QUANTITATIVE THYROID SCINTIGRAPHY AS A PREDICTOR OF SERUM THYROXIN CONCENTRATION IN NORMAL AND HYPERTHYROID CATS

Authors

  • Gregory B. Daniel DVM, MS,

    Corresponding author
    1. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37901-1071.
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  • Dorothy S. Sharp BS,

    1. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37901-1071.
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  • Janet A. Nieckarz DVM,

    1. Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37901-1071.
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  • William Adams DVM

    1. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37901-1071.
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Address correspondence and reprint requests to Gregory B. Daniel, D.V.M., M.S., Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, P.O. Box 1071, Knoxville, TN 37901-1071.

Abstract

Quantitative thyroid scintigraphy using pertechnetate was performed in 43 cats with various T4 concentrations and compared to eight normal control cats. Quantitative parameters included percentage dose uptake of the radioisotope by the thyroid, thyroid: salivary ratio and rate of thyroid uptake. All cats were anesthetized for the scan, and images were obtained using both low-energy all purpose (LEAP) and pinhole collimators. All quantitative parameters were significantly correlated to the serum T4 concentration, but the best correlation was obtained using the 20-minute thyroid: salivary ratio using only the most intense of the two thyroid lobes. The thyroid: salivary ratio was a good predictor of the metabolic status of the thyroid.

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