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Topic:Computed Tomography
Computed Tomography (CT) in horses is an advanced imaging technique used to obtain detailed cross-sectional images of equine anatomy. This non-invasive method utilizes X-ray technology combined with computer processing to create detailed images of bones, soft tissues, and other internal structures. CT is particularly useful for diagnosing complex conditions in the head, neck, and limbs of horses, offering enhanced visualization compared to traditional radiography. The technique is valuable for identifying fractures, dental issues, sinus diseases, and other abnormalities. This page compiles peer-reviewed research studies and scholarly articles that explore the applications, advancements, and clinical implications of computed tomography in equine medicine.
Intra- and interobserver agreement in the interpretation of navicular bones on radiographs and computed tomography scans. 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...
[Atypical dislocated dens fracture type II with rotational atlantoaxial luxation after a riding accident]. We present a rare case of a combined dislocated odontoid dens fracture type II (Anderson/D'Alonzo) and rotational atlantoaxial luxation in a 15-year-old girl who was involved in a riding accident.She fell off her horse after it had stopped suddenly, losing consciousness for a few minutes. At presentation in the hospital, she had no complaints other than limited, painful neck movement. Radiologically, a posterior dislocation of an odontoid type II fracture (Anderson/D'Alonzo) was found. Computed tomography reconstruction demonstrated a rotational, hooklike fixed luxation of the left atlantoaxia...
The computed tomographic appearance of equine temporohyoid osteoarthropathy. Equine temporohyoid osteoarthropathy is characterized by progressive osseous proliferation of the temporohyoid articulation and surrounding structures. The diagnosis has generally been made using radiography and endoscopy of the guttural pouch. Recently, computed tomography (CT) has been used in the diagnosis of temporohyoid osteoarthropathy. This study was performed to determine the CT imaging characteristics of temporohyoid osteoarthropathy and to compare these to radiographic and endoscopic findings. CT scans from 16 horses with a final diagnosis of temporohyoid osteoarthropathy were review...
Use of computed tomography to diagnose new bone formation associated with desmitis of the proximal aspect of the suspensory ligament in third metacarpal or third metatarsal bones of three horses. 3 horses with lameness localized to the proximal aspect of the metacarpus or metatarsus. Results: All horses had evidence of problems that originated from the proximal aspect of the suspensory ligament (PASL), including signs of pain on palpation, positive results of diagnostic nerve blocks, ultrasonographic detection of enlargement and diffuse areas of reduced echogenicity in the proximal region of insertion of the ligament, and radiographic detection of increased mineral opacity in the proximal aspect of the metacarpus or metatarsus. Desmitis of the PASL was diagnosed in each horse; however,...
In vivo effects of intra-articular injection of gelatin hydrogen microspheres containing basic fibroblast growth factor on experimentally induced defects in third metacarpal bones of horses. To evaluate the effect of intra-articular injection of gelatin hydrogel microspheres containing basic fibroblast growth factor (bFGF) on experimentally induced defects in third metacarpal bones (MC3s) of horses, in vivo. Methods: 6 healthy adult Thoroughbreds. Methods: Horses were anesthetized, and a hole (diameter, 4.5 mm) was drilled into the medial condyle of both MC3s of each horse. One milliliter (100 microg) of a solution of gelatin hydrogel microspheres (2 mg) containing bFGF was injected into the joint capsule of the right metacarpophalangeal joint of each horse (bFGF joint). One milli...
Computed tomographic anatomy of the temporomandibular joint in the young horse. The equine temporomandibular joint (TMJ) and its surrounding structures can be difficult to investigate in cases with a clinical problem related to the region. Little previous attention has been given either to a computed tomographic (CT) imaging protocol for the joint or an interpretation of the structures displayed in CT images of the normal joint. Objective: To provide a CT atlas of the normal cross-sectional anatomy of the equine TMJ using frozen and plastinated sections as anatomical reference. Methods: Eight TMJs from 4 immature pure-bred Spanish horses were examined by helical CT. Scans...
ISSLS prize winner: positron emission tomography and magnetic resonance imaging for monitoring interbody fusion with equine bone protein extract, recombinant human bone morphogenetic protein-2, and autograft. Prospective and randomized experimental study with anterior lumbar interbody fusion in a porcine model. Objective: To assess the early time-course of spinal fusion with equine bone protein extract (COLLOSS E), recombinant human bone morphogenetic protein-2 (rhBMP-2), and autograft using quantitative methods of positron emission tomography (PET)/computed tomography and magnetic resonance imaging (MRI). Background: Different growth and differentiation factors are currently being used for inducing bone formation in spinal fusion. However, the mechanisms and time-course of bone formation using the...
