COMPARISON OF FLAT-PANEL DIGITAL TO CONVENTIONAL FILM-SCREEN RADIOGRAPHY IN DETECTION OF EXPERIMENTALLY CREATED LESIONS OF THE EQUINE THIRD METACARPAL BONE

Radiographic diagnosis of equine bone disease using digital radiography is prevalent in veterinary practice. However, the diagnostic quality of digital vs. conventional radiography has not been compared systematically. We hypothesized that digital radiography would be superior to film-screen radiography for detection of subtle lesions of the equine third metacarpal bone. Twenty-four third metacarpal bones were collected from horses euthanized for reasons other than orthopedic disease. Bones were dissected free of soft tissue and computed tomography was performed to ensure that no osseous abnormalities were present. Subtle osseous lesions were produced in the dorsal cortex of the third metacarpal bones, and the bones were radiographed in a soft tissue phantom using indirect digital and conventional radiography at standard exposures. Digital radiographs were printed onto film. Three Diplomates of the American College of Veterinary Radiology evaluated the radiographs for the presence or absence of a lesion. Receiver operator characteristic curves were constructed, and the area under these curves were compared to assess the ability of the digital and film-screen radiographic systems to detect lesions. The area under the ROC curves for film-screen and digital radiography were 0.87 and 0.90, respectively ( P =0.59). We concluded that the digital radiographic system was comparable to the film-screen system for detection of subtle lesions of the equine third metacarpal bone.     

COMPARATIVE PERFORMANCE OF RADIOGRAPHY AND COMPUTED TOMOGRAPHY IN THE DIAGNOSIS OF MIDDLE EAR DISEASE IN 31 DOGS

The purpose of this study was to compare computed tomography (CT) and radiography for diagnosing the presence and severity of middle ear disease in dogs with a history of chronic otitis externa. Thirty-one dogs undergoing a total ear canal ablation and bulla osteotomy were studied. Three normal dogs served as controls. All dogs were examined using radiography and CT. Three radiologists independently evaluated imaging studies in random order. A visual analog scale method was used for scoring certainty and severity of middle ear disease. Surgical findings were recorded intra-operatively. Bulla lining samples were submitted for histopathologic evaluation and scored by a single pathologist who also used a visual analog scale system. Findings from both imaging modalities agreed more closely with surgical findings than with histopathologic findings. With either surgical or histopathologic findings as the gold standard, CT was more sensitive than and as specific as radiographs for predicting presence and severity of middle ear disease. Observer performance with CT was more consistent than the performance with radiographs in the detection of changes that occur with middle ear disease. Both radiography and CT were more accurate for predicting the severity of the disease than its presence. Findings indicate that CT is more accurate and reliable than radiography in diagnosing middle ear disease for dogs having concurrent otitis externa, but only when severity of disease is moderate or high. With low severity of disease, diagnostic certainty for both modalities becomes more variable.     

Results of Screw/Wire/Polymethylmethacrylate Composite Fixation for Acetabular Fracture Repair in 14 Dogs

Objective- To assess the clinical results in dogs with acetabular fractures stabilized using a screw-wire-polymethylmethacrylate (SWP) composite fixation.
Study Design- A retrospective study of client-owned dogs with acetabular fractures.
Animals- Fourteen dogs ranging in age from 4 to 95 months (mean, 34 ±25 months; median, 25 months) and body weight from 8 to 39 kg (mean, 25 ±6 kg; median, 27 kg).
Methods- Medical records and radiographs were retrospectively evaluated to determine location of the fracture, presence of preexisting degenerative joint disease, accuracy of fracture reduction and complications associated with surgery. Long-term results were evaluated by subjective assessment of lameness, elicitation of pain and/or crepitus on manipulation of the coxofemoral joint, measurements of pelvic limb circumference, coxofemoral joint goniometric measurements, and radiographic evaluation.
Results- Fracture reduction was considered anatomic in 13 dogs. At the time of the last follow-up evaluation (mean, 347 ±261 days; median, 380 days) 10 dogs were sound on the affected limb, three dogs had a subtle weight-bearing lameness of the affected limb, and the remaining dog had a consistent non-weight-bearing lameness of the affected limb. Mild (n = 10) or moderate (n = 1) degenerative changes of the affected coxofemoral joint attributed to the acetabular fracture and its repair were noted on the follow-up radiographs in 11 dogs. Limb circumference of the affected limb ranged from -8.2% to +10.8% (mean, -0.8 ±4.2%; median, -0.7%) of the contralateral limb.
Conclusions- The SWP composite fixation consistently maintained anatomic reduction, was associated with few complications, and yielded satisfactory clinical results.
Clinical Relevance- The SWP composite fixation technique would seem to be an acceptable means of stabilizing acetabular fractures in dogs.