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1.
Karen L.  Morrow  DVM  MS  Richard D.  Park  DVM  PhD  Thomas L.  Spurgeon  PhD  Ted S.  Stashak  DVM  MS  Billie  Arceneaux  RT 《Veterinary radiology & ultrasound》2000,41(6):491-497
The head from three horses euthanized due to diseases unrelated to the head and neck was imaged using computed tomography (CT). Gross cross-sectional slices of equine head #1 and skeleton of equine head #2 were compared with the CT images of the three equine heads to identify normal structures of the cranium, brain, paranasal sinuses, nasal cavity, and teeth. Labeled transverse CT images of the equine head are presented sequentially as a reference for normal anatomy.  相似文献   

2.
A technique for regional delivery of contrast medium to the foot of the horse to increase the diagnostic utility of computed tomography (CT) for the characterization of soft tissue structures within the hoof capsule was developed. An intraarterial catheter was placed under ultrasound guidance into the medial palmar artery at the level of the carpus to facilitate a steady-state infusion of iodinated contrast medium. Two 5 mm collimated contiguous acquisition CT scans were performed in 10 horses without lameness or radiographic evidence of distal sesamoid bone degeneration. CT examination was performed before and during regional arterial infusion of iodinated contrast medium administered at a rate of 2 ml/s. Cross-sectional area and mean pre- and post-contrast attenuation of the deep digital flexor tendon and the collateral ligaments of the distal interphalangeal joint were quantified from CT images. Soft tissue anatomy of the foot was also qualitatively characterized from pre- and postcontrast images. Catheterization was successful and without complication in all horses. The evaluated tendons and ligaments were clearly visible and had a small (8-20 Hounsfield Unit) but significant (P < 0.05, paired t-test) increase in attenuation during the steady-state infusion of contrast medium. This study should enhance the diagnostic potential of CT by providing baseline quantitative data for comparison with horses affected with soft tissue injuries in the distal extremity causing lameness that is alleviated with a palmar digital nerve block.  相似文献   

3.
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4.
Radiography is the most commonly applied imaging modality in equine practice and forms an essential part of the diagnostic work-up of lame horses. Radiographic signs of musculoskeletal pathology are frequently localized at sites of soft tissue attachment, which are often not clearly visible on radiographs. Different lesions carry different prognoses and require a variety of treatments, and a good knowledge of the position of the synovial structures in the distal limb of the horse is essential for practitioners in the interpretation of radiographs. This study describes a new technique for creating three-dimensional (3D) models of the synovial structures and superimposing them onto radiographs for the purpose of teaching radiographic anatomy. A set of standard radiographs was acquired of the metacarpophalangeal and the distal interphalangeal joints of a fresh cadaver leg while the leg was positioned in a material-testing machine to mimic the weight-bearing horse. Computed tomography of the same regions was performed after injection of negative contrast medium into the joints. 3D reconstructions of the joints were created using grayscale thresholding and polynomial surface meshing in Mimics. The resulting 3D reconstructions were superimposed on top of the radiographs using Adobe© Photoshop© CS3 Extended, thus allowing the visualization of the joint anatomy in relation to the bone on all projections. The main advantage of this technique is that it allows synovial structures to be visualized on radiographs where they are normally indistinct, which will serve as a teaching aid for anatomy.  相似文献   

5.
Positron emission tomography (PET) is a highly sensitive, noninvasive imaging technique for quantifying biological functions of tissues. However, at the time of this study, PET imaging applications had not been reported in the horse. The aim of this exploratory study was to determine whether a portable high‐resolution PET scanner could be used to image the equine distal limb. Images of the front feet and fetlocks of three research horses, with known lesions localized to the distal front limbs, were acquired under general anesthesia after administration of 18F‐fluorodeoxyglucose (18F‐FDG), with doses ranging from 1.5 to 2.9 MBq/kg. The radiation exposure measured during imaging was slightly higher than 99mTechnetium scintigraphy. However, the use of general anesthesia allowed the proximity and the contact time with the patient to be minimized for the staff involved. 18F‐FDG uptake was evident throughout the soft tissues, with the highest uptake in the coronary band and the lowest uptake in the tendons. Anatomic structures could be discriminated due to the high contrast between soft tissue and bone. Detected lesions included lysis of the flexor cortex of the navicular bone, lesions of flexor tendons and suspensory ligament, and abnormal uptake through the lamina of a laminitic subject. Findings indicated that tomographic molecular imaging is feasible in the equine distal limb and could be useful as a future diagnostic technique for clinical and research studies, especially those involving tendinopathy/desmopathy and laminitis.  相似文献   

