Comparison of concurrent imaging modalities for staging of dogs with appendicular primary bone tumours.

This study assessed the use of whole body computed tomography (CT) for the evaluation of metastasis in dogs with primary appendicular bone tumours compared to long bone survey radiography, bone scintigraphy and thoracic radiographs. Fifteen dogs were included in this pilot study. A construct reference standard was used for detection of bone metastasis, and negative thoracic radiographs were compared against CT. Definitive lesions were only identified on bone scintigraphy. Not all lesions agreed with the construct reference standard. No definitive lesions were identified on survey radiographs or CT. Lesions were identified on thoracic CT that were not visible radiographically. Equivocal ground glass pulmonary lesions progressed in three of four cases. Whole body CT was not a suitable alternative to bone scintigraphy; however, it was useful as an adjunctive diagnostic modality. Pulmonary lesions were visible on CT that were not seen radiographically and ground glass pulmonary lesions in dogs should be considered suspicious for metastasis.

Effectiveness of a nonpenetrating captive bolt for euthanasia of 3 kg to 9 kg pigs.

The objective of this study was to determine the effectiveness of a nonpenetrating captive bolt, Zephyr-E, for euthanasia of suckling and weaned pigs from 3 to 9 kg (5-49 d of age) using signs of insensibility and death as well as postmortem assessment of traumatic brain injury (TBI). The Zephyr-E was used by 15 stock people to euthanize 150 compromised pigs from 4 farrowing and nursery units from commercial farms and 2 research stations. Brainstem reflexes, convulsions, and heartbeat were used to assess insensibility, time of brain death, and cardiac arrest following Zephyr-E application. Skull fracture displacement (FD) was quantified from computed tomography (CT) scans (n = 24), macroscopic scoring was used to assess brain hemorrhage and skull fracture severity (n = 150), and microscopic scoring was used to assess subdural hemorrhage (SDH) and parenchymal hemorrhage within specific brain regions that are responsible for consciousness and vital function (n = 32). The Zephyr-E caused immediate, sustained insensibility until death in 98.6% of pigs. On average, clonic convulsions (CC) ceased in 82.2 s (± 3.4 SE), brain death was achieved in 144.9 s (± 5.4 SE), and cardiac arrest occurred in 226.5 s (± 8.7 SE). Time of brain death and cardiac arrest differed significantly among stock people (P = 0.0225 and P = 0.0369). Age was positively related to the duration of CC (P = 0.0092), time of brain death (P = 0.0025), and cardiac arrest (P = 0.0068) with shorter durations seen in younger pigs. Average FD was 8.3 mm (± 1.0 SE). Macroscopic scores were significantly different among weight classes for subcutaneous (P = 0.0402) and subdural-ventral (P = 0.0037) hemorrhage with the lowest severity hemorrhage found in the 9-kg weight category. Microscopic scores differed among brain sections (P = 0.0070) for SDH with lower scores found in the brainstem compared to the cerebral cortex and midbrain. Parenchymal hemorrhage differed among brain sections (P = 0.0052) and weight categories (P = 0.0128) with the lowest scores in the midbrain and brainstem and the 7- and 9-kg weight categories. The Zephyr-E was highly effective for the euthanasia of pigs up to 9 kg (49 d) based on immediate insensibility sustained until death. Postmortem results confirmed that severe skull fracture and widespread brain hemorrhage were caused by the Zephyr-E nonpenetrating captive bolt.

Effectiveness of a nonpenetrating captive bolt for euthanasia of piglets less than 3 d of age.

