Yoon Jeong Hee, Lee Jeong Min, Han Joon Koo, Choi Byung Ihn
Department of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 110-744, Korea.
J Ultrasound Med. 2014 Mar;33(3):437-47. doi: 10.7863/ultra.33.3.437.
The purpose of this study was to determine the optimal minimum number of liver stiffness measurements on shear wave elastography (SWE) and to evaluate the frequency of technical failures and unreliable stiffness measurements and the intraobserver reproducibility of SWE.
This retrospective study was approved by our Institutional Review Board, and informed consent was waived. From August 2011 to January 2013, 540 patients underwent abdominal sonography, including SWE. In 86 patients (group 1), the minimum number of examinations was determined by comparing the intraclass correlation coefficient (ICC) of subsets of the first 2 to 14 measurements with that from 15 measurements. In 454 patients (group 2), 2 SWE sessions were performed in the right lobe within 1 day. Technical failure was defined as when no or little signal was obtained in the elastogram during the first 5 acquisitions; unreliable SWE results were defined as when the interquartile range/median liver stiffness value exceeded 30%. Intraobserver reproducibility was assessed using ICCs and Bland-Altman plots.
In group 1, the ICCs did not significantly increase after the first 6 measurements. In group 2, there were technical failures and unreliable results in 47 patients (10.35%) and 74 patients (16.29%), respectively. In 407 patients, after excluding technical failures, there was no significant difference in the median liver stiffness values between the 2 sessions (6.95 versus 6.86 kPa; P > .05). The overall intraobserver reproducibility was excellent (ICC, 0.95).
In this study, the optimal minimum number of SWE measurements was 6, and SWE using 6 measurements showed excellent intraobserver reproducibility.
本研究的目的是确定剪切波弹性成像（SWE）时肝脏硬度测量的最佳最小次数，并评估技术失败和不可靠硬度测量的频率以及SWE的观察者内重复性。
本回顾性研究经我们机构审查委员会批准，且无需知情同意。2011年8月至2013年1月，540例患者接受了包括SWE在内的腹部超声检查。在86例患者（第1组）中，通过比较前2至14次测量子集与15次测量的组内相关系数（ICC）来确定最小检查次数。在454例患者（第2组）中，在1天内在右叶进行2次SWE检查。技术失败定义为在前5次采集期间弹性图中未获得信号或信号很少；不可靠的SWE结果定义为四分位间距/肝脏硬度中位数超过30%。使用ICC和Bland-Altman图评估观察者内重复性。
在第1组中，前6次测量后ICC没有显著增加。在第2组中，分别有47例患者（10.35%）出现技术失败和74例患者（16.29%）出现不可靠结果。在407例患者中，排除技术失败后，两次检查之间肝脏硬度中位数无显著差异（6.95对6.86 kPa；P>.05）。总体观察者内重复性良好（ICC，0.95）。
在本研究中，SWE测量的最佳最小次数为6次，使用6次测量的SWE显示出良好的观察者内重复性。
