Prevalence of gastroesophageal reflux in dogs undergoing MRI for a thoracolumbar vertebral column pathology.

OBJECTIVES: The aims of the study were to investigate the prevalence and extent of gastroesophageal reflux, and the prevalence of regurgitation in dogs undergoing thoracolumbar spine magnetic resonance imaging, and to explore possible associations of reflux and regurgitation with signalment (breed, age, sex, neuter status), bodyweight, body condition score and drugs used in the anaesthetic protocol. MATERIALS AND METHODS: The thoracic part of the oesophagus was retrospectively assessed for presence and quantification of fluid on two T2 weighted sequences. Patient breed, age, sex, neuter status, weight and body condition score were recorded. Anaesthetic records were reviewed for the presence of regurgitation and detailed anaesthetic protocols. RESULTS: Fifty percent (95% confidence interval: 45 to 57%) of included dogs had evidence of gastroesophageal reflux. Reflux was not associated with the individual breed, age, sex, neuter status or body weight. Brachycephalic dogs did not demonstrate significantly higher rates of reflux compared to non-brachycephalic dogs. A larger volume of reflux was associated with a higher chance of regurgitation. CLINICAL SIGNIFICANCE: Gastroesophageal reflux is a common finding in dogs undergoing thoracolumbar spine magnetic resonance imaging. Dogs which regurgitated had higher volumes of reflux. Early detection and quantification of the volume of reflux is helpful as it may allow the anaesthetist to take measures which may reduce the risk of associated complications.

The appearance of canine insulinoma on dual phase computed tomographic angiography.

OBJECTIVES: To further evaluate the appearance of insulinoma in dogs on dual-phase CT angiography, given the disparity of findings in recent publications. To establish whether CT angiographic localisation of insulinoma correlates with surgical findings. MATERIALS AND METHODS: Single centre study of dogs with a final diagnosis of insulinoma which underwent abdominal CT angiography. Scans were retrospectively re-evaluated for specific features by two board-certified veterinary radiologists. These findings were also subsequently compared to surgical and histopathological reports to determine the accuracy of lesion localisation on CT. RESULTS: Thirty-five cases were included in final analysis, with pancreatic nodules identified in 33. Twenty-one were confirmed as insulinoma with histopathology. Jack Russell Terriers were over-represented. Twenty of 21 cases with confirmed insulinoma and 27 of 33 overall showed hyperattenuation in the arterial phase. The mean size of pancreatic insulinoma on CT was 15.1 mm, and 18.2% were larger than 20 mm. Eighteen of 21 confirmed and eight of 12 suspected insulinomas caused a deformation of the pancreatic shape, with two only identified as a result of this feature as these lesions were isoattenuating throughout the study. Pancreatic insulinoma location at surgery matched that described on the CT images in 17 of 19 cases where location was described in the surgical report. CLINICAL SIGNIFICANCE: In contrast to recent publications, this study suggests hyperattenuation of insulinomas in the arterial phase is a predominant feature, and that hypoattenuation or isoattenuation are much less common. CT angiography is accurate in prediction of lesion location before surgery in most cases.

Classification of portosystemic shunts entering the caudal vena cava at the omental foramen in dogs.

OBJECTIVE: To re-evaluate the anatomy and classification of congenital extrahepatic portosystemic shunts entering the caudal vena cava at the level of the omental foramen. MATERIAL AND METHODS: A retrospective review of a consecutive series of dogs undergoing CT angiography as part of the diagnostic work-up for a congenital extrahepatic portosystemic shunt. RESULTS: In total, 53 dogs met the inclusion criteria revealing four anatomically distinct omental foramen shunt types; one of which (32 of 53 dogs) showed no shunting blood flow through the right gastric vein and three of which (21 of 53 dogs) involved shunting flow through this vessel. The anatomy of these four distinct shunt types, as defined by CT angiography, was found to be highly consistent. In all cases, regardless of the tributary vessels, the left gastric vein was the final vessel that communicated with the caudal vena cava. Using these findings, a more accurate naming classification for congenital portosystemic shunts entering the caudal vena cava at the level of the omental foramen was proposed. CLINICAL SIGNIFICANCE: A precise pre-treatment anatomical classification of congenital extrahepatic portosystemic shunts entering the caudal vena cava at the level of the omental foramen is important for a more complete understanding of the severity of clinical signs and prognosis, and for the better communication between clinicians and researchers in this clinical field.

