Summary Reasons for performing study : Marginal osteophytes represent a well known component of osteoarthritis in man and animals. Conversely, central subchondral osteophytes (COs), which are commonly present in human knees with osteoarthritis, have not been reported in horses. Objectives : To describe and compare computed radiography (CR), single‐slice computed tomography (CT), 1.5 Tesla magnetic resonance imaging (MRI), and histological features of COs in equine metacarpophalangeal joints with macroscopic evidence of naturally‐occurring osteoarthritis. Methods : MRI sequences (sagittal spoiled gradient recalled echo [SPGR] with fat saturation, sagittal T2‐weighted fast spin echo with fat saturation [T2‐FS], dorsal and transverse T1‐weighted gradient‐recalled echo [GRE], and sagittal T2*‐weighted gradient echo with fast imaging employing steady state acquisition [FIESTA]), as well as transverse and reformatted sagittal CT, and 4 computed radiographic (CR) views of 20 paired metacarpophalangeal joints were acquired ex vivo. Following macroscopic evaluation, samples were harvested in predetermined sites of the metacarpal condyle for subsequent histology. The prevalence and detection level of COs was determined for each imaging modality. Results : Abnormalities consistent with COs were clearly depicted on MRI, using the SPGR sequence, in 7/20 (35%) joints. They were identified as a focal hypointense protuberance from the subchondral plate into the cartilage, at the palmarodistal aspect (n = 7) and/or at the very dorsal aspect (n = 2) of the metacarpal condyle. COs were visible but less obvious in 5 of the 7 joints using FIESTA and reformatted sagittal CT, and were not identifiable on T2‐FS, T1‐GRE or CR. Microscopically, they consisted of dense bone protruding into the calcified cartilage and disrupting the tidemarks, and they were consistently associated with overlying cartilage defects. Conclusions : Subchondral osteophytes are a feature of osteoarthritis of equine metacarpophalangeal joints and they may be diagnosed using 1.5 Tesla MRI and CT. Potential relevance : Central subchondral osteophytes on MRI represent indirect evidence of cartilage damage in horses.
While abdominal ultrasound and ultrasound-guided fine-needle aspiration cytology are often combined to help determine the type of liver disease in dogs, little is known about the relationship that may exist between the results of these tests. We hypothesized that specific sonographic findings, or combinations of findings, may predict results of liver ultrasound-guided fine-needle aspiration cytology. Hepatic and extrahepatic sonographic findings were recorded prospectively using a standardized form in 70 dogs with clinically suspected liver disease and in which liver ultrasound-guided fine-needle aspiration cytology was performed. The predictive value of sonographic findings in regard to the category of cytology results was assessed with stepwise logistic regression analysis. Sonographic detection of a hepatic mass (> or = 3cm; risk ratio [RR] 3.83, 95% Wald confidence intervals [95% CI] 2.42-3.93, P = 0.0036), ascites (RR 3.82, 95% CI 1.94-4.28, P = 0.0044), abnormal hepatic lymph node(s) (RR 3.01, 95% CI 1.22-4.88, P= 0.0262), and abnormal spleen (RR 3.26, 95% CI 1.20-3.85, P = 0.0274) were the most predictive of liver neoplasia on cytology. Conversely, sonographic detection of hepatic nodules (< 3cm; RR 1.97, 95% CI 0.95-2.96, P = 0.0666) was most predictive of vacuolar hepatopathy on cytology. In dogs with suspected liver disease, several sonographic findings, alone or combined, are thus predictive of liver ultrasound-guided fine-needle aspiration cytology results. In the light of the fact that ultrasound-guided fine-needle aspiration cytology of the liver has limitations, these predictabilities could influence the selection of diagnostic tests to reach a reliable diagnosis.
We compared the ability of 1.5 T magnetic resonance imaging (MRI), computed tomography (CT), and computed radiography (CR) to evaluate noncartilaginous structures of the equine metacarpophalangeal joint (MCP), and the association of imaging changes with gross cartilage damage in the context of osteoarthritis. Four CR projections, helical single-slice CT, and MRI (T1-weighted gradient recalled echo [GRE], T2*-weighted GRE with fast imaging employing steady-state acquisition [FIESTA], T2-weighted fast spin echo with fat saturation, and spoiled gradient recalled echo with fat saturation [SPGR-FS]) were performed on 20 racehorse cadaver forelimbs. Osteophytosis, synovial effusion, subchondral bone lysis and sclerosis, supracondylar lysis, joint fragments, bone marrow lesions, and collateral desmopathy were assessed with each modality. Interexaminer agreement was inferior to intraexaminer agreement and was generally moderate (i.e., 0.4<κ<0.6). Subchondral bone sclerosis scores using CT or MRI were correlated significantly with the reference quantitative CT technique used to assess bone mineral density (P<0.0001). Scores for subchondral lysis and osteophytosis were higher with MRI or CT vs. CR (P<0.0001). Although differences between modalities were noted, osteophytosis, subchondral sclerosis, and lysis as well as synovial effusion were all associated with the degree of cartilage damage and should be further evaluated as potential criteria to be included in a whole-organ scoring system. This study highlights the capacity of MRI to evaluate noncartilaginous changes in the osteoarthritic equine MCP joint.
