Thyroid B-flow twinkling sign: a new feature of papillary cancer

Abstract

Background: Microcalcifications (aggregated with psammoma bodies), detected by ultrasound (US), are the most specific feature of papillary thyroid cancer (PTC). Using B-flow imaging (BFI), we identified a new sign (the twinkling sign; BFI-TS) in 'suspect' PTC nodules, which appeared to be generated by microcalcifications.

Objective: To evaluate whether the BFI-TS was predictive of malignancy, we correlated the BFI-TS with the results of fine needle aspiration cytology and histology.

Design: Cross-sectional cohort study from September 2006 to April 2008.

Setting: Department of Radiology and Endocrinology, University of Naples Federico II, and Department of Endocrinology, Second University of Naples.

Patients: A total of 306 consecutive patients with 539 thyroid nodules >8 mm in diameter.

Main outcome measure: US and BFI examinations were performed with the Logiq 9 system (General Electric Company, Milan, Italy); all patients underwent cytological examination.

Results: Cytology revealed 455 (84.4%) benign nodules and 84 (15.6%) malignant nodules; the latter were confirmed by postsurgical histological examination (76 cases of PTC, 7 follicular carcinoma, and 1 Hürthle cell carcinoma). All suspect nodules, namely, nodules with potential predictors of thyroid malignancy (e.g., microcalcifications and intra-nodal vascularity), were analyzed by cytology or histology (or both). Of 84, 68 (80.9%) of malignant nodules had >or=4 or more BFI-TSs in at least one scan versus only 12 of 455 (2.6%) of benign lesions.

Conclusions: Our results indicate that the BFI-TS could be a reliable diagnostic technique in the management of suspect thyroid nodules.

Figure 1

Ultrasound B-mode of a suspect thyroid nodule. (a) Transverse US image of a nodule containing multiple fine echogenicities (arrow) with no comet-tail artifact. (b) Addition of color Doppler mode shows flow within the mural component. (c) Transverse B-flow image of a nodule containing multiple twinkling signs, highly suggestive of malignancy. Fine needle aspiration and surgery confirmed papillary carcinoma. (d) Histological image showing a papillary cancer and psammoma body (arrow).

Figure 2

Mode and color Doppler of a non-suspect thyroid nodule. (a) Sagittal image of a solid nodule suggesting a benign lesion. (b) Addition of color Doppler mode did not show marked internal vascularity. (c) Sagittal B-flow image of a nodule containing multiple twinkling signs, suggesting malignancy. Fine needle aspiration and surgery confirmed papillary carcinoma. (d) Histological image showing a papillary cancer and psammoma body (arrow).