Ultrasonography and digital radiography findings in sheep with clinical disease associated with small ruminant lentivirus infection.

Digital radiography and ultrasonographic images were used in this case series to evaluate 4 ewes from a single flock for chronic weight loss and ill-thrift. On examination, all displayed tachypnea, dyspnea, coughing, and normothermia with abnormal thoracic auscultations. Three of the 4 animals were diagnosed with chronic respiratory disease associated with Maedi-visna (MV) infection confirmed via serologic testing. Diagnostic thoracic imaging identified characteristics consistent with pathological lesions associated with interstitial pneumonia in the 3 MV affected animals; these findings were absent in the animal that tested negative for MV. Key clinical message: Diagnostic imaging may be useful to clinicians looking to obtain further visualization of lung pathologies and as a reliable means of detecting thoracic lesions indicative of interstitial pneumonia on-farm. These results can be used to aid the practitioner in determining appropriate further diagnostic testing and treatment strategies while awaiting confirmatory test results for diagnosis of MV.

Résultats de l'échographie et de la radiographie numérique chez des ovins atteints d'une maladie clinique associée à une infection à lentivirus des petits ruminants. La radiographie numérique et les images échographiques ont été utilisées dans cette série de cas pour évaluer quatre brebis d'un seul troupeau présentant une perte de poids chronique et un retard de croissance. À l'examen, tous les animaux présentaient une tachypnée, une dyspnée, une toux et étaient normothermiques avec des auscultations thoraciques anormales. Trois des quatre animaux ont été diagnostiqués avec une maladie respiratoire chronique associée à une infection Maedi-visna (MV) confirmée via des tests sérologiques. L'imagerie thoracique diagnostique a identifié des caractéristiques compatibles avec des lésions pathologiques associées à une pneumonie interstitielle chez les trois animaux atteints de MV; ces résultats étaient absents chez l'animal qui a été testé négatif pour MV.Message clinique clé :L'imagerie diagnostique peut être utile aux cliniciens qui cherchent à obtenir une visualisation plus poussée des pathologies pulmonaires et comme un moyen fiable de détecter les lésions thoraciques indiquant une pneumonie interstitielle à la ferme. Ces résultats peuvent être utilisés pour aider le praticien à déterminer d'autres tests de diagnostic appropriés et des stratégies de traitement en attendant les résultats des tests de confirmation pour le diagnostic de MV.(Traduit par Dr Serge Messier).

Computed tomography evaluation of proposed implant corridors in canine thoracic vertebrae.

OBJECTIVE: Identify acceptable implant corridors in the normal canine thoracic vertebrae (T) from T1 to T9. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Computed tomographic (CT) studies of normal canine thoracic spines (n = 39). METHODS: CT imaging studies of normal T1-T9 canine spines were evaluated by five independent observers. Each identified a proposed corridor, measured the width, length, and angle off mid-sagittal that the corridor occupied. RESULTS: CT studies were from 39 dogs weighing 3.19-60 kg (mean 10.72, SD 9.9 kg). Vertebral corridors ranged in average width from 3.8 to 5.2 mm, the widest being located at T1. They ranged in average length from 13.3 to 17.5 mm, shortest being T1 and longest being T6. The angle of corridors varied the most between individual vertebrae at T1-T3. The average corridor angles were: T1 = 38°, T2 = 32°, T3 = 27°, T4 = 26°. T5-T9 angle ranged from 23° to 24°. CONCLUSION: The average dimensions of corridors measured in dogs weighing 3.1-60 kg were consistent with those of commercially available cortical screws and pins. CLINICAL SIGNIFICANCE: Corridor trajectories identified in this population can be achieved from a dorsal approach between T5 and T9. A dorsal approach for implant placement would be challenging for T1-T4 due to the variability found in these vertebrae as well as regional anatomical constraints.

Influence of plate type and placement on the immobilization of bilateral equine mandibular osteotomies: Ex vivo study.

OBJECTIVE: To determine the influence of plate fixation (locking or dynamic compression) and the site of application (ventral [V] or ventrolateral [VL]) on the resistance to bending of transverse mandibular fractures. STUDY DESIGN: Ex vivo, simple randomized study. SAMPLE POPULATION: Mandibles harvested from adult equine cadavers (n = 18). METHODS: Bilateral osteotomies were created 1 cm caudal to the mental foramen and perpendicular to the long axis of each mandible. Mandibles were fixed with 1 of 3 methods: (1) VL dynamic compression plate (DCP), (2) V-DCP, or (3) VL locking compression plating (LCP). Constructs were mounted on a custom testing jig and tested for resistance in bending by applying force to the rostral aspect of the mandible. Stiffness and change of distance of the dorsal osteotomy at 200 N were compared among constructs. RESULTS: VL-LCP constructs were 5.25 and 2.42 times stiffer than V and VL constructs, respectively (P<.001). Change in the width of the osteotomy gap at 200 N of load was reduced 6.04 times when osteotomies were stabilized with VL compared to V (P<.001); no difference was detected between the VL and VL-LCP constructs (P=.836). CONCLUSION: Ventrolateral LCP fixation of equine transverse mandibular osteotomies provided greater resistance to bending compared with V and VL constructs. CLINICAL SIGNIFICANCE: These results provide evidence to recommend fixation of transverse interdental mandibular fractures with VL-LCP rather than with DCP in horses.