Anatomical anomalies and variations of main thoracic vessels in dogs: a computed tomography study.

INTRODUCTION: There is scarce information about the prevalence of anomalies and anatomical variations of the main great thoracic vessels in dogs, particularly in dogs without congenital heart disease. ANIMALS: The study included 878 privately owned dogs. MATERIAL AND METHODS: Computerized tomography (CT) thoracic studies carried out between 2011 and 2014 for a variety of reasons were reviewed. The prevalence of anomalies and anatomical variations of the aorta and vena cava, the arterial branches of the aortic arch and the main branches of the intrathoracic veins in dogs with no evidence of congenital heart disease was evaluated. Poor-quality CTs, CTs with thoracic pathology that impaired visualization or those of young dogs with clinical evidence or suspicion of congenital cardiac disease were excluded. RESULTS: Eight hundred two CT studies were analysed. Eight dogs (1%) showed an anatomic anomaly. The most common anomaly was an aberrant retroesophageal right subclavian artery (n = 7, 0.8%). One dog showed a dilated azygos vein secondary to an interrupted vena cava. Three types of branching of the common carotid arteries were observed: both arteries arising at the same point (type I: n = 506/742; 68.2%), separated (type II: n = 212/742; 28.6%) or from a common trunk (type III: n = 24/742; 3.2%). CONCLUSIONS: Major anatomical variations or anomalies of the main great thoracic vessels in dogs without congenital cardiac disease were rare. An aberrant retroesophageal right subclavian artery was the most common anomaly found. Three slight variations of common carotid artery branching were identified. These findings might be of relevance for surgical or catheterization procedures.

Documenting the prevalence of hiatal hernia and oesophageal abnormalities in brachycephalic dogs using fluoroscopy.

OBJECTIVES: To report the prevalence of abnormal fluoroscopic findings in brachycephalic dogs that were presented to a referral hospital for obstructive airway syndrome. METHODS: Hospital records between May 2013 and November 2015 identified 36 brachycephalic dogs investigated for obstructive airway disease: 21 French bulldogs, six bulldogs, four Boston terriers, two pugs, two boxers and one shih-tzu. The presence or absence of hiatal hernia, delayed oesophageal transit, gastro-oesophageal reflux and redundant oesophagus were recorded. RESULTS: Of the 36 dogs, 16 had hiatal hernia, all of which were French bulldogs; 31 dogs had delayed oesophageal transit time, 27 had gastro-oesophageal reflux, and four had redundant oesophagus. CLINICAL SIGNIFICANCE: Clinical Significance: The prevalence of hiatal hernia is higher than expected in the French bulldog, and there was a high prevalence of oesophageal disease in this group in general. These results suggest a need to investigate similar cases for evidence of gastrointestinal disease that may also require attention.

Prevalence of spinous process impingement in thoracic vertebrae on radiographs of clinically-unaffected dogs.

OBJECTIVES: To assess the prevalence of impinged spinous processes in asymptomatic dogs. METHODS: One hundred and ninety lateral thoracic radiographs of asymptomatic dogs radiographed for reasons other than spinal pain, were retrospectively reviewed by two board-certified radiologists. Images were assessed for impinged spinous processes and graded for narrowing, sclerosis or remodelling of the spinous processes. RESULTS: The prevalence of impinged spinous processes in unaffected dogs was 33·2%. Seventy-five of 79 (95%) lesions were located between T8 and T11. Impingement of the spinous processes was more common in older dogs and larger dogs displayed more frequent and more severe impingement of the spinous processes compared with smaller breeds. CLINICAL SIGNIFICANCE: Spinous process impingement is common in animals with no history of spinal pain, indicating that this radiographic finding should be interpreted with caution.

