Development of three-dimensional cardiac models from computed tomography angiography.

Three-dimensional (3D) modeling and printing is an emerging technology in veterinary cardiovascular medicine allowing the fabrication of anatomically correct patient-specific models. These patient-specific models can be used for a wide range of purposes including medical teaching, assessment of cardiac function and movement of valve leaflets, design and assessment of devices created for interventional procedures, and pre-surgical planning [1-3]. Additionally, these 3D models can facilitate communication between the clinical team and the patient's owner. The process of creating 3D models starts with acquiring volumetric imaging data sets of the area of interest. Three-dimensional modeling and printing are reliable when high-quality volumetric imaging data are used to create these models. Currently, only ungated- and electrocardiogram (ECG)-gated computed tomography (CT), cardiac magnetic resonance imaging (CMRI), and 3D echocardiography provide the volumetric data sets needed to create these 3D models. These imaging data sets are imported into a software or open-source freeware platform and then segmented to create a virtual 3D model. This virtual 3D model can be further refined using computer-aided design (CAD) software and then be printed to create a physical 3D model. Cardiovascular 3D modeling and printing is a new medical tool which allows us to expand the way we plan interventional procedures, practice interventional skills, communicate with the medical team and owner, and teach future veterinarians.

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.

Evaluation of non-ECG and ECG-gated computed tomographic angiography for three-dimensional printing of anomalous coronary arteries in dogs with pulmonic stenosis.

INTRODUCTION/OBJECTIVES: Coronary artery abnormalities are described sporadically in dogs, most commonly with pulmonic stenosis. Computed tomographic angiography (CTA) allows non-invasive assessment of coronary anatomy. Three-dimensional (3D) models improve the understanding and visualization of spatially complex anatomy. The study objective was to evaluate coronary artery anomalies using CTA imaging and using rapid prototyping technology to create life-sized coronary artery models of these studies. ANIMALS, MATERIAL AND METHODS: Combined retrospective case and prospective pilot study. Inclusion criteria were dogs with reported coronary artery anomalies. The CTA data sets were imported into a medical imaging framework for the analysis of the coronary arteries and into a 3D-planning and printing software for creating printable 3D models. The 3D models were printed using fusion deposition modeling technology. RESULTS: Six male dogs with an R2A coronary artery anomaly and pulmonic stenosis diagnosed by CTA were included. Electrocardiogram (ECG)-gated CTA allowed better identification of anomalous coronary arteries than non-gated CTA. In all dogs, the right coronary artery had a smaller diameter than the left and the left coronary artery or its branch had a prepulmonic course. All ECG-gated studies were 3D printed while non-gated studies were not printable due to CTA artifacts. CONCLUSION: In dogs, CTA is effective for diagnosis of coronary artery anomalies. Printed 3D models of ECG-gated CTA studies were of excellent quality and allowed direct visualization of abnormal coronary artery anatomy. The usefulness of these models to improve the understanding of anomalous coronary artery anatomy could be evaluated in future studies.

Cardiac-gated computed tomography angiography in three alpacas with complex congenital heart disease.

BACKGROUND: The prevalence of congenital heart disease is higher in camelids than in other domestic species and complex defects, often involving the great vessels, are more frequently encountered in llamas and alpacas than in other species. Some of these complex defects can be difficult to accurately characterize via echocardiography, the most commonly used diagnostic imaging technique to evaluate the heart in veterinary patients. Contrast-enhanced, electrocardiogram (ECG)-gated computed tomography (CT) has proven utility for the evaluation of human patients with certain congenital heart defects, including those with conotruncal septation defects and other abnormalities involving the formation of the great vessels. METHODS: Three alpaca crias, 4 days, 5 weeks and 14 months of age were clinically evaluated and subjected to a complete color-flow Doppler echocardiogram and a contrast-enhanced ECG-gated CT. RESULTS: These alpacas exhibited a variety of clinical findings including lethargy, failure to thrive, exercise intolerance, heart murmur, and/or respiratory difficulty. All three crias were subsequently diagnosed with complex cardiac defects including pulmonary atresia with a ventricular septal defect (VSD), a truncus arteriosus with a large VSD, and a double outlet right ventricle with a large VSD and aortic hypoplasia. In each case, the diagnosis was confirmed by postmortem examination. CONCLUSION: Color flow echocardiographic evaluation identified all of the intra-cardiac lesions and associated flow anomalies but contrast-enhanced ECG-gated CT permitted more accurate assessment of the morphology of the extracardiac structures and permitted a more precise determination of the exact nature and anatomy of the great vessels.

Dental pathology in conventionally fed and pasture managed dairy cattle.