The objective of this study was to determine the effectiveness of a nonpenetrating captive bolt (NPCB), the Zephyr-Euthanasia (Zephyr-E), for euthanasia of neonatal piglets<72 h of age using signs of insensibility and death, as well as postmortem assessment of traumatic brain injury (TBI). The Zephyr-E was used by 10 stock people to euthanize 100 low viability neonatal piglets from 3 commercial farrowing units and 1 research farm. Brainstem reflexes, convulsions, and heartbeat were used to assess insensibility, time of brain death, and cardiac arrest after Zephyr-E application. Hemorrhage severity and skull fracture displacement (FD) were quantified from computed tomography scans (n=10), macroscopic scoring was used to assess brain hemorrhage and skull fracture (SK) severity (n=100), and microscopic scoring was used to assess subdural (SDH) and parenchymal (PH) hemorrhage within specific brain regions that are responsible for consciousness and vital function (n=10). All 100 piglets were rendered immediately insensible without return to sensibility. On average, clonic convulsions (CC) ceased in 101 s (±7.4 SE), brain death was achieved in 229 s (±9.18 SE), and cardiac arrest occurred in 420 s (±13.57 SE). Time of cardiac arrest differed significantly among stock people when either body weight (BW: P=0.0053) or body mass index (BMI: P=0.0059) was used as a covariate. The BMI was inversely related to the duration of CC (P=0.0227). Moderate to severe hemorrhage severity was reported in 9 of 10 piglets. There was no relationship between FD and BW (P=0.8408) or BMI (P=0.6439). Macroscopic analyses indicated moderate to severe hemorrhage and SK in all piglets. No differences were found among brain sections for SDH (P=0.2302); PH was greater in the cerebral cortex than in the midbrain and brainstem (P=0.0328). The Zephyr-E NPCB reliably caused immediate, sustained insensibility followed by death in neonatal piglets. Postmortem assessment confirmed that application of the Zephyr-E caused widespread, irreversible brain damage.

Hypercoagulability and ACTH-dependent hyperadrenocorticism in dogs.

BACKGROUND: Dogs with hyperadrenocorticism are at risk of thromboembolic disease, which might be caused by an underlying hypercoagulable state. HYPOTHESIS/OBJECTIVES: To assess hemostatic function in dogs with ACTH-dependent hyperadrenocorticism (ADHAC) before and after treatment. ANIMALS: Nineteen dogs with ADHAC and 40 normal dogs. METHODS: Prospective, observational study. Dogs with ADHAC were recruited from the referral hospital patient population; normal dogs were recruited from staff and students at the study's institution. Hemostasis was assessed before and at 3 and 6 months after treatment with trilostane (T0, T3, T6) by kaolin-activated thrombelastography with platelet mapping (TEG-PM), prothrombin time, activated partial thromboplastin time, fibrinogen concentration, and antithrombin activity (AT). RESULTS: Dogs with ADHAC had statistically significantly increased α-angle (P < .01) and maximum amplitude (MA)(thrombin) (P < .01) on TEG-PM, and significantly decreased κ (P < .005) at T0, T3, and T6. Platelet count (P < .001) and fibrinogen concentration (P < .001), but not AT activity, were increased in dogs with ADHAC at T0, T3, and T6. CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs with ADHAC have thrombelastographic evidence of hypercoagulability and remained hypercoagulable during treatment. AT deficiency does not appear to be involved in the pathogenesis of hypercoagulability in this population.

The effects of perineural and intrasynovial anaesthesia of the equine foot on subsequent magnetic resonance images.

REASONS FOR PERFORMING STUDY: Artefacts caused by regional anaesthesia can influence image interpretation of ultrasonography and nuclear scintigraphy. Perineural and intrasynovial anaesthesia are commonly performed prior to magnetic resonance imaging (MRI); and the effects on MR images, if any, are unknown. OBJECTIVES: To determine if perineural and intrasynovial anaesthesia of structures in the equine foot cause iatrogenic changes detectable with MRI. METHODS: A baseline MRI examination of both front feet was performed on 15 horses, 2-6 days prior to mepivacaine injection adjacent to the lateral and medial palmar digital nerves, and into the podotrochlear bursa, digital flexor tendon sheath and distal interphalangeal joint of one randomly assigned forelimb. Magnetic resonance imaging was repeated at 24 and 72 h post injection; then qualitative and quantitative assessments of MRI findings were performed. RESULTS: Magnetic resonance imaging findings associated with the palmar digital nerves, podotrochlear bursa and distal interphalangeal joint at 24 and 72 h after mepivacaine injection did not alter significantly from those at baseline. Compared with baseline, a significant increase in synovial fluid volume of the digital flexor tendon sheath was detected with MRI at 24 and 72 h post injection. CONCLUSIONS: Perineural anaesthesia of the palmar digital nerves and intrasynovial anaesthesia of the podotrochlear or distal interphalangeal joint did not interfere with the interpretation of MR images acquired at 24 or 72 h after injection. However, intrasynovial anaesthesia of the digital flexor tendon sheath caused an iatrogenic increase in synovial fluid, detectable on MR images for at least 72 h. POTENTIAL RELEVANCE: Although a definite time frame for resolution of digital flexor tendon sheath distension was not determined, we recommend waiting more than 3 days between intrasynovial anaesthesia of the digital flexor tendon sheath and evaluation with MRI.

