Elastic Mean Research Articles

Endoscopic Ultrasound Elastography for the Pancreas in Korea: A Preliminary Single Center Study

Background/AimsEndoscopic ultrasound elastography (EUS-EG) has been widely used for the evaluation of pancreatic cancer in the Western world. To date, there is very little experience with EUS-EG in Korea. We described the results of comparison between normal pancreas and pancreatic cancer in Korea.MethodsThe present study was performed at a tertiary hospital on 35 subjects comprising 20 with normal pancreas (control group) and 15 with pancreatic cancer (disease group). We compared the EUS-EG performance of the two groups.ResultsThe pancreas in the control group showed a mean elasticity value of 0.53% (95% confidence interval [CI], 0.45 to 0.61). The elasticity value was higher than that previously reported from Western country (0.47%; 95% CI, 0.38 to 0.57). In the disease group, the mean elasticity value of pancreatic lesions was 0.02% (95% CI, 0.01 to 0.02). The mean elasticity value of the disease group was significantly lower than that of the control group (p<0.0001).ConclusionsEUS-EG could be a highly sensitive diagnostic modality for pancreatic cancer in Korea with little EUS-EG experience. We also provided the reference range of elasticity value of normal pancreas, which might be valuable in the interpretation of pancreatic elasticity data for Korean adults.

Study of quantitative elastography with supersonic shear imaging in the diagnosis of breast tumours

This study was undertaken to evaluate the value of quantitative elastography in the diagnosis of breast tumours. Conventional ultrasound (US) and quantitative elastography were performed in 108 women with 114 breast lesions by two experienced radiologists, and pathological results were available in all cases. For each lesion, the maximum, mean, and minimum (min) elasticity and elasticity ratio between lesions and surrounding tissue were measured. The Breast Imaging Reporting and Data System (BI-RADS) categories were assessed with conventional US in all lesions. Malignant lesions exhibited significantly higher maximum and mean elasticity (111.57 ± 69.29 kPa and 54.49 ± 33.70 kPa) than did benign lesions (59.00 ± 45.3 kPa and 36.64 ± 26.18 kPa) (p<0.01). For maximum elasticity versus BI-RADS, performance results were sensitivity 60.9 % vs. 78.3%, specificity 85.3% vs. 98.5%, positive predictive value (PPV) 73.7% vs. 97.3 %, negative predictive value (NPV) 76.3% vs. 87.0 % and accuracy 75.4% vs. 90.3%. BI-RADS had significantly better accuracy than maximum elasticity (p<0.01). Maximum and mean elasticity of invasive ductal carcinoma (IDC) were significantly higher than those of fibroadenoma (p<0.01), whereas the difference was not statistically significant with fibroadenosis, papilloma and inflammation (p>0.01). Maximum and mean elasticity and elasticity ratio of BI-RADS 5 were all significantly higher than those of BI-RADS 3 (p<0.01). Reliability for maximum and mean elasticity were almost perfect [intraclass correlation coefficients (ICC)=0.87 and 0.79]. Shear-wave elastography gives quantitative elasticity information that could potentially help in breast-lesion characterisation, although it cannot replace conventional BI-RADS in the differentiation of breast lesions.

Differentiation of benign from malignant solid breast masses: comparison of two-dimensional and three-dimensional shear-wave elastography

To prospectively compare the diagnostic performances of two-dimensional (2D) and three-dimensional (3D) shear-wave elastography (SWE) for differentiating benign from malignant breast masses. B-mode ultrasound and SWE were performed for 134 consecutive women with 144 breast masses before biopsy. Quantitative elasticity values (maximum and mean elasticity in the stiffest portion of mass, Emax and Emean; lesion-to-fat elasticity ratio, Erat) were measured with both 2D and 3D SWE. The area under the receiver operating characteristic curve (AUC), sensitivity and specificity of B-mode, 2D, 3D SWE and combined data of B-mode and SWE were compared. Sixty-seven of the 144 breast masses (47 %) were malignant. Overall, higher elasticity values of 3D SWE than 2D SWE were noted for both benign and malignant masses. The AUC for 2D and 3D SWE were not significantly different: Emean, 0.938 vs 0.928; Emax, 0.939 vs 0.930; Erat, 0.907 vs 0.871. Either 2D or 3D SWE significantly improved the specificity of B-mode ultrasound from 29.9 % (23 of 77) up to 71.4 % (55 of 77) and 63.6 % (49 of 77) without a significant change in sensitivity. Two-dimensional and 3D SWE performed equally in distinguishing benign from malignant masses and both techniques improved the specificity of B-mode ultrasound.