Healthy teeth are important in the first stages of digestion for dairy cattle, yet little is known about bovine dental disease. This study aimed to investigate dental pathology of dairy cattle in two parts. First dairy cattle cadaver heads (n=11) were examined at the time of culling. Second, the authors performed oral exams in cattle fed a total mixed ration (TMR) (n=200) and pasture-based (n=71) grazing cattle. Cadaver heads were imaged using radiography and computed tomography before gross dissection to study dental anatomy and pathology. The most prevalent dental abnormalities were excessive transverse ridging of the occlusal surface, the presence of diastemas and third molar dental overgrowths (M3DO) in cadaver heads. Average thickness of subocclusal dentine ranged from 3.5 mm to 5.8 mm in cheek teeth but was >10 mm in maxillary teeth with M3DO. Radiographic findings were compared with oral examinations in live cattle. Prevalence of M3DO upon oral examination was 19 per cent and 28 per cent in herds of cattle fed a TMR diet and 0 per cent in a herd of grazing cattle. Dental abnormalities are prevalent in dairy cattle but due to thin subocclusal dentine in the cheek teeth, established equine dental treatment methodology is not appropriate for bovine cheek teeth with the exception of those that have developed M3DO.

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.

Vertebral fractures in two alpaca crias with rickets syndrome.

CASE REPORT: Two dark-coloured alpaca crias aged 5 and 5.5 months, respectively, born in September in the Pacific Northwest, USA, were presented for evaluation of acute recumbency. Both crias had cervical spine fractures and one had additional fractures in other locations within the spine. Both crias had valgus deformities of the forelimbs and one had similar deformities of the hindlimbs. Both crias showed characteristic radiological signs of rickets syndrome, including wide, irregular physes, cupping of the metaphyses, bowing of long bones, pathological fractures and enlarged costochondral junctions. One cria responded clinically to treatment with parenteral administration of vitamin D. The other cria was euthanased because of the multiple spinal fractures and postmortem examination supported the diagnosis of rickets syndrome. CONCLUSIONS: Hypovitaminosis D is associated with abnormal bone formation in young growing animals. The clinical and laboratory findings of rickets syndrome in camelids in the Pacific Northwest, and other regions with low annual sunlight exposure, have been described, although there are only few reports of the radiological signs associated with this condition in camelids and other animals. Additionally, vertebral fractures have not been previously reported in animals with rickets syndrome. Because vertebral fractures were identified in both crias in this report, it suggests that this is a common and clinically important manifestation of the disease in alpaca crias. Hence, in geographic regions with low sunlight exposure, rickets syndrome should be considered as a differential diagnosis in crias presenting with clinical signs consistent with vertebral fracture.

Primary synovial osteochondromatosis of the stifle in an English Mastiff.

A two-year-old, 97 kg, male neutered English Mastiff was evaluated for left pelvic limb lameness of five months duration localized to the stifle joint. Following radiographic, computed tomographic and arthroscopic examination, the lameness was subsequently diagnosed as being caused by primary synovial osteochondromatosis. In total, 194 osteochondral bodies were removed using arthroscopy in combination with a mini-arthrotomy. Histology and immunohistochemistry of the loose osteochondral fragments confirmed the diagnosis with a moderately high degree of differentiation and low cellularity. Nuclear staining for Ki-67 revealed decreasing differentiation and increasing cellularity in the fragments. At the 13 months telephone follow-up the owner reported that the dog was free from lameness and had a vastly improved function compared with preoperative levels, although mild lameness did occasionally occur. This is the first report of computed tomography, arthroscopy and immunohistochemistry confirming a case of primary synovial osteochondromatosis in a dog.

Surgical management of a Schmorl's node in an Airedale Terrier and review of the literature.

OBJECTIVE: To describe a clinical case of Schmorl's node affecting the lumbosacral disc in an Airedale Terrier including surgical management, short-term outcome, and review of the literature. METHODS: A five-year-old male Airedale Terrier with signs of chronic spinal pain and right hindlimb muscle fasciculation was diagnosed with a Schmorl's node with computed tomography. Repeat imaging performed two months later identified enlargement of the defect in the seventh lumbar vertebra (L7) and herniation of the lumbosacral disc into the spinal canal. RESULTS: Dorsal laminectomy and discectomy were performed and the defect was treated with curettage and stabilization of the L7 and first sacral vertebra disc space with pins and bone cement. Immediately postoperatively, the patient had proprioception deficits in the hindlimbs and decreased right patellar reflex. Over the next four months the dog's neurological condition improved and no neurological or gait deficits were present six months postoperatively. CLINICAL SIGNIFICANCE: Schmorl's node may be a cause of signs of chronic pain in dogs. Successful management may be achieved surgically, although in the case reported here, recovery was prolonged. To the authors' knowledge, this is the first report of progressive enlargement of a Schmorl's node in a dog.