Peer-reviewed veterinary case report
How vets check thyroid lobe size in hyperthyroid cats
By Scrivani, Peter V et al.·Published in Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association·2007·Department of Clinical Sciences, United States·View original on PubMed →
PetCaseFinder translated the abstract of this peer-reviewed paper into plain English so pet owners can read it. We do not publish original research — every detail traces back to the citation above. How we work →
Original publication title: Investigation of two methods for assessing thyroid-lobe asymmetry during pertechnetate scintigraphy in suspected hyperthyroid cats.
- Species:
- cat
Plain-English summary
A group of cats suspected of having hyperthyroidism (an overactive thyroid) underwent tests to check for thyroid-lobe asymmetry. Out of 48 cats, 33 were diagnosed with hyperthyroidism based on high thyroid hormone levels. Two methods were used to assess thyroid symmetry: measuring the thyroid-to-thyroid ratio and visual inspection. Both methods were effective, with the visual inspection showing excellent agreement among different veterinarians. This means that if your cat has an asymmetric thyroid, it could indicate hyperthyroidism, but some healthy cats may also have this condition, so further testing is important.
People also search for: cat hyperthyroidism symptoms · cat thyroid test results · how to treat hyperthyroidism in cats
Abstract
Our aim was to investigate thyroid:thyroid (T:T) ratio and visual inspection for assessing thyroid-lobe asymmetry in suspected hyperthyroid cats. Although thyroid-salivary asymmetry is a preferred test, inherent thyroid symmetry may assist image interpretation. Association was determined using a scatter plot and Spearman's rank correlation. Agreement was assessed using the kappa (K) statistic. Accuracy was assessed by sensitivity and specificity. Hyperthyroidism was diagnosed in 33/48 (69%) cats based on elevated serum total thyroxine level. Using two Wilcoxan rank-sum tests, a significant difference (P < 0.0001) was detected between cats with and without hyperthyroidism for both methods of assessing thyroid symmetry. For the 18 cats with T:T ratios < or = 1.5, there was poor correlation between the two methods (r(s) = 0.39). Using a cut-point of 1.5 for the T:T ratio, the test accurately predicted hyperthyroidism in 28/33 cats (sensitivity, 85%; 95% confidence interval (CI), 71-99%) and correctly predicted that hyperthyroidism was absent in 14/15 cats (specificity, 93%; CI, 77-100%). For visual inspection, agreement for diagnosing hyperthyroidism was excellent between methods (kappa = 0.82), within the same examiner (weighted kappa = 0.85) and between examiners (weighted kappa = 0.89). Considering cats with only definitely asymmetric thyroid lobes as positive, visual inspection accurately predicted hyperthyroidism in 28/33 cats (sensitivity, 85%; CI, 71-99%) and correctly predicted that hyperthyroidism was absent in 11/15 cats (specificity, 73%; CI, 48-99%). Thyroid-lobe asymmetry occurs more frequently in hyperthyroid than in euthyroid cats but caution should be exercised because some euthyroid cats have asymmetric thyroid glands.
Find similar cases for your pet
PetCaseFinder finds other peer-reviewed reports of pets with the same symptoms, plus a plain-English summary of what was tried across them.
Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/17691641/