[Observation of calcification of thyroid tumors determined by CR and CT]

Detection of calcification of the thyroid gland is very useful for the clinical diagnosis and therapy of thyroid cancer. In this study, we evaluated the usefulness of FCR (Fuji computed radiography) and CT by analyzing the correlation between the imaging findings of calcification and histological diagnosis. Fifty-one cases of follicular adenoma and 63 cases of differentiated carcinoma underwent FCR and CT. All cases undergoing operation received histological examination. Calcification was detected in 19.6% of follicular adenomas and in 46.0% of differentiated carcinomas by FCR, and 37.3% of follicular adenomas and in 63.5% of differentiated carcinomas by CT. Among cases without calcification on FCR, CT detected calcification in 26.7%. These differences between the results of FCR and CT were found in cases with small calcifications, low thyroid gland position and in whom differentiation between tracheal cartilage calcification and thyroid carcinoma calcification was difficult. In these cases, calcification was difficult to detect by FCR alone. Patients with follicular adenoma aged > or = 60 years showed a higher prevalence of calcification than younger patients. In cases of differentiated carcinoma, no relationship was seen between age and the prevalence of calcification. The classification of calcification shape by FCR showed that the majority of psammoma bodies, as well as sharp and irregular shapes, were found in differentiated carcinoma while round calcifications were found in follicular adenomas. On CT, calcification inside the tumor was found in 73.7% of follicular adenomas and in 92.5% of differentiated carcinomas. FCR and CT are more useful for the detection of calcification than conventional radiography and are of great value in screening for thyroid tumors.