Clinical efficacy of novel elastography using acoustic radiation force impulse (ARFI) for diagnosis of malignant thyroid nodules

Abstract

ObjectiveAcoustic radiation force impulse (ARFI) imaging is a recent ultrasound elastography technique; consequently, its efficacy is not fully known. In this study, we compared ARFI imaging with conventional strain elastography (SE) and shear wave velocities (SWVs) to evaluate the utility of ARFI imaging for diagnosing thyroid nodules.Subjects and MethodsIn this study we examined 233 thyroid nodules (183 benign nodules and 50 malignant nodules) isolated from human patients. The nodules were evaluated with SE and ARFI imaging, and SWVs of the nodules were simultaneously measured. ARFI images were classified using a four‐point score based on grayscale intensity of the images. The sensitivity, specificity, and diagnostic accuracy were compared between SE and ARFI imaging. Finally, SWVs for each score of SE and ARFI imaging were compared.ResultsThe new scoring system for ARFI imaging can be divided into four virtual touch imaging (VTI) scores. Nodules with a VTI score of 3 or 4 as determined by ARFI imaging were determined to be malignant. The sensitivity, specificity, and diagnostic accuracy, respectively, were 63.2%, 66.3%, and 65.6% for SE, compared with 80.0%, 86.3%, and 85.0% for ARFI imaging. The median SWVs of the nodules were 1.57 m/s, 1.73 m/s, 1.88 m/s, and 2.09 m/s for VTI scores of 1, 2, 3, and 4, respectively. The SWVs of VTI scores 3 and 4 were significantly higher than those of VTI scores 1 and 2.ConclusionsThe diagnostic accuracy of ARFI imaging for differentiating malignant thyroid nodules was higher than that of SE. The VTI scores of the nodules accurately reflected their SWVs.Level of Evidence4

How to perform shear wave elastography. Part I

“…In pSWE the small fixed-size ROI should be completely included within the nodule. In 2D-SWE the box should be large enough to include the whole nodule, avoiding nearby vessels or gland areas with cystic or fibrotic changes (fig 4) [5,91].…”

“…For pSWE 3 to 10 measurements should be acquired at the same location and the average of these should be calculated. For 2D-SWE at least three measurements must be performed [5,91].…”

Elastografía cuantitativa en la evaluación de nódulos tiroideos

“…16 17 Su mayor ventaja es que disminuye la variabilidad inter e intraobservador, porque es una prueba no operador dependiente. 16 18 19…”

“…Se obtiene un mapa de colores de los diferentes tejidos incluidos dentro de la caja que, según su grado de elasticidad, son: azul para los tejidos muy blandos, rojo para los muy rígidos, verde y amarillo para los valores intermedios de elasticidad. 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Se toman varias medidas mediante la colocación de una región de interés (ROI) dentro del nódulo y una medida de referencia del tejido tiroideo normal. Se evitará incluir dentro de la ROI las zonas quísticas y las calcificaciones.…”

Clinical Utility of Qualitative Elastography Using Acoustic Radiation Force Impulse for Differentiating Benign from Malignant Salivary Gland Tumors

“…Furthermore, although conventional SE measures strain on the tissue under manual compression using the whole probe, ARFI imaging measures displacement by evaluating the detailed differences in tissue stiffness in response to fine compression, utilizing an acoustic push pulse. In fact, ARFI imaging has been described in the literature as being superior to conventional SE when differentiating between benign and malignant tumors in regions of the breast and thyroid gland (Tozaki et al 2011;Xu et al 2014;Fukuhara et al 2018). This study aimed to elucidate the utility of ARFI imaging in differentiating benign from malignant salivary gland tumors.…”