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Introduction: Using computed tomography (CT) for quantifying adrenal volume could aid identification and management of adrenal disease. This study determined anatomic features associated with CT volume of adrenals of dogs, and validated an algorithm to estimate subject-specific adrenal volume. Application of the algorithm to clinical cases with known adrenal pathology is reported. Material and Methods: Dimensions and volume of the left (VLA) and right (VRA) adrenals, first lumbar vertebrae (L1), and aorta, from CT images of 150 dogs undergoing abdominal scans for reasons other than adrenal disease were used to model adrenal volume. Using cross validation, multiple linear regression established best-fit explanatory subsets and predictive models. Additional data from 29 dogs were used for external validation and agreement testing of estimated and measured volumes. The algorithm was retrospectively applied to 46 dogs that underwent adrenalectomy and histologic examination of excised glands. Linear measurements of caudal pole thickness and lesion diameter were also recorded. Results: Mean normal left and right adrenal volumes were 1.22cm3 (range 0.23 to 2.84cm3) and 1.11cm3 (0.14 to 2.97cm3), respectively, and were highly correlated (r=0.88). Bodyweight (W) was the best single explanatory variable for variance in each adrenal and improved with addition of L1 height (HL1). Algorithms after cross validation and adjustment for bias were: VLA= 0.154 + (0.02 x W) + (0.07 x HL1) (adjR2=0.62); and VRA= -0.116 + (0.02 x W) + (0.06 x HL1) (adjR2=0.64). Application of the algorithm to adrenals with known pathology identified enlargement in all dogs compared to inconsistent assessment using linear measurements. Conclusion: Left and right adrenal volume is associated with subject bodyweight and L1 height, and application of a validated algorithm consistently identified enlargement in adrenals with confirmed pathology.

Objective: To investigate the biomechanical properties of a 2.0 mm notched head T-plate (NHTP) and 8-hole 2.0 mm straight locking compression plate (LCP), in a simple transverse model with a short distal fragment, applied with various screw configurations that alter the working length of the plate. Methods: Two different screw configurations were compared for the NHTP and LCP, modelling short (configuration 1) and long working length (configuration 2) across two different distal fragments lengths (13 mm and 9 mm). Constructs were tested in three planes of non-destructive four point bending and torsion. Construct stiffness and plate strain was compared between screw configurations within and between each plate. Results: In the first investigation (13 mm fragment), the LCP was stiffer than the NHTP in all three planes of bending and in torsion (P<0.05). The NHTP had greater strain during compression bending and torsion at all ROI (P<0.0005). In the second investigation (9 mm fragment), the LCP was significantly stiffer than the NHTP in all three planes of bending (P<0.05) for both screw configurations. The NHTP was stiffer than the LCP in torsion (P<0.05) for both screw configurations. The NHTP had greater strain than the LCP during compression bending at three ROI (P<0.0005). The LCP had greater strain than the NHTP during torsion at three ROI (P<0.0005). In both investigations the short working length was stiffer in all three planes of bending and in torsion (P<0.05) than the longer working length for both plates. The long working length produced greater plate strain than the short working length at most ROI. Conclusions: The LCP with two screws in a short fragment, was significantly stiffer and had lower plate strain, in most planes of testing, than NHTP with three locking screws in the short fragment. Extending the working length of each construct by omitting locking screws in the long fragment adjacent to the fracture line significantly reduced construct stiffnes

Objective: To characterise acidic gastroesophageal reflux (GER) events using continuous oesophageal pH monitoring in dogs with no history of gastrointestinal disease following total intravenous anaesthesia in a hospital setting, and explore putative subject factors associated with GER. Study Design: Prospective case series. Animals: Client-owned dogs presenting for elective orthopaedic surgery. Methods: Dogs were sedated with intravenous methadone and medetomidine, followed by intravenous alfaxalone. The Digitrapper oesophageal dual pH monitoring probe was placed trans-nasally with the caudal-most extent in the distal oesophagus. The probe remained in place for 16-24 hours with the dog unsedated. A GER event was recorded when the oesophageal pH <4. Parameters reported included total number of GER events, number of GER events per hour, percentage duration of oesophageal exposure to acid (pH <4) and duration of single GER events. Results: Seventeen dogs were included, with a median age of 7 (range 1-12 years) and a median body weight of 24 kilograms (range 5.3-44 kg). The Digitrapper was well tolerated during a median data recording duration of 20.2 hours (range 15.7-24.1 hr). The median total number of proximal and distal GER events was 0 and 7, respectively. The longest distal GER event recorded was 12.7 minutes. The median number of distal GER events per hour was 0.3 and the median duration of distal oesophageal acid exposure was 0.4%. One dog recorded GER within one hour of eating. Regurgitation with oral expulsion was not recorded in any dog. Dogs older (>5 years), female and of ideal body condition tended to record higher GER events per hour and longer oesophageal acid exposure. Estimated upper reference limits for number of distal GER events per hour was 0.66 and duration of distal oesophageal acid exposure was 0.6%. Conclusion: Brief, infrequent episodes of GER and transient oesophageal acid exposure are expected in dogs without gastrointestinal disease follow