Shear wave elastography properties of vastus lateralis and vastus medialis obliquus muscles in normal subjects and female patients with patellofemoral pain syndrome

The aim of our study was to define and compare the mechanical properties of the vastus lateralis (VL) and vastus medialis obliquus muscles (VMO) by the way of quantitative shear-wave elastography in male and female healthy control (HC) subjects, and in female patients with patellofemoral pain syndrome (PFPS). Twenty-two healthy volunteers (11 male and 11 female) and 11 female patients with anterior knee pain were included in the study. The SWE examinations for VL and VMO were performed while the subjects were performing open kinetic chain exercises in neutral and 30° hip abduction. The contraction capacity (CC) and contraction ratio (CR) values were determined in resting and contraction phases in both hip positions. The mean elasticity values in the CC for VL and VMO muscles were significantly higher in male HC subjects when compared to female HC subjects (p < 0.05). The CR of the VL muscle in female patients with PFPS was not significantly different than the female HC group. The CR for the VMO muscle was significantly lower in female patients with PFPS when compared to female HC subjects (p < 0.05). We found a significant VMO weakness, and this method may provide quantitative data that might influence the diagnosis of muscle weakness, in female patients with PFPS.

Measurement of elasticity and transepidermal water loss rate of burn scars with the Dermalab®

This cross-sectional study investigated the reproducibility of repeated elasticity and transepidermal water loss (TEWL) measurements with the DermaLab® on 32 active burn scars and healthy skin. Intra- and inter-observer reproducibility was examined by means of intra-class correlation coefficients (ICC) and standard error of measurements (SEM). Results showed good ICC values and rather high SEM values for inter- and intra-observer reproducibility of elasticity measurements. For TEWL measurements, ICC values were good and SEM values were high for inter- and intra-observer reproducibility. There was a significant difference between the estimated mean elasticity values of normal skin and grafted scars and between normal skin and spontaneously healed scars (p≤0.003). For the estimated mean TEWL values, there was a significant difference between normal skin and spontaneously healed scars (p=0.036). A significant negative relation was reported between mean TEWL and time after burn (p=0.008). In clinical trials it is necessary to interpret patient-specific changes in elasticity and TEWL with caution, since the SEMs of both modes are rather high. We therefore recommend the use of a mean of repeated measurements of elasticity and TEWL to decrease the SEM.

Badanie elastyczności miąższu dużych gruczołów ślinowych w wybranych stanach patologicznych

Sonoelastography is a novel technique useful in noninvasive assessment of tissue elasticity. This method was found to date to be useful in noninvasive differentiation of benign and malignant lesions of multiple organs: thyroid gland, liver, prostate and breast. Elastograms were scored upon conventional subjective color scale and the detailed stiffness values in kPa were collected. was to examine usefulness of sonoelastography in assessment of salivary glands lesions. Material and Methods the group consisted of 99 patients treated in Department of Otolaryngology. 52 patients after radiotherapy for head and neck cancer, 4 treated for inflammatory disease - 2 Sjoegren syndrome, 2 acute sialoadenitis and 43 consecutive patients with parotid tumors. The control group constituted 54 healthy volunteers. the mean stiffness value in 10 malignant tumors was 146.6 kPa and 88.7 kPa in 33 benign, the mean stiffness value of glandular parenchyma after radiotherapy was 43.18 kPa and in inflammatory disease 63.66 kPa. Mean elasticity of reference glandular tissue was 24.23 kPa. sonoelastography is fast, repetitive, noninvasive and objective method and it is useful in assessment of salivary glands lesions.