Agreement between magnetic resonance imaging, myelography, and surgery for detecting recurrent, thoracolumbar intervertebral disc extrusion in dogs.

OBJECTIVES: Although magnetic resonance imaging (MRI) is reported to be superior to myelography to determine the location and site of first time disc herniation, comparison of these diagnostic methods in cases of recurrent intervertebral disc disease (IVD) herniation after a first surgery has not been evaluated. The objective was to compare the diagnostic accuracy of MRI and myelography in a series of dogs undergoing repeat surgical decompression for recurrent IVD extrusion when compared to the gold standard of surgery. METHODS: Ten dogs with recurrent IVD herniation underwent MRI and myelography followed by surgical decompression. Three observers reviewed the images to determine the site and side of the first surgery and the recurrent lesion. Agreement was determined by calculating a kappa (κ) score. RESULTS: Substantial interobserver agreement was noted for recurrent lesion site using MRI and myelography (κ = 0.77 vs. 0.73) and when comparing MRI and myelography to the reported surgical site (κ = 0.73 vs. 0.67). Interobserver agreement was greater with MRI for circumferential location compared to myelography (κ = 0.76 vs. 0.43), similar to what was found when comparing to surgical side (κ = 0.82 vs. 0.49). The previous surgical site in this study had no effect on ability to identify the new lesion. CLINICAL SIGNIFICANCE: Despite the limitations of MRI, there was greater agreement between observers using MRI for both the recurrent and first lesion.

Partial scapulectomy for treatment of an articular fracture of the scapula in a cat.

A seven-month-old cat was referred, after having been missing for one week, for evaluation and treatment of a right forelimb injury and facial fractures. On physical examination, a moderate partial weight-bearing lameness of the right forelimb was present, with palpable crepitus in the glenohumeral joint. Dental radiographs revealed a midline palatal fracture and rostral fractures of the left maxillary canine alveolar bone. Radiographs of the right shoulder revealed a Type III or intra- articular fracture of the scapula with moderate displacement of the fracture at the articular surface. Early fibrous healing of the fracture was observed and the caudal aspect of the medial glenohumeral ligament was ruptured. Due to the chronicity, reduction and stabilization was not attempted. Instead, the caudal aspect of the medial glenohumeral ligament was incised along its origin and approximately 30% of the glenoid was removed. The caudal glenohumeral ligament was attached to the subscapularis muscle. Three years after surgery, the owner reported that the cat continued to experience no visible lameness and led an active lifestyle. This case report demonstrates that a partial caudal scapulectomy can result in full return of function of the forelimbs in cats with scapular fractures, especially when joint involvement is severe and the articular cartilage is affected. To the authors' knowledge, this is the first report of a partial scapulectomy, utilized for fracture management, in the veterinary literature.

The Feline Acute Patient Physiologic and Laboratory Evaluation (Feline APPLE) Score: a severity of illness stratification system for hospitalized cats.

