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1.
Am J Vet Res ; 70(1): 30-6, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19119946

RESUMO

OBJECTIVE: To investigate effects of age on thickness and morphologic characteristics of hyaline cartilage, calcified cartilage, total cartilage, and subchondral bone (SCB) in the equine tarsometatarsal joint. SAMPLE POPULATION: 23 tarsal joints from cadavers of 23 ponies (11 days to 25 years old); ponies were limited to pasture exercise and euthanatized for reasons not related to this study. Procedures-Tarsi were allocated into several age groups (11 days old [n = 3], 6 to 9 months old [4], 2 to 3 years old [3], 6 to 8 years old [4], 11 to 17 years old [6], and 20 to 25 years old [3]). Histologic examination and histomorphometric measurement of hyaline cartilage, calcified cartilage, total cartilage, and SCB were performed at medial and lateral sites. RESULTS: A significant decrease was detected in thickness of hyaline cartilage and total cartilage with increasing age, but there was a significant increase in thickness of calcified cartilage and SCB with increasing age. Differences in chondrocyte and collagen fiber arrangement, tidemark, and osteochondral junction morphology were evident among age groups. CONCLUSIONS AND CLINICAL RELEVANCE: These findings suggested that the various tissues of the osteochondral unit change in different ways with age. The response of each tissue may be related to relative response of the tissues to strains induced by pasture exercise but could have an influence on how the overall properties of the osteochondral unit change with age. The findings may also be suggestive of changes that develop prior to the onset of osteoarthritis.


Assuntos
Cartilagem Articular/fisiologia , Cavalos/fisiologia , Articulações Tarsianas/fisiologia , Fatores Etários , Animais , Cartilagem Articular/anatomia & histologia , Cartilagem Articular/ultraestrutura , Histocitoquímica/veterinária , Cavalos/anatomia & histologia , Estatísticas não Paramétricas , Articulações Tarsianas/anatomia & histologia
2.
Vet Radiol Ultrasound ; 47(1): 1-16, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16429980

RESUMO

Palmar foot pain is a common cause of lameness. Magnetic resonance imaging (MRI) has the potential to detect damage in all tissues of the equine foot, but an understanding of the differences in magnetic resonance (MR) images between feet from horses with and without palmar foot pain is required. This study aimed to describe MR findings in feet from horses with no history of foot-related lameness, and to compare these with MR findings in horses with lameness improved by palmar digital local analgesia. Thirty-four limbs from horses euthanized with a clinical diagnosis of navicular syndrome (ameness >2 months duration, positive response to palmar digital nerve blocks and absence of other forelimb problems) (Group L), and 25 feet from age-matched horses with no history of foot pain (Group N) were examined. For each anatomic structure, MR signal intensity and homogeneity, size, definition of margins, and relationships with other structures were described. Alterations in MR signal intensity and homogeneity were graded as mild, moderate, or severe and compared between Groups L and N. Results revealed that there were significant differences in MR images between Groups N and L. Multiple moderate-severe MR signal changes were present in 91% of limbs from Group L and moderate (none were graded severe) in 27% of limbs from Group N. In most Group L limbs, more than three structures and frequently six to eight structures were abnormal. Concomitant abnormalities involved most frequently the deep digital flexor tendon, distal sesamoidean impar ligament, navicular bone, collateral sesamoidean ligament, and navicular bursa (with significant associations in severity grade between these structures), sometimes with involvement of the distal interphalangeal joint and/or its collateral ligaments. It was concluded that findings on MR images were different between horses with and without foot pain, and that pain localized to the foot was associated with MR changes in a variety of structures, indicating that damage to several structures may occur concurrently and that MR imaging was useful for evaluation of foot pain.


Assuntos
Doenças dos Cavalos/patologia , Coxeadura Animal/patologia , Imageamento por Ressonância Magnética , Ossos do Tarso/anormalidades , Animais , Cavalos , Coxeadura Animal/classificação , Coxeadura Animal/etiologia , Dor/etiologia , Dor/veterinária , Tendões/patologia
3.
Am J Vet Res ; 66(11): 1999-2005, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16334962