SINGLE-SHOT TURBO SPIN ECHO PULSE SEQUENCE FINDINGS IN DOGS WITH AND WITHOUT PROGRESSIVE MYELOMALACIA.

Progressive myelomalacia is an uncommon type of ischemic, hemorrhagic spinal cord infarction. Diagnosis can be difficult, but prompt recognition is important. We hypothesized that cerebrospinal fluid signal attenuation on magnetic resonance (MR) images would be more extensive in dogs that developed progressive myelomalacia vs. control dogs. A retrospective analytic cohort study was designed. Dogs were included if they presented for acute paraplegia and loss of deep pain perception and had undergone MR imaging using both sagittal single-shot turbo spin echo (SSTSE) and standard sagittal T2-weighted fast spin echo (T2W) pulse sequences. Dogs were divided into progressive myelomalacia and control groups for comparisons. All MR examinations were evaluated by three reviewers blinded to patient outcome. Length of cerebrospinal fluid attenuation was recorded as a ratio to the length of the L2 vertebral body in SSTSE and T2W sequences (CSF:L2SSTSE and CSF:L2T2 , respectively). Length of intramedullary spinal cord hyperintensity was recorded as a ratio to the length of the L2 vertebral body in T2W sequences. A total of 21 dogs were included (five in the progressive myelomalacia group and 16 in the control group). The mean CSF:L2SSTSE attenuation value was significantly higher in dogs that developed progressive myelomalacia (CSF:L2SSTSE = 10.7) compared to controls (CSF:L2SSTSE = 5.4; P = 0.015). A cut off ratio of attenuation >7.4 provided optimal differentiation between groups in this study. Findings supported the conclusion that dogs with CSF:L2SSTSE ≤ 7.4 are unlikely to develop progressive myelomalacia while dogs with CSF:L2SSTSE > 7.4 are indeterminate for progressive myelomalacia.

IATROGENIC MICROCHIP ARTERIAL EMBOLISM IN A CHILEAN FLAMINGO (PHOENICOPTERUS CHILENSIS).

Aberrant microchip migration has been reported in domestic animal species, but in most cases, this migration is atraumatic to the patient. Reports of microchip-associated trauma and sarcoma development also have been reported in a variety of mammal species. This report describes accidental arterial microchip insertion causing obstruction of the iliac artery in a Chilean flamingo (Phoenicopterus chilensis). Diagnostic imaging included digital radiography and pre- and post-contrast computed tomography to determine the location of the microchip. Surgical removal of the microchip was attempted; however, the flamingo died intraoperatively. Postmortem evaluation found trauma to the epicardium, without penetration of the ventricle. The descending aorta was found traumatized and identified as the most likely insertion point leading to the embolism.

COMPARISON OF FLUOROSCOPY AND COMPUTED TOMOGRAPHY FOR TRACHEAL LUMEN DIAMETER MEASUREMENT AND DETERMINATION OF INTRALUMINAL STENT SIZE IN HEALTHY DOGS.

Tracheal collapse is a progressive airway disease that can ultimately result in complete airway obstruction. Intraluminal tracheal stents are a minimally invasive and viable treatment for tracheal collapse once the disease becomes refractory to medical management. Intraluminal stent size is chosen based on the maximum measured tracheal diameter during maximum inflation. The purpose of this prospective, cross-sectional study was to compare tracheal lumen diameter measurements and subsequent selected stent size using both fluoroscopy and CT and to evaluate inter- and intraobserver variability of the measurements. Seventeen healthy Beagles were anesthetized and imaged with fluoroscopy and CT with positive pressure ventilation to 20 cm H2 O. Fluoroscopic and CT maximum tracheal diameters were measured by three readers. Three individual measurements were made at eight predetermined tracheal sites for dorsoventral (height) and laterolateral (width) dimensions. Tracheal diameters and stent sizes (based on the maximum tracheal diameter + 10%) were analyzed using a linear mixed model. CT tracheal lumen diameters were larger compared to fluoroscopy at all locations (P-value < 0.0001). When comparing modalities, fluoroscopic and CT stent sizes were statistically different. Greater overall variation in tracheal diameter measurement (height or width) existed for fluoroscopy compared to CT, both within and among observers. The greater tracheal diameter measured with CT and lower measurement variability has clinical significance, as this may be the imaging modality of choice for appropriate stent selection to minimize complications in veterinary patients.

