Morphologische Grundlagen der Schilddrüsensonographie bei der Katze

Morphological fundamentals for the sonographic examination of the feline thyroid gland The thyroid glands of 101 deceased cats were removed for morphological, sonographical, morphometrical, volumetrical and pathohistological assessment to investigate the morphological fundamentals for sonographic examination. The determined reference range extends over 0,08 – 0,27 ml in volume, 13,8 – 25,2 mm in length, 2,3 – 4,1 mm in width and 3,9 – 7,1 mm in height of the feline thyroid gland. These parameters are independent of body weight, age, sex and castration status of the cat. A correction factor of 0,45 has been established from the volumetrically and morphometrically measured values by sonographic survey. This makes it possible to apply the ellipsoid formula for the specific determination of the feline thyroid gland volume. However, comparative studies have shown a remarkably broad standard deviation for this method of calculating the thyroid gland volume in the cat. Its assessment by surveying the thyroid gland lobes` width and height is more expressive: the ratio should not be below 1:1,5. The number of detected thyroid alterations in the cat was surprisingly high. Mainly - in 48 out of 101 animals - nodular hyperplasia and adenomas have been found. Sonographic examination revealed characteristic features of nodular hyperplasia and adenoma cases. However, these examinations could not provide reliable distinctive marks. In addition, two adenocarcinomas were found. Their sonographic examination resulted in a list of characteristics of thyroid malignancies (e.g. outstanding size, knobby surface, inhomogeneous echostructure with poor echogenity) as reported in literature. Analogous to the proven etiology of human nodular hyperplasia and adenoma hypothetically the high incidence of those alterations in cats could be caused by chronic iodine deficiency. This hypothesis is in line with the recently detected deficitary iodine content of an average of commercial cat food. Nodular hyperplasia and adenoma are one of the major causes for feline hyperthyroidism. In the recent years their incidence has increased. The studies on hand emphasize the importance of the sonographic examination for detection of such morphologic thyroid gland alterations as a supplementary measure to laboratory diagnostics of hyperthyroidism.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Ludwig-Maximilians-Universität

Year

2001

Author dc:creator

• Kurzke, Ellen

Repository record source_url

https://edoc.ub.uni-muenchen.de/1333/

OAI identifier oai:identifier

oai:edoc.ub.uni-muenchen.de:1333