ULTRASONOGRAPHIC EXAMINATION OF THE THYROID GLAND OF HYPERTHYROID CATS

COMPARISON TO 99mTcO 4 SCINTIGRAPHY

Erik R Wisner, Alain P Theon, Med Vet, Thomas G. Nyland, William J. Hornof

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

High‐resolution ultrasonography was evaluated as an alternative to 99mTcO 4 scintigraphy for examining size and appearance of thyroid glands in hyperthyroid cats. Thyroid ultrasound examinations were performed on 6 normal cats and 14 cats with hyperthyroidism. Thyroid lobe volume was estimated from ultrasound images using the equation for a prolate ellipsoid, π/6 (length * height * width). Total thyroid volume was estimated by adding the volume estimations of the left and right lobes. Thyroid lobes of hyperthyroid cats were considered abnormal if estimated volume exceeded the 99% confidence interval for normal thyroid volume determined from the control group. Scintigraphic examinations performed on hyperthyroid cats were evaluated for unilateral versus bilateral disease and for the presence of ectopic activity. Mean thyroid lobe volume and total thyroid volume for normal cats was 85 and 169 mm3, respectively. Mean thyroid lobe volume and total thyroid volume for hyperthyroid cats was 578 and 889 mm3. There was a significant difference in mean estimated total thyroid volume of normal and hyperthyroid cats. Thyroid lobes with greater than normal TcO 4 uptake on scintigraphy were larger and had variable homogeneity, echogenicity, and margination on ultrasound examination. There also was an 85.7% agreement of scintigraphy and ultrasonography in differentiating normal from abnormal thyroid lobes. A fair correlation between estimated total thyroid volume of hyperthyroid cats and most recent pretherapy serum thyroxine values were also found. This preliminary study indicates that thyroid ultrasound examination may provide information that is useful for diagnosis and treatment of feline hyperthyroidism. Although ultrasound provides accurate evaluation of the thyroid glands, it cannot replace 99mTcO 4 scintigraphy for screening of metastatic lesions and ectopic glands.

Original languageEnglish (US)
Pages (from-to)53-58
Number of pages6
JournalVeterinary Radiology and Ultrasound
Volume35
Issue number1
DOIs
StatePublished - 1994

Fingerprint

thyroid gland
Hyperthyroidism
Thyroid Gland
Cats
cats
scintigraphy
Radionuclide Imaging
hyperthyroidism
ultrasonography
Ultrasonography
thyroxine
Phosmet
lesions (animal)
confidence interval
Felidae
Thyroxine
screening

Keywords

  • feline species
  • hyperthyroidism
  • scintigraphy
  • thyroid
  • ultrasonography

ASJC Scopus subject areas

  • veterinary(all)

Cite this

ULTRASONOGRAPHIC EXAMINATION OF THE THYROID GLAND OF HYPERTHYROID CATS : COMPARISON TO 99mTcO 4 SCINTIGRAPHY. / Wisner, Erik R; Theon, Alain P; Vet, Med; Nyland, Thomas G.; Hornof, William J.

In: Veterinary Radiology and Ultrasound, Vol. 35, No. 1, 1994, p. 53-58.

Research output: Contribution to journalArticle

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