The Heterogeneous Effects of Gasoline Taxes: Why Where We Live Matters

Using disaggregated confidential household data, we estimate spatial variation in household-level gasoline price elasticities and the welfare effects of gasoline taxes. A novel approach allows us to model a discrete-continuous household choice of vehicle bundles, while disaggregating the choice set and including vehicle-specific fixed effects and unobserved consumer heterogeneity. The mean elasticity of demand for gasoline is -0.67, but with tremendous variation across location and income. We find that rural households have 30 percent more negative welfare impacts than urban households from gasoline taxes. Finally, we explore different policies that can help to mitigate welfare inequalities due to these taxes.

Differentiating benign from malignant solid breast masses: value of shear wave elastography according to lesion stiffness combined with greyscale ultrasound according to BI-RADS classification

Background:The aim of this study was to assess the performance of shear wave elastography combined with BI-RADS classification of greyscale ultrasound images for benign/malignant differentiation in a large group of patients.Methods:One hundred and seventy-five consecutive patients with solid breast masses on routine ultrasonography undergoing percutaneous biopsy had the greyscale findings classified according to the American College of Radiology BI-RADS. The mean elasticity values from four shear wave images were obtained.Results:For mean elasticity vs greyscale BI-RADS, the performance results against histology were sensitivity: 95% vs 95%, specificity: 77% vs 69%, Positive Predictive Value (PPV): 88% vs 84%, Negative Predictive Value (NPV): 90% vs 91%, and accuracy: 89% vs 86% (all P>0.05). The results for the combination (positive result from either modality counted as malignant) were sensitivity 100%, specificity 61%, PPV 82%, NPV 100%, and accuracy 86%. The combination of BI-RADS greyscale and shear wave elastography yielded superior sensitivity to BI-RADS alone (P=0.03) or shear wave alone (P=0.03). The NPV was superior in combination compared with either alone (BI-RADS P=0.01 and shear wave P=0.02).Conclusion:Together, BI-RADS assessment of greyscale ultrasound images and shear wave ultrasound elastography are extremely sensitive for detection of malignancy.

Probabilistic model of the human cortical bone with mechanical alterations in ultrasonic range

The biomechanical materials are among the most complex mechanical systems. Most often, their microstructure is heterogeneous and random. This is the case for the human cortical bones which are considered in this paper. For such systems, a gradient of porosity can be observed in the thickness direction but, in this case, none of the usual theories of porous materials can be applied. For this reason, a simplified model with gradient for the elasticity tensor is presented. The predictability of this model is improved by taking into account uncertainties. We propose a prior stochastic model of the tensor-valued elasticity field corresponding to an extension of a previous work in which the random elasticity field was constant in space. This extension consists in introducing two ingredients: the introduction of a spatial gradient for the mean elasticity tensor and spatial statistical fluctuations in the thickness direction. The stochastic model which is constructed shows that the observed responses are effectively sensitive with respect to the values of the gradient and to the level of statistical fluctuations. In this sense, this stochastic model will be well adapted to perform its identification solving a stochastic inverse problem that is not the purpose of the present paper.