6.
Access to volumetric imaging modalities, such as magnetic resonance imaging (MRI) and computed tomography (CT), has increased over the past decade and has revolutionised the way clinicians evaluate equine anatomy. More recent advancements have resulted in the development of multiple commercially available cone-beam CT (CBCT) scanners for equine use. CBCT scanners modify the traditional fan-shaped beam of ionising radiation into a three-dimensional pyramidal- or cone-shaped beam of radiation. This modification enables the scanner to acquire sufficient data to create diagnostic images of a region of interest after a single rotation of the gantry. The rapid acquisition of data and divergent X-ray beam causes some artifacts to be more prominent on CBCT images—as well as the unique cone-beam artifact—resulting in decreased contrast resolution. While the use of CT for evaluation of the equine musculoskeletal anatomy is not new, there is a paucity of literature and scientific studies on the capabilities of CBCT for equine imaging. CBCT units do not require a specialised table for imaging and in some cases are portable for imaging in the standing or anaesthetised patient. This review article summarises the basic physics of CT technology, including how CBCT imaging differs, and provides objective information about the strengths and limitations of this modality. Finally, potential future applications and techniques for imaging with CT which will need to be explored in order to fully consider the capabilities of CT imaging in the horse are discussed.  相似文献   

7.
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8.
Reasons for performing study: To date, few reports exist comparing magnetic resonance imaging (MRI) and computed tomography (CT) for imaging of the equine distal limb, yet clinicians are required to decide which modality to use regularly. Objectives: To report and compare anatomic visualisation scores obtained for CT, contrast enhanced CT (CECT) and standing low‐field MRI (LFMRI) in the equine foot. Hypothesis: Anatomic visualisation score discrepancies would exist between CT, CECT and LFMRI. Methods: Images of 22 lame horses (31 limbs) undergoing both CT and LFMRI of the foot were reviewed. When available, CECT images were reviewed. The deep digital flexor tendon (DDFT) was categorised into proximal to distal levels (A–D), structures were assigned visualisation scores (Grades 0–3) and technique comparisons were made using the paired marginal homogeneity test. Results: Computed tomography and LFMRI had similar visibility scores for the navicular bone, middle phalanx, DDFT‐B, collateral ligaments of the distal interphalangeal joint and collateral sesamoidean ligament of the navicular bone. The proximal and distal phalanx had lower visibility scores with LFMRI. The distal DDFT (C–D), distal sesamoidean impar ligament and synovial structures had higher scores with LFMRI. Contrast enhanced CT lowered DDFT and collateral sesamoidean ligament scores and raised distal interphalangeal synovium CT visualisation scores. Conclusions and potential relevance: Visualisation scores differ depending on imaging technique and anatomic structure of interest. This information increases our understanding of the limitations of CT, CECT and LFMRI to visualise anatomy in clinical cases.  相似文献   

9.
Understanding radiographic anatomy and the effects of varying patient and radiographic tube positioning on image quality can be a challenge for students. The purposes of this study were to develop and validate a novel technique for creating simulated radiographs using computed tomography (CT) datasets. A DICOM viewer (ORS Visual) plug‐in was developed with the ability to move and deform cuboidal volumetric CT datasets, and to produce images simulating the effects of tube‐patient‐detector distance and angulation. Computed tomographic datasets were acquired from two dogs, one cat, and one horse. Simulated radiographs of different body parts (n = 9) were produced using different angles to mimic conventional projections, before actual digital radiographs were obtained using the same projections. These studies (n = 18) were then submitted to 10 board‐certified radiologists who were asked to score visualization of anatomical landmarks, depiction of patient positioning, realism of distortion/magnification, and image quality. No significant differences between simulated and actual radiographs were found for anatomic structure visualization and patient positioning in the majority of body parts. For the assessment of radiographic realism, no significant differences were found between simulated and digital radiographs for canine pelvis, equine tarsus, and feline abdomen body parts. Overall, image quality and contrast resolution of simulated radiographs were considered satisfactory. Findings from the current study indicated that radiographs simulated using this new technique are comparable to actual digital radiographs. Further studies are needed to apply this technique in developing interactive tools for teaching radiographic anatomy and the effects of varying patient and tube positioning.  相似文献   

