Reproducibility Of Shear Wave Elastography Research Articles

Quantifying canine tissue stiffness change patterns using shear-wave elastography: implications for time of death estimation

ABSTRACT This study investigates the applicability and reproducibility of shear-wave elastography (SWE) in detecting changes in tissue stiffness of canine carcasses. SWE was performed on six canines by two operators. The target organs were liver, spleen, kidney, and thigh muscles. SWE was performed ante-mortem and up to 48-hours post-mortem at specific intervals. The Mann-Whitney U-test and Spearman correlation coefficient showed insignificant correlation between gender and weight with shear-wave velocity (SWV) in ante-mortem scans. The Kruskal-Wallis H-test showed significant differences in SWV for all organs. Intraclass correlation coefficient (ICC) showed excellent correlation for all target organs except for kidneys. Pairwise comparison showed a similar SWV trend for abdominal organs. Accuracy metrics were calculated for determining the post-mortem interval using SWV values. The liver had the highest accuracy (0.69–0.83) across different post-mortem interval thresholds within the cut-off values of ≥2.0 m/s, 1.8–2.0 m/s, <1.8 m/s indicating ≤6 hours post-mortem, 12–18 hours post-mortem and >18 hours post-mortem. The spleen, kidney and thigh muscle demonstrated moderate-to-poor accuracy within the same cut-off parameters. Post-mortem SWV changes in canine solid organs, and soft tissues, particularly the liver, demonstrate a reproducible pattern, which may have value in determining the post-mortem interval.

Anisotropy and reproducibility of ultrasound shear wave elastography in patella tendons with and without tendinopathy

PurposeUltrasound shear wave elastography (SWE) is a tool that can be utilized to assess biomechanical properties of tendons. Anisotropy, an ultrasound imaging artifact has been commonly cited as a potential source of error in the accuracy and reproducibility of SWE. The aim of the study was to assess reproducibility in performing SWE of patella tendons and differences in SWE and anisotropy between normal patella tendons and patellar tendinopathy. MethodsAfter obtaining the Institutional Review Board approval and written informed consent, we prospectively measured the shear wave velocity (SWV) of patella tendons with and without tendinopathy in 25 volunteers. SWVs were measured in three anatomic planes: longitudinal, perpendicular transverse, and tilted transverse with the probe tilted 15–30° from the perpendicular transverse plane by three operators with varied levels of experience. Anisotropy coefficient (A) was calculated by formula of A = (SWVLongitudinal − SWVTransverse) / SWVTransverse. ResultsDifferences in SWV and anisotropy coefficient between normal tendons and tendons with tendinopathy were significant (p < 0.05). The intra- and inter-observer reproducibility in performing SWE were moderate to good (intraclass correlation coefficient: 0.81–0.95). The mean difference of 95% Bland-Altman limits of agreement for measuring tendon SWV ranged −0.08 to 0.41 (upper 0.08 to 1.14, lower −1.22 to −0.22) between senior and junior operators. ConclusionThe results of this study suggest that SWE and anisotropy coefficient are feasible tools to differentiate patellar tendinopathy from normal patella tendons. The reproducibility of performing SWE of patella tendons is moderate to good.

Accuracy and reproducibility of shear wave elastography according to the size and elasticity of lesions: A phantom study.

While the extrinsic factors affecting reproducibility of shear wave elastography (SWE) have been well documented, there are few resources assessing intrinsic characteristics of the lesion affecting the reproducibility and accuracy of SWE. In this regard, this study aimed to evaluate the accuracy of measured elasticity and the reproducibility of SWE according to the lesion size and stiffness. Two breast radiologists examined 20 targets of 4 different levels of stiffness and 5 different sizes (2.5, 4, 7, 11, and 18 mm) in a customized elasticity phantom. The B-mode image, color elastography image, and kPa measurement were obtained twice by each examiner with a 1-week interval. Inter- and intra-observer reproducibility and the accuracy of measured kPa were analyzed using intraclass correlation coefficient (ICC) and Bland-Altman analysis. Subgroup analysis was run to evaluate the effect of lesion size and stiffness on the reproducibility and accuracy of measured kPa. Inter- and intraobserver reproducibility for measuring kPa showed excellent agreement (ICC: 0.9742 and 0.9582; ICC: 0.9932 and 0.9294). The size and stiffness of the targets did not affect reproducibility. The overall accuracy of measured kPa was very high (ICC: 0.8049). In the subgroup analysis, targets that were ≤4 mm in size showed lower accuracy (ICC: 0.542), whereas targets that were 7 and 11 mm in size showed higher accuracy (ICC: 0.9832 and 0.9656, respectively). SWE shows excellent reproducibility regardless of lesion size or stiffness in phantom targets. The accuracy of measured kPa is high in lesions that are 7 and 11 mm in size but is low in lesions that are ≤4 mm in size.