2034 QUANTATIVE SHEAR WAVE ELASTOSONOGRPAHY IN THE DETECTION OF PROSTATE CANCERS

You have accessJournal of UrologyImaging/Radiology: Uroradiology I1 Apr 20122034 QUANTATIVE SHEAR WAVE ELASTOSONOGRPAHY IN THE DETECTION OF PROSTATE CANCERS Sarfraz Ahmed, Omar Aboumarzouk, Stephen Lang, and Ghulam Nabi Sarfraz AhmedSarfraz Ahmed Dundee, United Kingdom More articles by this author , Omar AboumarzoukOmar Aboumarzouk Dundee, United Kingdom More articles by this author , Stephen LangStephen Lang Dundee, United Kingdom More articles by this author , and Ghulam NabiGhulam Nabi Dundee, United Kingdom More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.2198AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Shear wave elastosonography is a new method of obtaining quantitative tissue elasticity data during transrectal ultrasound biopsies procedure. The aims of this study were (1) to determine the whether shear wave elastsonography can help in picking up extra cancer foci to the currect12 core biopsies technique (2) to compare quantitative shear wave elastosonography for benign/malignant classification. METHODS Using the Aixplorer® ultrasound system (SuperSonic Imagine, Aix en Provence, France), 32 men with suspected prostate cancer underwent transrectal 12- core systematic biopsies. Additional biopsies were directed using shearaave mode of the machine, if the lesions appeared to be outside the biopsied area. Two orthogonal elastography images were obtained of each region of the biopsied areas. Elastsonography measurements were correlated with histology results. After preliminary experience with 10 patients a mean elasticity cut off value of 70 kilopascals (kPa) was selected for benign/malignant differentiation. RESULTS Thirty one of 32 men had abnormal foci seen on transrectal elastosonography. Twenty one of these lesions were diagnosed as cancer or PIN. There were fourteen foci which were not targeted by 12-core-systematic biopsies and could have been missed, had shearwave elastosonography not being used in these men. All of these cancers were significant with majority being in the lateral zone. One man missed on two previous 12-core biopsies sets was diagnosed with shear wave directed biopsies on the third occasion. There was a significant difference between elasticity measurement of benign and malignant tissues ( p value 0.028). CONCLUSIONS Shear wave elastography provides quantitative information about the prostatic tissue and in our preliminary observation can accurately direct biopsies to the cancer foci within the prostate. This has huge potential for focal treatment and future prostate biopsies protocols. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e820-e821 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Sarfraz Ahmed Dundee, United Kingdom More articles by this author Omar Aboumarzouk Dundee, United Kingdom More articles by this author Stephen Lang Dundee, United Kingdom More articles by this author Ghulam Nabi Dundee, United Kingdom More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

A 2D non-invasive ultrasonic method for simultaneous measurement of arterial strain and flow pattern

Many cardiovascular diseases are closely associated with the mechanical properties of arterial wall and hemodynamic parameters. Simultaneous measurements of the arterial strain and flow pattern may aid diagnosis of cardiovascular diseases and may be useful to study fluid-structure interaction between blood and vessel. This paper proposes a 2D non-invasive ultrasonic method to simultaneously measure arterial strain and flow pattern with sub-pixel accuracy. The method uses a multiple iterative algorithm to estimate the geometrical transformations of arterial wall and high-velocity gradient flows simultaneously. The accuracy of the method was validated by an in vitro arterial phantom and in vivo common carotid arteries (CCAs) of 12 mice using a Sonix RP (10 MHz) and a VisualSonics Vevo 2100 (30 MHz) ultrasound imaging system, respectively. For the arterial phantom, the calculated elasticity modulus from the strain profile shows good agreement with the mechanical testing value, deviating no more than 9.3%. The calculated flow velocity agrees well with the value obtained from the rotameter, deviating only 4.3%. For the CCAs of mice, good agreement is found between the calculated flow velocity and the measured value by ultrasound Doppler. The mean elasticity modulus of CCAs is 134.62 ± 54.3 kPa, which is in accordance with published data. The proposed method is capable of measuring the arterial wall strain and flow velocity pattern. This may be clinically useful for early detecting and monitoring cardiovascular diseases and may provide an essential tool in modelling the fluid-structure interaction between the blood and blood vessel.

A Note on Allen’s Arc Elasticity with Arithmetic, Geometric and Harmonic Means

Discussion and debate on the application of Allen’s arc elasticity has continued into the 21st century. This note demonstrates three points. First, perceived differences between Allen’s geometric mean elasticity and a constant demand elasticity based on an assumed isoelastic demand curve are negligible for small changes in price and quantity, which comprise the vast majority of such changes. Second, in some cases of rapid security or commodity price movements, the harmonic mean may provide the most accurate elasticity estimates across measures of central tendency. Third, because the arithmetic and harmonic means serve as bounds for the geometric mean, an elasticity based on the geometric mean may be considered a prudent choice among these three on this basis alone.