At The Animal Hospital at Murdoch University (TAHMU), an abnormal signal was observed in the tonsillar region of two dogs on brain MRI. Both dogs did not present with or demonstrate clinical signs of oropharyngeal disease. The abnormal signal in the two cases was interpreted as possible foreign bodies by veterinary teleradiologists. However, despite the abnormal signal in both cases demonstrating similar MRI features, the interpretation of the nature of the foreign body was different. In one of the two cases, the veterinary teleradiologist suspected that the abnormal signal in the tonsillar region was a metallic foreign body and likely a component of the endotracheal (ET) tube. Objectives: (1) Describe and characterise the appearance of the tonsillar region of dogs on brain MRI examinations. (2) Describe and characterise any abnormal signal detected in the tonsillar region of dogs on brain MRI examinations at TAHMU. (3) Investigate if any detected abnormality is associated with the ET tube used in anaesthetised dogs. Material and Methods: Retrospectively, all canine brain MRI examinations performed from 2017 to 2021 at TAHMU were reviewed. Prospectively, 20 dogs undergoing brain MRI for clinical investigation of neurological disease were included. An oral examination was performed at intubation, and details regarding the ET tube were recorded (ET tube diameter and manufacturer). During the review of the MRI images, the tonsillar region was evaluated for the presence of an abnormal signal (termed tonsillar abnormality; TA). If TA was detected, its location, size, shape, margin and signal intensity in pre-and post-contrast sequences were evaluated. Results: Foci of signal void in one or both tonsillar regions, consistent with gas, were detected in 160/170 retrospective studies. In 3/170 studies, TA was observed in the right tonsillar region at the level of the temporomandibular joint. All three TA exhibited a peripheral hyperintense rim and a less intense centre that

Acute kidney injury (AKI) is a syndrome associated with high morbidity and mortality due to an abrupt decline in renal function. One of the most common causes of AKI in dogs is ischaemia reperfusion injury (IRI), as may occur during severe hypotension during anaesthesia. Favourable outcomes following AKI are more likely if therapeutic interventions are instigated early, within the first few hours of injury. Unfortunately, conventional diagnostic tests for AKI rely on markers of renal functional deterioration such as serum creatinine, that may change significantly until several days after the initial injury. Several protein biomarkers have been shown to be useful for the early diagnosis of AKI in animals and people. Multiplex assays for the simultaneous measurement of multiple renal biomarkers in canine samples have recently become available, representing a potentially efficient and cost-effective tool for investigators; however, there is limited data to support their reliable use in dogs. This thesis aimed to validate one of these multiplex assays for use with canine urine and blood, and then to document changes in urinary biomarker concentration alongside conventional diagnostic tests for AKI following ischaemia reperfusion injury in anaesthetised dogs. An experimental model of IRI AKI was utilised in six male anaesthetised greyhounds by inducing 1-hour of renal ischaemia (severe hypotension induced by acute haemorrhage) and 2-hours of reperfusion (intravenous fluid resuscitation). Urine and blood collected before, and after IRI, was used to compare the performance of two commercial multiplex assays to validated enzyme-linked immunoassays (ELISA) for the measurement of five biomarkers: clusterin, cystatin C (CysC), kidney injury molecule-1, monocyte chemoattractant protein 1, and neutrophil gelatinase-associated lipocalin (NGAL). Subsequently, extensive analytical validation was performed on one of the multiplex assays for canine urine and serum. Additionally, refe