Inter-operator and inter-device reproducibility of shear wave elastography in healthy muscle tissues.

PurposeThe study aimed to assess whether the more limiting factor in reproducibility of shear wave elastography (SWE) would be the operator dependency or the incompatibility of different ultrasound (US) devices. The interrater agreement with less experienced operators was studied.MethodsA total of 24 healthy volunteers participated in the study (18 females, 6 males; range of age 27–55 years). SWE of biceps brachii (BB) and tibialis anterior (TA) muscles was performed on both sides from all participants in both longitudinal and transverse orientation of the transducer in respect to muscle fibers. Two operators repeated the SWE with two different US devices from different manufacturers (scanners 1 and 2).ResultsIntraclass correlation coefficient between the two operators was 0.91 (CI 0.88–0.93) for scanner 1 and 0.81 (CI 0.74–0.86) for scanner 2, respectively. Instead, there were significant differences in the SWE measurements between the two scanners, emphasizing in transverse orientation of the transducer. In the transverse transducer orientation, the mean shear wave velocity (SWV) in TA was 1.45 m/s (standard deviation [SD] ± 0.35 m/s) with scanner 1 and 2.35 m/s (SD ± 0.83 m/s) with scanner 2 (p < 0.001). In BB, the mean transverse SWV was 1.49 m/s (SD ± 0.35 m/s) with scanner 1 and 2.29 m/s (SD ± 0.63 m/s) with scanner 2 (p < 0.001). In longitudinal transducer orientation, the mean SWV in TA was 3.00 m/s (SD ± 0.73 m/s) with scanner 1 and 3.26 m/s (SD ± 0.42 m/s) with scanner 2 (p = 0.050). In BB, the mean longitudinal SWV was 3.60 m/s (SD ± 0.77 m/s) with scanner 1 and 3.96 m/s (SD ± 0.62 m/s) with scanner 2 (p = 0.019). The presented mean values were obtained by operator 1, there were no significant differences in the SWE measurements performed by the two operators.ConclusionThe results implicate that the reproducibility of the SWE measurements depends rather on the used US device than on the operator. It is recommendable that clinics collect reference values with their own US device and consider threshold values presented in previous studies only directional.

An evaluation of the objectivity and reproducibility of shear wave elastography in estimating the post-mortem interval: a tissue biomechanical perspective.

Cadaveric rigidity-also referred to as rigor mortis-is a valuable source of information for estimating the time of death, which is a fundamental and challenging task in forensic sciences. Despite its relevance, assessing the level of cadaveric rigidity still relies on qualitative and often subjective observations, and the development of a more quantitative approach is highly demanded. In this context, ultrasound shear wave elastography (US SWE) appears to be a particularly well-suited technique for grading cadaveric rigidity, as it allows non-invasive quantification of muscle stiffness in terms of Young's modulus (E), which is a widely used parameter in tissue biomechanics. In this pilot study, we measured, for the first time in the literature, changes in the mechanical response of muscular tissues from 0 to 60h post-mortem (hpm) using SWE, with the aim of investigating its applicability to forensic practice. For this purpose, 26 corpses were included in the study, and the muscle mechanical response was measured at random times in the 0-60hpm range. Despite the preliminary nature of this study, our data indicate a promising role of SWE in the quantitative determination of cadaveric rigidity, which is still currently based on qualitative and semiquantitative methods. A more in-depth study is required to confirm SWE applicability in this field in order to overcome some of the inherent limitations of the present work, such as the rather low number of cases and the non-systematic approach of the measurements.

Reproducibility of shear wave elastography among operators, machines, and probes in an elasticity phantom.