Muscle Crush Injury of Extremity: Quantitative Elastography with Supersonic Shear Imaging

The aim of this study was to determine the characteristic of muscle crush injury at quantitative ultrasonographic elastography using supersonic shear imaging (SSI). Twenty-three New Zealand rabbits underwent crush injury to left hind leg caused by a special balloon cuff device. Conventional ultrasonography and SSI quantitative elastography were performed at both crushed and uncrushed regions of the left hind legs. Quantitative lesion elasticity was measured using the Young’s modulus (in kilopascals) at 0.5 h, 2 h, 6 h, 24 h and 72 h after the release of the crushing pressure. Compared with those from the uncrushed regions, both the maximum and mean elasticity values at these time points from the crushed regions were significantly higher (p < 0.001). A receiver operating characteristic (ROC) analysis was employed to assess diagnostic performance. ROC curves showed that extremity crush injury was diagnosed using elasticity value and the greater the elasticity value, the greater the diagnostic value. SSI provides quantitative elasticity measurements, thus, adding complementary information that potentially could help in crush injury characterization with conventional ultrasonography.

Liver Elasticity in NASH Patients Evaluated with Real-Time Elastography (RTE)

Liver elasticity as assessed by real-time elastography (RTE) has been shown to be correlated to liver fibrosis in various chronic liver diseases. The aim of our study was to assess the RTE performance in the evaluation of liver fibrosis in nonalcoholic steatohepatitis (NASH), as well as the histopathologic variables determining the eventual discordance between the RTE-predicted and the biopsy-proven fibrosis. Fifty-two consecutive biopsy proven NASH patients and 20 controls were studied. Liver tissue elasticity measurements were performed using the Hitachi EUB-8500 sonographer and the EUP-L52 Linear (3–7 MHz) probe. RTE liver tissue mean elasticity (TME) values were calculated and correlated to the histologic fibrosis, activity and steatosis scores. A decrease in TME was observed with increasing fibrosis (r = −0.75). Similarly, TME varied together consistently with steatosis (r = −0.3). In contrast, TME did not show any correlation with the severity of inflammation. Multiple regression analysis showed that fibrosis was the only variable able to significantly (p < 0.0001) modify TME values. The diagnostic accuracy of TME measurement for F > 0 evaluated by AUC-ROC analysis was 0.86. The diagnostic accuracy of TME measurement for F ≥ 2 was 0.92. We suggest that RTE could be used as a complementary imaging method to evaluate liver fibrosis in NASH patients. Future studies of larger patient cohorts are necessary for the validation of the technique.

Shear-wave Elastography Improves the Specificity of Breast US: The BE1 Multinational Study of 939 Masses

To determine whether adding shear-wave (SW) elastographic features could improve accuracy of ultrasonographic (US) assessment of breast masses. From September 2008 to September 2010, 958 women consented to repeat standard breast US supplemented by quantitative SW elastographic examination in this prospective multicenter institutional review board-approved, HIPAA-compliant protocol. B-mode Breast Imaging Reporting and Data System (BI-RADS) features and assessments were recorded. SW elastographic evaluation (mean, maximum, and minimum elasticity of stiffest portion of mass and surrounding tissue; lesion-to-fat elasticity ratio; ratio of SW elastographic-to-B-mode lesion diameter or area; SW elastographic lesion shape and homogeneity) was performed. Qualitative color SW elastographic stiffness was assessed independently. Nine hundred thirty-nine masses were analyzable; 102 BI-RADS category 2 masses were assumed to be benign; reference standard was available for 837 category 3 or higher lesions. Considering BI-RADS category 4a or higher as test positive for malignancy, effect of SW elastographic features on area under the receiver operating characteristic curve (AUC), sensitivity, and specificity after reclassifying category 3 and 4a masses was determined. Median participant age was 50 years; 289 of 939 (30.8%) masses were malignant (median mass size, 12 mm). B-mode BI-RADS AUC was 0.950; eight of 303 (2.6%) BI-RADS category 3 masses, 18 of 193 (9.3%) category 4a lesions, 41 of 97 (42%) category 4b lesions, 42 of 57 (74%) category 4c lesions, and 180 of 187 (96.3%) category 5 lesions were malignant. By using visual color stiffness to selectively upgrade category 3 and lack of stiffness to downgrade category 4a masses, specificity improved from 61.1% (397 of 650) to 78.5% (510 of 650) (P<.001); AUC increased to 0.962 (P=.005). Oval shape on SW elastographic images and quantitative maximum elasticity of 80 kPa (5.2 m/sec) or less improved specificity (69.4% [451 of 650] and 77.4% [503 of 650], P<.001 for both), without significant improvement in sensitivity or AUC. Adding SW elastographic features to BI-RADS feature analysis improved specificity of breast US mass assessment without loss of sensitivity.

