Shear Wave Velocity Values Research Articles

Influence of injection methods on calcareous sand cementation by EICP technique

Calcareous sands are widely distributed on continental shelves, coastal zones, islands and reefs in the tropical oceans. For being used as construction materials, calcareous sands should be artificially treated to improve their engineering properties. Enzymatically induced carbonate precipitation (EICP) is an innovative soil treatment technique. In this paper, urease was extracted from soybean powder using artificial seawater for calcareous sands cementing by the EICP technique. Cementation tests were conducted with three injection methods (the pre-mixed, staged and proposed parallel injections) and two injection rates (2 and 5 mL/min). The hydraulic conductivity, shear wave velocity (SWV) and unconfined compressive strength tests were conducted and the cementation effects were evaluated. The hydrodynamic diameter of the particles generated in the mixed solutions was measured with reaction time by a laser particle size analyzer and the influence of injection rate on the CaCO3 distribution in the specimen was discussed. The coefficient of variation of the SWV values along the cemented specimen height was calculated for evaluation of the cementation uniformity. Results show that a high injection rate was conducive to reducing clogging and improving the cementation uniformity by completing injection within the urea hydrolysis phase. The promising parallel injection method proposed in this study provided a lag time for reaction by simultaneous injection of crude urease and cementation solutions using two separate tubes. Specimens treated at a high parallel injection rate were uniformly cemented with high mechanical strengths and high overall hydraulic conductivities because of a high proportion of CaCO3 in contact-cementing distribution.

The potential of shear wave velocity as an erosion risk index

Soil erosion is a captious environmental problem in regions of hot tropical climates, causing loss of land and natural disasters such as river sedimentation, flooding, and slope failures. Based on soil properties and their response to erosion agents, efforts have been made to develop simplified models and indices for the estimation of erosion. ROM scale is proven to be effective in forecasting risk levels for erosion assessment. However, the method requires soil sampling and laboratory experimentation, which is time-consuming and laborious, especially when analyzing huge areas. Therefore, this study aims to develop a relation between ROM scale and shear wave velocity estimated by the spectral-analysis-of-surface-waves (SASW) method. For this purpose, 36 soil samples were extracted, and twelve SASW tests were conducted at twelve sites identified along Sungai Langat. Soil particle distribution was carried out to calculate the ROM erosion index value for all the extracted soil samples. The fast Fourier Transform (FFT) algorithm was used to transform the time-recorded signals into the frequency domain, and the dispersion curves were generated after the masking process. The shear wave velocity erosion risk ranged from 10 m/s to 120 m/s, indicating critical risk and low risk, respectively. Low erosion risk levels were observed for high shear wave velocity values, representing a decaying pattern in exponential relation. The resulting correlation between ROM scale and shear wave velocity produced a coefficient of determination value of 0.71, indicating a strong relation. This study indicated the potential of shear wave velocity as an erosion risk index.

Shear wave elastography combined with electromyography to assess the effect of botulinum toxin on spastic dystonia following stroke: A pilot study.

BackgroundShear wave elastography (SWE) is a method for carrying out a quantitative assessment of the mechanical properties of soft tissues in terms of stiffness. In stroke survivors, the paretic muscles may develop hypertonia due to both neural-mediated mechanisms and structural alterations with consequent muscular fibrous-fatty remodeling.MethodsFourteen adult patients with spastic dystonia following stroke were recruited. Muscle hypertonia was assessed using the modified Ashworth scale (MAS). Muscle activation was measured by surface electromyography (sEMG) with the selected muscle in shortened (spastic dystonia) and stretched (dynamic stretch reflex) positions. SWE was performed on a selected paretic muscle and on the contralateral non-paretic one to calculate shear wave velocities (SWV) along and across muscular fibers. The modified Heckmatt scale (MHS) pattern was also determined. All evaluations were performed shortly before BoNT-A injections (T0) and one month later (T1).ResultsAll SWV on paretic muscles were higher than contralateral non-paretic ones (p < 0.01). After BoNT-A injection, a significant reduction in MAS (p = 0.0018), spastic dystonia (p = 0.0043), and longitudinal SWE measurements, both in shortened (p = 0.001) and in stretched muscular conditions (p = 0.0029), was observed. No significant changes in SWV on non-paretic muscles were observed. Higher SWV resulted along the direction of muscular fibers vs. across them (p = 0.001). No changes resulted from the MHS evaluations after BoNT-A. There was a positive correlation between MHS scores and SWV values while the muscle was in the shortened position, but not with spastic dystonia recorded by sEMG.ConclusionsThis is the first study evaluating the effect of BoNT-A on muscle hypertonia following stroke, assessed by both SWE and sEMG. These findings support SWE as a useful method to disclose intrinsic muscular remodeling, independently of the effect of spastic dystonia, in particular, while muscles were assessed in a neutral position. SWE measurements of muscle stiffness cannot tell apart neural-mediated and intrinsic muscle hypertonia. Interestingly, when sEMG activity is very limited, as in spastic muscles kept in a shortened position, SWE can provide a measurement of stiffness due almost completely to intrinsic muscle changes. Alongside sEMG, SWE could aid clinicians in the assessment of responses to treatments.

