Background: No previous studies have reported the direct comparison between Ultrasonography
(US) and Computed Tomography (CT) features of Calcified Thyroid Nodules (CTNs).
Objective: This study aimed to compare the patterns and types of CTNs examined by preoperative
neck US and CT.
Methods: From January to June 2011, 224 patients who underwent neck US and CT before thyroid
surgery were included. Out of the 224 patients, 165 had a CTN showing a clear match on US and
CT. The CTN patterns were classified as follows: peripheral, central, and combined. The CTN
types were classified as follows: micro-, nodular, eggshell, curvilinear, pure, and mixed.
Results: Out of the 165 CTNs in 165 patients, 143 were papillary thyroid carcinomas, 2 follicular
thyroid carcinomas, 7 follicular adenomas, and 13 nodular hyperplasias. The most common CTN
pattern on US and CT was combined and central, respectively, and a statistical difference was observed
in the CTN patterns between US and CT (p < 0.0001). In the type of CTNs, the most common
type on US was microcalcification (64.2%, 106/165), whereas the prevalence rate of punctate
calcification on CT was only 9.1% (15/165). A statistical difference was observed in the type of
CTNs between US and CT (p < 0.0001).
Conclusion: US is superior to CT in the evaluation of microcalcifications, whereas macrocalcifications
showed the different features between US and CT. Recognizing the different features of
CTNs on US and CT may be helpful in the evaluation of thyroid nodules.