Shear wave elastography for breast masses is highly reproducible.

ObjectivesTo evaluate intra- and interobserver reproducibility of shear wave elastography (SWE) for breast masses.MethodsFor intraobserver reproducibility, each observer obtained three consecutive SWE images of 758 masses that were visible on ultrasound. 144 (19%) were malignant. Weighted kappa was used to assess the agreement of qualitative elastographic features; the reliability of quantitative measurements was assessed by intraclass correlation coefficients (ICC). For the interobserver reproducibility, a blinded observer reviewed images and agreement on features was determined.ResultsMean age was 50 years; mean mass size was 13 mm. Qualitatively, SWE images were at least reasonably similar for 666/758 (87.9%). Intraclass correlation for SWE diameter, area and perimeter was almost perfect (ICC ≥ 0.94). Intraobserver reliability for maximum and mean elasticity was almost perfect (ICC = 0.84 and 0.87) and was substantial for the ratio of mass-to-fat elasticity (ICC = 0.77). Interobserver agreement was moderate for SWE homogeneity (κ = 0.57), substantial for qualitative colour assessment of maximum elasticity (κ = 0.66), fair for SWE shape (κ = 0.40), fair for B-mode mass margins (κ = 0.38), and moderate for B-mode mass shape (κ = 0.58), orientation (κ = 0.53) and BI-RADS assessment (κ = 0.59).ConclusionsSWE is highly reproducible for assessing elastographic features of breast masses within and across observers. SWE interpretation is at least as consistent as that of BI-RADS ultrasound B-mode features.Key Points• Shear wave ultrasound elastography can measure the stiffness of breast tissue • It provides a qualitatively and quantitatively interpretable colour-coded map of tissue stiffness • Intraobserver reproducibility of SWE is almost perfect while intraobserver reproducibility of SWE proved to be moderate to substantial • The most reproducible SWE features between observers were SWE image homogeneity and maximum elasticity

Sonoelastography for 1786 non-palpable breast masses: diagnostic value in the decision to biopsy

To evaluate the diagnostic value of sonoelastography by correlation with histopathology compared with conventional ultrasound on the decision to biopsy. Prospectively determined BI-RADS categories of conventional ultrasound and elasticity scores from strain sonoelastography of 1786 non-palpable breast masses (1,523 benign and 263 malignant) in 1,538 women were correlated with histopathology. The sensitivity and specificity of two imaging techniques were compared regarding the decision to biopsy. We also investigated whether there was a subset of benign masses that were recommended for biopsy by B-mode ultrasound but that had a less than 2% malignancy rate with the addition of sonoelastography. The mean elasticity score of malignant lesions was higher than that of benign lesions (2.94 ± 1.10 vs. 1.78 ± 0.81) (P < 0.001). In the decision to biopsy, B-mode ultrasound had higher sensitivity than sonoelastography (98.5% vs. 93.2%) (P < 0.001), whereas sonoelastography had higher specificity than B-mode ultrasound (42.6% vs. 16.3%) (P < 0.001). BI-RADS category 4a lesions with an elasticity score of 1 had a malignancy rate of 0.8%. Sonoelastography has higher specificity than B-mode ultrasound in the differentiation between benign and malignant masses and has the potential to reduce biopsies with benign results. • Sonoelastography has higher specificity than B-mode ultrasound in distinguishing benign from malignant masses. • Sonoelastography could potentially help reduce the number of biopsies with benign results. • Lesion stiffness on sonoelastography correlated with the malignant potential of the lesion.