RESUMO

OBJECTIVE: To validate use of magnetic resonance images (MRIs) for measurement of equine articular cartilage and subchondral bone thickness by comparison with measurements in histologic specimens. SAMPLE POPULATION: 32 cadaveric carpal joints from 16 horses. PROCEDURE: Magnetic resonance imaging was performed by use of 3-dimensional fast spoiled gradient echo (SPGR) and T2* 3-dimensional fast gradient echo (GRE) pulse sequences with and without fat saturation. Standard sites on the medial and lateral facets of the intermediate, radial, and third carpal bones were used for subchondral bone and articular cartilage thickness measurements. Digital image analysis software was used for MRI measurements 10 mm from the dorsal extent and perpendicular to the articular surface. Histomorphometric measurements of hyaline, calcified cartilage, and subchondral bone thickness were obtained at selected sites. Comparisons between histomorphometric and MRI measurements and between magnetic resonance pulse sequences were evaluated. RESULTS: There were significant correlations between GRE and SPGR and SPGR and histologic measurements of articular cartilage, with no significant difference between measurements and good agreement. When calcified cartilage was excluded from the histologic measurement, MRI measurements were significantly greater than histologic measurements. For subchondral bone thickness, there was significant correlation between GRE and SPGR but GRE was significantly greater than SPGR measurements. Histomorphometric and MRI measurements were strongly correlated and not significantly different. CONCLUSIONS AND CLINICAL RELEVANCE: Magnetic resonance imaging provides a good representation of cartilage and subchondral bone thickness, supporting its use in the study and clinical diagnosis of osteochondral structure and alteration.


Assuntos
Osso e Ossos/anatomia & histologia , Carpo Animal/anatomia & histologia , Cartilagem Articular/anatomia & histologia , Cavalos/anatomia & histologia , Imageamento por Ressonância Magnética/veterinária , Animais , Doenças dos Cavalos/diagnóstico , Imageamento por Ressonância Magnética/métodos , Estatísticas não Paramétricas
4.
Vet Radiol Ultrasound ; 46(2): 171-8, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15869163

RESUMO

Distal tarsal pain is a common reason for hind limb lameness, but diagnosis cannot always be made on radiographic examination. Scintigraphy may allow detection of subtle changes undetected by other diagnostic methods. We hypothesized that (1) distal tarsal pain would be associated with a loss of the expected pattern of radiopharmaceutical uptake (RU) detected in normal horses, (2) distal tarsal RU would be greater in limbs with tarsal pain than without pain, (3) RU in painful tarsi with radiographic evidence of osteoarthritis (OA) would be greater than in distal tarsal pain with no radiographic evidence of OA. The study aimed to describe radiopharmaceutical distribution in the distal tarsal region of horses with distal tarsal pain, and to compare this with the contralateral limb and results from horses without tarsal pain. Retrospective evaluation of scintigraphic images of the distal tarsal region was performed for 52 horses with distal tarsal pain: 15 with no radiographic evidence of OA (Group 1) and 37 with radiographic evidence (Group 2). The images were assessed using vertical and horizontal profile analysis across the distal tarsal region and regions of interest comparisons between the distal tarsal region and tibia within each horse (RU ratio). Painful limbs in unilaterally lame horses from Groups 1 and 2 had a significantly greater RU ratio than the respective contralateral limbs, and were significantly greater than the RU ratio in normal horses. On plantar images, mean region of interest counts were greater in the lame than the contralateral limb in Group 2 but not in Group 1. Although there was a positive correlation between lame and contralateral limb RU ratio in group 1, this was lost in group 2 horses. In lame limbs, the normal vertical activity profile was lost in 85% of group 1 and all of group 2, and the normal horizontal activity profile was lost in all of group 1 and 96% of group 2. There was a significant effect of lameness, but not of group on sites of peak activity on all profiles. The results of this study indicate that distal tarsal pain is associated with loss of the expected pattern of RU detected in normal horses. The findings also suggest that distal tarsal RU in lame limbs is greater than in limbs without pain, and that painful limbs with radiographic evidence of OA have a greater RU than painful limbs without radiographic evidence of OA.


Assuntos
Doenças dos Cavalos/diagnóstico por imagem , Osteoartrite/veterinária , Tarso Animal/diagnóstico por imagem , Animais , Inglaterra/epidemiologia , Feminino , Doenças dos Cavalos/epidemiologia , Doenças dos Cavalos/patologia , Cavalos , Coxeadura Animal/etiologia , Masculino , Osteoartrite/complicações , Osteoartrite/diagnóstico por imagem , Cintilografia/veterinária , Compostos Radiofarmacêuticos/farmacocinética , Registros/veterinária , Estudos Retrospectivos , Tarso Animal/metabolismo
5.
Vet Radiol Ultrasound ; 45(4): 345-51, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15373263