Off-epicentral measurement of laser-ultrasonic shear-wave velocity and its application to elastic-moduli evaluation

This study investigates the off-epicentral measurement system and methodology of laser-ultrasonic shear waves in the ablative regime, subsequently focusing on its application to the elastic-moduli evaluation. The proposed scheme facilitates the measurement of the shear-wave velocity by using the crosscorrelation of successive shear-wave pulse echoes, ensuring high reliability and reproducibility of the calculation results. Since the geometric diffraction induced by the finite dimensions of laser-ultrasonic source and receiver can increase the measurement error, far-field diffraction correction for the off-epicenter detection has been derived theoretically. Results have shown that the far-field diffraction correction error is of the same order as random error mainly caused by the finite observation time, signal-to-noise ratio and frequency bandwidth, and therefore cannot be neglected. The feasibility of this approach is then demonstrated by inspecting annealed commercial purity titanium plates. Good agreement of experimentally measured and theoretical values of shear-wave velocity confirms the validity of the proposed approach. The ultrasonic measurement-determined shear modulus shows a maximum deviation of ＋3.6% from the standard value of an isotropic material.

Tools for the efficient analysis of surface waves from active and passive seismic data: exploring an NE-Italy perilagoon area with significant lateral variations

A series of reclamation works that took place during the twentieth century, almost completely destroyed the dune system that characterized the eastern part of the Grado-Marano perilagoonal area (NE Italy). Because of the limited data available, so far very little was known about the local subsurface conditions and the present paper presents the main outcomes of the seismic exploration accomplished with a twofold goal: collecting comprehensive data about the subsurface conditions (which geologists need to be able to reconstruct the formation processes of the local geomorphological elements) and testing a series of efficient and unconventional methodologies based on the analysis of surface waves from both active and passive seismic data. The survey was designed and accomplished also considering the local digital terrain model (DTM) and some resistivity and penetrometer data. In the present paper we focus on three main areas and, from the methodological point of view, special emphasis is given to the Holistic analysis of Surface waves (HS) and the Horizontal-to-Vertical Spectral Ratio (HVSR), since both these techniques require simple field procedures and a light equipment. It is also show the wealth of information that the simple spectral analysis of multi-offset passive data can provide in particular for the identification of possible lateral variations. In fact, in spite of the low-energy depositional environment, the area reveals extremely complex with major and abrupt lateral variations that require special care and prevent from using coarse methodologies that cannot properly handle their identification. Collected geophysical data provide a consistent overall scenario: while the area is in general dominated by soft (silty) sediments, the residual dunes are constituted by cemented sandy materials (medium-grained calcarenite) responsible for anomalously high shear-wave velocity (VS) values already at the surface. Parallel to such residual sandy dunes we also identified a series of peat channels characterized by distinctive low VS values due to a significant amount of organic components.Graphical