BACKGROUND: Scores allowing objective stratification of illness severity are available for dogs and horses, but not cats. Validated illness severity scores facilitate the risk-adjusted analysis of results in clinical research, and also have applications in triage and therapeutic protocols. OBJECTIVE: To develop and validate an accurate, user-friendly score to stratify illness severity in hospitalized cats. ANIMALS: Six hundred cats admitted consecutively to a teaching hospital intensive care unit. METHODS: This observational cohort study enrolled all cats admitted over a 32-month period. Data on interventional, physiological, and biochemical variables were collected over 24 hours after admission. Patient mortality outcome at hospital discharge was recorded. After random division, 450 cats were used for logistic regression model construction, and data from 150 cats for validation. RESULTS: Patient mortality was 25.8%. Five- and 8-variable scores were developed. The 8-variable score contained mentation score, temperature, mean arterial pressure (MAP), lactate, PCV, urea, chloride, and body cavity fluid score. Area under the receiver operator characteristic curve (AUROC) on the construction cohort was 0.91 (95% CI, 0.87-0.94), and 0.88 (95% CI, 0.84-0.96) on the validation cohort. The 5-variable score contained mentation score, temperature, MAP, lactate, and PCV. AUROC on the construction cohort was 0.83 (95% CI, 0.79-0.86), and 0.76 (95% CI, 0.72-0.84) on the validation cohort. CONCLUSIONS AND CLINICAL IMPORTANCE: Two scores are presented enabling allocation of an accurate and user-friendly illness severity measure to hospitalized cats. Scores are calculated from data obtained over the 1st 24 hours after admission, and are diagnosis-independent. The 8-variable score predicts outcome significantly better than does the 5-variable score.

Osteosarcoma masked by osteomyelitis and cellulitis in a dog.

CASE DESCRIPTION: This clinical report describes a 10-year-old female spayed German Shepherd dog cross that was presented with cellulitis of the left proximal forelimb and osteomyelitis of the left proximal humerus, and was ultimately diagnosed with metastatic osteosarcoma. CLINICAL FINDINGS: The diagnosis of cellulitis and osteomyelitis was made using ultrasound, radiography, cytology and histopathology, all of which were consistent with cellulitis and osteomyelitis. Cultures were negative. TREATMENT: The patient was treated using two surgical debridements and long-term broad-spectrum antibiotic drugs. Despite surgical and medical treatment, the dog's condition progressed. A lytic lesion of the left proximal humerus was identified radiographically. OUTCOME: One hundred forty-one days after initial presentation, the dog was presented with a non-weight bearing lameness of the left forelimb. An amputation was scheduled. Preoperative computed tomography scan of the thorax revealed gross metastatic disease to the lungs. The patient was euthanatized and a post-mortem examination revealed osteosarcoma of the left proximal humerus with widespread metastasis. CLINICAL RELEVANCE: To our knowledge, this case is the first reported case of osteomyelitis masking osteosarcoma in a dog. It serves as a reminder to maintain a high index of suspicion when managing cases with a signalment, history and radiographic lesion that are consistent with a primary bone tumour.

The acute patient physiologic and laboratory evaluation (APPLE) score: a severity of illness stratification system for hospitalized dogs.

BACKGROUND: Objective risk stratification models are used routinely in human critical care medicine. Applications include quantitative and objective delineation of illness severity for patients enrolled in clinical research, performance benchmarking, and protocol development for triage and therapeutic management. OBJECTIVE: To develop an accurate, validated, and user-friendly model to stratify illness severity by mortality risk in hospitalized dogs. ANIMALS: Eight hundred and ten consecutive intensive care unit (ICU) admissions of dogs at a veterinary teaching hospital. METHODS: Prospective census cohort study. Data on 55 management, physiological, and biochemical variables were collected within 24 hours of admission. Data were randomly divided, with 598 patient records used for logistic regression model construction and 212 for model validation. RESULTS: Patient mortality was 18.4%. Ten-variable and 5-variable models were developed to provide both a high-performance model and model maximizing accessibility, while maintaining good performance. The 10-variable model contained creatinine, WBC count, albumin, SpO(2) , total bilirubin, mentation score, respiratory rate, age, lactate, and presence of free fluid in a body cavity. Area under the receiver operator characteristic (AUROC) on the construction data set was 0.93, and on the validation data set was 0.91. The 5-variable model contained glucose, albumin, mentation score, platelet count, and lactate. AUROC on the construction data set was 0.87, and on the validation data set was 0.85. CONCLUSIONS AND CLINICAL IMPORTANCE: Two models are presented that enable allocation of an accurate and user-friendly illness severity index for dogs admitted to an ICU. These models operate independent of primary diagnosis, and have been independently validated.