PurposeThis study was aimed to investigate the reproducibility of shear wave elastography (SWE) among operators, machines, and probes in a phantom, and to evaluate the effect of depth of the embedded inclusions and the accuracy of the measurements.MethodsIn vitro stiffness measurements were made of six inclusions (10, 40, and 60 kPa) embedded at two depths (1.5 cm and 5 cm) in an elastography phantom. Measurements were obtained by two sonographers using two ultrasound machines (the SuperSonic Imagine Aixplorer with the XC6-1, SL10-2 and SL18-5 probes, and the General Electric LOGIQ E9 with the 9L-D probe). Variability was evaluated using the coefficient of variation. Reproducibility was calculated using intraclass correlation coefficients (ICCs).ResultsFor shallow inclusions, low variability was observed between operators (range, 0.9% to 5.4%). However, the variability increased significantly for deep inclusions (range, 2.4% to 80.8%). The measurement difference between the operators was 1%-15% for superficial inclusions and 3%-43% for deep inclusions. Inter-operator reproducibility was almost perfect (ICC>0.90). The measurement difference between machines was 0%-15% for superficial inclusions and 38.6%-82.9% for deep inclusions. For superficial inclusions, the reproducibility among the three probes was excellent (ICC>0.97). The mean stiffness values of the 10 kPa inclusion were overestimated by 16%, while those of the 40 kPa and 60 kPa inclusions were underestimated by 42% and 48%, respectively.ConclusionPhantom SWE measurements were only reproducible among operators, machines, and probes at superficial depths. SWE measurements acquired in deep regions should not be used interchangeably among operators, machines, or probes.

Feasibility and reproducibility of shear wave elastography in pediatric cranial ultrasound.

Head ultrasound (US) is commonly used to evaluate the neonatal brain but may be limited by its lack of sensitivity and specificity. Ultrasound shear wave elastography (SWE) might provide additional information to conventional gray-scale imaging. To assess whether SWE of brain parenchyma can be (1) successfully performed at a large academic medical center where US technologists perform the majority of examinations and (2) used to detect intracranial pathology. Pediatric patients undergoing head ultrasound underwent simultaneous SWE examination. We included normal examinations (n=70) and those with intracranial pathology (n=8) for analysis. We analyzed inter-reader variability and examination success rates and assessed the stiffness of white matter and deep gray nuclei in normal and pathological states across multiple gestational age groups. Average gestational age of the term, pre-term and extreme pre-term groups were 38.4±1.2weeks, 29.0±3.7weeks and 28.3±3.1weeks, respectively. Overall examination success rate was 79.5%. We observed a decrease in the SWE examination time from the first month (5.9±3.7min) to the second month (4.1±1.7min; P=0.01). Forty-one repeat examinations were performed on 14 children by different technologists, with an intraclass correlation coefficient (ICC) of 0.91. Mean stiffness in the periventricular white matter was lower than in the deep gray nuclei in all gestational age groups: term group (1.3m/s vs. 1.5m/s, P<0.001), pre-term (1.3m/s vs. 1.4m/s P=0.12), and extremely preterm group (1.2m/s vs. 1.4m/s, P=0.001). Mean stiffness for the deep gray nuclei differed between the term (1.5±0.3m/s) and pre-term (1.4±0.2m/s) groups (P<0.01). No significant differences in white matter stiffness were seen in relation to gestational age. Infants with large intraparenchymal hemorrhage had increased white matter stiffness (1.3±0.1m/s) and deep gray nuclei stiffness (1.6±0.2m/s) compared to full-term infants with normal head ultrasounds. These differences approached statistical significance with P=0.09 and P=0.06, respectively. We demonstrated that SWE performed by pediatric sonography technologists is reproducible. We found differences in stiffness between deep gray nuclei and periventricular white matter across multiple age groups.

The Propagation Display Method Improves the Reproducibility of Pancreatic Shear Wave Elastography

Evaluation of the pancreatic elastic modulus (PEM) using shear wave elastography (SWE) requires at least 5 measurements to ensure reproducibility. The aim of this study was to evaluate improvement in reproducibility of SWE, using the propagation display method in normal pancreas ([NP] phase 1) and to examine the differences in PEM between NP and chronic pancreatitis (CP), intraductal papillary mucinous neoplasm (IPMN) and autoimmune pancreatitis ([AIP] phase 2). In phase 1, the measurement success rate, median PEM in repeated measurements and appropriate number of SWE measurements were determined in 109 cases with NP. In phase 2, PEM was measured in CP (n = 10), IPMN (n = 31) and AIP (n = 5), using the required number of SWE measurements determined in phase 1. In phase 1, the measurement success rate was 93.9% (92/109 cases). The median PEM for NP was 14.6 kPa and the appropriate number of SWE measurements was at least 3. In phase 2, the median PEMs in CP, IPMN and AIP were 19.6, 18.1 and 17.2 kPa, respectively, with significant differences between NP and CP (p = 0.0133) and between NP and IPMN (p = 0.0436). Use of the propagation display method in SWE improves the reproducibility of measurement of PEM.