Malign ve benign tiroid nodüllerinin ayrımında ARFI elastografi

Aim: To examine the diagnostic performance of virtual touch tissue quantification (VTQ) mode of Acoustic Radiation Force Impulse (ARFI) elastography imaging in differentiating benign and malignant thyroid nodules. Materials and Methods: Two hundred four solid and mostly solid nodules &amp;gt;5mm were prospectively evaluated with ultrasonography, VTQ mode of ARFI elastography, fine needle aspiration biopsy, and when indicated with tissue pathology. Three shear-wave velocities (SWV) measurements were done in 196 nodules. The SWV ratio for each nodule was calculated as the mean value of the SWV of the nodule divided by the mean value of the adjacent parenchyma. The diagnostic performance of SWV value and SWV-ratio were assessed by a receiver-operating characteristic (ROC) curve analysis. Results: The mean SWV value in the normal parenchyma, in benign and malign thyroid nodules, were 2.13±0.44 m/s, 2.06±0.80 m/s, and 2.06±0.88 m/s respectively. The SWV-ratios were 0.97±0.37 for benign thyroid nodules and 1.02±0.40 for malignant thyroid nodules. There was no significant difference between benign and malign nodules in terms of mean SWV values (t=0.008) (P=0.994) or SWV-ratios (t =0.596; P=0.527). No cut-off point was found to predict malignancy. In subgroup analysis, AUCs for the SWV and SWV-ratio were significantly different between nodules ˂10 mm and those ≥10 mm, but not with any other two groups (all P&amp;gt;0.05) (Table-2). The cutoff points for the differential diagnosis were 2.59 m/s for SWV and 1.0 for SWV- ratio respectively for nodules &amp;lt;10 mm. Conclusion: VTQ mode of ARFI imaging does not have a good diagnostic performance for detecting malignancy and cannot contribute to reducing unnecessary thyroid biopsies.

ARFI elastography for differentiating malignant and benign thyroid nodules

Aim: To examine the diagnostic performance of virtual touch tissue quantification (VTQ) mode of Acoustic Radiation Force Impulse (ARFI) elastography imaging in differentiating benign and malignant thyroid nodules.&#x0D; Materials and Methods: Two hundred four solid and mostly solid nodules &gt;5mm were prospectively evaluated with ultrasonography, VTQ mode of ARFI elastography, fine needle aspiration biopsy, and when indicated with tissue pathology. Three shear-wave velocities (SWV) measurements were done in 196 nodules. The SWV ratio for each nodule was calculated as the mean value of the SWV of the nodule divided by the mean value of the adjacent parenchyma. The diagnostic performance of SWV value and SWV-ratio were assessed by a receiver-operating characteristic (ROC) curve analysis.&#x0D; Results: The mean SWV value in the normal parenchyma, in benign and malign thyroid nodules, were 2.13±0.44 m/s, 2.06±0.80 m/s, and 2.06±0.88 m/s respectively. The SWV-ratios were 0.97±0.37 for benign thyroid nodules and 1.02±0.40 for malignant thyroid nodules. There was no significant difference between benign and malign nodules in terms of mean SWV values (t=0.008) (P=0.994) or SWV-ratios (t =0.596; P=0.527). No cut-off point was found to predict malignancy. In subgroup analysis, AUCs for the SWV and SWV-ratio were significantly different between nodules ˂10 mm and those ≥10 mm, but not with any other two groups (all P&gt;0.05) (Table-2). The cutoff points for the differential diagnosis were 2.59 m/s for SWV and 1.0 for SWV- ratio respectively for nodules

The value of ultrasound elastography combined with multi-parameters in the diagnosis of BI-RADS 4 breast lesions.

Female breast cancer has surpassed lung cancer as the most commonly diagnosed cancer, with an estimated 2.3 million new cases (11.7%) in the global cancer statistics 2020. To evaluate the diagnostic value of ultrasound elastography combined with multi-parameters in differentiating category 4 benign and malignant lesions in the breast imaging reporting and data system (BI-RADS). This study retrospectively analyzed 206 patients (213 breast lesions) who visited the Department of Breast Surgery and underwent a breast core needle biopsy in the Department of Ultrasound in Peking University First hospital from April to December 2019. The shear wave velocity (SWV) values were collected at the following locations by virtual touch tissue imaging quantification (VTIQ): breast lesion interior, breast lesion margin, surrounding glands, and surrounding fat. Simultaneously, the strain ratio (SR) of breast lesions to glands and the area ratio (AR) of breast lesions were collected under strain elastography and a two-dimensional ultrasound mode. Univariate analysis found that the SWV value, measured by ultrasound elastography parameters, and the AR between the elasticity and the two-dimensional ultrasound breast lesions showed statistical differences when differentiating benign and malignant lesions (p< 0.05). Binary logistic regression analysis found that the SWV values of the lesion interior and the surrounding glands were statistically significant. The joint predictors were calculated and analyzed by Receiver Operating Characteristic (ROC), and it was found that the joint predictors and the SWV values of the lesion interior have great diagnostic value. The cut-off value, sensitivity and specificity of the joint predictor and the SWV value of the lesion interior were > 3.65, 88.35% and 76.36% and > 5.55 m/s, 79.61% and 82.73%, respectively. Ultrasound elastography combined with multi-parameters has good diagnostic value in differentiating BI-RADS 4 breast lesions.

