± SD central substance-to-superficial margin and central substance-to-deep margin thickness ratios were 8.4 ± 1.2 and 9.0 ± 0.9, respectively; supraspinatus tendon-to-triceps brachii muscle signal intensity ratio was 1.3 ± 0.2; and tendon volume was 445 ± 20 mm3. The superficial and deep margins histologically resembled other tendons with highly ordered collagen fibers. The central substance was comprised of water-rich glycosaminoglycans interspersed among haphazardly arranged collagen bundles. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated histologically normal canine supraspinatus tendons have a trilaminar appearance on MRI images. In dogs, a diagnosis of supraspinatus tendinosis should not be based solely on the tendon having a hyperintense signal on MRI images; other MRI evidence of shoulder joint disease and diagnostic findings are necessary to support such a diagnosis.

OBJECTIVE To acquire MRI diffusion data (apparent diffusion coefficient [ADC] and fractional anisotropy [FA] values, including separate measures for gray and white matter) at 3.0 T for multiple locations of the brain of neurologically normal dogs. ANIMALS: 13 neurologically normal dogs recruited from a group of patients undergoing tibial plateau leveling osteotomy. PROCEDURES: MRI duration ranged from 20 to 30 minutes, including obtaining preliminary images to exclude pathological changes (T2-weighted fluid-attenuated inversion recovery transverse and dorsal images) and diffusion-weighted images., RESULTS: Globally, there were significant differences between mean values for gray and white matter in the cerebral lobes and cerebellum for ADC (range of means for gray matter, 0.8349 × 10(−3) s/mm2 to 0.9273 × 10(−3) s/mm2; range of means for white matter, 0.6897 × 10(−3) s/mm2 to 0.7332 × 10(−3) s/mm2) and FA (range of means for gray matter, 0.1978 to 0.2364; range of means for white matter, 0.5136 to 0.6144). These values also differed among cerebral lobes. In most areas, a positive correlation was detected between ADC values and patient age but not between FA values and patient age. CONCLUSIONS AND CLINICAL RELEVANCE: Cerebral interlobar and cerebellar diffusion values differed significantly, especially in the gray matter. Information about diffusion values in neurologically normal dogs may be used to diagnose and monitor abnormalities and was the first step in determining the clinical use of diffusion imaging. This information provided an important starting point for the clinical application of diffusion imaging of the canine brain.

OBJECTIVE To evaluate the usefulness of diffusion and perfusion MRI of the cerebrum in cats with familial spontaneous epilepsy (FSECs) and identify microstructural and functional deficit zones in affected cats. ANIMALS 19 FSECs and 12 healthy cats. PROCEDURES Diffusion-weighted, diffusion tensor, and perfusion-weighted MRI of the cerebrum were performed during interictal periods in FSECs. Imaging findings were compared between FSECs and control cats. Diffusion (apparent diffusion coefficient and fractional anisotropy) and perfusion (relative cerebral blood volume [rCBV], relative cerebral blood flow [rCBF], and mean transit time) variables were measured bilaterally in the hippocampus, amygdala, thalamus, parietal cortex gray matter, and subcortical white matter. Asymmetry of these variables in each region was also evaluated and compared between FSECs and control cats. RESULTS The apparent diffusion coefficient of the total amygdala of FSECs was significantly higher, compared with that of control cats. The fractional anisotropy of the right side and total hippocampus of FSECs was significantly lower, compared with that of control cats. The left and right sides and total hippocampal rCBV and rCBF were significantly lower in FSECs than in control cats. The rCBV and rCBF of the parietal cortex gray matter in FSECs were significantly lower than in control cats. CONCLUSIONS AND CLINICAL RELEVANCE In FSECs, diffusion and perfusion MRI detected microstructural changes and hypoperfusion (lowered function) in the cerebrum during interictal periods from that of healthy cats. These findings indicated that diffusion and perfusion MRI may be useful for noninvasive evaluation of epileptogenic foci in cats.

OBJECTIVE To evaluate the usefulness of autologous bone marrow–derived mesenchymal stem cell (BM-MSC) therapy for the treatment of dogs with experimentally induced acute kidney injury. ANIMALS 6 healthy dogs. PROCEDURES After induction of kidney injury (day 0) with cisplatin (5 mg/kg, IV), dogs immediately received saline (0.9% NaCl) solution (10 mL; n = 3) or BM-MSCs (1 × 106 cells/kg in 10 mL of saline solution; 3) IV. A CBC, serum biochemical analysis, and urinalysis were performed for each dog before administration of cisplatin and on days 1 through 4. Glomerular filtration rate was determined for all dogs on days −7 and 2; BM-MSC tracking by MRI was performed on BM-MSC–treated dogs on days −14 and 4. After sample collection and BM-MSC tracking on day 4, all dogs were euthanized; kidney tissue samples underwent histologic evaluation, immunohistochemical analysis, and cytokine profiling via reverse transcriptase PCR assays. RESULTS Kidney tissue from both groups had mononuclear inflammatory cell infiltration, tubular necrosis, dilated tubules, and glomerular damage. However, there was less fibrotic change and increased proliferation of renal tubular epithelial cells in the BM-MSC-treated dogs, compared with findings for the control dogs. Expressions of tumor necrosis factor-α and transforming growth factor-β were lower in the BM-MSC-treated group, compared with findings for the control group. Laboratory data revealed no improvement in the renal function in BM-MSC-treated dogs. CONCLUSIONS AND CLINICAL RELEVANCE Results of this study suggested that autologous BM-MSCs may accelerate renal regeneration after experimentally induced acute kidney injury in dogs.