Intra-rater reproducibility of shear wave elastography in the evaluation of facial skin.

IntroductionRecently, esthetic medicine has been gaining its momentum worldwide, mostly due to the development of minimally invasive techniques. In our opinion, elastography can be a candidate for an objective quantitative method to evaluate facial skin condition. The aim of this study was to determine intra-rater reproducibility of shear wave elastography (SWE) in the evaluation of facial skin in patients qualified for minimally invasive nonsurgical facial rejuvenation treatment.AimTo determine intra-rater reproducibility of shear wave elastography (SWE) in the evaluation of facial skin in patients qualified for minimally invasive nonsurgical facial rejuvenation treatment.Material and methodsThe study included 57 women between 40 and 67 years of age (mean: 51.5 ±7.3 years). Prior to the laser treatment, all participants were subjected to ultrasonographic examination and elastography of the skin. Upon visualization of the area of interest, the thickness of the dermis, subcutaneous tissue and superficial muscular aponeurotic system (SMAS) in millimeters was measured. Then, SWE was performed.ResultsNo statistically significant differences were found in intraclass coefficient values (ICC) for elastographic parameters of the skin on the right and left side of the face (0.953 ±0.001 vs. 0.953 ±0.001, p = 0.992). Moreover, no significant differences were observed in the ICC values for the SWE parameters of various skin layers: dermis, subcutaneous tissue and SMAS (0.945 ±0.001 vs. 0.953 ±.001 vs. 0.961 ±0.001, p = 0.597). Women with normal body weight and overweight did not differ significantly in terms of their elastographic parameters of facial skin.ConclusionsShear wave elastography is a reliable method for the evaluation of facial skin elasticity, providing highly reproducible results in all patients, regardless of their age and body weight.

Clinical Implications of Shear Wave Elastography in Patients with Chronic Hepatitis B

Chronic liver disease is one of the leading causes of significant morbidity and mortality. Accurate evaluation of liver fibrosis is important because management and prognosis depend on the degree of liver fibrosis. Liver biopsy has been gold standard for evaluating the degree of liver fibrosis in patients with chronic liver diseases. However, because it is an invasive procedure and can cause serious complication, several serological and radiological noninvasive surrogates have been developed. Of these, excellent diagnostic accuracy and reproducibility of shear wave elastography (SWE) in patients with chronic liver diseases have been reported in recent studies. Furthermore, it has been also known that SWE can monitor disease progression or predict the risk of developing liver cirrhosis and hepatocellular carcinoma. In this review, we discussed the clinical implications of SWE in patients with chronic hepatitis B. Keywords: Elastography; Liver fibrosis; Hepatitis B, Chronic; Liver cirrhosis; Carcinoma, Heptocellular 중심 단어: ê°„íƒ„ë ¥ë„ê²€ì‚¬; ê°„ì„¬ìœ í™”; 만성 B형간염; 간경변증; 간세포암

Determination of Normal Breast and Areolar Skin Elasticity Using Shear Wave Elastography.

In this study, we aimed to determine reference values for normal breast and areolar skin elasticity using shear wave elastography. The right breasts of 200 female participants were evaluated. The age, weight, body mass index, menopausal status, and parity number of all participants were noted. The elasticity values and thickness of the areolar skin and 4 quadrants of the breast skin of all participants were measured. To assess the reproducibility of shear wave elastography, a randomly selected subgroup of 35 participants was reevaluated by a second observer. The mean age of the participants ± SD was 48.79 ± 10.74 years (range, 18-79 years). The mean elasticity measurements for the superior, inferior, lateral, and medial regions of the breast and areolar skin were 33.54, 29.84, 30.16, 29.20, and 31.35 kPa, respectively. The mean of the 4-quadrant measurements of breast skin elasticity was 30.68 ± 9.11 kPa. Age had a moderate negative correlation with breast skin elasticity (r = -0.353; P < .001) and a weak negative correlation with areolar skin elasticity (r = -0.237; P = .001). The parity number had weak negative correlations with breast (r = -0.150; P = .034) and areolar (r = -0.207; P < .001) skin elasticity. The interobserver agreement varied from good to excellent (intraclass correlation coefficients, 0.67-0.91) for the breast and areolar skin elasticity measurements. Shear wave elastography is a reproducible imaging modality for evaluations of breast and areolar skin elasticity, and our results may provide important pilot data for evaluations of clinical entities that affect the breast and areolar skin structures.