RESUMO

Bone-phase scintigraphy is sensitive to the dynamic process of bone modeling and remodeling, which may be adaptive or pathologic. Our knowledge of normal patterns of radiopharmaceutical uptake (RU) is limited, making interpretation of images problematic. It is therefore important to characterize normal patterns of RU at specific sites and relate these to age and exercise, to ensure valid interpretation of images in clinical cases with subtle lesions. This study aimed to characterize patterns of uptake of radiopharmaceutical in the distal tarsal region in clinically normal horses, and to investigate the effects of age and work discipline. Retrospective evaluation of nuclear scintigraphic images of the distal tarsal region of 30 clinically sound, high-level show-jumpers and lower-level riding horses was performed. All images were acquired dynamically as a series of 35 two-second frames, which were then motion corrected and summated. The images were assessed using vertical and horizontal profile analysis across the distal tarsal region, and regions of interest comparisons between the distal tarsal region and tibia within each horse. There was a repeatable pattern of RU across the distal tarsal region in both horizontal and vertical directions. There was significantly greater RU on the dorsal compared with plantar aspect, and lateral compared with medial aspect of the distal tarsal region. RU in the right distal tarsal region was significantly greater than in the left. Elite showjumpers had significantly higher RU ratio compared with the lower-level riding horses, but no significant alterations in the pattern of RU were detected.


Assuntos
Cavalos/anatomia & histologia , Compostos Radiofarmacêuticos/administração & dosagem , Tarso Animal/anatomia & histologia , Tarso Animal/diagnóstico por imagem , Medronato de Tecnécio Tc 99m/administração & dosagem , Animais , Injeções Intravenosas/veterinária , Cintilografia/veterinária , Valores de Referência , Estudos Retrospectivos
6.
Vet Radiol Ultrasound ; 45(2): 103-11, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15072140

RESUMO

Injury of the distal aspect of the deep digital flexor tendon (DDFT) is a recognized cause of lameness, but diagnosis is difficult. This study aimed to improve understanding of DDFT morphology and pathology using retrospective evaluation of magnetic resonance (MR) images. We hypothesized that: (1) The distal aspect of the DDFT in normal horses would have a repeatable proximal/distal pattern and symmetry between limbs and between lobes; (2) DDFT dimensions would be related to bodyweight, navicular bone dimensions and hoof size; (3) this symmetry and pattern would be lost in DDFT injury; and (4) DDFT size would increase with injury. MR images of 64 live horse limbs, 26 with no identified DDFT lesion and 38 with identified DDFT abnormalities, and 19 normal cadaver limbs were analyzed. Using standardized transverse images, measurements of DDFT cross-sectional area, medial-lateral (ML) width and dorsal-palmar depth were obtained at six preselected sites. A uniform distal to proximal shape pattern was identified in all horses. The flattened crescent shape at the insertion changed to a deeper bilobed shape more proximally, with the mid-navicular area having the greatest cross-sectional area. Strong ML (P < 0.0006) and left/right symmetry (P < 0.02) were observed. In addition, there was a strong association between DDFT cross-sectional area and horse weight (P = 0.005) and between DDFT and navicular bone ML width (P = 0.004). Symmetry between sides or between lobes was lost at sites with a unilateral lesion and correlation between horse weight and DDFT cross-sectional area was lost in the presence of lesions. DDFTs with core lesions had a consistent increase in cross-sectional area overall, but other lesion types had no significant increase in size. The shape and symmetry seen in normal tendons could be related to the mechanical demands placed upon individual lobes. The limited increase in cross-sectional area with injury may be explained by the restrictive structures of the hoof, possibly explaining the ongoing pain seen in such lesions.


Assuntos
Doenças dos Cavalos/patologia , Cavalos/lesões , Tendinopatia/veterinária , Traumatismos dos Tendões , Tendões/patologia , Animais , Estudos de Casos e Controles , Membro Anterior/patologia , Processamento de Imagem Assistida por Computador , Coxeadura Animal/etiologia , Coxeadura Animal/patologia , Imageamento por Ressonância Magnética/veterinária , Estudos Retrospectivos , Tendinopatia/complicações , Tendinopatia/patologia
7.
Vet Radiol Ultrasound ; 44(6): 609-17, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-14703239

RESUMO

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.


Assuntos
Doenças do Pé/veterinária , Doenças dos Cavalos/diagnóstico por imagem , Doenças dos Cavalos/patologia , Imageamento por Ressonância Magnética/veterinária , Animais , Doença Crônica , Doenças do Pé/diagnóstico por imagem , Doenças do Pé/patologia , Membro Anterior/diagnóstico por imagem , Membro Anterior/patologia , Membro Posterior/diagnóstico por imagem , Membro Posterior/patologia , Cavalos , Coxeadura Animal/diagnóstico por imagem , Coxeadura Animal/patologia , Valor Preditivo dos Testes , Radiografia
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