Abstract
The thyroid scanning of thirty five patients with chronic thyroiditis (Hashimoto's thyroiditis) in whom the diagnosis was confirmed by the needle biopsy of the thyroid gland was studied. The results were as follows:
a) When the images were classified into four patterns by the distribution of the intrathyroidal radioactive isotope (ITRI), normal and homogeneous appearance (type I) was seen in eight cases (23%). Mottled and/or heterogenous appearance (type II) thirteen cases (37%). Prominent defect appearance (type III a) ten cases (29%). And equivocal defect appearance (type III b) four cases (11%).
b) Twenty three patients with 131I-scan (66%) and twelve patients with 99mTc-scan (34%) were studied. 131I-uptake at twenty four hour was 4 to 42 percent (the mean value is 24.5%) in type II. Therefore, mottled type with 131I-scan could not be due to the low thyroidal uptake of 131I-iodine.
C) About the thyroid function at the time of scanning, 30 patients were euthyroid, 4 patients hypothyroid, and 1 patient hyperthyroid respectively.
d) Anti-thyroglobulin titer was higher in type II and type IIIa, and was lower in type I and type III b.
e) There were two patients with microscopically mixed presentation of the chronic thyroiditis and the thyroid carcinoma. They belonged to type III a.