Extracellular histones decrease the expression of membrane complement regulators

Evaluation of the pancreatic elastic modulus (PEM) using shear wave elastography (SWE) requires at least 5 measurements to ensure reproducibility. The aim of this study was to evaluate improvement in reproducibility of SWE, using the propagation display method in normal pancreas ([NP] phase 1) and to examine the differences in PEM between NP and chronic pancreatitis (CP), intraductal papillary mucinous neoplasm (IPMN) and autoimmune pancreatitis ([AIP] phase 2). In phase 1, the measurement success rate, median PEM in repeated measurements and appropriate number of SWE measurements were determined in 109 cases with NP. In phase 2, PEM was measured in CP (n = 10), IPMN (n = 31) and AIP (n = 5), using the required number of SWE measurements determined in phase 1. In phase 1, the measurement success rate was 93.9% (92/109 cases). The median PEM for NP was 14.6 kPa and the appropriate number of SWE measurements was at least 3. In phase 2, the median PEMs in CP, IPMN and AIP were 19.6, 18.1 and 17.2 kPa, respectively, with significant differences between NP and CP (p = 0.0133) and between NP and IPMN (p = 0.0436). Use of the propagation display method in SWE improves the reproducibility of measurement of PEM.

Reproducibility of shear wave elastography measuresof the Achilles tendon.

To assess the reproducibility of shear wave elastography (SWE) measures in the Achilles tendon (AT) in vivo. Shear wave velocity (SWV) of 14 healthy volunteers [7 males, 7 females; mean age 26.5 ± 3.8years, mean height 171.6 ± 10.9cm, mean Victorian Institute of Sports Assessment Achilles questionnaire (VISA-A) score 99.4 ± 1.2] was measured with the foot relaxed and fixed at 90°. Data were collected over five consecutive measures and 5 consecutive days. Mean SWV values ranged from 7.91m/s-9.56m/s ± 0.27-0.50m/s. Coefficient of variation (CV), correlations and intra-class correlation coefficient (ICC) scores ranged from 2.9%-6.3%, 0.4-0.7 and 0.54-0.85 respectively. No significant differences were noted for longitudinal or transverse data with respect to protocol or time and no significant differences were noted for foot position in transverse data. Significant differences in SWV values were noted between foot positions for longitudinal scanning (p = <0.05), with a relaxed foot position providing SWV values on average 0.47m/s faster than a fixed position. Increased reproducibility was obtained with the foot relaxed. ICC between operators was 0.70 for transverse and 0.80 for longitudinal scanning. Reproducible SWE measures were obtained over a 1-h period as well as a period of 5 consecutive days with more reliable measures obtained from a longitudinal plane using a relaxed foot position. SWE also has a high level of agreement between operators making SWE a reproducible technique for quantitatively assessing the mechanical properties of the human AT in vivo.

Reproducibility of shear wave elastography (SWE) in patients with chronic liver disease.

The presence of significant fibrosis is an indicator for liver disease staging and prognosis.The aim of the study was to determine reproducibility of real-time shear wave elastography using a hepatic biopsy as the reference standard to identify patients with chronic liver disease. Forty patients with chronic liver disease and 12 normal subjects received shear wave elastography performed by skilled operators. Interoperator reproducibility was studied in 29 patients. Fibrosis was evaluated using the Metavir score. The median and range shear wave elastography values in chronic liver disease subjects were 6.15 kPa and 3.14–16.7 kPa and were 4.49 kPa and 2.92–7.32 kPa in normal subjects, respectively. With respect to fibrosis detected by liver biopsy, shear wave elastography did not change significantly between F0 and F1 (p = 0.334), F1 and F2 (p = 0.611), or F3 and F4 (0.327); a significant difference was observed between the F0-F2 and F3-F4 groups (p = 0.002). SWE also correlated with inflammatory activity (Rs = 0.443, p = 0.0023) and ALT levels (Rs = 0.287, p = 0.0804). Age, sex and body mass index did not affect shear wave elastography measurements. Using receiver operator characteristic curves, two threshold values for shear wave elastography were identified: 5.62 kPa for patients with fibrosis (≥F2; sensitivity 80%, specificity 69.4%, and accuracy 77%) and 7.04 kPa for patients with severe fibrosis (≥F3; sensitivity 88.9%, specificity 81%, and accuracy 89%). Overall interobserver agreement was excellent and was analysed using an interclass correlation coefficient (0.94; CI 0.87–0.97).This study shows that shear wave elastography executed by skilled operators can be performed on almost all chronic liver disease patients with high reproducibility. It is not influenced by age, sex or body mass index, identifies severely fibrotic patients and is also related to inflammatory activity.