OBJECTIVE To characterize and compare gait variables in Doberman Pinschers with and without cervical spondylomyelopathy (CSM). ANIMALS 18 Doberman Pinschers (9 clinically normal dogs and 9 CSM-affected dogs). PROCEDURES A neurologic examination was performed on all dogs. The diagnosis of CSM was confirmed with MRI. Temporospatial and kinetic gait variables were measured by use of a pressure-sensitive walkway. Temporospatial variables evaluated included stance phase duration, swing phase duration, gait cycle duration, stride length, and gait velocity. Kinetic variables evaluated included peak vertical force and vertical impulse. Random-effects linear regression was used to determine the difference between CSM-affected and clinically normal dogs for each of the 7 variables. RESULTS Values for temporospatial variables were significantly smaller in the thoracic limbs of CSM-affected dogs, compared with values for the thoracic limbs of clinically normal dogs. For the kinetic variables, peak vertical force was significantly higher in the thoracic limbs than the pelvic limbs for all dogs. Vertical impulse values were higher in the thoracic limbs than the pelvic limbs. There were significant differences in mean vertical impulse between the thoracic and pelvic limbs for both groups. CONCLUSIONS AND CLINICAL RELEVANCE In this study, significant differences in temporospatial variables were identified between the thoracic limbs of clinically normal and CSM-affected dogs, with the values being smaller for the CSM-affected dogs than for the clinically normal dogs. A pressure-sensitive walkway may provide a valid, practical option for rapid, objective assessment of gait and response to treatment in dogs with CSM.

OBJECTIVE To develop a novel method for use of diagnostic imaging, finite element analysis (FEA), and simulated biomechanical response behavior of brain tissue in noninvasive assessment and estimation of intracranial pressure (ICP) of dogs. SAMPLE MRI data for 5 dogs. PROCEDURES MRI data for 5 dogs (1 with a geometrically normal brain that had no detectable signs of injury or disease and 4 with various degrees of geometric abnormalities) were obtained from a digital imaging archiving and communication system database. Patient-specific 3-D models composed of exact brain geometries were constructed from MRI images. Finite element analysis was used to simulate and observe patterns of nonlinear biphasic biomechanical response behavior of geometrically normal and abnormal canine brains at various levels of decreasing cerebral perfusion pressure and increasing ICP. RESULTS Changes in biomechanical response behavior were detected with FEA for decreasing cerebral perfusion pressure and increasing ICP. Abnormalities in brain geometry led to observable changes in deformation and biomechanical response behavior for increased ICP, compared with results for geometrically normal brains. CONCLUSIONS AND CLINICAL RELEVANCE In this study, patient-specific critical ICP was identified, which could be useful as a method to predict the onset of brain herniation. Results indicated that it was feasible to apply FEA to brain geometry obtained from MRI data of clinical patients and to use biomechanical response behavior resulting from increased ICP as a diagnostic and prognostic method to noninvasively assess or classify levels of brain injury in clinical veterinary settings.

Objective—To construct and optimize a fiducial marker suitable for both CT and MRI. Sample—Fiducial markers containing serial dilutions of iopamidol mixed with water. Procedures—IV tubing sets were infused with serial dilutions (0% to 100%; increments of 10%) of iopamidol. Tubing ends were sealed; additional seals were added to create an equilateral triangle. A reference point was created by placing a crimp in 1 side. Markers were fixed to a gelatin soft tissue–attenuating phantom and evaluated by use of CT and MRI. For CT, simple linear regression analysis was used to assess the relationship between the percentage of marker contrast medium and quantitative variables, including marker attenuation, attenuation changes in the phantom, and beam-hardening artifact length. A subjective grading scheme for artifact creation on CT images and marker visibility on MRI images was used. Measurements were obtained by investigators who were unaware of the contents of each marker. Results—Percentage of contrast medium in each marker was strongly correlated with marker attenuation (r2 = 0.96), artifact length (r2 = 0.765), and mean attenuation changes within the phantom (r2 = 0.826) for CT. Subjective CT scores indicated that concentrations of contrast medium > 50% resulted in excessive artifacts. Markers with concentrations of iopamidol > 50% had poor subjective MRI visibility scores. No artifacts were seen on MRI. Conclusions and Clinical Relevance—A marker containing a 10% solution of iodinated contrast medium mixed with water provided ideal contrast for both CT and MRI.