Successful medical treatment of an orbital osteoma in a dog.

A 6-year-old neutered male German Shepherd-mixed breed with a 2-month history of bilateral conjunctival hyperemia, epiphora, and a firm, slowly progressive swelling of the medial canthal region of the left eye (OS) was examined. Ophthalmic examination OS revealed a firm and smooth mass, extending from the medial canthus toward the medial orbital wall. Indirect ophthalmoscopy revealed indentation of the nasal part OS, which corresponded to the position of the orbital mass. Orbital neoplastic diseases were the main differential considerations. Computerized tomography revealed a bony smooth orbital mass without bone destructive features. Biopsy was performed, and histologic features were suggestive of osteoma. Systemic nonsteroidal anti-inflammatory (NSAID) drugs resulted in complete mass regression and absence of clinical signs for 5 years following initial diagnosis. This report describes the first case of canine orbital osteoma, which was responsive to NSAIDs.

Retroperitoneal pyogranulomatous and fibrosing inflammation secondary to fungal infections in two dogs.

CASE DESCRIPTIONS: A 4-year-old spayed female Golden Retriever (dog 1) was examined because of acute edema and erythema in the left hind limb and an inguinal mass, and a 5-year-old female Jack Russell Terrier (dog 2) was examined because of a recurring retro-peritoneal mass. CLINICAL FINDINGS: Dog 1 had an edematous, hyperemic left hind limb with a fixed inguinal mass. Monocytic neutrophilic leukocytosis and hypoalbuminemia were detected. Diagnostic imaging revealed abnormal tissue surrounding the larger vessels and ureters and complete occlusion of the left limb veins. Surgery resulted in incomplete removal of the mass. Histologic examination revealed fibrosing pyogranulomatous inflammation. Results of a Histoplasma antigen test were positive, and reanalysis of the tissues revealed yeast cells indicative of Histoplasma capsulatum. Dog 2 had incomplete removal of a retroperitoneal mass. Histologic examination revealed fibrosing pyogranulomatous inflammation. The mass recurred 8 months later in dog 2; exploratory abdominal surgery at that time resulted in substantial hemorrhage from the adhered caudal aorta. Histologic examination of tissue sections from the second surgery revealed yeast cells consistent with Blastomyces dermatitidis. TREATMENT AND OUTCOME: Both dogs had temporary improvement after surgery. Full clinical resolution required treatment for fungal disease. Dog 1 was treated with itraconazole, then fluconazole (total treatment time, 23 weeks). Dog 2 was treated with fluconazole for 36 weeks. CLINICAL RELEVANCE: Retroperitoneal pyogranulomatous fibrosis caused by fungal infections has not been reported in veterinary medicine. There was substantial morbidity, but the prognosis can be good when this abnormality is recognized and antifungal medications are administered.

Replacing the enzyme alpha-L-iduronidase at birth ameliorates symptoms in the brain and periphery of dogs with mucopolysaccharidosis type I.

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disease caused by loss of activity of α-l-iduronidase and attendant accumulation of the glycosaminoglycans dermatan sulfate and heparan sulfate. Current treatments are suboptimal and do not address residual disease including corneal clouding, skeletal deformities, valvular heart disease, and cognitive impairment. We treated neonatal dogs with MPS I with intravenous recombinant α-l-iduronidase replacement therapy at the conventional 0.58 mg/kg or a higher 1.57 mg/kg weekly dose for 56 to 81 weeks. In contrast to previous results in animals and patients treated at a later age, the dogs failed to mount an antibody response to enzyme therapy, consistent with the induction of immune tolerance in neonates. The higher dose of enzyme led to complete normalization of lysosomal storage in the liver, spleen, lung, kidney, synovium, and myocardium, as well as in the hard-to-treat mitral valve. Cardiac biochemistry and function were restored, and there were improvements in skeletal disease as shown by clinical and radiographic assessments. Glycosaminoglycan levels in the brain were normalized after intravenous enzyme therapy, in the presence or absence of intrathecal administration of recombinant α-l-iduronidase. Histopathological evidence of glycosaminoglycan storage in the brain was ameliorated with the higher-dose intravenous therapy and was further improved by combining intravenous and intrathecal therapy. These findings argue that neonatal testing and early treatment of patients with MPS I may more effectively treat this disease.

Normal canine brain maturation at magnetic resonance imaging.