Evaluation of the severity of capsular contracture using elastography after breast implant reconstruction.

Capsular contracture around implants is a common complication after breast reconstruction. Strain elastography (STE) and shear-wave elastography (SWE) are noninvasive imaging techniques that can measure tissue stiffness and thickness of the capsule. The purposes of the study were to compare STE and SWE for measurement of capsular contracture after breast implant reconstruction using intra-class correlation coefficients (ICCs) and to investigate the correlation of these data with the Baker score, which is the most frequently used clinical staging scale for capsule contracture. The subjects were 20 patients (27 implants) who underwent breast reconstruction. The reproducibility of SWE (ICC: 0.878) was higher than that of STE (ICC: 0.724) for measurement of capsular contracture. The correlation coefficient between measurements with the two methods was low (r = 0.6788). The Baker score had a higher correlation with measurements with SWE (r = 0.8124) compared to those with STE (r = 0.6983). These results suggest that SWE is a better tool for assessment of the degree of capsule contracture surrounding implants after breast reconstruction.

Is the reproducibility of shear wave elastography of thyroid nodules high enough for clinical use? A methodological study.

To systematically assess the reproducibility of thyroid ultrasonographic shear wave elastography (SWE). SWE has been suggested as a potential tool for thyroid nodule evaluation, but assessment of its reproducibility has been insufficiently addressed. SWE examinations were performed prospectively by two investigators. Seventy-two patients (male/female: 19/53; mean age: 53 ± 14 years; malignant/benign 17/55) undergoing thyroid surgery were enrolled in the study. Repeated and blinded measurements of elasticity index (EI) in predefined regions of interest (ROI) were collected. The inter- and intrarater agreement, along with the day-to-day agreement, was evaluated in terms of the 95% limits of agreement (LOA). Results are presented as a ratio, by which 1·0 indicates perfect agreement. The interrater, intrarater and day-to-day LOA showed ratios between repeated measurements of 1·7-3·6, 1·8-3·7 and 2·2-2·9, respectively. These values reflect a low to moderate degree of agreement for all EI outcomes. The interrater LOA was higher for malignant nodules compared with benign nodules for six of seven EI outcomes (P < 0·001-0·03). The proportion of agreement calculated from the optimum cutoff point for differentiating malignant from benign nodules was 63-88% for the investigated EI outcomes. In this methodological study, EI measured by thyroid SWE seems suboptimal for clinical use, due to a low inter- and intrarater agreement. That EI varies from day to day furthermore jeopardizes the validity of the method. Although the proportion of agreement was acceptable for some EI parameters, it is questionable whether EI assessments can reliably differentiate malignant from benign nodules in the individual patient.

Intra- and Interobserver Reproducibility of Shear Wave Elastography for Evaluation of the Breast Lesions

Intra- and Interobserver Reproducibility of Shear Wave Elastography for Evaluation of the Breast Lesions

Liver Stiffness in Pediatric Patients with Fatty Liver Disease: Diagnostic Accuracy and Reproducibility of Shear-Wave Elastography.

