Thyroid Imaging Reporting and Data System (TIRADS) for solid nodules: the impact of quantitative strain elastography for better stratification of cancer risks
Study group: All cases with uninodular or polinodular goiter, larger than 5 mm in diameter, that have planned surgery in the near future or will have indication for surgery, after the evaluation will be considered in this analysis.
FNAB will be recommended in all solid nodules.
Only cases with performed UGFNA will be considered in the final evaluation.
In the cases of polinodular goiter we will considered the dominant nodule or the nodule with malignancy.
The score for the images will be made according to the TIRADS classification proposed by Russ:
TIRADS 2 (constantly benign aspect): simple cyst, spongiform nodules, “White knight”, isolated macrocalficication, nodular hyperplasia: nonencapsulated, mixed nodule, with solid portion, izoechoic, expansible, vascularized nodules with hyperechoic spots
TIRADS 3 (very probably benign): no signs of high suspicion, isoechoic or hyperechoic, partial in capsulated
TIRADS 4A (undetermined): no signs of high suspicion, mildly hypoechoic, incapsulated nodule
TIRADS 4B (suspicious): irregular shape/ taller than wide, irregular borders, Microcalfications, markedly hypoechoic, high stiffness with elastography; 1 or 2 signs and no lymph node metastasis
TIRADS 4C -5 (highly suspicious): irregular shape/ taller than wide, irregular borders, Microcalfications, markedly hypoechoic, high stiffness with elastography than; 3 to 5 signs and/or lymph node metastasis
Conventional and strain elastography will be performed with a Hitachi Preirus, multi frequency linear probe, 6-13 MHz, Hitachi Medical Corporation, Tokyo, Japan. Strain elastography will be performed, as recommended with mild external pressure, always checked on the pressure scale, using only 3-4 grade images and loops. Two observes with more than 5 years of experience in thyroid ultrasound, independently will evaluate the nodules using TIRADS classification and strain elastography. All the above-mentioned conventional ultrasound characteristics will be checked for each evaluated nodule. For each nodule, the observers will record not only the qualitative ES score, according to the standard blue red green color map, but also will calculat the strain ration comparing the nodule with the surrounding healthy, non nodular thyroid tissue. The Tsukuba classification will used for qualitative SE.
High stiffness was considered in cases of ES score 4 and 5 in qualitative evaluation, confirmed by a strain ratio higher than the value of 4. Regardless of the color map result, if the strain ratio was higher than 4, one criteria on TIRADS model will be checked. If there was an apparent color map 4 results, but with a strain ration below 4, the elastography criteria will not be considered as present/positive.
Unilateral lobectomy or total thyroidectomy will be performed according to the bilateral or unilateral lesion, and also the results of FNAB. In selected cases lymph node excision will be performed.
Each extracted piece will be conserved in formalin and embedded in paraffin, both nodular and apparent healthy surrounding tissue. The histological diagnosis, will be made in the Pathology Department of our hospital by the thyroid specialist. Imunohistochemical evaluation, HBME, CH-19, K067 and TTF reactions will be performed in selected cases.
Aim: The aim of the present study is to evaluate TIRADS with quantitative strain elastography for the assessment of thyroid nodules.