Objective:

To investigate the agreement and difference between ultrasonography (US) and computed tomography (CT) in identifying calcifications inside papillary carcinoma and microcarcinoma of the thyroid

and to compare the accuracies of US and CT in the diagnosis of papillary carcinoma and microcarcinoma of the thyroid.

Methods:

The data of 3 678 cases of thyroid carcinoma were reviewed including the pre-operative reports of US and CT and post-operative pathological results. The inclusion criterion was calcification reported by either US

CT or pathology in thyroid carcinoma.

Results:

Out of 3 678 records

91.0% were found to have calcifications by US; while 52.9% showed calcifications in CT images. There was significant difference between US and CT (

P

0.000 5). The calcification rates of papillary carcinoma and microcarcinoma detected by US were similar (91.2%

vs

. 90.6%

P

=0.491); while CT showed higher calcification rate for papillary carcinoma than microcarcinoma (56.3%

vs

. 47.3%

P

0.000 5). In terms of the diagnostic accuracy of malignancy

US was superior to CT (95.7%

vs

. 38.1%

P

0.000 5). For papillary carcinoma and microcarcinoma

US showed no significant difference in the diagnostic accuracy (95.9%

vs

. 95.4%，

P

=0.404)

while CT showed higher superiority in diagnosing papillary carcinoma than microcarcinoma (45%

vs

. 27%

P

0.000 5).

Conclusion:

US is equivalent in the detection of calcification and diagnosis of malignancy between thyroid papillary carcinoma and microcarcinoma

while CT detects more calcifications and predicts more malignancy in papillary carcinoma than microcarcinoma.