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Summary

Lymphoscintigraphic evaluation of the thoracic duct (td) was performed in 10 healthy and 12 dogs with experimentally created td abnormalities (6 dogs with td lacerations and 6 dogs with cranial vena ligations). Complete imaging took 4 hours and caused no adverse effects or complications. Lymphoscintigraphy of healthy dogs failed to image the td; however, background activity in the abdomen and thorax, and radioactivity in the kidneys, bladder, liver, and heart were noticed.

Lacerations and transections of the td were experimentally created in 6 dogs to ascertain whether td rupture could be detected with lymphoscintigraphy. Lymphoscintigraphy was performed within 48 hours of creating the td defect. There was no significant difference in the scintigraphic pattern of healthy dogs and those with experimentally created td defects.

Ligation of the cranial vena cava was performed in 6 dogs; 3 dogs developed chylothorax. In those 3 dogs, diffuse radioactivity was imaged in the thorax and was compatible with thoracic lymphangiectasia. In one of these dogs, linear activity consistent with the td and localized regions of radioactivity cranial to the heart (compatible with the mediastinal lymph nodes) were noticed. Lymphoscintigraphic findings in these dogs correlated with lymphangiographic findings.

Free access
in American Journal of Veterinary Research

Summary

Twenty-five animals (21 dogs and 4 cats) in which hepatobiliary scintigraphy (hbs) was performed between 1982 and 1989 were included in a retrospective study to determine the utility of hbs for diagnosis of extrahepatic biliary obstruction. Final diagnoses, which were based on liver biopsy results and surgical findings in all animals, were hepatocellular disease alone (n = 17), hepatocellular disease and extrahepatic biliary obstruction (n = 7), and normal liver (n = 1). Hepatobiliary scintigraphy was performed by use of 99mTc-diisopropyl iminodiacetic acid in all cases. All 7 cases of extrahepatic biliary obstruction were confirmed at surgery. In animals with biliary obstruction, hbs failed to demonstrate radiolabel within either the gallbladder or intestine at any time. Using nonvisualization of the intestine by 180 minutes as the scintigraphic criterion for diagnosis of biliary obstruction, sensitivity was 83% and specificity was 94% in this series. Hepatobiliary scintigraphy was concluded to be an accurate indicator of extrahepatic biliary obstruction in this group of animals. High serum bilirubin concentration at the time hbs was performed did not appear to reduce the diagnostic usefulness of the scintigraphic findings.

Free access
in Journal of the American Veterinary Medical Association

Summary

To measure tracheal mucociliary transport rate (tmtr) in awake dogs, restrained in dorsal recumbency 99mtechnetium-labeled macroaggregated albumin was administered by tracheal injection, and the cephalic movement of boluses containing the radiopharmaceutical was detected by a gamma camera positioned lateral to the dog's head and neck. The distance traveled by each bolus was measured, relative to external markers placed a known distance apart. Tracheal mucociliary transport rates were calculated by dividing the measured distance of radiopharmaceutical movement by elapsed time. The technique was efficient and well tolerated. Mean (± sd) tmtr was 35.3 ± 15.9 mm/min. Significant (P = 0.029) difference in tmtr was found between males and females, but significant difference attributable to age of the dog was not detected. This method of measuring tmtr in awake dogs has potential for evaluation of clinical animal patients with suspected tracheal mucociliary abnormalities.

Free access
in American Journal of Veterinary Research

SUMMARY

Four methods of evaluating renal function were performed in 6 cats anesthetized with halothane in oxygen. Glomerular filtration rate (gfr) was measured simultaneously in each cat by exogenous creatinine clearance (ecc), bolus inulin clearance, and 99mTc(Sn)-diethylenetriaminepentaacetic acid (dtpa) clearance determined by 2 different methods. In the first dtpa clearance method (dtpa-1), we measured radioactivity in serial blood specimens to construct plasma disappearance curves for calculation of gfr. In the second dtpa clearance method (dtpa-2), we used serial external head counts of radioactivity and a single blood specimen to construct plasma disappearance curves for calculation of gfr. Bolus inulin clearance was calculated from plasma disappearance curves using a 1-compartment open pharmacokinetic model (IN- 1) and a 2-compartment open pharmacokinetic model (IN- 2). Glomerular filtration rates were measured over 3 hours, for creatinine and dtpa methods, and over 4 hours for the inulin methods.

The gfr obtained with the reference method (ecc) was 2.56 ± 0.61 ml/min/kg of body weight (mean ± SD). Values for gfr determined by ecc and dtpa-1 were significantly correlated (r = 0.852; P ≤ 0.05). Correlation between ecc and dtpa 2 was not as good (r = 0.783; P ≤ 0.10), but the 2 dtpa methods significantly correlated with one another (r = 0.897; P ≤ 0.05). Regardless of the method of calculation, bolus inulin clearance was poorly correlated with ecc (IN-1: r = 0.538, P ≥ 0.10; in-2: r = 0.430, P ≥ 0.10) and dtpa-1 in-1: r = 0.601, P ≥ 0.10; in-2: r = 0.625, P ≥ 0.10). The 2 methods of calculating inulin clearance were highly correlated (r = 0.927; P ≤ 0.01). The dtpa clearance calculated from directly measured plasma disappearance curves (dtpa-1) compared favorably with ecc as an estimate of gfr and appears to be a safe, reliable, and less invasive method of determining gfr in cats.

Free access
in American Journal of Veterinary Research