Comparison of cardiac function and coronary angiography between conventional pigs and micropigs as measured by multidetector row computed tomography

Pigs are the most likely source animals for cardiac xenotransplantation. However, an appropriate method for estimating the cardiac function of micropigs had not been established. Computed tomography (CT) analysis aimed at estimating cardiac function and assessing the coronary arteries has not been carried out in micropigs. This study determined the feasibility of evaluating cardiac function in a micropig model using multidetector row computed tomography (MDCT) and compared the cardiac function values with those of conventional pigs. The mean age of the conventional pigs and micropigs was approximately 80 days and approximately 360 days, respectively. The mean body weight in the conventional pigs and micropigs was 29.70 ± 0.73 and 34.10 ± 0.98 kg, respectively. Cardiac MDCT detected ejection fractions of 52.93 ± 3.10% and 59.00 ± 5.56% and cardiac outputs of 1.46 ± 0.64 l/min and 1.21 ± 0.24 l/min in conventional pigs and micropigs, respectively. There were no significant differences in cardiac function between conventional pigs and micropigs in the reconstructed CT images. There were also no differences in the coronary angiographic images obtained by MDCT. It is expected that the results of this study will help improve understanding of cardiac function in micropigs. The data presented in this study suggest that MDCT is a feasible method for evaluating cardiac function in micropigs.     

A three-dimensional pelvimetric assessment on pelvic cavity of gazelle (Gazella subgutturosa) by computed tomography

The gazelles (Gazella subgutturosa), which are at the risk of extinction and are legally protected, have a cultural and aesthetic value in Turkey. It becomes incredibly important to increase their numbers in order to ensure their survival. In this context, it is required to examine thoroughly the pelvic cavity which contains reproductive organs and is used as the birth canal, as well. This study was conducted to determine the pelvimetric data of the gazelles by scanning their pelvic cavity via a multidetector computed tomography (MDCT) and preparing three-dimensional models of the pelvic cavity. Twelve adult (6 females, 6 males) gazelle carcasses were used in the study. After the pelvic cavity was scanned using the MDCT device with 64 detectors at 80 kV, 200 mA, 639 mGY and 0.625 mm cross-section thickness, the MDCT images were obtained. The three-dimensional models of the images obtained using MIMICS 20.1 (The Materialise Group, Leuven, Belgium) program were prepared. Pelvimetric measurements of the pelvic cavity were taken using these models. It was determined based on the pelvimetric examinations that there was a significant difference between the female and male gazelles in terms of conjugate diameter, vertical diameter, intermediate traversal diameter, and cranial and medial transverse diameter data at p < .05. Also, there was a significant difference in their data related to caudal transverse diameter and ischial arch at p < .01. Consequently, it is thought that the use of pelvimetric values belonging to the pelvic cavity of gazelles would reveal the sexual dimorphism of the species and its differences with other species and would contribute to clinical sciences.     

Optimal placement of the region of interest for bolus tracking on brain computed tomography angiography in Beagle dogs

This study aimed to determine the optimal placement of the region of interest (ROI) among four anatomical sites—pulmonary artery (PA), pulmonary vein (PV), aortic arch (AA), and carotid artery (CA)—in computed tomography (CT) brain angiography with automatic bolus tracking in healthy beagle dogs. Six beagles were included, and CT brain angiography was performed four times for each dog, to cover each ROI. The scan parameters, amount, and injection rate of the contrast medium were the same. The major intracranial arteries were selected for quantitative and qualitative evaluation: caudal cerebellar artery (CcA), basilar artery (BA), rostral cerebellar artery (RcA), caudal cerebral artery (CCA), middle cerebral artery (MCA), and rostral cerebral artery (RCA). Quantitative evaluation showed significantly higher CT attenuation values for the RcA, CCA, and MCA in the PA group and RcA and MCA in the PV group than in the CA group. Qualitative analysis revealed significantly higher scores for the BA, CCA, and MCA in the PA and PV groups than in the CA group. Venous contamination did not differ significantly among the ROIs, but the mean scores of the AA and CA groups were higher than those of the PA and PV groups. CT brain angiography using bolus tracking in the beagle dogs showed that the ROI should be placed at the PA or PV rather than at the CA for optimal images with strong contrast enhancement of the BA, RcA, CCA, and MCA and minimal venous contamination.     