Unilateral absence of the right pulmonary artery with associated aortopulmonary collaterals and bullous lung lesions in a dog.

This case report describes a combination of congenital cardiopulmonary abnormalities found in a 1-year-old Labrador Retriever. To the authors' knowledge this combination of cardiopulmonary abnormalities has not been previously reported in veterinary medicine. Unilateral absence of the right pulmonary artery associated with unilateral right-sided aortopulmonary collaterals was observed. These aortopulmonary collaterals preserved the blood supply to the right lung lobes but led to left ventricular volume overload. There was also evidence of severe bullous lung disease in the right lung, which was suspected to be secondary to pulmonary sequestration as a result of the anomalous hemi-pulmonary circulation. The diagnosis of left-sided volume overload was achieved by radiography and echocardiography while the remainder of the findings was diagnosed on computed tomography angiography. The owner refused surgery for occlusion of the shunting vessels and therapy at standard doses of benazepril, spironolactone and pimobendan was initiated. In spite of the severe volume overload, the dog remained stable with static non-progressive clinical signs and stable echocardiographic findings at 1-year follow-up. The case report also acts as a reminder of the possible occurrence of unusual extra-cardiac shunts in the presence of an unexplained left ventricular volume overload.

Inter- and intraobserver agreement in interpretation of CT features of medial coronoid process disease.

OBJECTIVES: To evaluate inter- and intraobserver reliability of the assessment of computed tomography features commonly used in the identification and classification of medial coronoid process disease and to assess inter- and intraobserver variability in the identification of the percentage ulna sclerosis from single transverse computed tomography images. METHODS: Eight observers, on two occasions, reviewed 84 standardised single transverse computed tomography images acquired at the level of the apex of the medial coronoid process. Observers assessed: medial coronoid process disease, coronoid process fragmentation, osteophytes, sclerosis grade and sclerosis delineation with normal bone defined using a sclerometer. Cohen's kappa and intraclass correlation coefficient were calculated. RESULTS: Inter-observer agreement was fair to moderate for identification of computed tomography changes consistent with medial coronoid process disease, moderate to almost perfect for fragmentation, and moderate for osteophyte detection. Agreement was poor for sclerosis grading. Percentage sclerosis measured with a sclerometer had moderate to almost perfect inter- and intraobserver agreement. CLINICAL SIGNIFICANCE: These findings suggest that subjective assessment of computed tomography images is less repeatable than more quantitative methods.

Validation of the accuracy of needle placement as used in diagnostic local analgesia of the maxillary nerve for investigation of trigeminally mediated headshaking in horses.

Diagnostic local anaesthesia of the maxillary nerve is a valuable aid in the diagnosis of trigeminally mediated headshaking in horses. Our objective is to validate the accuracy of needle placement in this procedure and to identify any correlation between accuracy of the technique and operator experience. Using a small volume of contrast medium, the procedure was performed bilaterally on 30 horse cadaver heads by three groups with different levels of experience with the technique. The location of deposition was then identified using computed tomography (CT). Contrast medium was deposited around the target site in 53.3% (32/60) of injections. An experienced operator succeeded in deposition around the target area significantly (p<0.05) more often (80%, 16/20) than did the less and non-experienced performers (40%, 16/40). A negative response to diagnostic local anaesthesia of the maxillary nerve does not disprove facial dysaesthesia as the cause of headshaking in that horse as a false negative response could arise due to failure to deposit local anaesthetic around the target area. Increased experience in performing the procedure decreases the probability of false negative results.

Computed tomographic evaluation of elbow congruity during arthroscopy in a canine cadaveric model.

