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- Author or Editor: William J. Hornof x
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Summary
Medical records of 176 animals that underwent transcolonic sodium pertechnetate Tc 99m scintigraphy between September 1988 and June 1992 were reviewed. The study included 162 dogs, 10 cats, and 4 potbellied pigs. Whenever possible, scan results were confirmed during exploratory surgery or necropsy. For animals that did not undergo surgery or necropsy, additional medical information, (ie, results of histologic examination of hepatic biopsy specimens, clinicopathologic testing, abdominal ultrasonography, and clinical outcome) was evaluated to estimate the likelihood that the scan interpretation was correct. Interpretations were classified as confirmed true, probable true, possible false, or unconfirmed results. Of the 97 scans interpreted as positive for portosystemic shunting, 85 were classified as confirmed true-positive results, 5 were classified as probable true-positive results, and 7 were classified as unconfirmed results. None were classified as confirmed or possible false-positive results. Of the 79 scans interpreted as negative for portosystemic shunting, 3 were classified as confirmed true-negative results, 54 were classified as probable true-negative results, 1 was classified as a possible false-negative result, and 21 were classified as unconfirmed results. Our results suggest that transcolonic pertechnetate scintigraphy has satisfactory performance as a diagnostic test for macrovascular portosystemic shunting.
Abstract
Objective—To evaluate the effect of infection with bovine respiratory syncytial virus (BRSV) on clearance of inhaled antigens from the lungs of calves.
Animals—Eleven 6- to 8-week-old Holstein bull calves.
Procedures—Aerosolized 99mtechnetium (99mTc)-labeled diethylene triamine pentacetate (DTPA; 3 calves), commonly used to measure integrity of the pulmonary epithelium, and 99mTc-labeled ovalbumin (OA; 8 calves), commonly used as a prototype allergen, were used to evaluate pulmonary clearance before, during, and after experimentally induced infection with BRSV or sham inoculation with BRSV. Uptake in plasma (6 calves) and lung-efferent lymph (1 calf) was examined.
Results—Clearance of 99mTc-DTPA was significantly increased during BRSV infection; clearance of 99mTc-OA was decreased on day 7 after inoculation. Clearance time was correlated with severity of clinical disease, and amounts of 99mTc-OA in plasma and lymph were inversely correlated with clearance time. Minimum amounts of 99mTc-OA were detected at time points when pulmonary clearance of 99mTc-OA was most delayed.
Conclusions and Clinical Relevance—BRSV caused infection of the respiratory tract with peak signs of clinical disease at 7 or 8 days after inoculation. Concurrently, there was a diminished ability to move inhaled protein antigen out of the lungs. Prolonged exposure to inhaled antigens during BRSV infection may enhance antigen presentation with consequent allergic sensitization and development of chronic inflammatory lung disease.
Impact for Human Medicine—Infection of humans with respiratory syncytial virus early after birth is associated with subsequent development of allergic asthma. Results for BRSV infection in these calves suggested a supportive mechanism for this scenario.
Abstract
Thyroid gland scintigraphy was performed in 29 dogs with histologically confirmed thyroid tumors. Twenty dogs were female, and 9 were male. Median age was 10 years. Of the 29 dogs, 21 were initially examined because of cervical swelling or a cervical mass. Of the 29 tumors, 24 were thyroid adenocarcinomas, 1 was a C-cell carcinoma, 3 were undifferentiated carcinomas, and 1 was a thyroid adenoma. Serum triiodothyronine and thyroxine concentrations were determined in 25 dogs. Sixteen dogs were euthyroid, 6 were hyperthyroid, and 3 were hypothyroid.
In all 29 dogs, results of scintigraphy were abnormal. The most common scintigraphic appearance (13 dogs) was a unilateral thyroid mass with increased radionuclide uptake, relative to that of the parotid salivary glands. There did not appear to be an association between distribution of radionuclide uptake and histologic diagnosis, although there appeared to be an association between distribution of uptake and histologic degree of capsular invasion. All 4 dogs with extensive capsular invasion and 11 of 17 dogs with limited capsular invasion had poorly circumscribed, heterogeneous uptake of pertechnetate by the tumor. All hyperthyroid dogs had intense uptake, and 5 of 6 hyperthyroid dogs had well-circumscribed, homogenous uptake. Scintigraphy did not appear to offer any additional benefit, compared with thoracic radiography, for detection of pulmonary metastases.
Summary
Radiography and soft tissue- and bone-phase scintigraphy were performed on 14 clinically normal horses and 35 horses in which definite, probable, or possible navicular disease had been diagnosed. The specificity of radiography and scintigraphy in revealing signs of navicular disease were nearly equal; however, the sensitivity of scintigraphy appeared to be greater than that of radiography. The greatest sensitivity and specificity were achieved when the results of radiography and scintigraphy were evaluated together. Differences in sensitivity were greatest when scintigraphy revealed lesions not detected by radiography. Although a diagnosis of navicular disease was sometimes made when only soft tissue-phase or only bone-phase scintigraphy revealed lesions, results obtained during the 2 phases generally were similar. It was concluded that scintigraphy can be a valuable aid in diagnosing navicular disease in horses, especially when radiographic findings do not support clinical findings.