Purpose To evaluate the diagnostic accuracy of shear-wave elastography (SWE) in identifying different degrees of fibrosis in a cohort of consecutive children and adolescents with nonalcoholic steatohepatitis (NASH). Materials and Methods Consecutive pediatric patients scheduled to undergo liver biopsy were studied with an ultrasonography-based SWE system. Elastography was performed in 68 of 69 patients with biopsy-proved NASH (37 boys and 31 girls; mean age, 12.6 years ± 2.48; age range, 8-17 years). The correlations among laboratory findings, liver stiffness, and fibrosis score were analyzed, and the area under the receiver operating characteristic curve (AUC) was used to assess the presence of any fibrosis (score ≥F1) or significant fibrosis (score ≥F2). Findings from histologic examination were used as the standard of reference. Results SWE showed a very high correlation with liver fibrosis (P < .001) at univariate and multivariate analyses. The AUCs for the association of any and significant fibrosis were 0.92 (95% confidence interval [CI]: 0.86, 0.98) and 0.97 (95% CI: 0.95, 0.99), respectively. The intraclass correlation coefficient for absolute agreement was 0.95 (95% CI: 0.90, 0.97). Conclusion SWE is an accurate and reproducible noninvasive technique that efficiently depicts the presence of significant liver fibrosis and, less accurately, mild liver fibrosis in pediatric patients with nonalcoholic fatty liver disease. Larger clinical prospective studies are warranted to confirm SWE accuracy and establish threshold values for fibrosis grading in comparison or in combination with other noninvasive methods. © RSNA, 2016.

Utility of Real-Time Shear Wave Elastography in the Assessment of Testicular Torsion.

Real-time shear-wave elastography (SWE) is a newly developed method which can obtain the stiffness of tissues and organs based on tracking of shear wave propagation through a structure. Several studies have demonstrated its potential in the differentiation between diseased and normal tissue in clinical practices, however the applicability to testicular disease has not been well elucidated. We investigated the feasibility and reproducibility of SWE in the detection of testicular torsion. This prospective study comprised 15 patients with complete testicular torsion. Results obtained from SWE along with conventional gray-scale and color Doppler sonography and post-operative pathology were compared. The results revealed that (i) the size of injured testis was increased and the twisted testis parenchyma was heterogeneous. The blood flow signals in injured testis were barely visible or absent; (ii) The Young’s modulus, including Emean, Emax, Emin and SD values in the border area of torsional testis were higher than those of normal testis (Emean, 78.07±9.01kPa vs 22.0±5.10kPa; Emax,94.07±6.53kPa vs 27.87±5.78kPa; Emin, 60.73±7.84 kPa vs 18.90±4.39kPa; SD, 7.67±0.60 kPa vs 2.30±0.36 kPa, [P<0.05]); The Emax and SD values in the central area of the torsional testis were higher than the corresponding area of the normal testis (Emax, 8.23±0.30 kPa vs 3.97±0.95kPa; SD, 1.5±0.26kPa vs 0.67±0.35kPa,[P<0.05]) and Emin values was lower than those of normal testicles(0.93±0.51kPa vs 1.6±0.36kPa; [P<0.05]); (iii) The Young's modulus measurement between two physicians showed good agreement. The pathological findings were accordance with SWE measurement. SWE is a non-invasive, convenient and high reproducible method and may serve as an important alternative tool in the diagnosis and monitoring the progression of the acute scrotums, in additional to conventional Doppler sonography.

Shear wave elastography assessment in the prostate: an intraobserver reproducibility study

PurposeTo assess the intraobserver reproducibility of shear wave elastography (SWE) in the prostate. Materials and methodsThis study was institutional review board approved with waiver of informed consent. Eighty men (mean age, 66.2±9.2years) with suspected prostate cancer underwent SWE. Young modulus (kPa) was measured at 24 locations in the prostate (superficial and deep locations in paramedian and lateral aspects at the base, mid-gland, and apex levels). The intraobserver reproducibility of two repeated measurements was determined using intraclass correlation coefficients (ICC) and was compared among measurement location, prostate volume, age, and prostate-specific antigen level. ResultsThe overall intraobserver reproducibility was excellent (ICC=0.876). In addition, intraobserver reproducibility was excellent for all specified subgroups according to location, prostate volume, and clinical variables (ICC=0.826–0.917). With regard to location, SWE measurements showed substantially higher ICC values in the mid-gland than in the base and apex, in the paramedian prostate than in the lateral prostate, and in superficial locations than in deeper locations. No substantial differences in ICC values were observed according to the prostate volume and clinical variables. ConclusionIntraobserver reproducibility of SWE measurements in the prostate gland was excellent. There was variability in the intraobserver reproducibility according to location within the prostate, and the operator should be aware of this and take extra caution when performing SWE in these areas.