Clinical Significance of Shear Wave Ultrasound Elastography in Patients With Idiopathic Adhesive Capsulitis: Can It Be Used Instead of Magnetic Resonance Imaging as an Early Indicator?

The aim of this study was to evaluate the elasticity of the supraspinatus (SSp) and infraspinatus (ISp) tendons and coracohumeral ligament (CHL), as well as the thickness of CHL in patients diagnosed with adhesive capsulitis (AC) using ultrasound (US) and 2D shear wave elastography (2D-SWE), determining their contributions to diagnosis and stage differentiation.This prospective case-control study was conducted between January 2020 and May 2021. In all cases, the ultrasound examinations were performed using the virtual touch quantification and expressed as shear wave velocity (SWV) in meters per second. After US examinations, magnetic resonance imaging (MRI) was planned for all cases.The measurements made in US and MRI revealed that CHL thicknesses and SWV values of CHL and SSp and ISp tendons were statistically substantially higher in the patient group. The diagnostic performance of 2D-SWE in predicting AC was evaluated using receiver operating characteristics curve analysis. When the cutoff value of the mean SWE for CHL was taken as 4.67 m/s, the sensitivity of SWE was found to be 90.2% and the specificity 85.7%.Our study results suggest that CHL thickness on B-mode US, as well as SWV values of CHL and SSp and ISp tendons in 2D-SWE examination, can be used as a useful tool for AC diagnosis without the need for MRI, a costly and time-consuming examination.

Hybrid broadband ground-motion simulation validation of small magnitude active shallow crustal earthquakes in New Zealand

This article presents a comprehensive validation of the hybrid broadband ground-motion simulation approach (via the commonly used Graves and Pitarka method) in a New Zealand context with small magnitude point source ruptures using an extensive set of 5218 ground motions recorded at 212 sites from 479 active shallow crustal earthquakes across the country. Modifications to the simulation method inferred from a previous New Zealand validation are implemented, and the improvements are explicitly quantified. Empirical ground-motion models are also considered to provide a benchmark for simulation prediction accuracy and precision. Examination of intensity measure residuals identifies that the simulation method modifications lead to reduced model prediction bias and within-event variability and provides evidence toward the use of spatially varying coefficient models for simulation parameters, such as the high-frequency Brune stress parameter. Additional biases identified include, among others, underprediction of significant durations at soft soil sites and overprediction of short-period pseudo-spectral accelerations at stiff alluvial gravel and rock sites due to low-estimated 30 m time-averaged shear-wave velocity values.

Empirical nonlinear site effects in Japanese megathrust earthquakes

In the course of developing ground-motion models (GMMs) of peak ground acceleration (PGA) for Japanese megathrust earthquakes, we discovered that empirical nonlinear site effects from these events are very different from those found for shallow crustal earthquakes in California and other global active tectonic regions. In particular, nonlinearity in site response is much less prominent in Japan than these other regions, which is consistent with other empirical and theoretical ground-response studies using recordings from both crustal and subduction earthquakes. In this study, we used the residuals from Japanese megathrust GMMs that account for linear site response to develop a nonlinear site-response term that uses the value of PGA on rock as a measure of ground-motion severity and the value of time-averaged shear-wave velocity in the top 30 m of a site ( VS30) as a measure of site properties. The resulting residuals are unbiased and trendless over all PGA values of interest. We also investigated whether soil nonlinearity can be modeled using proxies for shear stress and shear strain. We found deviations from expected linearity unrelated to nonlinear site effects at small values of strain—believed to be due to network accelerograph trigger thresholds—and at large earthquake magnitudes, believed to be due to the shape of the source spectrum.