Summary
Five radiographic protocols for detecting pulmonary metastases in dogs were compared by analyzing receiver operating characteristic curves for the protocols. Protocols compared were a right lateral view only, a left lateral view only, right lateral and dorso- ventral views, both lateral views, and all 3 views. Three radiologists used each of the protocols to evaluate 99 sets of thoracic radiographs. Fifty-two sets of radiographs were from dogs confirmed histologically to have pulmonary metastases and 47 were from dogs proven at necropsy to be free of pulmonary metastases. Results of the 5 protocols were not statistically different. We concluded that a third view is not necessary when routinely screening dogs with cancer for pulmonary metastases and that the standard 2-view thoracic examination should be adequate. However, in individual cases, a third view may be the determining factor in establishing a radiographic diagnosis and should be obtained if any suspicious areas are seen.
Abstract
Objective—To define the reference range for laminar blood flow (BF) and vascular permeability (VPM) in horses without laminitis by use of dynamic contrast-enhanced computed tomography (CT).
Animals—9 adult horses that were not lame and had no abnormalities of the laminae or phalanges detectable via radiographic examination.
Procedures—Each horse was anesthetized by use of a routine protocol. Horses were placed in right or left lateral recumbency with the dependent forelimb in the CT gantry; only 1 limb of each horse was scanned. Serial 10-mm collimated transverse CT images were acquired at the same location every other second for 90 seconds during infusion of ionic, iodinated contrast medium. Custom software was used to estimate BF, VPM, and fractional vascular volume (FVV) in the dorsal, dorsomedial, and dorsolateral laminar regions.
Results—Among the 9 horses' forelimbs, mean ± SD dorsal laminar BF was 0.43 ± 0.21 mL•min−1•mL−1. Mean dorsomedial and dorsolateral laminar BFs were 0.26 ± 0.16 mL•min−1•mL−1 and 0.24 ± 0.16 mL•min−1•mL−1, respectively. Mean dorsal laminar VPM was 0.09 ± 0.03 mL•min−1•mL−1. Mean dorsomedial and dorsolateral laminar VPMs were 0.16 ± 0.06 mL•min−1•mL−1 and 0.12 ± 0.06 mL•min−1•mL−1, respectively. Mean dorsal laminar FVV was 0.63 ± 0.20 and dorsomedial and dorsolateral laminar FVV were 0.37 ± 0.14 and 0.34 ± 0.17, respectively.
Conclusions and Clinical Relevance—In horses, laminar BF, VPM, and FVV can be non-invasively measured by use of dynamic contrast-enhanced CT.
Abstract
Objective—To characterize a genetic component to cricopharyngeal dysfunction (CD) in Golden Retrievers.
Animals—117 dogs.
Procedure—The CD phenotype was determined by videofluoroscopy, and dogs were classified as affected if the upper esophageal sphincter (UES) did not open, if there were morphologic abnormalities of the UES, or if opening of the UES was delayed for ≥ 6 videofluoroscopic frames (0.2 seconds) after closure of the epiglottis. All survey radiographic and videofluoroscopic studies were reviewed by the same radiologist.
Results—Of the 117 dogs (47 males and 70 females) with a CD phenotype determined via videofluoroscopy, 21 dogs (18.0%) had abnormalities of the UES (affected). Of these 21 dogs, 9 were males (19.1% of all males) and 12 were females (17.1% of all females). The heritability of CD in a threshold model was estimated as 0.61, which established that CD could be passed from parent to offspring. Results of complex segregation analysis suggested that a single recessive allele of large effect contributed to the expression of this disease in Golden Retrievers.
Conclusions and Clinical Relevance—The determination that CD is inherited in Golden Retrievers is an important step in providing information for veterinarians attending dogs with this disorder. Breeders also require this information to make informed breeding decisions. ( Am J Vet Res 2004;65:344–349)
Abstract
Objective—To provide a detailed description of the vascular anatomy of the distal portion of the forelimbs of horses by use of computed tomography angiography (CTA).
Sample Population—6 forelimbs of 5 horses and 1 forelimb from an equine cadaver; none of the horses had orthopedic or vascular disease.
Procedure—Horses were anesthetized and CTA was conducted on the dependent forelimb. A catheter was inserted in the median artery, and contrast medium was infused at a rate of 3 mL/s. A computed tomography (CT) scanner was used to obtain contiguous slices from the region of the proximal sesamoid bones to the toe. All horses were allowed to recover from anesthesia. To help identify vessel patterns in the distal portion of the forelimb, the median artery and lateral palmar digital vein of a heparinized forelimb obtained from an equine cadaver were infused with red and blue polymethylmethacrylate and the distal portion of that forelimb was then sectioned to correspond to CTA images.
Results—Vessel patterns in CTA images matched vascular anatomic structures of the cadaver forelimb and were consistent with published anatomic structures. Major and minor vessels were consistently visible in CTA images of all horses. There were no complications reported in any horses.
Conclusions and Clinical Relevance—Use of CTA provided a highly detailed depiction of the vasculature of the distal portion of the equine forelimb. This was a safe technique and should be useful in the evaluation of the blood supply to the distal portion of the forelimb. (Am J Vet Res 2004;65:1409–1420)
