Shear wave elastography in medullary thyroid carcinoma diagnostics

Abstract

Shear wave elastography (SWE) is a modern method for the assessment of tissue stiffness. There has been a growing interest in the use of this technique for characterizing thyroid focal lesions, including preoperative diagnostics.AimThe aim of the study was to assess the clinical usefulness of SWE in medullary thyroid carcinoma (MTC) diagnostics.Materials and methodsA total of 169 focal lesions were identified in the study group (139 patients), including 6 MTCs in 4 patients (mean age: 45 years). B-mode ultrasound and SWE were performed using Aixplorer (SuperSonic, Aix-en-Provence), with a 4–15 MHz linear probe. The ultrasound was performed to assess the echogenicity and echostructure of the lesions, their margin, the halo sign, the height/width ratio (H/W ratio), the presence of calcifications and the vascularization pattern. This was followed by an analysis of maximum and mean Young's (E) modulus values for MTC (EmaxLR, EmeanLR) and the surrounding thyroid tissues (EmaxSR, EmeanSR), as well as mean E-values (EmeanLRz) for 2 mm region of interest in the stiffest zone of the lesion. The lesions were subject to pathological and/or cytological evaluation.ResultsThe B-mode assessment showed that all MTCs were hypoechogenic, with no halo sign, and they contained micro- and/ or macrocalcifications. Ill-defined lesion margin were found in 4 out of 6 cancers; 4 out of 6 cancers had a H/W ratio > 1. Heterogeneous echostructure and type III vascularity were found in 5 out of 6 lesions. In the SWE, the mean value of EmaxLR for all of the MTCs was 89.5 kPa and (the mean value of EmaxSR for all surrounding tissues was) 39.7 kPa Mean values of EmeanLR and EmeanSR were 34.7 kPa and 24.4 kPa, respectively. The mean value of EmeanLRz was 49.2 kPa.ConclusionsSWE showed MTCs as stiffer lesions compared to the surrounding tissues. The lesions were qualified for fine needle aspiration biopsy based on B-mode assessment. However, the diagnostic algorithm for MTC is based on the measurement of serum calcitonin levels, B-mode ultrasound and FNAB.

Rekomendacje Polskich Towarzystw Naukowych „Diagnostyka i leczenie raka tarczycy”. Aktualizacja na rok 2018

“…SoR: G1; QoE: + / PolCon 62/62 5.6. Elastography may be helpful in the selection of a lesion for FNAB; however, it is not obligatory [10][11][12][13][14] SoR: G1; QoE: PolCon 62/62 6. Indications for FNAB after diagnosis of thyroid lesion by other imaging modalities.…”

Elastografia fali poprzecznej nie pozwala na odróżnienie zmian w sterczu o charakterze złośliwym i łagodnym – analiza porównawcza wyników biopsji, badania histopatologicznego i elastografii

“…showed medullary thyroid carcinoma to reveal lesions that were stiffer than the surrounding tissues but were unable to draw clear conclusions about the usefulness of SWE. In both cases the authors recommend caution and call for larger-scale studies at a level of evidence higher than that attained until now: for liver, 4 on the Oxford scale ( 12 , 14 ) ; for thyroid ( 13 ) , and for the present study the level is similar, as all of these studies are based on case series. In contrast to this, the guidelines of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) posit that elastometry can be useful in distinguishing between mild liver fibrosis (or none) on the one hand and significant liver fibrosis on the other ( 15 ) .…”

“…Similar studies have been conducted in other organs. These have included, inter alia , the liver (reviewed by Conti et al ( 12 ) ) and the thyroid gland ( 13 ) . In both cases potentially promising results have been obtained.…”

“…wątroby (patrz: praca poglądowa Conti i wsp. (12) ) oraz tarczycy (13) . W obu przypadkach uzyskano obiecujące wyniki.…”

“…w rdzeniastym raku tarczycy wykazali obecność zmian, które były sztywniejsze niż otaczająca je tkanka, ale nie byli w stanie wyciągnąć jednoznacznych wniosków dotyczących przydatności techniki SWE. W obu przypadkach autorzy zalecają ostrożność i przyznają, że konieczne są dalsze, większe badania, o wyższym poziomie dowodu naukowego niż te uzyskane dotychczas dla wątroby (4 w skali oksfordzkiej (12,14) ) i dla tarczycy (13) . W przypadku przedstawionego badania poziom dowodu jest podobny, ponieważ wszystkie wspomniane prace oparte są na serii przypadków.…”