Value of shear-wave elastography and cerebral–placental–uterine ratio in women diagnosed with preeclampsia and fetal growth restriction in prediction of adverse perinatal outcomes

Purpose The aim of this study was to measure placental stiffness with shear-wave elastography technique and to evaluate the relationship with cerebral–placental–uterine ratio (CPUR) and adverse perinatal outcomes in patient groups diagnosed with preeclampsia (PE) and fetal growth restriction (FGR) in the second and third trimesters compared to the control group. Materials and methods This prospective cross-sectional study was conducted at our hospital between March 2019 and March 2020. The study groups were divided into three groups: PE, FGR, and low risk pregnancy (LRP) group. The study population had singleton pregnancies and the placental site was at the anterior wall. Both shear-wave elasticity (SWE) and shear-wave velocity (SWV) were measured in the placenta during pregnancy. CPUR was calculated for each group. Results A total of 147 patients were included in this study. The mean SWE (kilopascals) values in the PE group were significantly higher than in the FGR and controls (difference of means = 3.67, 9.45; 95% CI (1.23–6.1, 7–11.8); p < .05), respectively. The mean SWV values were significantly higher in PE and FGR groups than controls (p < .05). CPUR showed correlation with central maternal surface of placenta (p: .02, r: −0.184), central fetal surface of placenta (p < .001, r: −0.288), peripheral maternal surface of placenta (p: .002, r: −0.252), and peripheral fetal surface of placenta SWE values (p: .03, r: −0.181). NICU admission was correlated with central fetal surface of placenta SWE values (p: .002, r: 0.258). Conclusion In conclusion, we demonstrated increased placental stiffness in both the PE and the FGR group. Also, this difference was found to be more prominent in preeclampsia. This technique seems useful for assessment of placental function and may strengthen the utility of Doppler parameters for predicting adverse perinatal outcomes in high-risk pregnancies.

Verification of surface electromyographic activity of the oblique externus abdominis using ultrasound shear wave elastography.

This study used ultrasound shear wave elastography (SWE) to revalidate whether surface electromyographic (EMG) electrodes placed on the oblique externus abdominis (OE) can detect only the OE activity without the confounding activity of the underlying oblique internus abdominis (OI). During left and right trunk rotations, the EMG activity was acquired using surface EMG electrodes placed on the right OE. Shear wave velocity (Vs) values of the right OE and OI were acquired using SWE. The EMG activity during the left and right trunk rotations significantly increased as the level of exertion increased (25%, 50%, 75%, and 100% of the one‐repetition maximum [1RM]). The Vs of the right OE was significantly different only between 25% and 75% 1RM in the right trunk rotation, but significantly increased from 25% to 75% 1RM during the left trunk rotation. The Vs of the right OI during the right trunk rotation significantly increased with increased levels of exertion, except between 50% and 75% 1RM. The results for the Vs of the OE and OI in the right trunk rotation suggest that surface EMG electrodes placed on the OE would detect not only the antagonistic OE activity but also the agonistic OI activity.

SJÖGREN SENDROMUNDA ULTRASON ELASTOGRAFİ BULGULARI

Background/Aims: In Sjögren’s syndrome the basic histopathology in all affected organs is progressive lymphocyte infiltration This causes a change in tissue elasticity in the major salivary glands. The purpose of this study is to investigate salivary gland stiffness in primary Sjögren’s syndrome via shear wave elastography.&#x0D; Material and Methods: According to the 2016 American European Consensus Group criteria, 47 female cases were included in the study as the "patient group" by two rheumatologists. A total of 41 healthy female volunteers, who were in a similar age group and had no symptoms of dry mouth or sicca, and no diagnosis of salivary gland disease, constituted the "control group" of the study .The paired parotid and submandibular glands of all subjects were examined with shear wave elastography. The study was conducted between October 2018-October 2019&#x0D; Results: In our study, there was a significant difference in both parotid glands' tissue elasticity values in both speed and kPA values in cases with pSS compared to the control group. However, when the submandibular glands were evaluated, no significant difference was found between the two groups. In our study, no relationship was found between the duration of symptoms and elasticity values.&#x0D; Conclusions :The fact that shear wave velocity (m / sec) and elasticity value (kPA) values are higher in the evaluation of the parotid gland by SWE technique in patients with pSS than the control group makes SWE an easy, non-invasive, and effective imaging method in Sjögren's Syndrome.

