Eriko, Matsuda1; Takahiro, Fukuhara1; Satoshi, Koyama1; Ryohei, Donishi1; Naritomo, Miyake1; Kazunori, Fujiwara1; Hiroya, Kitano1; Hiromi, Takeuchi1
1 Department of Otolaryngology-Head and Neck Surgery, Tottori University Faculty of Medicine, Yonago, Japan
Background: Acoustic radiation force impulse (ARFI) imaging is reported as being useful for thyroid nodules. It is thought that ARFI imaging has possibility to distinguish between benign and malignant nodules by showing the color black for papillary thyroid carcinoma (PTC). However, it has not been clarified how chronic autoimmune thyroiditis (CAT) affects ARFI imaging for thyroid nodules.
Objective: To elucidate the effect of CAT on ARFI imaging of PTC in the thyroid.
Method: The subjects were 50 PTCs (39 without CAT, 11 with CAT) whose histopathology was clarified by surgery. ARFI imaging was performed for each PTC using the ACUSON S2000 ultrasound system (Siemens Medical Solutions USA, Inc., Malvern, PA) before surgery and was classified into four grades based on grayscale levels. Then, we compared the ARFI imaging between the two groups (with or without CAT).
Results: ARFI imaging was categorized as grades 1, 2, 3, and 4, respectively, in 2, 2, 7, and 28 cases for the 39 PTCs without CAT, compared with 1, 0, 5, and 5 cases for the 11 PTCs with CAT. The PTCs included four cases of follicular variant of PTC.
Discussion and conclusion: The contrast differences in the ARFI imaging between the legions and thyroid glands in the group with CAT were inferior as compared with another group without CAT. However, at a high rate of approximately 90%, PTCs indicated grades of 3 or 4 by AFRI imaging for both groups. We concluded that ARFI imaging is useful for detecting PTC with coexistent CAT.