Objective—To evaluate the possible association
between facet joint geometry and intervertebral disk
degeneration in German Shepherd Dogs.
Animals—25 German Shepherd Dogs and 11 control
dogs of similar body weight and condition.
Procedure—Facet joint angles in the caudal portion
of the lumbar region of the vertebral column (L5-S1)
were measured by use of computed tomography, and
the intervertebral discs were evaluated microscopically.
The relationship between facet joint geometry
and disk degeneration was evaluated by use of statistical
Results—German Shepherd Dogs had significantly
more facet joint tropism than control dogs, but an
association with disk degeneration was not found.
However, German Shepherd Dogs had a different
facet joint conformation, with more sagittally oriented
facet joints at L5-L6 and L6-L7 and a larger angle difference
between the lumbar and lumbosacral facet
joints, compared with control dogs.
Conclusion and Clinical Relevance—A large difference
between facet joint angles at L6-L7 and L7-S1 in
German Shepherd Dogs may be associated with the
frequent occurrence of lumbosacral disk degeneration
in this breed. (Am J Vet Res 2002;63:86f–90)
Objective—To determine whether contrast harmonic ultrasonography (CHUS) can be used in dogs to distinguish splenic hemangiosarcoma from hematoma and to accurately detect and characterize liver nodules.
Animals—20 dogs with a splenic mass.
Procedures—Routine abdominal ultrasonography was followed by CHUS of hepatic and splenic lesions. Qualitative evaluation included location, enhancement pattern, and vascularity of lesions. Quantitative evaluation included peak mean pixel intensity, interval to peak intensity, area under the curve (spleen), and liver-to-lesion intensity ratio (liver). Histologic findings were compared with CHUS lesion characteristics.
Results—Histologic evaluation of the spleen was performed in 19 dogs, resulting in diagnoses of hemangiosarcoma (n = 11), hematoma (7), and undifferentiated sarcoma (1). Benign and malignant processes in the spleen were indistinguishable via CHUS. Histologic evaluation of the liver was performed in 18 dogs, resulting in a diagnosis of hemangiosarcoma in 5 dogs. None of the dogs with splenic hematomas had evidence of hepatic lesions by means of con-ventional or contrast ultrasonography, and none had histologic evidence of liver metastases. In 3 of 18 dogs, isoenhancing liver nodules were detected and all were histologically benign. Five dogs had liver nodules that remained hypoechoic after contrast agent was injected; all had histologic evidence of metastatic hemangiosarcoma. Results of CHUS were used to characterize hepatic metastases with 100% sensitivity and specificity.
Conclusions and Clinical Relevance—Contrast harmonic ultrasonography was a noninvasive and accurate means of differentiating metastatic versus benign hepatic disease in dogs with splenic hemangiosarcoma but was not useful in distinguishing splenic hemangiosarcoma from hematoma.
Objective—To describe a method for ultrasonographic and color-flow Doppler ultrasonographic imaging of the 4 direct cutaneous arteries commonly used for axial pattern skin flaps in dogs.
Animals—20 clinically normal dogs.
Procedures—Dogs were manually restrained and fundamental and harmonic ultrasonographic and colorflow Doppler ultrasonographic examinations of the superficial cervical, thoracodorsal, deep circumflex iliac (cranial and caudal branches), and caudal superficial epigastric arteries were performed by a resident in diagnostic imaging. The level of confidence in locating these vessels was subjectively graded as high, moderate, or low.
Results—High-frequency fundamental and harmonic ultrasonography was important for maximizing image resolution, and color-flow Doppler ultrasonography was important for vessel identification. The superficial cervical artery was the most difficult vessel to identify; confidence in correct vessel identification was low or moderate. The thoracodorsal and deep circumflex iliac arteries were identified with a moderate or high level of confidence. The caudal superficial epigastric artery was the easiest vessel to identify; confidence in correct vessel identification was high. Except for the superficial cervical artery, the level of confidence in correct vessel identification improved over time as operator experience increased.
Conclusion and Clinical Relevance—Results suggest that the combination of fundamental ultrasonographic and color-flow Doppler ultrasonographic imaging is an easy and noninvasive method for identifying the 4 direct cutaneous arteries commonly used for axial pattern skin flaps in dogs. This method could be useful in planning axial pattern skin flaps, particularly in dogs with regional soft tissue trauma in which the integrity of the vessel is in question.
Objective—To develop a quantitative method of interpreting tibial scintigrams of Thoroughbred racehorses with tibial stress fractures that may facilitate diagnosis of fractures and to provide prognostic information regarding future performance of affected horses.
Animals—35 Thoroughbred racehorses.
Procedures—Static bone-phase scintigrams of tibial stress fractures were quantitatively analyzed by use of ratios of the mean radionuclide counts per pixel in a region of interest (ROI) drawn around the area of increased uptake of radiopharmaceutical to mean counts per pixel in a second ROI drawn around an apparently normal area of the tibial diaphysis. In horses with unilateral fractures, ratios for the contralateral tibia were determined by use of 2 ROIs drawn at the same positions as the ROIs in the fractured tibia. Ratios were compared between fractured versus apparently normal tibias, between horses that returned to racing versus those that did not, and among horses with various grades of lameness. The association between ratios for fractured tibias and intervals between diagnosis and return to racing was also assessed.
Results—Mean ratio of ROIs in apparently normal tibias was 1.35 (95% confidence interval [CI], 1.21 to 1.50); that in tibias with stress fractures was 3.55 (95% CI, 2.50 to 4.60). These ratios were significantly different. None of the associations between ratios for fractured tibias and grades of lameness or performance outcomes were significant.