Site-Specific Ground Response Analysis using the Geotechnical Dataset in Moderate Seismicity Region

An understanding of the soil response to dynamic waves from the earthquakes is an important aspect of engineering safety measures against tremors. This research presents the equivalent linear site response analysis of the Miri district by using a geotechnical dataset. The main objective of this paper is to study the amplification factor for the district of Miri. Analysis of site response is critical in determining the earthquake risk and harm allocation during earthquakes. The standard penetration test ‘N’ value (SPT-N) has been used in this study. A specific soil-type relationship has been used between shear wave velocity and SPT-N value to produce profiles of shear wave velocity in each borehole site in the Miri district. For all SPT-N borehole sites, site response parameters were interpolated to produce site response maps and shear wave velocity maps in the geographical information system (GIS) environment. The research showed that the Malaysian national annex to Eurocode 8 (MNA-EC8) site class C, D and E are dominant in the Miri district. Due to the inadequacy of records of input ground motions of low-to-moderate seismicity regions, this research used an earthquake record from other locations well-matched from a target response spectrum with similar characteristics obtained from the Pacific Earthquake Engineering Research Center (PEER) online database (PEER NGA). The equivalent linear method (EQL) using DEEPSOIL is an extensively researched numeric technique that is used for assessment of site response. From the results, it has been found that the amplification ratio varies from 2.1 to 4.79 and it suggests that it is vital to study the site effect in the seismic hazard assessment of the Miri district. The work also emphasizes the relationship between seismic microzonation and site response analysis in order to reduce the adverse effects of earthquakes in Miri city by planning a proper land use.

Assessment of Stromal Elastin Fibers in Breast Cancer and Fibroadenomas: Is There a Correlation With Ultrasound Elastography Findings?

The stiffness of a breast lesion provides information on the likelihood of malignancy. The most important factor affecting this stiffness is the composition of the extracellular matrix (ECM). The aim of this study was to assess the elastin fiber contents of malignant breast lesions and fibroadenomas and investigate any relationship between the shear wave velocity (SWV) measured by ultrasonography, and the elastin fiber content of lesions. Consecutive patients with breast lesions were enrolled. The SWV values of the lesions were analyzed. Histopathological analysis of elastin in excised lesions was performed by the method of Shivas and Douglas. Breast cancer patients were reviewed according to their lymph node status and tumor diameter. The relationship between SWV value and tissue elastin fiber score was analyzed. The correlation between breast cancer grade and elastin fiber score in malignant lesions was investigated. A total of 167 consecutive breast lesions in 167 patients were included in this study (75 invasive cancer, 92 fibroadenomas). High elastic fiber score was significantly more common (p = 0.001) in malignant lesions (n = 61; 81.3%) than fibroadenomas (n = 13; 14.1%). There was a negative correlation between the mean SWV and the elastin fiber score of fibroadenomas (p = 0.001). A low grade in breast cancer was associated with high elastin fiber score (p = 0.01). Malignant lesions tend to have higher elastin fiber scores than fibroadenomas. Elastin fiber assessment may provide additional prognostic information in malignant lesions. Changes in elastin fiber content may account for the variation in elasticity in fibroadenomas.

Seismic site characterization of a few Indian coal ash deposits using multichannel analysis of surface waves

This study presents the outcome of an extensive field experiment undertaken to characterize coal ash deposits in terms of dynamic properties. In-situ shear wave velocity ( V s ) was measured over three hydraulically deposited coal ash deposits (two active ponds and one abandoned pond) situated in the central and southern parts of India. Multichannel analysis of surface waves was performed at twenty-one different locations on the ash deposits and the dyke top to measure the V s profiles along the depth ( z ). V s profiles measured for the abandoned coal ash deposits were greater than those of the active deposits. Moreover, the empirical association of V s profiles from active and abandoned coal ash deposits in India, based on the present study and reported literature, yields a piecewise linear relationship between shear wave velocity and depth. • Shear wave velocity (V s ) values from MASW for three coal ash ponds in India. • Box and whisker plots for inter and intra-site variations in V s profiles. • Comprehensive data on the variation of V s vs. z for all Indian coal ash deposits. • Empirical association between in-situ average shear wave velocity, V s,a vs. z for Indian ashes.

Evaluation of Ultrasound-Based Point Shear Wave Elastography for Differential Diagnosis of Pancreatic Diseases.