10.
Vascular alterations play important roles in many orthopedic diseases such as osteoarthritis, tendonitis, and synovitis in both human and equine athletes. Understanding these alterations could enhance diagnosis, prognosis, and treatment. Contrast‐enhanced ultrasound (CEUS) could be a valuable method for evaluation of blood flow and perfusion of these processes in the equine distal limb, however no reports were found describing feasibility or safety of the technique. The goal of this prospective, experimental study was to describe the feasibility and safety of distal limb CEUS in a sample of six horses. For each horse, CEUS of the distal limb was performed after intravenous injections of 5 and 10 ml, as well as intra‐arterial injections of 0.5 and 1 ml contrast medium. Vital parameters were monitored and CEUS images were assessed qualitatively and quantitatively for degree of contrast enhancement. None of the horses had clinically significant changes in their vital parameters after contrast medium injection. One horse had a transient increase in respiratory rate, and several horses had mild increases of systolic blood pressure of short duration after intravenous, but not after intra‐arterial injections. Intra‐arterial injection was possible in all horses and resulted in significantly improved contrast enhancement both quantitatively (P = 0.027) and qualitatively (P = 0.019). Findings from this study indicated that CEUS is a feasible and safe diagnostic test for evaluation of the equine distal limb. Future studies are needed to assess the clinical utility of this test for horses with musculoskeletal diseases.  相似文献   

11.
With the advancement of technology, more tools and methods are being made available for the assessment of bone density in the live animal. Computed tomography (CT) is one such tool. In a CT scan, x-rays are passed through a subject and detectors record transmitted energy. The CT computer then constructs cross-sectional images from this data to represent the internal anatomy.The first objective of this study was to investigate CT as a means of estimating bone mineral content of the equine third metacarpal bone. Our hypothesis was that the cross-sectional area of the third metacarpal bone, as measured on CT images, would correlate significantly with ash weight of that section. Our second objective was to use CT to measure and compare bone density in the dorsal, palmar, lateral and medial cortices of the equine third metacarpus. We hypothesized that CT would detect differences in density by cortex.Twelve cadaver thoracic limb specimens, from horses of varying age, breed and prior use, were scanned on a CT 9800 (GE Medical Systems). Scanned sections of the limb were then skinned, dried, ether-extracted and ashed in a muffle furnace. Bone mineral content was expressed as grams of ash/cm section of bone. The image recorded by the CT was developed and assessed using an imaging photodensitometer and a corresponding software package to estimate the area of each bone section. Correlation was determined using SAS (6.12). Differences in bone density by cortex were calculated using a simple t-test. The maximum, minimum and mean estimates of third metacarpal bone cross-sectional area as determined by CT were 519, 351 and 423 mm2, respectively, while the maximum, minimum and mean ash weights were 8.9, 4.8 and 6.4 g/cm, respectively. Estimates of bone mineral content by ash and cross-sectional area as determined by CT were significantly correlated (r=.91, P=.0001). There was no difference in CT density numbers between lateral and medial cortices, however the dorsal cortex was lower in density than the lateral (P<.05) and the palmar cortex was lower in density than all other cortices (P<.05). This data suggests that in a research setting, CT is an effective method by which to calculate cross-sectional area and, hence, estimate bone mineral content. Computed tomography was also able to detect differences in bone density by cortex.  相似文献   