Quantitative Assessment of Normal Soft-Tissue Elasticity Using Shear-Wave Ultrasound Elastography

The aim of this study was to measure the elasticity of various tissues and report it in kilopascals. The thyroid, submandibular, and parotid glands, masseter and gastrocnemius muscles, supraspinatus and Achilles tendons, renal cortex and pelvis, pancreas, and spleen of 127 healthy volunteers (89 women, 38 men; mean age, 37.72 ± 9.11 years; range, 17-63 years) were evaluated with shear-wave ultrasound elastography. The mean elasticity values were determined to be 10.97 ± 3.1 kPa for the thyroid, 10.92 ± 3.1 kPa for the submandibular glands, 10.38 ± 3.5 kPa for the parotid glands, 10.4 ± 3.7 kPa for the masseter muscle, 11.1 ± 4.1 kPa for the gastrocnemius muscle, 31.2 ± 13 kPa for the supraspinatus muscle, 51.5 ± 25.1 kPa for the Achilles tendons, 5.0 ± 2.9 kPa for the renal cortex, 23.6 ± 5.4 kPa for the renal pelvis, 4.8 ± 3 kPa for the pancreas, and 2.9 ± 1.8 kPa for the spleen. Elasticity values were determined for different tissues with shear-wave ultrasound elastography. Further studies comparing the elasticity values of normal and pathologic tissues are necessary to determine the diagnostic role of this technique.

Parameters identification of polymer concrete using a fracture mechanics test method and full-field measurements

In the present work it is proposed an easy-to-implement alternative procedure to identify not only the fracture properties but also the mean elasticity modulus E and Poisson’s ratio ν of arbitrary polymer concretes. Only one test using a standard single-edge-cracked three-point bend specimen is necessary. Digital image correlation (DIC) method is used to obtain the full-field displacement close to the crack tip. The mean properties ( E, ν) are determined by fitting analytical expressions for the displacement field to the experimental data. The adequacy of the proposed methodology is checked by comparing the material parameters obtained using the proposed procedure with the ones obtained through standard procedures.

Clinical application of shear wave elastography (SWE) in the diagnosis of benign and malignant breast diseases

Shear wave elastography (SWE) is an emerging technique which can obtain quantitative elasticity values in breast disease. We therefore evaluated the diagnostic performance of SWE for the differentiation of breast masses compared with conventional ultrasound (US). Conventional US and SWE were performed by three experienced radiologists for 158 consecutive women who had been scheduled for US-guided core biopsy or surgical excision in 182 breast masses (89 malignancies and 93 benign; mean size, 1.76cm). For each lesion, quantitative elasticity was measured in terms of the Young's modulus (in kilopascals, kPa) with SWE, and BI-RADS final categories were assessed with conventional US. The mean elasticity values were significantly higher in malignant masses (153.3kPa±58.1) than in benign masses (46.1kPa±42.9), (P<0.0001). The average mean elasticity values of invasive ductal (157.5±57.07) or invasive lobular (169.5±61.06) carcinomas were higher than those of ductal carcinoma in situ (117.8kPa±54.72). The average mean value was 49.58±43.51 for fibroadenoma, 35.3±31.2 for fibrocystic changes, 69.5±63.2 for intraductal papilloma, and 149.5±132.4 for adenosis or stromal fibrosis. The optimal cut-off value, yielding the maximal sum of sensitivity and specificity, was 80.17kPa, and the sensitivity and specificity of SWE were 88.8% (79 of 89) and 84.9% (79 of 93). The area under the ROC curve (Az value) was 0.898 for conventional US, 0.932 for SWE, and 0.982 for combined data. In conclusion, there were significant differences in the elasticity values of benign and malignant masses as well as invasive and intraductal cancers with SWE. Our results suggest that SWE has the potential to aid in the differentiation of benign and malignant breast lesions.