OBJECTIVE: To assess the effect of arthroscope insertion, using a carbon-fibre rod model, on humero-radial, humero-ulnar and radio-ulnar congruity, as assessed by computed tomography (CT). METHODS: Cadaveric Greyhound elbow joints were assessed at a flexion angle of 135 ± 5° using CT. For condition 1, a 36 mm fulcrum induced cubital valgus, as used to aid arthroscope insertion. For conditions 2 and 3, a single 1.8 or 2.5 mm diameter rod was inserted under arthroscopic guidance to simulate arthroscope position for assessment of the medial coronoid process. Repeat CT scans were obtained for all conditions and parasagittal sections were reconstructed to evaluate medial, axial and lateral positions within the elbow. Humero-radial, humero-ulnar, and radio-ulnar congruity measurements were obtained. Differences between groups were assessed using repeated measures analysis of variance. RESULTS: Mean (±SD) change in radio-ulnar step between conditions 1 and 3 was 0.6 ± 0.3 mm (axial), 0.8 ± 0.6 mm (medial), and 0.5 ± 0.1 mm (lateral). Insertion of rods induced a significant decrease in radio-ulnar step in all planes. Significant differences were also identified between groups for humero-radial, humero-ulnar, and radio-ulnar congruity. CLINICAL SIGNIFICANCE: Insertion of carbon-fibre rods as a model for elbow arthroscope insertion induces elbow incongruity. Changes in radio-ulnar congruity are small but the effect of arthroscope diameter should be considered when assessing elbow congruity.

Prevalence of Chiari-like malformations in clinically unaffected dogs.

BACKGROUND: The importance of Chiari-like malformation (CM) in the generation of clinical signs or the formation of syringomyelia in dogs is incompletely understood, partly because the prevalence of various CM definitions in unaffected dogs is unknown. HYPOTHESIS/OBJECTIVES: The aims were: to estimate the prevalence of CM in dogs asymptomatic for CM or syringomyelia, according to 3 currently used definitions; and, to investigate the effect of brachycephaly and head position during magnetic resonance (MR) imaging on estimates of the prevalence of CM. ANIMALS: One ninety-nine client-owned dogs without apparent signs of CM or syringomyelia. METHODS: Blinded, retrospective analysis. Archived MR images were analyzed for evidence of cerebellar indentation and impaction into or herniation through the foramen magnum. Logistic regression analysis was used to investigate the relationship of CM diagnosis with head position and the cranial index (a measure of brachycephaly). RESULTS: In 185 non-Cavalier King Charles Spaniel (CKCS) dogs, indentation was identified in 44% (95% CI, 47-51%) and impaction in 22% (95% CI, 16-28%). No asymptomatic, non-CKCS dogs showed herniation. Regression analysis showed a significant increase in the odds of indentation and impaction in an extended head position and as the cranial index increased (became more brachycephalic). CONCLUSIONS AND CLINICAL IMPORTANCE: The high prevalence of cerebellar indentation and impaction suggests that they may be normal anatomical variations and therefore unsuitable as definitions of CM. We suggest that future research into CM in dogs should define cases and controls more strictly so that overlap between normal and abnormal animals is minimized.

Use of negative contrast computed tomography for diagnosis of a colonic duplication in a dog.

A 24-week-old dog was presented with recurrent rectal prolapse because of colonic duplication. Colonic duplication is an extremely uncommon congenital abnormality, with only six cases reported in veterinary medicine, one diagnosed at necropsy and five after barium enema, colonoscopy, abdominal ultrasound, exploratory laparotomy either alone or in combination. In this case, these techniques failed to identify the abnormality and diagnosis was ultimately achieved via negative contrast computed tomography. The evaluation generated by the computed tomography images allowed a refined surgical approach. To the authors' knowledge, negative contrast computed tomography has not yet been reported in the veterinary literature to diagnose gastrointestinal pathologies. Colonic duplication in this case was treated by removal of the intercolonic septum via colotomy.

CT assessment of the influence of dynamic loading on physiological incongruency of the canine elbow.