12.
Charles R.  Pugh  DVM  MS  Phillip J.  Johnson  BVSc  MS  Gregory  Crawley  DVM  MS  Susan T.  Finn  DVM  MS 《Veterinary radiology & ultrasound》1994,35(3):183-188
The equine shoulder region is difficult to investigate by conventional imaging modalities. Diagnostic ultrasound has proven valuable for investigation of soft tissue injuries of the human shoulder. In a horse with shoulder lameness, the authors employed diagnostic ultrasound to augment the use of conventional radiography. A defect in the subchondral bone layer of the medial humeral tuberosity, with adjacent bony fragments were clearly identified with ultrasound. Ultrasound was used for initial evaluation of the bicipital tendon and bursa. The technique was subsequently used to follow and evaluate the post-operative condition of the proximal cranial humerus, bicipital tendon and bursa in this patient. The bicipital regions of 2 immature and 3 adult normal horses were also examined with to illustrate the normal ultrasonographic anatomy of the cranial shoulder region.  相似文献   

13.
Biomechanical models that compute the lengths and forces of muscle-tendon units are broadly applicable to the study of factors that promote injury and the planning and effects of orthopedic surgical procedures in equine athletes. A three-dimensional (3D) generic musculoskeletal model of the equine forelimb comprised of bony segment, muscle-tendon, and ligament information, was developed based on high-resolution computed tomographic (CT) and T1-weighted magnetic resonance (MR) images from an isolated forelimb of a Thoroughbred racehorse. Image fusion was achieved through coregistration of CT and MR images with an image analysis program (Analyze) by adjustment of the relative position and orientation of fiducial markers visible in both modalities until the mutual information between the images was maximized. 3D surfaces of the bones and origin/insertion sites, centroid paths and volumes of the muscle-tendon and ligamentous structures were obtained from the multimodal (CT/MR) images using semiautomated and manual segmentation combined with sagittal and transverse color-cryosection anatomic images obtained from three other cadaveric equine forelimbs. Once bony and soft-tissue structures were reconstructed in the same coordinate system, data were imported to a software package for interactive musculoskeletal modeling (SIMM). The combination of integrated CT and MR acquisitions and anatomical images provided an accurate and efficient means of generating a 3D model of the musculoskeletal structures of an average-sized equine adult horse.  相似文献   

14.
Ultrasonography has gained increased utility to diagnose pelvic fractures in horses; however, internal pelvic contours can be difficult to appreciate from external palpable landmarks. We developed three‐dimensional (3D) simulations of the pelvic ultrasonographic examination to assist with translation of pelvic contours into two‐dimensional (2D) images. Contiguous 1 mm transverse computed tomography (CT) images were acquired through an equine femur and hemipelvis using a single slice helical scanner. 3D surface models were created using a DICOM reader and imported into a 3D modeling and animation program. The bone models were combined with a purchased 3D horse model and the skin made translucent to visualize pelvic surface contours. 3D models of ultrasound transducers were made from reference photos, and a thin sector shape was created to depict the ultrasound beam. Ultrasonographic examinations were simulated by moving transducers on the skin surface and rectally to produce images of pelvic structures. Camera angles were manipulated to best illustrate the transducer–beam–bone interface. Fractures were created in multiple configurations. Animations were exported as QuickTime movie files for use in presentations coupled with corresponding ultrasound videoclips. 3D models provide a link between ultrasonographic technique and image generation by depicting the interaction of the transducer, ultrasound beam, and structure of interest. The horse model was important to facilitate understanding of the location of pelvic structures relative to the skin surface. While CT acquisition time was brief, manipulation within the 3D software program was time intensive. Results were worthwhile from an instructional standpoint based on user feedback.  相似文献   

15.
Although horses are affected by cranial nerve disease, our understanding of these structures' imaging anatomy is limited, and the optimal modality for imaging of each of these nerves is unclear. The aim of this study was to describe the imaging appearance of the equine cranial nerves on high‐resolution 1.5T magnetic resonance imaging (MRI) and computed tomography (CT) scans of a cadaver head, and with these as standards, examine the utility of MRI and CT performed in clinical cases. High‐resolution MRI and CT images were prospectively acquired of the head of a normal Thoroughbred gelding following euthanasia. Ten clinical cases undergoing high‐field MRI under general anaesthesia and 10 clinical cases undergoing CT in the standing horse under sedation were retrospectively evaluated by three reviewers to assess cranial nerve visibility. On high‐resolution, thin‐slice, MRI scans of the normal cadaver head, each of the 12 cranial nerves and their topographic location could be appreciated. On high‐resolution cadaver CT, cranial nerves II, V and VII were clearly visible, but others were less easily identified; osseous structures were clearly visualised. Clinical MRI and CT allowed for variable visualisation of the cranial nerves, dependent on the sequence and the orientation of scan planes. High‐field MRI allowed excellent visualisation of equine cranial nerves, whereas CT allowed for more detailed visualisation of the osseous canals and foramina. In live horses, the ability to identify all 12 nerves is challenging with either MRI or CT; however, high‐field MRI enables better visualisation of the nerve bundles than CT.  相似文献   