Mechanical properties of subchondral bone in the distal aspect of third metacarpal bones from Thoroughbred racehorses. To characterize the mechanical properties of subchondral bone (SCB) of the distopalmar aspect of the condyles of the third metacarpal bone (MC3) and their correlations with structural aspects of MC3s in Thoroughbred racehorses. Methods: 12 pairs of MC3s from Thoroughbred racehorses euthanized for various reasons. Methods: MC3s were collected from horses with mild (n = 6) and with severe (6) SCB changes, as determined by micro-computed tomography (CT). Specimens of SCB plate and trabecular bone were cut from the distopalmar aspect of condyles and sagittal ridge and examined with 3-dimensional m...
Structural characterization of subchondral bone in the distal aspect of third metacarpal bones from Thoroughbred racehorses via micro–computed tomography. To characterize the microstructure of subchondral bone (SCB) plate and trabecular bone (TBB) of the distopalmar aspect of the condyles of third metacarpal bones (MC3s) from Thoroughbred racehorses at 2 different stages of SCB disease via micro-computed tomography (CT). Methods: 12 pairs of MC3s from Thoroughbred racehorses euthanized for various reasons. Methods: MC3s were collected from horses with mild (n = 6) or severe (6) SCB disease, as determined via micro-CT. Cubic (6 x 6 x 6-cm) specimens of SCB plate and TBB were cut from the palmar aspect of condyles and sagittal ridges and examined ...
Correlation of quantitative computed tomographic subchondral bone density and ash density in horses. The purpose of this study was to compare subchondral bone density obtained using quantitative computed tomography with ash density values from intact equine joints, and to determine if there are measurable anatomic variations in mean subchondral bone density. Five adult equine metacarpophalangeal joints were scanned with computed tomography (CT), disarticulated, and four 1-cm(3) regions of interest (ROI) cut from the distal third metacarpal bone. Bone cubes were ashed, and percent mineralization and ash density were recorded. Three-dimensional models were created of the distal third metacarpal...
Computed tomography-guided brain biopsy for in vivo diagnosis of a cholesterinic granuloma in a horse. An 8-year-old warmblood mare was evaluated following an acute onset of neurologic abnormalities. Results: Computed tomography of the head revealed large masses in both lateral ventricles, and a presumptive diagnosis of cholesterinic granuloma was made. Results: Freehand biopsy of the intracranial masses was performed under computed tomographic guidance, and histologic examination of biopsy specimens confirmed the diagnosis. No adverse effects associated with the brain biopsy procedure were encountered. Clinical signs resolved, and long-term follow-up did not reveal any recurrence of neurologic...
Necrosis of the nasal conchae in 12 horses. Twelve horses with a history of a unilateral malodorous nasal discharge were examined clinically, endoscopically and radiographically. The head of one of the horses was examined by computed tomography. Tissue samples were taken for microbiology from four of the horses and for histology from three. The conchal necrosis was unilateral in 11 of the horses and bilateral in the other, and no particular concha was affected more than the others. The affected tissue was removed transendoscopically with a polypectomy snare while the horses were sedated and standing. Mild disinfectants were used locally...
Exophthalmus secondary to a sinonasal cyst in a horse. A 13-year-old female Miniature Horse was evaluated for progressive unilateral exophthalmia of the left globe of 3 weeks' duration. Results: Results of a physical examination were unremarkable. Ophthalmic examination identified exophthalmus of the left globe with complete resistance to retropulsion and mild blepharoconjunctivitis. Computed tomography revealed a large, space-occupying mass within the left caudal maxillary and left conchofrontal sinuses. The mass extended into the left retrobulbar space and contacted the cribriform plate. Trephination yielded copious amounts of turbid yellow flui...
Comparison of mean bone densities of three preparations of the distal portion of the equine third metacarpal bone measured by use of quantitative computed tomography. To evaluate whether cutting equine subchondral bone to demarcate specific regions of interest (ROIs) influences the mean density for that bone as measured via quantitative computed tomography (QCT). Sample population-2 metacarpophalangeal joints from equine cadavers. Methods: The distal portion of the third metacarpal bone of each intact metacarpophalangeal joint was scanned via CT to simulate in vivo conditions. Each joint was subsequently disarticulated and dissected, and the distal portion of the dissected third metacarpal bone in air was scanned. Then, six 1-cm(2) areas representing ROIs w...