Nonselective computed tomography angiography for detecting arterial blood flow to the distal limb following trauma in two small equids

Two equids weighing <250 kg were examined several days after suffering severe mid‐diaphyseal dorsal metatarsal lacerations. Distal limb vascular disruption was suspected in both cases. Nonselective computed tomography angiography with contrast medium injected peripherally via the jugular veins was used to evaluate the vascular supply to the distal limb. The use of this imaging technique demonstrated either intact or disrupted distal limb vasculature. The imaging results were verified with a positive long‐term outcome in the case with a diagnosis of an intact vasculature and with histological findings of avascular necrosis in the case with a diagnosis of disrupted vasculature.     

Non-selective computed tomography angiography of a vascular ring anomaly in a dog

Non-selective computed tomography angiography (CTA) is an emerging imaging technique that will have continued application in veterinary medicine because of its short scan time, use of a single, peripheral venous injection and availability of more detailed anatomic information—including 3-dimensional reconstructions. The improved anatomic detail may facilitate veterinary students' learning of complex aortic arch malformations and details relative to the surgical approach. Herein we describe application of its use in a dog with a vascular ring anomaly due to a persistent right fourth aortic arch and left ligamentum arteriosum. Additionally, we compare images with a normal dog.     

Comparison of Doppler,oscillometric, auricular and carotid arterial blood pressure measurements in isoflurane anesthetized New Zealand white rabbits

ObjectiveTo assess agreement between carotid arterial pressure and auricular arterial, thoracic limb Doppler or thoracic limb oscillometric blood pressure measurements.Study designProspective experimental study.AnimalsSix adult New Zealand white rabbits.MethodsRabbits were anesthetized with isoflurane in oxygen at 1, 1.5 and 2 MAC on two separate occasions. Catheters in the auricular and the contralateral external carotid artery were connected to calibrated pressure transducers via non-compliant tubing. Inflatable cuffs of width equal to approximately 40% of the limb circumference were placed above the carpus on both thoracic limbs with a Doppler transducer placed distal to the cuff on one. Systolic (SAP) and mean (MAP) arterial blood pressure measurements were obtained at each dose, on each occasion. Agreement between measurement techniques was evaluated by repeated measures Bland Altman analysis with carotid pressure as the reference. Variation in bias over the measurement range was evaluated by regression analysis.ResultsCarotid MAP and SAP ranged from 20 to 65 mmHg and 37 to 103 mmHg respectively. Bias and 95% limits of agreement for auricular and oscillometric MAP were 7 (0–14) and ?5 (?21–11) mmHg, respectively, and for auricular, oscillometric and Doppler SAP were 23 (8–37), ?2 (?24–20) and 13 (?14–39) mmHg, respectively. Bias varied significantly over the measurement range (p < 0.001) for all three SAP techniques but not for MAP measurements.Conclusions and clinical relevanceLimits of agreement for all measurements were large but less so for MAP than SAP. Variation in bias with SAP should be considered when using these measurements clinically.     

Anatomical evaluation of hepatic vascular system in healthy beagles using X-ray contrast computed tomography

Liver contrast X-ray computed tomography (CT) has been used for evaluation of hepatic vessels for liver transplantation, liver lobectomy, interventional radiology and diagnosis of hepatocellular carcinoma in humans. However, there remains scant available anatomical information on normal hepatic vessels in the veterinary field. In this study, visualization of hepatic vessels was evaluated in 32 normal beagle dogs by X-ray contrast CT using triple phase images. The following hepatic vessels were clearly visualized: arterial, portal and hepatic veins. With regards to the running patterns of the portal vein and hepatic vein, there were no significant differences between the dogs. However, the hepatic artery exhibited some differences in each dog. In particular, the hepatic artery of the quadrate lobe and the right lateral lobe had many running patterns. The results of the present study could be useful for veterinary diagnosis, surgery and interventional radiology.     

Characterization of triple-phase computed tomography in dogs with pancreatic insulinoma

