Nadebaum David P, Nicoll Amanda J, Sood Siddharth, Gorelik Alexandra, Gibson Robert N
Department of Gastroenterology and Hepatology, Royal Melbourne Hospital, Parkville, Victoria, Australia.
Department of Melbourne Epicenter, Royal Melbourne Hospital, Parkville, Victoria, Australia.
J Ultrasound Med. 2018 Mar;37(3):647-656. doi: 10.1002/jum.14375. Epub 2017 Sep 29.
A new 2-dimensional (2D) shear wave elastographic (SWE) device has been developed for the noninvasive assessment of liver fibrosis. Guidelines on measurement acquisition parameters are not yet well established for this technique. Our study aimed to assess 2D SWE measurement variability and to determine the number of measurements required per patient to reliably assess liver stiffness.
Two-dimensional SWE was assessed in 55 patients with mixed-etiology chronic liver disease on an Aplio 500 ultrasound system (Toshiba Medical Systems Corporation, Tochigi, Japan). Ten measurements were obtained per patient by an operator blinded to all preceding readings. Results were analyzed with clinical information obtained from medical records.
The median interquartile range/median ratio for 2D SWE was 0.131 (quartiles 1-3, 0.089-0.174). Five readings provided an approximation within 0.11 m/s, or 4.2% of the median velocity of 10 measurements. Factors associated with increased measurement variability included body mass index (ρ = 0.388; P = .01), increased skin-to-liver capsule distance (ρ = 0.426; P = .002), and measurements taken within 1.5 cm of the liver capsule (P < .001). Measurements with heterogeneous shear wave profiles (indicated by a region of interest [ROI] SD/speed ratio > 0.15) showed greater deviation from the set's median velocity than those with an ROI SD/speed ratio of 0.15 or lower (0.42 versus 0.22 m/s; P = .001).
Two-dimensional SWE showed low overall measurement variability, with a minimum of 5 readings providing equivalent precision to the existing method using 10 samples. Obesity, increasing abdominal wall thickness, subcapsular measurements and an ROI SD/speed ratio of greater than 0.15 were all associated with increased measurement variability. The ROI SD/speed ratio warrants further evaluation as a quality assessment metric, to allow objective operator assessment of individual 2D SWE measurement reliability in real time.
已开发出一种新型二维（2D）剪切波弹性成像（SWE）设备，用于肝纤维化的无创评估。该技术的测量采集参数指南尚未完全确立。我们的研究旨在评估二维SWE测量的变异性，并确定每位患者为可靠评估肝脏硬度所需的测量次数。
在Aplio 500超声系统（日本东芝医疗系统公司，枥木）上，对55例病因混合的慢性肝病患者进行二维SWE评估。由对之前所有读数不知情的操作人员对每位患者进行10次测量。结果与从病历中获取的临床信息进行分析。
二维SWE的四分位间距中位数/中位数比率为0.131（四分位数1 - 3，0.089 - 0.174）。五次读数的结果与中位数速度相差在0.11m/s以内，即10次测量中位数速度的4.2%。与测量变异性增加相关的因素包括体重指数（ρ = 0.388；P = 0.01）、皮肤至肝包膜距离增加（ρ = 0.426；P = 0.002）以及在距肝包膜1.5cm内进行的测量（P < 0.001）。与剪切波轮廓不均匀（由感兴趣区域[ROI]标准差/速度比率> 0.15表示）的测量相比，ROI标准差/速度比率为0.15或更低的测量与该组中位数速度的偏差更大（分别为0.42对0.22m/s；P = 0.001）。
二维SWE总体测量变异性较低，最少5次读数可提供与使用10个样本的现有方法相当的精度。肥胖、腹壁厚度增加、包膜下测量以及ROI标准差/速度比率大于0.15均与测量变异性增加相关。ROI标准差/速度比率作为质量评估指标值得进一步评估，以便操作人员实时客观评估个体二维SWE测量的可靠性。