Simulation of turbulent airflow using a CT based upper airway model of a racehorse. Computational model for airflow through the upper airway of a horse was developed. Previous flow models for human airway do not hold true for horses due to significant differences in anatomy and the high Reynolds number of flow in the equine airway. Moreover, models that simulate the entire respiratory cycle and emphasize on pressures inside the airway in relation to various anatomical diseases are lacking. The geometry of the airway was created by reconstructing images obtained from computed tomography scans of a thoroughbred racehorse. Different geometries for inhalation and exhalation were ...
Effects of exercise vs experimental osteoarthritis on imaging outcomes. To identify changes in imaging outcomes in a controlled model of osteoarthritis (OA) vs exercise. Methods: Sixteen 2-year-old horses were randomly assigned to an exercise control (n=8) or an exercise OA (n=8) group. All horses had middle carpal joints arthroscopically explored and an osteochondral fragment was induced in one middle carpal joint of the OA group. All horses were treadmill exercised for the duration of the study (91 days). Clinical, radiographic, nuclear scintigraphic, computed tomographic and magnetic resonance imaging (MRI) examinations were performed and outcomes of these were...
Micro-computed tomography of early lesions of osteochondrosis in the tarsus of foals. Osteochondrosis (OC) is an important developmental orthopedic disease of human and equine patients. The disease is defined as a focal disturbance in enchondral ossification. In horses, the disturbance can occur secondary to failure of the blood supply to growth cartilage. Diagnosis of the early, subclinical stages that can clarify the etiology is currently confined to cross-sectional histological examination. The potential for micro-computed tomography (micro-CT) with angiography to detect early lesions of OC has not yet been investigated. Methods: Nine Standardbred foals bred from parents wit...
Evaluation of computed tomographic anatomy of the equine metacarpophalangeal joint. To determine the detailed computed tomography (CT) anatomy of the metacarpophalangeal (MCP) joint in healthy horses. Methods: 10 cadaveric forelimbs from 10 adult horses without orthopedic disease. Methods: CT of the MCP joint was performed on 4 forelimbs. In 1 of the limbs, CT was also performed after intra-articular injection of 30 mL of contrast medium (40 mg of iodine/mL). Transverse slices 1-mm thick were obtained, and sagittal and dorsal planes were reformatted with a slice thickness of 2 mm. The CT images were matched with corresponding anatomic slices from 6 additional forelimbs. Resul...
Donkey dental anatomy. Part 1: Gross and computed axial tomography examinations. Post-mortem examination of 19 donkey skulls showed that donkeys have a greater degree of anisognathia (27% width difference between upper and lower jaws) compared to horses (23%). Teeth (n=108) were collected from 14 skulls and examined grossly and by computed axial tomography (CAT). A greater degree of peripheral enamel infolding was found in mandibular cheek teeth (CT) compared to maxillary CT (P<0.001). A significant increase in peripheral cementum from the apical region to the clinical crown was demonstrated in all CT (P16 years) than in the younger (<15 years) donkeys studied. Based...
Simulation of local anaesthetic nerve block of the infraorbital nerve within the pterygopalatine fossa: anatomical landmarks defined by computed tomography. To provide anaesthesia of the maxillary cheek teeth, a local block of the infraorbital nerve in the pterygopalatine fossa has been suggested. The aim of this study was to re-examine the anatomy of the pterygopalatine fossa, giving special attention to relevant arteries, veins and nerves; simulate the infiltration of an anaesthetic by injecting a contrast medium; improve the injection technique to avoid puncturing of relevant anatomical structures. Five heads and two living horses were investigated using contrast medium injections and computed tomography (CT). Needles were inserted using two in...
Measurement of equine laminar blood flow and vascular permeability by use of dynamic contrast-enhanced computed tomography. To define the reference range for laminar blood flow (BF) and vascular permeability (VPM) in horses without laminitis by use of dynamic contrast-enhanced computed tomography (CT). Methods: 9 adult horses that were not lame and had no abnormalities of the laminae or phalanges detectable via radiographic examination. Methods: Each horse was anesthetized by use of a routine protocol. Horses were placed in right or left lateral recumbency with the dependent forelimb in the CT gantry; only 1 limb of each horse was scanned. Serial 10-mm collimated transverse CT images were acquired at the same locat...
Future tools for early diagnosis and monitoring of musculoskeletal injury: biomarkers and CT. This article provides an overview of two relatively new techniques that can be used for the early detection of musculoskeletal injury: biochemical markers and CT. The emphasis in the biomarker section is on the early detection of joint disorders because these are most important clinically and most of the research has been conducted in this area. In the section on CT, bone is the target tissue.