Conclusions and Clinical Relevance—Tibial stress fracture scintigrams can be quantitatively analyzed. A prospective study with a controlled rehabilitation period is necessary to evaluate the possible applications of this method.
To investigate the use of microwave ablation (MWA) with cooling urethral perfusion and with no perfusion (MWA-UP and MWA-NP, respectively) for prostate gland ablation in canine cadavers.
Cadavers of 18 sexually intact male dogs.
After technique refinement in 2 cadavers, laparotomy with ultrasound-guided MWA-UP (n = 8) or MWA-NP (8) of the prostate gland was performed in 16 cadavers. Normograde cystourethroscopy was performed before and after treatment; recorded images were reviewed in a blinded manner for scoring of urethral mucosal discoloration and loss of integrity. Difficulty with cystoscope insertion was recorded if present. Excised prostate glands were fixed for serial sectioning, gross measurements, and calculation of percentage ablation. Percentages of prostate tissue necrosis from MWA, denuded urethral mucosa, and depth of epithelial surface loss in an adjacent section of the colon were estimated histologically. Variables of interest were statistically analyzed.
Difficulty with cystoscope insertion after treatment was significantly more common and scores for urethral mucosal discoloration and loss of integrity were significantly higher (indicating more severe lesions) for the MWA-NP group than for the MWA-UP group. The histologically assessed percentage of denuded urethral mucosa was also greater for the MWA-NP group. Overall median percentage prostate gland ablation was 73%; this result was not associated with prostate gland volume or chronological order of treatment.
CONCLUSIONS AND CLINICAL RELEVANCE
MWA-UP induced subtotal thermal necrosis of prostate glands in canine cadavers while limiting urethral mucosal injury. Further study is required to optimize the technique and evaluate its safety and efficacy in vivo as a future curative-intent treatment for prostatic tumors in dogs.
Objective—To evaluate the 3-dimensional motion
pattern including main and coupled motions of the
caudal lumbar and lumbosacral portions of the vertebral
column of dogs.
Animals—Vertebral columns of 9 German Shepherd
Dogs (GSDs) and 16 dogs of other breeds with similar
body weights and body conditions .
Procedure—Main and coupled motions of the caudal
lumbar and lumbosacral portions of the vertebral column
(L4 to S1) were determined by use of a testing
apparatus that permitted precise application of known
pure moments to the vertebral column. Motion was
compared between GSDs and dogs of other breeds.
Results—All specimens had a similar motion pattern
consisting of main motion and a certain amount of
coupled motion including translation. Vertebral
columns of GSDs had significantly less main motion
in all directions than that of dogs of other breeds.
Translation was similar in GSDs and dogs of other
breeds and was smallest at the lumbosacral motion
Conclusions and Clinical Relevance—Results indicated
that motion in the caudal lumbar and lumbosacral
portions of the vertebral column of dogs is
complex and provided a basis for further studies evaluating
abnormal vertebral columns. ( Am J Vet Res 2004;65:544–552)
Objective—To determine the association between the 3-dimensional (3-D) motion pattern of the caudal lumbar and lumbosacral portions of the canine vertebral column and the morphology of vertebrae, facet joints, and intervertebral disks.
Sample Population—Vertebral columns of 9 German Shepherd Dogs and 16 dogs of other breeds with similar body weights and body conditions.
Procedure—Different morphometric parameters of the vertebral column were assessed by computed tomography (CT) and magnetic resonance imaging. Anatomic conformation and the 3-D motion pattern were compared, and correlation coefficients were calculated.
Results—Total range of motion for flexion and extension was mainly associated with the facet joint angle, the facet joint angle difference between levels of the vertebral column in the transverse plane on CT images, disk height, and lever arm length.
Conclusions and Clinical Relevance—Motion is a complex process that is influenced by the entire 3-D conformation of the lumbar portion of the vertebral column. In vivo dynamic measurements of the 3-D motion pattern of the lumbar and lumbosacral portions of the vertebral column will be necessary to further assess biomechanics that could lead to disk degeneration in dogs.
Objective—To determine the incidence of adverse events within 24 hours after contrast-enhanced ultrasonography (CEUS) in dogs and cats and compare the risk of death within 24 hours after imaging for animals that underwent ultrasonography with and without injection of a contrast agent.
Design—Retrospective case-control study.
Animals—750 animals (411 case dogs, 238 control dogs, 77 case cats, and 24 control cats).
Procedures—At 11 institutions, medical records were reviewed of dogs and cats that had CEUS performed (cases) as were medical records of dogs and cats with clinical signs similar to those of case animals that had ultrasonography performed without injection of a contrast agent (controls). Information regarding signalment; preexisting disease; type, dose, and administration route of contrast agent used; immediate (within 1 hour after CEUS) and delayed (> 1 and ≤ 24 hours after CEUS) adverse events; and occurrence and cause of death (when available) was extracted from each medical record. Risk of death within 24 hours after ultrasonography was compared between case and control animals.
Results—Of the 411 case dogs, 3 had immediate adverse events (vomiting or syncope) and 1 had a delayed adverse event (vomiting). No adverse events were recorded for case cats. Twenty-three of 357 (6.4%) clinically ill case animals and 14 of 262 (5.3%) clinically ill control animals died within 24 hours after ultrasonography; risk of death did not differ between cases and controls.
Conclusions and Clinical Relevance—Results indicated that CEUS was safe in dogs and cats.