| Abstract | Nineteen cats with abnormally high serum T4 concentrations underwent thyroid scintigraphy using technetium-99m pertechnetate (99mTcO4) before and after 36 +/- 6 days of methimazole administration (approximately 2.5mg PO q 12 h). Thyroid-to-salivary gland ratios (T:S ratios) and percentage thyroidal uptake of injected radioactivity at 20 and 60min after injection of 99mTcO4 were compared before and after methimazole treatment. Serum thyroid stimulating hormone (TSH) concentration was measured before and after methimazole treatment. Quantitatively, there was a positive association between the thyroid uptake of 99mTcO4 and the serum T4 before treatment (r = 0.74-0.83). TSH suppression was present when cats were first evaluated for hyperthyroidism. Methimazole treatment did not relieve TSH suppression in 17 cats. Two cats with unilateral thyroid uptake developed bilateral, asymmetric thyroid uptake of 99mTcO4 after treatment and had the greatest increase in TSH concentration after treatment. Quantitatively, thyroid scintigraphy did not significantly change after methimazole treatment (P>0.1). Evaluation of serum TSH concentration may be helpful in identifying methimazole-induced changes in the scintigraphic features of hyperthyroidism in mildly hyperthyroid cats. |
| Authors | Anthony J Fischetti, William Tod Drost, Stephen P DiBartola, Dennis J Chew, Patricia A Schenck, Cheyney Meadows
(Affiliation: Department of Veterinary Clinical Sciences, The Ohio State University, 601 Vernon L. Tharp St., Columbus, OH 43210, USA.)
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| Journal | Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association
(Vet Radiol Ultrasound)
2005 May-Jun
Vol. 46
Issue 3
Pg. 267-72
ISSN: 1058-8183 United States |
| PMID | 16050288
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
|
| Chemical References |
- Antithyroid Agents
- Radiopharmaceuticals
- Sodium Pertechnetate Tc 99m
- Methimazole
|
| Topics |
- Animals
- Antithyroid Agents
(pharmacology)
- Cat Diseases
(metabolism, radionuclide imaging)
- Cats
- Drug Interactions
- Female
- Hyperthyroidism
(radionuclide imaging, veterinary)
- Male
- Methimazole
(pharmacology)
- Prospective Studies
- Radiopharmaceuticals
(pharmacokinetics)
- Sodium Pertechnetate Tc 99m
(pharmacokinetics)
- Thyroid Gland
(metabolism)
|