Development of equine upper airway fluid mechanics model for Thoroughbred racehorses. Computational fluid dynamics (CFD) models provide the means to evaluate airflow in the upper airways without requiring in vivo experiments. Objective: The physiological conditions of a Thoroughbred racehorse's upper airway during exercise could be simulated. Methods: Computed tomography scanned images of a 3-year-old intact male Thoroughbred racehorse cadaver were used to simulate in vivo geometry. Airway pressure traces from a live Thoroughbred horse, during exercise was used to set the boundary condition. Fluid-flow equations were solved for turbulent flow in the airway during inspiratory an...
Regionalisation of the muscle fascicle architecture in the equine longissimus dorsi muscle. The longissimus dorsi is the largest muscle in the equine back and plays an important role in locomotor ability and performance in the horse. In vivo studies suggest that the mechanical function varies between different muscle segments, in part determined by anatomy. It is possible therefore that variations in function reflect variations in the anatomy of the longissimus dorsi along its length. Objective: To identify if there are regional variations in muscle architecture of the longissimus dorsi. Methods: Computed tomography scans were obtained from 8 cadaver backs to identify the cross-secti...
Effect of age on bone mineral density and micro architecture in the radius and tibia of horses: an Xtreme computed tomographic study. The effect of age on the bone mineral density and microarchitecture of the equine radius and tibia was investigated. Fifty-six bones from 15 horses aged four to 21 years were used. There were nine geldings and six mares, and none of the horses had any disease influencing bone properties. Xtreme computed tomography was used to evaluate a 9-mm segment of the diaphysis and metaphysis of each bone. The following variables were determined: length of the bone, circumference and diameter in the frontal and sagittal planes in the middle of the bone.Diaphysis: total volume, bone volume, bone volume rat...
Comparison of gross and histopathologic findings with quantitative computed tomographic bone density in the distal third metacarpal bone of racehorses. Comparison of subchondral bone density determined by quantitative computed tomography (CT) with gross and histopathologic changes have not been made in horses. The goal of this study was to determine if mean quantitative CT density and mean voxel standard deviation are associated with the presence and severity of osteochondral lesions in the palmar aspect of the distal third metacarpal bone in racing horses. Metacarpophalangeal joints from nine racehorses were imaged using CT and scored for gross damage. Four-millimeter-thick sagittal and 30 degrees palmar dorsal plane sections were cut, decal...
Effects of exercise on chondrocyte viability and subchondral bone sclerosis in the distal third metacarpal and metatarsal bones of young horses. The objective was to determine the effects of early exercise on the articular cartilage and subchondral bone at specific sites of the distal third metacarpal and metatarsal bones of 12 young Thoroughbred horses allowed free choice exercise at pasture. Six of the horses had additional controlled exercise 5 days per week from mean age of 21+/-20 days of age (range: 3-83 days) until 17.1 months of age. Confocal laser scanning microscopy was used to quantify viable and non-viable chondrocytes. Proteoglycan scoring and modified Mankin scoring was performed and subchondral bone mineral density measu...
Endoscopic removal of a molariform supernumerary intranasal tooth (heterotopic polyodontia) in a horse. A 3-year-old Thoroughbred mare was evaluated because of abnormal upper respiratory tract sounds (that had become apparent during race training) of 3 to 4 months' duration. Results: On initial physical evaluation, there were no abnormal findings. During trotting, an abnormal upper airway expiratory sound was audible. Endoscopic examination revealed a small mass protruding into the right ventral nasal meatus. Radiographic images of the skull revealed no abnormal findings. Computed tomography of the head revealed an abnormal structure in the same location as the mass that was observed during endo...
Diagnostic imaging of the equine tarsal region using radiography and ultrasonography. Part 2: bony disorders. This is the second part of a two-part review of the structures and disorders of the equine tarsus. In this part the bones of the tarsal region are considered and the technical aspects of taking radiographic, ultrasonographic and scintigraphic images of the different lesions are addressed. The diagnostic use of arthroscopy, computed tomography and magnetic resonance are discussed. In current clinical practice the most frequently used combination to arrive at a diagnosis is still radiography and ultrasonography.
Evaluation of increased subchondral bone density in areas of contact in the metacarpophalangeal joint during joint loading in horses. To quantitatively evaluate contact area under 2 loads and subjectively compare contact areas with subchondral bone (SCB) density patterns in intact metacarpophalangeal joints of horses. Methods: 6 forelimbs from horses without musculoskeletal disease. Methods: Computed tomographic scans of intact metacarpophalangeal joints were analyzed to obtain SCB density measurements. Each limb was loaded on a materials testing system to 150 degrees and 120 degrees extension in the metacarpophalangeal joint, and the joint was stained via intra-articular injection with safranin-O or toluidine blue, respecti...