Introduction: A variety of imaging techniques exists for the diagnosis of pancreatic disorders. None of the broadly applied diagnostic methods utilizes elasticity as an indicator of tissue damage. A well-known fact is that both chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDA) are associated with the development of prominent fibrosis (increased tissue stiffness). Purpose: To prospectively assess the accuracy of point shear wave elastography (pSWE) in differentiating between benign and malignant pancreatic diseases, establish a cut-off value for the diagnosis of PDA, and evaluate the influence of certain variables on the obtained results. Materials and methods: The present study included 78 patients who were admitted at the Department of Gastroenterology at the university hospital “Kaspela” between December 2017 and August 2021 for diagnosis and/or treatment of pancreatic disorders. Based on the clinical criteria, diagnostic imaging, and histological findings, patients were divided into the CP and PDA group. The ultrasound based pSWE technique was applied and shear wave velocity (SWV) was measured. The depth of region of interest (ROI) and successful measurement rate were also recorded. Results: The mean ± SD SWV values established through pSWE were 1.75 ± 0.34 m/s and 2.93 ± 0.91 m/s for the CP and PDA, respectively. With a cut-off value of 2.09 m/s, we calculated the sensitivity (Se), specificity (Sp), and accuracy for differentiating between CP and PDA of 89.47%, 91.20%, and 88.60%, respectively. Of the examined variables, BMI and depth of ROI in the CP group and sex in the PDA group showed a statistically significant influence on the obtained results. Conclusions: pSWE may be utilized as a differential diagnostic modality in patients with suspected CP or PDA.

Two-dimensional shear wave elastography of the pancreas: measurement success rate, repeatability, and factors affecting measurement values.

We aimed to evaluate the success rate, repeatability, and factors affecting the measurement values of two-dimensional ultrasonic shear wave elastography (2D-SWE) for measuring pancreatic stiffness. This prospective study recruited 100 healthy participants. 2D-SWE was performed on the pancreatic head, body, and tail. We compared the success rates of pancreatic stiffness measurements of different body positions and ultrasonic scans, with and without probe pressurization, as well as the effects of sex, age, body mass index (BMI), and region of interest (ROI) depth on measurement values. Intra- and inter-operator repeatabilities were assessed in 20 participants. The influence of ROI depth was verified using a tissue-like phantom. The median 2D-SWE measurements of the pancreatic head, body, and tail were 1.44, 1.45, and 1.56m/s, respectively. The success rates for the pancreatic head and body were significantly higher than that of the tail. The success rate for the semi-recumbent position was higher than that of the supine position (P < 0.001). The intra-operator values for same-day and inter-operator reliability were excellent. Univariate analyses showed that probe pressurization, age, BMI, and ROI depth were correlated with pancreatic shear wave velocity (SWV) (P < 0.05); only ROI depth had a significant effect on SWV values. The inclusion phantom showed that the SWV value increased as the ROI depth increased. 2D-SWE had a high success rate and good repeatability for measuring pancreatic head and body stiffness. The ROI depth was the main factor affecting pancreatic SWV, which increased with ROI depth.

Sonoelastographic Evaluation of Recurrent Thyroid Nodules in Patients with Operated Recurrent Nodular Goiters.

Alterations in neck anatomy after thyroid surgery and post-operative fibrosis may be misleading by causing sonoelastographic changes in recurrent tissues in patients with recurrent nodular goiter and so may result in unnecessary biopsies or surgical procedures. Here, the aim was to examine thyroid sonoelastography values in patients developing a recurrence and presenting with recurrent nodular goiter with benign cytology after total or near-total thyroidectomy (T/N-TT). Twenty-nine nodules from 22 patients with a recurrence after T/N-TT whose biopsies were found to be benign constituted the patients, and 23 nodules from 23 participants among the non-operated patients having solitary or multiple thyroid nodules and with age, gender and body mass index values similar to those of the patients constituted our controls. Shear-wave velocity (SWV) values were measured. Average elapsed time after T/N-TT was 11.82 (4:25) y. No difference was detected between the groups in terms of localization and sonographic structures of the nodules. Nodule SWV values were higher in the operated recurrent nodular goiter group than in the controls (2.93 ± 0.87 m/s vs. 2.43 ± 0.33 m/s, respectively, p=0.011). Because SWV values are high in operated recurrent nodular goiter patients, the utilization of reference sonoelastography values in those with unoperated goiter may yield misleading results in the differentiation of benign and malignant lesions.