Intra- and Inter-Observer Reproducibility of a 2-D Shear Wave Elastography Technique and the Impact of Ultrasound Experience in Achieving Reliable Data

The aim of the study described here was to evaluate the reproducibility of a new shear-wave elastography (SWE) technique, 2-D SWE.GE, and the impact of ultrasound experience in acquiring reliable measurements, as no official recommendations are available for this system. Elastographic measurements (EMs) were obtained in 60 patients using 2-D-SWE with the GE Logiq E9. Three examiners with different levels of experience in ultrasound-based elastography performed 10 valid EMs on each subject: a novice (C.P.) who had no experience in liver elastography and had performed fewer than 50 ultrasound examinations; an elastography expert (A.M.S.) who had more than 1 y of liver elastographic experience in four elastographic methods and had performed more than 1000 ultrasonography examinations; and an ultrasound expert (T.M.) who had no experience in liver elastography and had performed more than 1000 ultrasound examinations. Medians and interquartile ranges were calculated (m/s). We used the inter-class correlation coefficient and Bland–Altman plots with 95% lower and upper limits of agreement to assess the inter- and intra-observer reproducibility of 2-D-SWE.GE measurements. The final study group included 60 patients, 56.7% women and 43.3% men, with a mean age of 33.08?±?13.83 y and mean body mass index of 22.85?±?4.04?kg/m². In this group, 73.3% were healthy volunteers and 26.7% had compensated liver cirrhosis. We did not find significant differences between EMs taken by the examiners overall and across study groups. The overall agreement between examiners was excellent: 0.915 (95% confidence interval [CI]: 0.870–0.946). The agreement between the novice and the experienced examiners, respectively, was good to excellent (novice and ultrasound expert: 0.908, 95% CI: 0.846–0.945; novice and elastography expert: 0.885, 95% CI: 0.808–0.931). The intra-observer reproducibility for each of the examiners was excellent; however, the inter-class correlation coefficients were higher for the examiners more experienced in elastography: 0.936 (95% CI: 0.896–0.963) versus 0.966 (95% CI: 0.943–0.980) versus 0.984 (95% CI: 0. 973–0.991). The good ICCs for the median values indicate that 2-D-SWE.GE is a reproducible method. Ultrasound experience did not significantly influence the results.     

Normal Liver Stiffness in Healthy Adults Assessed By Real-Time Shear Wave Elastography and Factors That Influence This Method

Real-time shear wave elastography (SWE) is a novel two-dimensional elastographic method that is used to estimate the severity of liver fibrosis. However, the normal range of liver stiffness (LS) and the possible factors that influence SWE are not well understood. The aims of the current study are to define the normal range of LS in healthy subjects and to explore the factors that may affect SWE. A total of 509 healthy subjects underwent SWE to determine the stiffness of their livers, and the effects of gender, age and body mass index (BMI) on LS were analyzed. The effects of different factors on SWE, including the testing position, measurement depth and size of the region of interest (ROI), were analyzed in 137 subjects. SWE imaging was successfully performed in 502 healthy subjects (98.6%, 502/509). The mean value of the SWE measurements in 502 individuals was 5.10 ± 1.02 kPa, and the 95% confidence interval was 5.02–5.19 kPa (range: 2.4–8.7 kPa). We found that the detective position within the liver had a significant impact on the liver stiffness measurement (LSM), and the lowest coefficient of variation (CV = 8%) was obtained for LSMs made at segment V. LS was greater at a depth >5 cm (5.78 ± 1.66 kPa) compared with depths ≤5 cm (4.66 ± 0.77 kPa, p < 0.001); LS was also greater in men than in women (5.45 ± 1.02 kPa vs. 4.89 ± 0.96 kPa, p < 0.001). However, there were no significant differences in the LS values regarding the size of the ROI, age or BMI (all p > 0.05). The mean LS value in all 502 healthy subjects was 5.10 ± 1.02 kPa. The mean LS value obtained by SWE was not influenced by the size of the ROI, age or BMI, but the mean value was significantly influenced by the different segments of the liver, the detection depth and gender.     