Little information is available regarding triple-phase computed tomography (CT) of canine pancreatic insulinoma. A few case reports with small numbers of cases have indicated that hyper-attenuation in the arterial phase was a common finding on multi-phasic CT in dogs with insulinoma. Our purpose was to clarify the characteristic findings of dogs with insulinoma on triple-phase CT. Nine dogs with insulinoma that underwent triple-phase CT were included in the present study. Attenuation patterns in the arterial phase indicated hypo-attenuation in 4 cases and hyper-attenuation in 2 cases. In the remaining 3 cases, 1 case showed hypo-attenuation and 1 case showed hyper-attenuation in the pancreatic phase, and 1 case presented hyper-attenuation in the later phase. Altogether, 5 cases showed hypo and 4 cases showed hyper-attenuation in at least one phase. The enhancement pattern was homogenous in 7 cases and heterogeneous in 2 cases. Tumor margins were well-defined in 5 cases and ill-defined in 4 cases. Capsule formation was present in 5 cases and absent in 4 cases. In conclusion, it is important to note that hypo-attenuation was as common as hyper-attenuation in dogs with insulinoma in triple-phase CT in at least one phase. Additionally, mass lesions were most conspicuous not only in the arterial phase but in the pancreatic and later phases in some cases. Therefore, it is important to perform triple-phase CT and notice about variable findings for the detection of canine pancreatic insulinoma.     

A comparison of computed tomography, computed radiography, and film-screen radiography for the detection of canine pulmonary nodules

Computed tomography (CT) has become more widely available and computed radiography (CR) has replaced film-screen radiography for canine thoracic imaging in many veterinary practices. There are limited data comparing these modalities in a veterinary clinical setting to detect pulmonary nodules. We compared CT, CR, and film-screen radiography for detecting the presence, number, and characteristics of pulmonary nodules in dogs. Observer performance for a variety of experience levels was also evaluated. Twenty-one client-owned dogs with a primary neoplastic process underwent CT and CR; nine also received film-screen radiographs. Positive/negative classification by consensus agreed between the three modalities in 8/9 dogs and between CR and CT in the remaining 12. CT detected the greatest (P = 0.002) total number of nodules and no difference was seen between CR and films. The greatest number of nodules was seen in the right middle and both caudal regions, but only using CT (P < 0.0001). Significantly smaller nodules were detected with CT (P = 0.0007) and no difference in minimum size was detected between CR and films. Observer accuracy was high for all modalities; particularly for CT (90.5-100%) and for the senior radiologist (90.5-100%). CT was also characterized by the least interobserver variability. Although CT, CR, and film-screen performed similarly in determining the presence or absence of pulmonary nodules, a greater number of smaller nodules was detected with CT, and CT was associated with greater diagnostic confidence and observer accuracy and agreement.     

Comparisons of computed tomography, contrast-enhanced computed tomography and standing low-field magnetic resonance imaging in horses with lameness localised to the foot. Part 2: Lesion identification

Reasons for performing study: No previous study compares computed tomography (CT), contrast‐enhanced computed tomography (CECT) and standing low‐field magnetic resonance imaging (LFMRI) to detect lesions in horses with lameness localised to the foot. This study will help clinicians understand the limitations of these techniques. Objectives: To determine if CT, CECT and LFMRI would identify lesions within the distal limb and document discrepancies with lesion distribution and lesion classification. Methods: Lesions in specific structures identified on CT and MR images of feet (31 limbs) from the same horse were reviewed and compared. Distributions of lesions were compared using a Chi‐squared test and techniques analysed using the paired marginal homogeneity test for concordance. Results: Lesions of the deep digital flexor tendon (DDFT) were most common and CT/CECT identified more lesions than LFMRI. Deep digital flexor tendon lesions seen on LFMRI only were frequently distal to the proximal extent of the distal sesamoid and DDFT lesions seen on CT/CECT only were frequently proximal to the distal sesamoid. Lesions identified on LFMRI only were core (23.3%) or splits (43.3%), whereas lesions identified only on CT were abrasions (29.8%), core (15.8%), enlargement (15.8%) or mineralisation (12.3%). Contrast‐enhanced CT improved lesion identification at the DDFT insertion compared to CT and resulted in distal sesamoidean impar ligament and collateral sesamoidean ligament vascular enhancement in 75% of cases. Low‐field MRI and CT/CECT failed to identify soft tissue mineralisation and bone oedema, respectively. Conclusions and potential relevance: Multiple lesions are detected with CT, CECT and LFMRI but there is variability in lesion detection and classification. LFMRI centred only on the podotrochlear apparatus may fail to identify lesions of the pastern or soft tissue mineralisation. Computed tomography may fail to identify DDFT lesions distal to the proximal border of the distal sesamoid.     

Technical set‐up and radiation exposure for standing computed tomography of the equine head

The recent adaptation of human computed tomography (CT) machines to enable scanning of the equine head via standing sedation has revolutionised our ability to acquire images of this complex anatomical region. There are a small number of CT systems installed worldwide and it is to be expected that this will increase in the next few years; however, currently, there is no publication that describes the technical set‐up required to permit CT scanning of the equine head. This paper describes the technical set‐up, technique and exposures necessary to accomplish CT scanning of the horse under standing sedation to diagnose disorders of the equine head.     

