Computed tomography of tympanic bullae in pre-weaned dairy calves diagnosed with clinical respiratory disease.

Clinical disease from otitis media in calves is a significant problem in the dairy industry and evaluation of disease severity, chronicity, and imaging remains a challenge. Our objectives were to compare imaging findings in calves with an early diagnosis of respiratory disease to calves with treatment failure. This was a prospective study of 30 Jersey heifer calves, 26-95 days of age, with elevated clinical respiratory scores. Ten clinically healthy calves served as controls for clinical scoring. Three groups of calves were selected based on elevated scores using the McGuirk respiratory scoring system and treatment history. Group A included new cases, group B included primary treatment failures, and group C included multiple treatment failures. Calves underwent a skull CT, four view radiography, post-mortem photography of the tympanic bulla and bacteriological diagnostics. Imaging and post-mortem results were evaluated using normalized scoring schemes. Computed tomography imaging of the tympanic bulla differentiated calves early in the course of disease (group A) from calves that had not responded to treatment (groups B and C). Radiographs differentiated only group C from groups A and B. Use of a 35 degree angle dorsal-right or dorsal-left ventral oblique projection for radiography allowed effective evaluation of the tympanic bulla. Clinical respiratory scores were similar among all three groups. Computed tomography imaging can differentiate early from advanced otitis media. Radiographs, which can be performed in the field, also have utility to identify advanced otitis media to aid management decisions.

Interreader agreement of radiographic left atrial enlargement in dogs and comparison to echocardiographic left atrial assessment.

INTRODUCTION: Assessing left atrial (LA) size is an integral part of the cardiac evaluation in dogs. Left atrial size is routinely evaluated by thoracic radiographs or echocardiography. OBJECTIVES: The objectives of the study were to assess agreement of subjective radiographic left atrial enlargement (LAE) between readers, to compare subjective radiographic LAE with echocardiography, and to assess the accuracy and reliability of commonly used Roentgen signs for LAE. ANIMALS: One hundred one dogs with thoracic radiographs and echocardiography performed on the same day at a veterinary teaching hospital were retrospectively reviewed. METHODS: Thoracic radiographs were reviewed by two cardiologists, two radiologists, and two small animal rotating interns. Radiographs were evaluated for the subjective presence and severity of LAE and for seven Roentgen signs. Echocardiographic LA size was evaluated objectively by the left atrial-to-aortic root ratio and LA volume indexed to body weight. Interreader agreement of radiographic LAE evaluation and agreement between radiographic LAE assessment and echocardiographic LAE were assessed by linearly weighted kappa and intraclass correlation coefficient. RESULTS: Interreader agreement for the presence and degree of radiographic LAE ranged from moderate to substantial. The agreement between subjective radiographic LAE and echocardiographic LAE was moderate. Single Roentgen signs had poor to fair correlation with echocardiographic LAE. CONCLUSIONS: The present study found that interreader agreement for radiographic classification of LAE was substantial among specialists and moderate for all readers. Subjective, global assessment of radiographic LAE is better than using any single Roentgen sign.

Use of computed tomography to compare two femoral head and neck excision ostectomy techniques as performed by two novice veterinarians.

OBJECTIVES: To compare the results of femoral head and neck excision (FHNE) ostectomy performed by two novice veterinarians using an osteotome and mallet or microsagittal saw. METHODS: In this ex vivo cadaveric study, hindlimbs of eight canine cadavers were randomized to FHNE with osteotome or micro sagittal saw as performed by two recently graduated veterinarians. The hindimbs were imaged by computed tomography (CT) before and after the osteotomy. Post FHNE CT images were evaluated by a board certified radiologist blinded to the ostectomy technique for assessment of the number of bone fragments, fissures, smoothness of osteotomy margination, and volume of residual femoral neck. RESULTS: Femoral head and neck excision performed with the osteotome produced more peri-ostectomy bone fragments, cortical fissures, irregular margins, and residual femoral neck volume, compared with osteotomy using a saw. CLINICAL RELEVANCE: Compared to FHNE performed with a sagittal saw, osteotome FHNE resulted in a greater bone trauma and residual neck bone volume, which would require post-ostectomy modification in a clinical setting.

Decreased dose of radiation to dogs during acquisition of elbow radiographs using draped shielding.

Protective lead equivalent shielding of patients is not routinely used in veterinary radiology. The goal of this study was to determine whether the use of lead equivalent shielding results in a significant reduction in dose of radiation to dogs during acquisition of elbow radiographs. The authors measured radiation doses in the primary beam and over and under protective lead equivalent shielding that was placed at the level of the eyes, body and gonads during acquisition of elbow radiographs using 0.01 mSv sensitivity dosimetry badges. Shielding consisted of 0.5 mm lead equivalent aprons and thyroid shields placed over bodies and eyes, respectively. All badges in the primary beam-detected radiation. Shielding significantly decreased the dose of radiation with significantly less scatter and tube leakage radiation detected under compared with over shielding (P=0.0001). The dose of radiation detected over shielding was significantly greater than zero (P=0.0001), while that under shielding did not differ significantly from zero (P=0.09). Based on these results, the authors recommend protective shielding be used on veterinary patients during radiography.

