Department of Radiology, Soonchunhyang University College of Medicine, Cheonan Hospital, Cheonan, Chungcheongnam-do, Korea.
Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Ultrasound Med Biol. 2019 Dec;45(12):3261-3268. doi: 10.1016/j.ultrasmedbio.2019.08.006. Epub 2019 Sep 4.
The aim of this study was to determine the factors influencing stiffness and conspicuity of focal lesions in deep organs by focusing on target properties using 2-D shear wave elastography (SWE). Two normal (4 ± 1 kPa) and cirrhotic (16 ± 2 kPa) liver-mimicking phantoms with spherical inclusions (23 ± 3 kPa) were used. Inclusions of three sizes (20, 15 and 10 mm in diameter) were arranged in a row at depths of 3, 5 and 7 cm. Two observers acquired quantitative stiffness values and a qualitative five-grade morphologic score at each inclusion using SWE. The coefficients of variation (CVs) of stiffness were calculated to assess measurement reliability. The generalized estimating equation was used to identify whether stiffness, CV and morphologic score were independent of background stiffness, depth and size of inclusions and observer. In the quantitative assessment, stiffness of the inclusion and CV were dependent on the type of phantom and depth of inclusion (p < 0.001). There were no significant differences in stiffness and CV according to the observer. Morphologic score differed significantly only in the size of the inclusion (p < 0.001). When the depth of the inclusion was 7 cm, the stiffness was the highest, and the 10 mm-sized inclusions had lower morphologic scores than the other inclusions (all p values < 0.001). In conclusion, 2-D SWE assessment of focal lesions could be affected by background stiffness and depth of focal lesions, and may be limited in evaluating focal hepatic lesions.
本研究旨在通过使用二维剪切波弹性成像（2-D SWE）聚焦于目标特性，确定影响深部器官局灶性病变硬度和可视性的因素。使用两个正常（4 ± 1 kPa）和肝硬化（16 ± 2 kPa）肝脏模拟体模，其中包含球形内含物（23 ± 3 kPa）。将三种大小（直径为 20、15 和 10 mm）的内含物排列成一行，深度分别为 3、5 和 7 cm。两名观察者使用 SWE 在每个内含物处获得定量硬度值和定性五级形态评分。计算硬度的变异系数（CV）以评估测量可靠性。广义估计方程用于确定硬度、CV 和形态评分是否独立于背景硬度、内含物的深度和大小以及观察者。在定量评估中，内含物的硬度和 CV 取决于体模的类型和内含物的深度（p < 0.001）。观察者之间的硬度和 CV 没有显著差异。形态评分仅在内含物的大小上有显著差异（p < 0.001）。当内含物的深度为 7 cm 时，硬度最高，而 10 mm 大小的内含物的形态评分低于其他内含物（所有 p 值均 < 0.001）。总之，二维 SWE 对局灶性病变的评估可能会受到背景硬度和局灶性病变深度的影响，并且可能在评估局灶性肝病变方面受到限制。