Comparison of cardiac measurements by multi-detector computed tomography angiography and transthoracic echocardiography in English bulldogs

Introduction

Transthoracic echocardiography (TTE) is the primary tool for the assessment of cardiac structure and function in dogs but is challenging in English bulldogs due to dorsoventral compression of the thorax, obesity, and narrow intercostal spaces. Multi-detector computed tomography angiography (CTA) may overcome the conformational obstacles of cardiac imaging in this breed.

Histopathology and computed tomography of age‐associated degeneration of the equine temporohyoid joint

Reasons for performing study: The aetiology of temporohyoid osteoarthropathy (THO) is unknown; both primary infectious and degenerative causes have been suggested. Hypothesis: There is a significant association between increasing age and severity of temporohyoid joint degeneration. To examine the histopathology of the temporohyoid articulation in aged horses and to compare the appearance of the joint with computed tomography (CT) and peripheral quantitative CT (pQCT). Methods: pQCT scans of the temporohyoid articulations were obtained bilaterally from 31 horses (range age 1–44 years) post mortem and images were graded by 2 blinded observers on 2 occasions for the presence of osteophytes, irregularity of the joint surface and mineralisation. Eight heads had been examined previously by CT, with the images similarly graded for the shape and density of the proximal stylohyoid bones, bone proliferation surrounding the joint, mineralisation of the tympanohyoid cartilage and the relationship of the petrous temporal bone to the stylohyoid bone. Sixteen temporohyoid joints were then evaluated histologically. Results: There was significant association between the mean pQCT degeneration score and age (rho = 0.75; P<0.0001), between the pQCT and CT score (rho = 0.63; P = 0.01) and between the degenerative changes identified within each temporohyoid joint within each horse (rho = 0.81; P<0.0001). Age‐associated changes included the development of a club shape by the proximal stylohyoid bone, rounding of the synostosis with the petrous temporal bone and extension of osteophytes from the petrous temporal bone to envelope the stylohyoid head and bridge the joint. In no horse was there any evidence of osteomyelitis within the petrous temporal bone, stylohyoid bone or tympanohyoid cartilage. Conclusions: This study provides evidence that age is associated with increasing severity of degenerative changes in the equine temporohyoid joint and that similar changes are commonly found bilaterally. Potential relevance: The changes identified appear similar, albeit milder to the changes reported in horses with THO, suggesting that degenerative, rather than infectious causes may underlie the aetiology of THO. Future work should be directed at examining the histopathology of clinical THO cases.     

Use of multi‐detector computed tomographic angiography in the diagnosis of a parapharyngeal aneurysm in a 6‐week‐old foal

Multidetector‐row computed tomographic contrast angiography (MDCTA) is routinely employed to investigate vascular masses in human patients but, to date, the use of this technique to investigate an aneurysmal mass has not been reported in an equine case. The potential of MDCTA to investigate a right‐sided parapharyngeal mass in a 6‐week‐old Thoroughbred foal was therefore investigated. A 4‐slice helical computed tomography scanner was used on a superficial, firm, ovoid mass yielding arterial blood on fine needle aspiration. MDCTA enabled identification of the vessels involved thus assisting in forming a diagnosis based on the morphology of the lesion and aided surgical planning. Histology confirmed the presence of mural thrombus and calcification within the smooth muscle wall consistent with a true aneurysm. MDCTA provided additional information to conventional imaging in this case of vascular masses of the head and neck. The technique therefore has the potential to improve diagnosis and assist in the management of such lesions.     

The use of computed tomography to assist orthopaedic surgery in 86 horses (2002–2010)