Evaluation of the diagnostic accuracy of four-view radiography and conventional computed tomography analysing sacral and pelvic fractures in dogs.

OBJECTIVE: The purpose of our study was (1) to determine whether four-view radiography of the pelvis is as reliable and accurate as computed tomography (CT) in diagnosing sacral and pelvic fractures, in addition to coxofemoral and sacroiliac joint subluxation or luxation, and (2) to evaluate the effect of the amount of training in reading diagnostic imaging studies on the accuracy of diagnosing sacral and pelvic fractures in dogs. METHODS: Sacral and pelvic fractures were created in 11 canine cadavers using a lateral impactor. In all cadavers, frog-legged ventro-dorsal, lateral, right and left ventro-45°-medial to dorsolateral oblique frog leg ("rollover 45-degree view") radiographs and a CT of the pelvis were obtained. Two radiologists, two surgeons and two veterinary students classified fractures using a confidence scale and noted the duration of evaluation for each imaging modality and case. The imaging results were compared to gross dissection. RESULTS: All evaluators required significantly more time to analyse CT images compared to radiographic images. Sacral and pelvic fractures, specifically those of the sacral body, ischiatic table, and the pubic bone, were more accurately diagnosed using CT compared to radiography. Fractures of the acetabulum and iliac body were diagnosed with similar accuracy (at least 86%) using either modality. CLINICAL SIGNIFICANCE: Computed tomography is a better method for detecting canine sacral and some pelvic fractures compared to radiography. Computed tomography provided an accuracy of close to 100% in persons trained in evaluating CT images.

Augmentation of diaphyseal fractures of the radius and ulna in toy breed dogs using a free autogenous omental graft and bone plating.

OBJECTIVES: Evaluation of the short-term outcome, duration of bone healing, and complications following bone plate fixation in dogs weighing ≤6 kg, with and without the use of a free autogenous greater omental graft (OG). MATERIALS AND METHODS: A retrospective clinical study reviewed the medical records of 25 dogs of body weight <6 kg with mid to distal diaphyseal fractures of the radius and ulna (29 fractures) treated with open reduction bone plate fixation. Thirteen out of 29 fractures were implanted with an additional 2-3 cm³ OG lateral, cranial, and medial to the fracture site, adjacent to the bone plate. RESULTS: Median time to radiographic healing in OG fractures (n = 11) was 70 days (range 28-98) compared to 106 days (range: 56-144) in non-OG grafted fractures (n = 14). The OG dogs had no major complications; minor complications included oedema, erythema, and mild osteopenia. Six of the eight non-OG dogs for which follow-up could be obtained developed osteopenia necessitating implant removal, four of which re-fractured the radius one to five months after implant removal, with one dog re-fracturing the limb a second time and resulting in amputation. Telephone follow-up of owners of OG dogs (n = 11) three to 15 months (median 10) post-surgery did not identify any signs of lameness or other complications. Owners of the non-OG dogs (n = 8) reported that there were not any signs of lameness six to 48 months (median 36) post-surgery. CLINICAL RELEVANCE: Free autogenous omental grafting of diaphyseal fractures of the radius and ulna was associated with radial and ulnar healing with minimal complications in dogs weighing less than 6 kg.

Use of multidetector computed tomography in the assessment of dogs with pericardial effusion.

BACKGROUND: Contrast-enhanced multidetector computed tomography (MDCT) allows high spatial and temporal resolution imaging of cardiac, thoracic, and abdominal structures. Accurate determination of the cause of pericardial effusion (PE) is essential to providing appropriate treatment and prognosis. Echocardiography and pericardial fluid analysis may not differentiate between causes of PE and cannot identify extracardiac metastasis. HYPOTHESIS/OBJECTIVES: Describe the thoracic and abdominal MDCT findings and evaluate the utility of MDCT to differentiate between neoplastic and nonneoplastic causes of PE in dogs. ANIMALS: Eleven client-owned dogs with PE diagnosed by echocardiography. METHODS: Prospective observational study. Transthoracic echocardiography (TTE), 3-view thoracic radiography, and contrast-enhanced thoracic and abdominal MDCT images were evaluated for the presence of cardiac masses, pulmonary metastases, and abdominal masses. Histopathology in 5 dogs and survival analysis in all dogs were evaluated. RESULTS: A neoplastic cause was identified in 6/11 dogs and a nonneoplastic cause was identified in 5/11. Cardiac MDCT findings were consistent with TTE findings in all dogs with right atrial (5/5) and heart base masses (1/1). Pulmonary metastases were identified in 1/11 dogs by thoracic radiography and in 2/11 dogs by MDCT. MDCT identified splenic or hepatic lesions consistent with neoplasia in 6/11 and 5/11 dogs, respectively. Focal MDCT pericardial changes at the pericardiocentesis site were noted in 3/11 dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: Multidetector computed tomography did not improve the detection of cardiac masses in dogs with PE over echocardiography. The benefit of MDCT was primarily in the detection of pulmonary metastases and extracardiac lesions using a single imaging modality.