16.
Comminuted fractures of the middle phalanx have been well described in the horse. Choice of treatment, surgical planning and prognosis have traditionally been based upon evaluation of radiographs. However, the complex nature of comminuted fractures makes radiographic interpretation difficult. Computed tomography (CT) allows the production of cross-sectional images with spatial separation of structures which are superimposed on survey radiographs. This allows accurate assessment of the number and direction of fracture lines within the bone. In this paper we report the use of CT in the evaluation of 6 comminuted middle phalangeal fractures. Computed tomography is potentially useful in deciding the type of treatment, surgical planning and determining the prognosis.  相似文献   

17.
The head of a newborn dolphin (Tursiops truncatus), that died shortly after birth was imaged using computed tomography (CT). Gross cross-sectional slices of the head were compared with the CT images to identify normal structures of the cranium, brain, and respiratory and digestive pathways. Labelled transverse CT images of the dolphin head are presented sequentially as a reference for normal anatomy.  相似文献   

18.
Chronic laminitis is a severe disease affecting the equine digit. It was hypothesized that magnetic resonance (MR) imaging would improve visualization of structures within the foot and pathology associated with chronic laminitis. This study aimed to describe the MR imaging findings in chronic laminitis, compare different pulse sequences for visualization of pathology, and to compare MR imaging with standard radiography. Twenty (10 forelimb, 10 hindlimb) cadaver limbs from 10 horses clinically diagnosed with chronic laminitis (group L) and 10 limbs without laminitis (group N) were used. Lateromedial radiographs and sagittal and transverse MR images of the foot were obtained. Radiographs and MR images were evaluated for anatomic definition and evidence of pathology. Dorsal hoof wall thickness and angle of rotation and displacement distance of the distal phalanx were measured. Comparisons were made between group L and N, forelimb and hindlimb within each horse, and MR imaging and radiography. Features consistently noted with MR images in group L, but not detected using radiography, included laminar disruption, circumscribed areas of laminar gas, laminar fluid, and bone medullary fluid. Other findings seen only on MR images included increased size and number of vascular channels, alterations in the corium coronae, and distal interphalangeal joint distension. Magnetic resonance imaging allowed better definition of laminar gas lines and P3 surface irregularity observed on radiographs. Based on measurements, group L had a greater angle of rotation, distal displacement, and dorsal hoof wall thickness than group N; forelimb hoof wall thickness was greater than hindlimb; and distal displacement and hoof wall thickness measurements were smaller using MR imaging than radiography, but had a similar pattern. It is concluded that there are features of chronic laminitis consistently observed using MR imaging and that these may be additional to features observed radiographically.  相似文献   

19.
Per  Martens  DVM  Carl F.  Ihler  DVM  PhD  Jan  Rennesund  DVM 《Veterinary radiology & ultrasound》1999,40(4):346-349
A horse with a suspected injury of the distal phalanx was examined using radiography at day two and 19 after the onset of the lameness, with no definite diagnosis. Using computed tomography an incomplete fracture of the lateral wing of the distal phalanx was diagnosed at day 25. Based on computed tomography it was determined that the fracture probably did not enter the joint or involve the palmar cortex throughout its length which were of prognostic importance. The day following the CT examination a new oblique radiographic projection was made. In this radiography which was based on, and never would have been attempted without, the information about the geometric pattern of the fracture achieved by CT examination, a radiolucent area indicative of a wing fracture was seen. This report emphasizes the value of computed tomography in diagnosing a geometric complicated nonarticular oblique fracture of the palmar process of the pedal bone in a horse.  相似文献   

20.
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.  相似文献   

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