OBJECTIVES: To present a novel technique for loading of the canine elbow joint and to quantify changes in congruency with increasing load using computed tomography. MATERIALS AND METHODS: Five pairs of thoracic limbs were mounted at a mid stance angle in a custom made jig. Elbow joints were loaded to 0, 33, 66 and 100% of total individual cadaver bodyweight. At each load computed tomography of the elbow was performed. Joint space measurement was performed on sagittal plane central, lateral and medial compartment images at humero-radial (R1 , R2 , R3 ), humero-ulnar (U1 , U2 ) and radio-ulnar loci. The effect of loading on joint spaces was assessed (P<0.05). RESULTS: With increasing load; for central an increase in R1 and radio-ulnar distance and decreased R3 occurred; for medial R1 increased; and for lateral R1 and radio-ulnar distance increased. The largest increases were seen in the lateral compartment. CLINICAL SIGNIFICANCE: Significant changes in humero-radio-ulnar congruency occurred suggesting pronation of the radius with respect to the ulna was induced during loading. This movement may influence the load experienced by the medial coronoid process and could play a role in the aetiopathogenesis of medial coronoid process disease.

Lack of associations between ultrasonographic appearance of parenchymal lesions of the canine liver and histological diagnosis.

OBJECTIVE: To assess if there are any ultrasonographic features that may enable tentative diagnosis of hepatic parenchymal disease. METHODS: Records of 371 dogs that had abdominal ultrasonography and abnormal liver on biopsy or necropsy were reviewed. RESULTS: Histological diagnoses were hepatitis (n=77), nodular hyperplasia (n=47), vacuolar change (n=45), fibrosis (n=32), primary hepatic carcinoma (n=30), lymphoma (n=28), metastatic neoplasia (n=27), necrosis (n=21), lipidosis (n=17), haemangiosarcoma (n=13), round cell tumour (n=9), hepatocellular adenoma (n=8), degenerative change (n=6), steroid hepatopathy (n=7) and extramedullary haematopoiesis (n=4). The most prevalent ultrasonographic features were multifocal lesions (63% livers with haemangiosarcoma and 43% livers with hepatocellular carcinoma), diffuse lesions (71% livers with steroid hepatopathy, 44% livers with fibrosis and 40% livers with vacuolar hepatopathy), hyperechoic lesions (71% livers with steroid hepatopathy, 41% livers with lipidosis and 38% livers with fibrosis), heterogeneous lesions (62% livers with haemangiosarcoma), hepatomegaly (43% livers with steroid hepatopathy) and peritoneal fluid (62% livers with haemangiosarcoma). Target lesions were associated with malignancy in 67% instances. Marked variability in ultrasonographic appearance of lesions was observed for all diagnoses, and no statistically significant associations between ultrasonographic appearance and diagnosis were found. CLINICAL SIGNIFICANCE: Histological examination remains essential for diagnosis of canine hepatic disease.

Is the KT1000 knee ligament arthrometer reliable?

We set up a trial to test whether the KT1000 arthrometer would give consistent measurements of anteroposterior laxity when used by the same and different examiners on the knees of the same subjects on the same day. The results showed substantial inter- and intra-examiner variation in the measurements both of absolute displacement in single knees and of side-to-side differences between pairs of knees. This casts doubt on the reliability of the instrument when used to compare the results of different techniques for reconstructing injured cruciate ligaments.

Non-union of the scaphoid: Russe graft vs Herbert screw.

The results of treatment in 50 consecutive patients with established non-union of the scaphoid are presented. All patients were treated under the care of a single consultant, for the same indications. Russe bone graft is compared with wedge bone graft plus Herbert screw fixation, in terms of union and function. Overall, a higher success rate was obtained by wedge graft plus Herbert screw, and a significantly better range of movement. However, Russe bone graft appears equally satisfactory for fibrous non-union.

Operation for acromioclavicular dislocation. A review of 29 cases treated by one method.

The place and effectiveness of surgery for acromioclavicular dislocation is disputed. We have reviewed 29 patients all treated by an operation which holds the clavicle down to the coracoid process. This was effective in both acute and late cases, with rapid return to work, a low incidence of complications and no requirement for secondary procedures. We consider it to be the method of choice when operation is indicated.