Imaging‐assisted orthopaedic surgery is becoming part of routine orthopaedic practice in horses and several techniques have been reported. However, there are no published reports describing the use of intraoperative computed tomography (CT) for surgical guidance and immediate post operative control in the horse. This use of CT in equine orthopaedics is currently limited because of the logistic problems associated with availability of CT scans in surgical theatres as well as concerns over radiation safety. The aim of this report was retrospectively to report CT assisted orthopaedic surgical cases in our practice through identifying the types of surgery where it was used, to list the technical problems that were encountered, to describe solutions to these, and to discuss the applications of the technique. All surgical procedures were performed with the assistance of a peripheral quantitative computed tomography (pQCT) scanner. CT assisted orthopaedic surgery in 86 patients during the study period. Reasons for CT included: 1) use of CT at the beginning of the surgical procedure to document the lesion and identify surgical landmarks (n = 75); 2) pre, intra‐ and post operative use of CT in comminuted fractures of the middle or proximal phalanx to guide and control internal fixation (n = 7); and 3) post operative use of CT to monitor the results of the surgical procedure (n = 4). Proper planning in both the draping steps and the use of polyvinyl splints to stabilise the limb allowed for movements of the gantry around the limb. The time required to obtain one slice was not dissimilar to the time that is necessary to take and process a single digital radiograph. The radiation dose with the pQCT described here is <0.5 µSv and its acquisition time should be balanced against radiation risks of conventional CT systems.     

Medial insertion of the patent ductus arteriosus characterized by computed tomography angiography in a cat and dog

Surgical ligation of a left-to-right shunting patent ductus arteriosus was attempted in two animals. In both cases, a young cat and dog, ligation was complicated by poor visualization of the ductus resulting in unsuccessful ligation. Post-operatively, both the cat and dog underwent computed tomography angiography to characterize the location and morphology of the patent ductus arteriosus. In both cases, computed tomography angiography revealed a left-to-right shunting patent ductus arteriosus with an insertion location medial to the left pulmonary artery branch compared to the typical location. We hypothesize that this atypical location resulted in a difficult surgical visualization from the left thoracotomy approach. Transvenous coil embolization of the duct from the external jugular vein was performed in both cases and resulted in successful occlusion. Variations in the medial-lateral insertion of the ductus arteriosus may have consequences for surgical intervention. If an atypical location of a patent ductus arteriosus is suspected on transthoracic echocardiography, computed tomography angiography prior to ligation may be useful to further define ductal location and help guide the surgical approach.     

Histological and morphometric evaluation of the urethra and penis in male New Zealand White rabbits

This stereudy aimed at performing a histological and morphometric evaluation of the urethra and penis of male rabbits. Seven male New Zealand White rabbits weighing 2.1–3 kg were used in the study. The whole urethra, from the urinary bladder to the external urethral orifice, was dissected from the rabbits, and the tissue was sliced into sections at an interval of 2 mm. The sections were stained with haematoxylin–eosin, Masson–Goldner trichrome stain, Van Gieson's stain and Movat–Russell modified pentachrome stain. A detailed evaluation of the morphology and morphometry was performed. The parameters assessed were the type and height of epithelium, thickness and composition of connective tissue, and thickness and structure of muscularis. The histological structure of the rabbit urethra was found to be similar to humans. However, although the rabbits were found to have the same type of penis as the humans, the internal structure of the corpora cavernosa, the relative thickness of the tunica albuginea and the rudimentary glands of the penis were found to differ in these animals. The results of the present study may be useful in the designing of implants, drug testing or surgical procedures on the physiological and pathological urethra.     

Intra‐ and interobserver agreement in the interpretation of navicular bones on radiographs and computed tomography scans

Reasons for performing study: Criteria for the radiographic evaluation of navicular bones in horses have been published to standardise classification of radiographic signs. However, intra‐ and interobserver agreement have not been established. Objective: To determine intra‐ and interobserver agreement in the evaluation of radiographic and computed tomographic (CT) navicular changes. It was hypothesised that: 1) intraobserver agreement would be better than interobserver agreement; 2) agreement would be better for CT than for radiography; and 3) pathological changes would be recognised with greater certainty with CT. Methods: Radiographs and CT scans of 60 cadaver navicular bones were evaluated by 3 observers using published criteria. A subset of 30 studies was evaluated twice by one observer. Agreement was tested using the kappa statistic. Certainty about pathological changes was evaluated by giving the observers the option to choose ‘not sure’. Results: Agreement varied from poor to almost perfect for radiographic evaluation and from poor to substantial for CT evaluation. For radiographic evaluation mean interobserver agreement was fair, as it was for CT evaluation. For radiographic evaluation mean intraobserver agreement was moderate as it was for CT evaluation. Pathological changes were evaluated with greater certainty on CT scans compared to radiographs; however, this was not associated with improved agreement. Conclusions: Variations in classification of navicular lesions in radiographic and CT studies were considerable between and within observers and challenge the use of such studies for diagnostic and prognostic purposes. Potential relevance: The results of this study allowed the identification of evaluation criteria with sufficient precision to be useful for navicular bone evaluation.