Brain and skull lesions resulting from use of percussive bolt, cervical dislocation by stretching, cervical dislocation by crushing and blunt trauma in turkeys.

Three experiments were conducted to assess brain damage resulting from percussive bolt shooting and cervical dislocation by crushing (neck crushing) in turkey hens (mean [se] bodyweight 11.4 [0.1] kg); percussive bolt shooting and blunt trauma in turkey toms (13.1 [0.2] kg); and percussive bolt shooting, blunt trauma and cervical dislocation by stretching (neck stretching) in broiler turkeys (3.9 [0.3] kg). Brain and skull damage were assessed using macroscopic and microscopic evaluations and CT. Macroscopic subcutaneous haemorrhage was significantly greater with the percussive bolt in all three experiments (hens P=0.01, toms P=0.02, broilers P=0.0003), and skull fractures were more severe for toms (P<0.0001) and broilers (P=0.03) killed with the percussive bolt versus blunt trauma. In a subsample of turkeys, microscopic brain damage was present in all turkeys killed by percussive bolt shooting (five hens, 10 toms and four broilers) and blunt trauma (nine toms and three broilers), but only in one of four turkeys killed by neck crushing and one of four turkeys killed by neck stretching. Percussive bolt shooting and blunt trauma most likely caused death by directly disrupting brain function, whereas neck stretching and neck crushing probably resulted in death from cerebral hypoxia and ischaemia.

Behavioural and cardiorespiratory effects of a constant rate infusion of medetomidine and morphine for sedation during standing laparoscopy in horses.

REASONS FOR PERFORMING STUDY: Standing surgical procedures are performed commonly in horses under sedation. This approach minimises the morbidity/mortality risks associated with general anaesthesia. The use of a medetomidine and morphine combination has not been investigated in horses despite the usefulness of each drug individually. OBJECTIVE: To determine the efficacy of a medetomidine and morphine combination to produce standing sedation with minimal cardiorespiratory changes and adequate analgesia for exploratory laparascopy in mature horses. HYPOTHESIS: The combination of medetomidine and morphine will induce reliable sedation with minimal cardiorespiratory changes. METHODS: Medetomidine (5 microg/kg bwt i.v.) followed in 10 min by morphine (50 microg/kg bwt i.v.) and 10 min later by a constant rate infusion (CRI) of medetomidine and morphine (5 and 30 microg/kg bwt/h, respectively) was administered in 7 horses undergoing standing exploratory laparoscopy. Quality of sedation and cardiorespiratory function were assessed. RESULTS: Sedation was satisfactory after the medetomidine and morphine bolus. The CRI of both drugs enhanced sedation and ataxia. Mean visual analogue scores on a scale of 10 varied between 7.8 and 8.8 and were similar between anaesthesiologists and surgeons. Heart rate, respiratory rate and packed cell volume (PCV) decreased significantly after medetomidine and, at some periods, during the CRI. Blood pressure only increased significantly at 5 min and arterial O2 decreased significantly at 10 min post medetomidine. PCV remained significantly lower and total protein decreased post morphine and CRI administration. Arterial CO2 increased towards the end of the CRI. Cardiac output did not change significantly over time. CONCLUSION AND CLINICAL RELEVANCE: The combination of medetomidine and morphine results in reliable sedation and stable cardiorespiratory function in horses undergoing exploratory laparascopy.

MRI measurement of the canine auditory pathways and relationship with brainstem auditory evoked responses.

