To assess the value of the location of thyroid micronodules in helping identify their nature.

The location and ultrasonographic features of 426 thyroid micronodules confirmed by pathology at the Second Hospital of Lanzhou University from January 2018 to November 2020 were retrospectively analyzed. Binary logistic regression analysis was applied to identify the independent risk factors for thyroid cancer. Receiver operating characteristic (ROC) curve was drawn to compare the diagnostic efficacy of American College of Radiology thyroid imaging reporting and data system (ACR TI-RADS) alone and nodule location combined with ACR TI-RADS in the diagnosis of benign and malignant nodules.

Of the 426 thyroid micronodules included, 128 were benign and the remaining 298 were malignant. There was no significant difference in the numbers of benign and malignance nodules in the left lobe, right lobe, and isthmus, and in the ventral, middle, and dorsal sides of transverse sections (P＞0.05), while there were statistically significant differences in the upper, middle, and lower poles of longitudinal section (benign nodules: 23, 53, and 52; malignant nodules: 82, 128, and 88; χ²=6.716, P=0.035), and in the medial, middle, and lateral sides of transverse section (benign nodules: 47, 39, and 52; malignant nodules: 125, 58, and 115; χ²=6.180, P=0.045). Logistic regression showed that nodule location was an independent risk factor for thyroid cancer. The areas under the ROC curves of ACR TI-RADS classification alone and nodule location combined with ACR TI-RADS classification for differential diagnosis of benign and malignant thyroid nodules were 0.801 and 0.822, respectively, and there was a significant difference between the two groups (Z=2.738, P=0.006).

The location of thyroid micronodules is of great value in the differential diagnosis of benign and malignant nodules.