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
Sample Population—32 cadaveric carpal joints from
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
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. (Am J Vet Res
Objective—To describe the effects of prednisone and acetylsalicylic acid (ASA) on results of thromboelastography in healthy dogs.
Animals—16 male mixed-breed dogs.
Procedures—Dogs were randomly assigned to 3 treatment groups (4 dogs/group) that received prednisone (median dose, 2.07 mg/kg), ASA (median dose, 0.51 mg/kg), or both drugs, PO, every 24 hours from days 0 through 6. Another group received no treatment (control dogs; n = 4). Thromboelastography variables (reaction time, clotting time, α-angle, maximum amplitude [MA], global clot strength, coagulation index, and percentage of clot lysis at 60 minutes [CL60]) were evaluated in blood samples collected (prior to drug administration in treated dogs) on days 0 (baseline), 2, 4, and 6.
Results—Administration of ASA alone did not alter TEG variables. For treatment effect, mean global clot strength was increased in the prednisone and drug combination groups, compared with values for control dogs; MA was also increased in the prednisone and drug combination groups, compared with that of controls. For treatment-by-time effect, median CL60 was increased in the prednisone group on day 6, compared with baseline value in the same dogs and with median CL60 of the control group on day 6. Median CL60 was also increased in the drug combination group on day 6, compared with the baseline value and with that of the control group on day 6.
Conclusions and Clinical Relevance—Prednisone administered at approximately 2 mg/kg/d, PO, for 7 days with or without concurrently administered ASA increased clot strength and decreased clot lysis in healthy dogs.
CASE DESCRIPTION A 2-year-old primiparous miniature Scottish Highland cow with an unknown breeding date was evaluated for suspected hydrops.
CLINICAL FINDINGS Transabdominal and transrectal ultrasonographic examination identified a large amount of hypoechoic fluid within an enlarged uterus; the fetus could not be identified. Presence of a severely distended uterus and concerns regarding associated health risks to the cow led to the decision to induce labor. Although fluids were expelled, parturition did not progress further over the following 48 hours. Vaginal examination revealed a partially dilated cervix and an abnormally shaped fetus that was too large to pass vaginally.
TREATMENT AND OUTCOME Supportive care was provided to the cow, and a stillborn bull calf was delivered by cesarean section. Grossly evident chondrodystrophic dwarfism with hydrocephalus, compatible with so-called bulldog calf malformations, was confirmed by diagnostic imaging and histopathologic evaluation. The cow recovered from surgery uneventfully and was discharged from the hospital the following day. Genetic analysis of DNA from hair roots collected from the sire and dam confirmed both were carriers of an aggrecan-1 gene mutation (bulldog dwarfism1) previously associated with dwarfism and bulldog calf malformations in Dexter cattle.
CLINICAL RELEVANCE To our knowledge, this is the first reported case of bulldog calf malformations associated with an aggrecan-1 gene mutation in miniature Scottish Highland cattle, confirming that at least 1 genetic mutation associated with this condition is found in cattle breeds other than Dexter. The findings highlighted the clinical importance of testing for known genetic diseases in breeding cattle, particularly among miniature breeds.
A 4-year-old spayed female mixed-breed rabbit was evaluated because of a 3-year history of sneezing and nasal discharge that were refractory to medical management.
Signs of chronic left-sided rhinitis and sinusitis were observed on physical examination and confirmed by CT evaluation. Lysis of the rostral aspect of the left maxillary bone and destruction of nasal turbinates were evident on CT images.
TREATMENT AND OUTCOME
Pararhinotomy of the left maxillary sinus through the facies cribrosa was performed. Purulent material was removed from the maxillary sinus recesses, a middle meatal antrostomy was completed to allow permanent drainage into the left middle nasal meatus, and the tissues were closed routinely. Microbial culture of a sample from the maxillary sinus recesses revealed Bordetella bronchiseptica, undetermined fastidious nonenteric bacteria, and Streptococcus viridans. Medical management was continued, and nasal discharge resolved but sneezing persisted. Increased sneezing and bilateral nasal discharge developed 1.5 years later; CT examination revealed right-sided rhinitis, and culture of a nasal swab sample revealed Bordetella spp, Staphylococcus spp, and Micrococcus spp. Right-sided pararhinotomy and middle meatal antrostomy were performed, and medical management continued. A subsequent recurrence was managed without additional surgery; 4 years after the initial surgery, the rabbit was still receiving medical treatment, with mild intermittent nasal discharge and sneezing reported.
This report describes a surgical approach for treatment of chronic rhinitis in companion rabbits with maxillary sinus involvement that included creation of a permanent drainage pathway from the maxillary sinus to the middle nasal meatus.