A 10-year-old spayed female dalmatian dog developed acute vomiting and abdominal pain. Ultrasound examination of the abdomen showed right hydronephrosis and proximal ureter dilation with mild retroperitoneal free fluid. Computed tomography (CT) of the abdomen confirmed the ultrasonographic findings and revealed, additionally, a right ureteral stone. Spontaneus rupture of the right ureter was confirmed with CT post ultrasound-guided percutaneous antegrade pyelography. Pyeloureteral rupture and the presence of a ureteral stone were confirmed at surgery.Pyélographie antégrade percutanée guidée par échographie avec tomodensitométrie pour le diagnostic d’une rupture urétrale partielle spontanée chez un chien. Une chienne Dalmatien stérilisée âgée de 10 ans a manifesté des vomissements et de la douleur abdominale aigus. Une échographie de l’abdomen a montré de l’hydronéphrose à droite et une dilatation proximale de l’urètre avec un peu de liquide rétropéritonéal libre. Une tomodensitométrie de l’abdomen a confirmé les résultats de l’échographie et a révélé, en plus, un calcul urétéral droit. Une rupture spontanée de l’urètre droit a été confirmée par tomodensitométrie après une pyélographie antégrade percutanée guidée par échographie. La rupture pyélo-urétérale et la présence de calcul urétéral ont été confirmées à la chirurgie.(Traduit par Isabelle Vallières).
Osteoarthritis (OA) structural changes take place over decades in humans. MRI can provide precise and reliable information on the joint structure and changes over time. In this study, we investigated the reliability of quantitative MRI in assessing knee OA structural changes in the experimental anterior cruciate ligament (ACL) dog model of OA.
Methods:
OA was surgically induced by transection of the ACL of the right knee in five dogs. High resolution three dimensional MRI using a 1.5 T magnet was performed at baseline, 4, 8 and 26 weeks post surgery. Cartilage volume/thickness, cartilage defects, trochlear osteophyte formation and subchondral bone lesion (hypersignal) were assessed on MRI images. Animals were killed 26 weeks post surgery and macroscopic evaluation was performed.
Results:
There was a progressive and significant increase over time in the loss of knee cartilage volume, the cartilage defect and subchondral bone hypersignal. The trochlear osteophyte size also progressed over time. The greatest cartilage loss at 26 weeks was found on the tibial plateaus and in the medial compartment. There was a highly significant correlation between total knee cartilage volume loss or defect and subchondral bone hypersignal, and also a good correlation between the macroscopic and the MRI findings.
Conclusion:
This study demonstrated that MRI is a useful technology to provide a non-invasive and reliable assessment of the joint structural changes during the development of OA in the ACL dog model. The combination of this OA model with MRI evaluation provides a promising tool for the evaluation of new disease-modifying osteoarthritis drugs (DMOADs).
A 3-year-old African hedgehog ( Atelerix albiventris) was presented to the Exotic Animal Clinic of the University of Montreal for evaluation of a mass growing on the right thoracic wall. The diagnostic workup, which included helical computed tomography, confirmed the presence of a large mass, originating from the right 7th rib, infiltrating the thoracic wall and cavity. The animal was euthanized due to the poor prognosis. At necropsy, a well-demarcated mass penetrated the thoracic wall and incorporated the 6th to 8th ribs. Cut sections of the tumor were white, glistening, firm, and gritty. Microscopically, it was composed of polyhedral to elongated cells with interspersed trabeculae of osteoid and large areas of coagulative necrosis. On the basis of histopathologic findings, a diagnosis of osteoblastic osteosarcoma was made. To the authors' knowledge, this is the first report of an osteoblastic osteosarcoma on the thoracic wall of an African hedgehog, as well as the first report of the use of helical computed tomography in that species.
The costochondral junction constitutes a potential site of infection in septic foals and it could be favored by thoracic trauma. Standard radiographs and ultrasonography are useful tools for diagnosis of this condition and ultrasound-guided needle aspiration could permit the definitive confirmation of infection.
