Factors that Influence Kidney Shear Wave Speed Assessed by Acoustic Radiation Force Impulse Elastography in Patients without Kidney Pathology

Our aim was to assess kidney shear wave speed by means of acoustic radiation force impulse (ARFI) elastography in patients without kidney pathology (“normal” patients) and to identify the factors that influence it. We analyzed 91 “normal” patients in whom kidney shear wave speed was assessed by means of ARFI elastography. Five valid ARFI elastographic measurements were obtained in all “normal” patients in both kidneys. In univariate analysis, age (r = −0.370, p = 0.003), gender (female vs. male, r = −0.305, p = 0.003) and measurement depth (r = −0.285, p = 0.01) were significantly correlated with kidney shear wave speed values assessed by ARFI elastography, whereas body mass index, kidney length and renal parenchyma thickness were not correlated. In multivariate analysis, only age (p = 0.006) and gender (p = 0.03) were significantly correlated with kidney shear wave speed values. In conclusion, kidney shear wave speed values assessed by ARFI elastography in “normal” patients are influenced mainly by age and gender and less by measurement depth.     

声触诊组织定量技术鉴别诊断乙肝相关性小肝癌与增生结节的应用价值

目的 探讨声触诊组织定量（VTQ）技术鉴别诊断乙肝相关性小肝癌与增生结节的临床价值。方法 选取经手术或穿刺病理证实的小肝癌患者54例和增生结节患者30例,均行常规超声及VTQ检查,获得其剪切波速度（SWV）,并绘制受试者工作特征（ROC）曲线进行统计学分析良恶性结节的最佳截断值,曲线下面积,敏感度,特异度,阳性预测值,阴性预测值,阳性似然比,阴性似然比等。结果 小肝癌患者的SWV值高于增生结节患者,54例小肝癌的SWV均值（3.45±1.44）m/s,95%可信区间（3.06,3.85）m/s,30例增生结节的SWV均值（1.87±0.40）m/s,95%可信区间（1.72,2.02）m/s,Kappa值为0.82,P＜0.05,显示病灶VTQ成像检测的一致性较好。诊断小肝癌的ROC曲线下面积为0.96,SWV为2.455 m/s时敏感度为90.74%,特异度为93.33%,阳性预测值96.08%,阴性预测值84.85%,阳性似然比13.61,阴性似然比0.10。结论 VTQ检查能够通过SWV反映出结节的硬度,在早期判定乙肝相关性小肝癌鉴别诊断中具有重要价值,是常规超声的有效补充。     

Intra-Individual Comparison between 2-D Shear Wave Elastography (GE System) and Virtual Touch Tissue Quantification (Siemens System) in Grading Liver Fibrosis

Ultrasound-based shear wave elastography (SWE) has recently gained substantial attention for non-invasive assessment of liver fibrosis. The purpose of this study was to perform an intra-individual comparison between 2-D shear wave elastography (2-D-SWE with a GE system) and Virtual Touch Tissue Quantification (VTTQ with a Siemens system) to assess whether these can be used interchangeably to grade fibrosis. Ninety-three patients (51 men, 42 women; mean age, 54 y) with liver disease of various etiologies (hepatitis B virus?=?47, hepatitis C virus?=?22; alcohol?=?6, non-alcoholic steatohepatitis?=?5, other?=?13) were included. Using published system-specific shear wave speed cutoff values, liver fibrosis was classified into clinically non-significant (F0/F1) and significant (≥F2) fibrosis. Results indicated that intra-modality repeatability was excellent for both techniques (GE 2-D-SWE: intra-class correlation coefficient?=?0.89 [0.84–0.93]; VTTQ: intra-class correlation coefficient?=?0.90 [0.86–0.93]). Intra-modality classification agreement for fibrosis grading was good to excellent (GE 2-D-SWE: κ?=?0.65, VTTQ: κ?=?0.82). However, inter-modality agreement for fibrosis grading was only fair (κ?=?0.31) using published system-specific shear wave speed cutoff values of fibrosis. In conclusion, although both GE 2-D-SWE and Siemens VTTQ exhibit good to excellent intra-modality repeatability, inter-modality agreement is only fair, suggesting that these should not be used interchangeably.     

Quantitative Assessment of Skin Stiffness Using Ultrasound Shear Wave Elastography in Systemic Sclerosis

This study was aimed at investigating the performance of ultrasound shear wave elastography (US-SWE) in the assessment of skin (the dermis) stiffness in patients with systemic sclerosis (SSc). The thickness and elastic modulus of the skin were measured using US-SWE at 6 sites in 60 SSc patients and 60 healthy volunteers: the bilateral middle fingers and forearms and the anterior chest and abdomen. To evaluate clinical scores, the measurements were also extended to 17 skin sites in 30 patients. The diagnostic performance of US-SWE in the differentiation of SSc from healthy skin was determined by receiver operating characteristic (ROC) curve analysis, and the reliability of the measurement was evaluated with intra- and inter-class correlation coefficients. The results of US-SWE were compared with modified Rodnan skin thickness scores. Our results indicated that (i) the elastic modulus values were significantly higher in SSc patients than in controls, with or without normalization by skin thickness; (ii) receiver operating characteristic analysis revealed normalized US-SWE cutoff values with a very high accuracy for right and left fingers (areas under the curve?=?0.974 and 0.949), followed by left forearm (0.841), anterior abdomen (0.797), right forearm (0.772) and anterior chest (0.726); (iii) the reliability of US-SWE measurements was good for all examined sites with intra-observer correlation coefficients of 0.845–0.996 and inter-observer correlation coefficients of 0.824–0.985; and (iv) total scores of skin involvement determined at 17 sites (modified Rodnan skin thickness scores) correlated with skin stiffness (r?=?0.832) and thickness (r?=?0.736). In conclusion, US-SWE is a quantitative method with high specificity, sensitivity and reliability in the detection of SSc involvement. This non-invasive, real-time and operator-independent imaging technique could be an ideal tool for the assessment of SSc disease.