Diagnostic Accuracy of 2-D Shear Wave Elastography for the Non-Invasive Staging of Liver Fibrosis in Patients with Elevated Alanine Aminotransferase Levels

This study assessed the diagnostic accuracy of 2-D shear wave elastography (2-D-SWE) for the non-invasive staging of liver fibrosis and compared the findings with those for biochemical markers (the aspartate aminotransferase-to-platelet index and fibrosis-4 index) of liver fibrosis in patients with elevated alanine aminotransferase (ALT) levels (>5?×?the upper limit of normal). Patients with chronic liver diseases and elevated ALT levels who underwent liver biopsy were consecutively included. Receiver operating characteristic (ROC) curves were constructed to assess overall accuracy and to identify optimal cutoff values. After exclusions, data from 105 patients were analyzed. The areas under the ROC curves (AUROCs) for significant fibrosis, severe fibrosis and cirrhosis were 0.83, 0.86 and 0.91, respectively. The optimal cutoff values for predicting significant fibrosis, severe fibrosis and cirrhosis were 10.6, 13.2 and 17.6?kPa, respectively. The AUROCs of 2-D-SWE were significantly higher than those of biochemical markers for predicting significant fibrosis, severe fibrosis and cirrhosis (all p values?<?0.05). Therefore, the diagnostic performance of 2-D-SWE in assessing liver fibrosis stages in patients with elevated ALT levels was promising. The optimal cutoff values were increased but appropriate for this cohort because the baseline levels of liver stiffness measurements were increased in these patients, even in the absence of fibrosis.     

The value of shear wave elastography in the quantification of corpus cavernosum penis rigidity and its alteration with age

ObjectiveThe goal of this study was to measure corpus cavernosum (CC) penis rigidity with shear wave elastography (SWE) in healthy volunteers and to evaluate the change of rigidity with age.MethodsSWE was performed in 60 healthy volunteers (age range 20–71, mean 47 ± 12,83 years). Volunteers were divided into 2 groups by age (Group 1 age <50, group 2 age ≥50). We assessed SWE in 3 parts of penis (proximal, middle and glans penis) on both sides of CC. All values of SWE (in kilo Pascal) were noted along with volunteers’ ages. The measurements were done both with transverse (T) and longitudinal (L) sections. We compared all SW values of penis parts and their alterations with age.ResultsThe shear wave elastography values of CC penis increased with increasing age (p < 0,01). There was no significant difference between both sides of CC penis (p < 0,05). We calculated no significant difference between T and L sections of all parts of penis (p < 0,05).ConclusionsSWE can provide noninvasive quantitative data of CC penis rigidity and its alteration with age. These data may create a new approach in the evaluation process and treatment options for penile pathologies.     

冠桥拆除的力学分析

本文介绍了拆除冠桥的力学原理和有效方法，就破冠锤击法拆冠或桥以及冠桥拆除机理进行力学分析。分析显示：冠粘固后对拉伸力极为敏感，拉伸力越大，冠越容易脱位。因此，从生物力学的角度提示破冠锤击拆冠法优于传统的临床拆冠方法。     

Feasibility of two-dimensional ultrasound shear wave elastography of human fetal lungs and liver: A pilot study

PurposeThe first aim was to evaluate feasibility and reproducibility of 2-dimensional ultrasound (2D) shear wave elastography (SWE) of human fetal lungs and liver between 24 and 34 weeks of gestation. The second aim was to model fetal lung-to-liver elastography ratio (LLE ratio) and to assess its variations according to gestational age and maternal administration of corticosteroids.Material and methods2D-SWE examinations were prospectively performed in fetuses of women with an uncomplicated pregnancy (group 1) and fetuses of women with a threatened preterm labor requiring administration of corticosteroids (group 2). Two 2D-SWE examinations were performed at “day 0” and “day 2” in group 1; before and 24 hours after a course of corticosteroid in group 2. Three operators performed 2 cycles of 3 measurements on the lung (regions A1, A2, A3) and the liver (regions IV, V, VI). Repeatability and reproducibility of measurements were calculated. The fetal LLE ratio was modeled from the most reproducible regions.ResultsFifty-five women were enrolled in group 1 and 48 in group 2. For the lung, 8.6% of measurements were considered invalid and 6.9% for the liver. The most reproducible region for the lung was A3 [ICC between 0.70 (95% CI: 0.42–0.85) and 0.78 (95% CI: 0.48–0.90)] and region VI for the liver [ICC between 0.70 (95% CI: 0.40–0.85) and 0.84 (95% CI: 0.60–0.94)]. According to gestational age, a moderate positive linear correlation was found for stiffness values of A3 (R = 0.56), V (R = 0.46) and VI (R = 0.44). LLE ratio values at “day 0” were not different between the two groups but decreased at “day 2” in group 2 (0.2; 95% CI: 0.07–0.34; P < 0.001).ConclusionQuantitative fetal lung and liver stiffness measurements are possible with 2D-SWE with acceptable reproducibility.