How the preoperative ultrasound examination and BFI of the cervical lymph nodes modify the therapeutic treatment in patients with papillary thyroid cancer

BACKGROUND Ultrasound is considered the best diagnostic method for the detection of metastatic cervical lymph nodes (LNs) in patients with papillary thyroid carcinoma (PTC). According to current guidelines, all patients undergoing thyroidectomy for malignancy should undergo preoperative neck ultrasound of the thyroid and central and lateral neck LNs, followed by fine needle aspiration of suspicious LNs. Cervical LN involvement determenes the extent of surgery. Complete surgical resection disease at the initial operation decreases likelihood of future surgery for recurrent disease and may impact survival. We use a new technique, B-flow imaging (BFI), recently used for evaluation of thyroid nodules, to estimate the presence of BFI twinkling signs (BFI-TS), within metastatic LNs in patients with PTC. METHODS Between September 2006 and December 2012, 304 patients with known PTC were examined for preoperative sonographic evaluation with gray-scale US, color Doppler US and BFI. Only 157 with at least one metastatic LN were included in our study. All patients included underwent surgery, and the final diagnosis was based on the results of histologic examination of the resected specimens. The following LN characteristics were evaluated: LN shape, abnormal echogenicity, the absent of hilum, calcifications, cystic appearance, peripheral vascularization and the presence of BFI-TS. RESULTS A total of 767 LNs were analyzed. 329 out of 767 were metastatic, according to the histopathologic findings. BFI-TS, showed 99.5% specificity and 81,5% sensitivity. We detected BFI-TS in 6 metastatic LNs that were negative to the other conventional US features. CONCLUSIONS Our results indicate that the BFI-TS has a diagnostic accuracy higher than the other conventional sonographic signs. Our findings suggest that BFI can be helpful in the selection of suspicious neck LNs that should be examined at cytologic examination or open biopsy for accurate preoperative staging and individual therapy selection.