The objective of this study was to determine direct measurements of auditory pathways by magnetic resonance imaging (MRI) during the growth period of healthy Beagles, and to discover how canine brainstem auditory evoked response (BAER) latencies vary in relation to these MRI measurements. Eighty healthy Beagles were tested at eight, 16 and 52 weeks of age (stages 1, 2, 3, respectively) with BAER and brain MRI. The BAER interpeak latency (IPL) II-V and brain MRI neural generators of BAER waves II and V were identified. A linear distance was calculated in millimeters in order to determine the approximate length of auditory pathways. Sensory nerve conduction velocity (SNCV) of the auditory pathway between peak II and peak V was calculated for each group. A significant difference was observed between brain MRI distances among the three stages. Mean BAER IPL II-V were not significantly different between the three stages. The progressive growth of the skull and brain witnessed by the progressive increased distance of the MRI auditory pathways between peak II and peak V was not associated with a progressive maturation of the BAER IPL II-V. The SNCV of the auditory pathway between peak II and peak V was 6.14 m/sec for group 1; 6.76 m/sec for group 2; and 7.32 m/sec for group 3.

Relationships between ultrasonographic image attributes, histomorphology and proliferating cell nuclear antigen expression of bovine antral follicles and corpora lutea ex situ.

The aim of this study was to examine the relationships between quantitative ultrasonographic image characteristics, histological attributes and cell proliferating ability of bovine antral follicles and corpora lutea (CL) ex situ. Bovine ovaries (n = 30) from animals at various reproductive states (metoestrus-early dioestrus, n = 8; mid-dioestrus, n = 12; oestrous phase of peripubertal heifers, n = 6; and pregnancy, n = 4) were collected at the slaughterhouse. High-resolution ultrasonographic images of the ovaries were obtained in the water bath, digitized and subjected to computerized image analyses. The analyses utilized line and spot techniques designed to determine pixel values of the follicular wall (the largest follicles >2 mm in diameter in each ovary) and CL, respectively. Individual ovarian structures were dissected and processed for histology and immunohistochemical detection of proliferating cell nuclear antigen (PCNA). The mean follicular diameter was negatively correlated with total cell density (r = -0.45, p < 0.05), granulosa layer thickness (r = -0.67, p < 0.001) and the percentage of PCNA-positive cells (r = -0.57, p < 0.001). Numerical pixel values and heterogeneity of the follicular wall were positively correlated with total cell density (r = 0.42, p < 0.05 and r = 0.62, p < 0.05; respectively), granulosa layer thickness (both r = 0.39, p < 0.05), and the percentage of PCNA-positive cells (r = 0.54, p < 0.01 and r = 0.69, p < 0.001, respectively). Estimates of cell density and proliferating cell index were not correlated with the ultrasonographic image attributes of CL. We conclude that follicular size and echotextural variables, as determined by computer-assisted image analysis of ovaries ex situ, are reliable markers of the histophysiological properties of bovine antral follicles, but the ultrasonographic characteristics are not indicative of cell density and proliferation in the bovine CL.

Computed tomography dacryocystography evaluation of the nasolacrimal apparatus.

Computed tomography-dacryocystography (CT-DCG) was used to evaluate the nasolacrimal system in four patients (three dogs and one horse) that were admitted for evaluation of chronic epiphora, facial swelling, or facial trauma. The four patients are reviewed and the technique for performing CT-DCG is described. Additionally, the indications for this procedure are discussed. CT-DCG is advantageous because cross-sectional imaging provides superior resolution of the nasolacrimal apparatus and the relatively long, small-diameter, bony nasolacrimal canal in most veterinary patients.

Computed tomographic appearance of choanal atresia in an alpaca cria.

A 6-hour-old alpaca cria was admitted for evaluation of respiratory distress since birth. Contrast radiography confirmed the presence of bilateral choanal atresia, and computed tomography (CT) evaluation was planned to aid in the surgical treatment. Due to deterioration in the cria's condition, euthanasia was performed prior to the CT examination. Postmortem CT examination was performed to determine the appearance of choanal atresia. The embryology and CT appearance of choanal atresia is discussed.