The normal neonatal canine brain exhibits marked differences from that of the mature brain. With development into adulthood, there is a decrease in relative water content and progressive myelination; these changes are observable with magnetic resonance imaging (MRI) and are characterized by a repeatable and predictable time course. We characterized these developmental changes on common MRI sequences and identified clinically useful milestones of transition. To accomplish this, 17 normal dogs underwent MRI of the brain at various times after birth from 1 to 36 weeks. Sequences acquired were T1-weighted (T1W), T2-weighted (T2W), fluid attenuated inversion recovery, short tau inversion recovery, and diffusion weighted imaging sequences. The images were assessed subjectively for gray and white matter relative signal intensity and results correlated with histologic findings. The development of the neonatal canine brain follows a pattern that qualitatively matches that observed in humans, and which can be characterized adequately on T1W and T2W images. At birth, the relative gray matter to white matter signal intensity of the cortex is reversed from that of the adult with an isointense transition at 3-4 weeks on T1W and 4-8 weeks on T2W images. This is followed by the expected mature gray matter to white matter relative intensity that undergoes continued development to a mostly adult appearance by 16 weeks. On the fluid attenuated inversion recovery sequence, the cortical gray and white matter exhibit an additional signal intensity reversal during the juvenile period that is due to the initial high relative water content at the subcortical white matter, with its marked T1 relaxation effect.

Electrocardiography-guided and retrospective analysis of central venous catheter placement in the dog.

OBJECTIVE: To compare the success rates of central venous catheter placement (CVCP) in dogs using electrocardiograph (ECG)-guided and external landmark ('blind') techniques. To report success rates determined retrospectively of CVCPs in dogs using external landmarks at a tertiary referral institution. STUDY DESIGN: Prospective blinded comparison of techniques. Retrospective analysis of case records. ANIMALS: Adult Beagles weighing 11.9 +/- 2.6 kg were used in the experimental group (n = 38). Various breeds of dogs were in the retrospective clinical group (n = 33). METHODS: Laboratory dogs were anesthetized and CVCPs were placed using a modified Seldinger technique. Catheter tip position was first based on external landmarks and then the catheter was repositioned using an ECG-guided placement. The ECG-guided technique used the V-lead with the positive electrode attached to the guide wire. Catheter placement was determined by moving the catheter cephalad and caudad to the point of maximum p-wave amplitude and then withdrawing the catheter 1-2 cm from this point. Catheter position with each technique was determined using a lateral thoracic radiograph. Retrospective data were collected from the medical records of dogs that had CVCPs using anatomical landmarks and corresponding thoracic radiographs. RESULTS: The number of successful CVCP attempts was the same for both prospective groups (21/38). There was no statistically significant difference in success between the ECG-guided technique and the blind technique. From the retrospective investigation 10/33 of the cases that fit the criteria had correct CVCPs. CONCLUSIONS AND CLINICAL RELEVANCE: The odds of correctly placing a central venous catheter by ECG-guidance were the same as the external landmark technique. The ECG-guided technique may be useful in situations where external landmarks are not readily available.

A vascular hamartoma arising from the cervical spine of a cat.

A 15-month-old cat presented for evaluation of worsening generalized proprioceptive ataxia. Computed tomography of the cervical spine revealed the presence of a compressive extradural bony mass involving the dorsal aspect of C1. Surgical exploration and debulking of the mass was performed. Histological evaluation of the mass revealed fibrovascular tissue consistent with a vascular hamartoma. This mass was deemed to be originating from the soft tissue associated with the C1 vertebra with subsequent bony proliferation. Surgical debulking of the mass resulted in complete resolution of clinical signs with no evidence of recurrence 2 years after surgery.

The relationship between limb function and radiographic osteoarthrosis in dogs with stifle osteoarthrosis.

OBJECTIVE: To evaluate the relationship between limb function and radiographic evidence of stifle osteoarthrosis (OA) in dogs. STUDY DESIGN: The relationship between force platform data and radiographic OA score was evaluated on 2 separate days using regression analysis. Interday variation was also assessed. ANIMALS: Forty-one dogs with visible lameness and radiographic evidence of stifle OA. METHODS: Force platform data were collected at a velocity of 1.7 to 2.0 m/s for 5 trials on day 1 and day 8. Radiographs taken on day 1 were scored using a previously reported OA scoring system. RESULTS: No significant relationship was found between force platform data and OA score. No significant differences were found between any day 1 and day 8 force platform values. CONCLUSIONS: Although radiographic evidence of stifle OA provides evidence of pathology, it does a poor job of representing limb function. In addition, the absence of significant differences between day 1 and day 8 values in this population of dogs supports use of only a single force platform evaluation before measuring a treatment effect. CLINICAL RELEVANCE: The presence of OA in the stifle joint does not correlate with clinical function; radiographic outcome should be used cautiously as a predictor of clinical outcome.