Application Of Shear Wave Elastography Research Articles

Shear wave elastography to assess stiffness of the human ovary and other reproductive tissues across the reproductive lifespan in health and disease†.

The ovary is one of the first organs to show overt signs of aging in the human body, and ovarian aging is associated with a loss of gamete quality and quantity. The age-dependent decline in ovarian function contributes to infertility and an altered endocrine milieu, which has ramifications for overall health. The aging ovarian microenvironment becomes fibro-inflammatory and stiff with age, and this has implications for ovarian physiology and pathology, including follicle growth, gamete quality, ovulation dynamics, and ovarian cancer. Thus, developing a non-invasive tool to measure and monitor the stiffness of the human ovary would represent a major advance for female reproductive health and longevity. Shear wave elastography is a quantitative ultrasound imaging method for evaluation of soft tissue stiffness. Shear wave elastography has been used clinically in assessment of liver fibrosis and characterization of tendinopathies and various neoplasms in thyroid, breast, prostate, and lymph nodes as a non-invasive diagnostic and prognostic tool. In this study, we review the underlying principles of shear wave elastography and its current clinical uses outside the reproductive tract as well as its successful application of shear wave elastography to reproductive tissues, including the uterus and cervix. We also describe an emerging use of this technology in evaluation of human ovarian stiffness via transvaginal ultrasound. Establishing ovarian stiffness as a clinical biomarker of ovarian aging may have implications for predicting the ovarian reserve and outcomes of Assisted Reproductive Technologies as well as for the assessment of the efficacy of emerging therapeutics to extend reproductive longevity. This parameter may also have broad relevance in other conditions where ovarian stiffness and fibrosis may be implicated, such as polycystic ovarian syndrome, late off target effects of chemotherapy and radiation, premature ovarian insufficiency, conditions of differences of sexual development, and ovarian cancer. Summary sentence: Shear Wave Elastography is a non-invasive technique to study human tissue stiffness, and here we review its clinical applications and implications for reproductive health and disease.

The Application of Shear Wave Elastography to Determine the Elasticity of the Levator Ani Muscle and Vaginal Tissue in Patients With Pelvic Organ Prolapse.

The changes of the extracellular matrix of the connective tissue have significantly contributed to the incidence of pelvic organ prolapse (POP). It seems reasonable that sonoelastography could be a useful tool to evaluate the elasticity of pelvic floor tissue in patients with POP and compare it to those without POP. The main aim of this pilot study was to determine if there are differences in the elasticity of the levator ani muscle (LAM) and vaginal tissue between patients with and without POP. Prospective observation study, including 60 patients (30 with POP and 30 without POP). Sonoelastography was performed to evaluate the elasticity (in kilopascals, kPa) of the following regions of interest: vagina at the level of middle third of the urethra; vagina at the level of the bladder trigone; vagina in the anterior and posterior fornix; vagina at the level of middle third of the anorectal canal; posterior third of the LAM. A total of 60 patients completed the study (30 with POP, 30 without POP). In the POP group, 18/30 (60%) had an anterior vaginal wall prolapse, 3/30 (10%) a uterine prolapse, 15/30 (50%) a rectocele, and 6/30 (20%) a enterocele. Patients with POP had higher elasticity in all anatomical study areas, with statistically significant differences in the anterior fornix (13.6 vs 11.2 kPa; P: .012). A multiple regression (controlling age, menopausal stage, and parity) allowed to detect statistically significant differences in the elasticity of the middle third of the urethra (P: .03) and the middle third of the anorectal canal (P: .019). It is possible to evaluate the elasticity of the LAM and vaginal tissue using sonoelastography, detecting a higher elasticity in patients with POP than in those without POP.

Is musculoskeletal pain associated with increased muscle stiffness? Evidence map and critical appraisal of muscle measurements using shear wave elastography.

Approximately 21% of the world's population suffers from musculoskeletal conditions, often associated with sensations of stiff muscles. Targeted therapy requires knowing whether typically involved muscles are objectively stiffer compared to asymptomatic individuals. Muscle stiffness is quantified using ultrasound shear wave elastography (SWE). Publications on SWE-based comparisons of muscle stiffness between individuals with and without musculoskeletal pain are increasing rapidly. This work reviewed and mapped the existing evidence regarding objectively measured muscle stiffness in musculoskeletal pain conditionsand surveyed current methods of applying SWE to measure muscle stiffness. A systematic search was conducted in PubMed and CINAHL using the keywords "muscle stiffness","shear wave elastography","pain","asymptomatic controls" and synonyms. The search was supplemented by a hand search using Google Scholar. Included articles were critically appraised with the AXIS tool, supplemented by items related to SWE methods. Results were visually mapped and narratively described. Thirty of 137 identified articles were included. High-quality evidence was missing. The results comprise studies reporting lower stiffness in symptomatic participants, no differences between groupsand higher stiffness in symptomatic individuals. Results differed between pain conditions and muscles, and also between studies that examined the same muscle(s) and pathology. The methods of the application of SWE were inconsistent and the reporting was often incomplete. Existing evidence regarding the objective stiffness of muscles in musculoskeletal pain conditions is conflicting. Methodological differences may explain most of the inconsistencies between findings. Methodological standards for SWE measurements of muscles are urgently required.

Shear Wave Elastography for the Assessment of Carotid Plaque Vulnerability: A Systematic Review

Evidence for the management of asymptomatic carotid stenosis and possibly symptomatic nonstenosing carotid artery disease is limited. In contrary to calcified plaques, soft plaques are considered vulnerable and prone to rupture. Shear wave elastography (SWE), a novel ultrasound technique which uses acoustic wave force to propagate shear wave in tissues, can quantify tissue stiffness through the estimation of Young’s modulus (YM) in kPa or shear wave velocity in meter/second. This systematic review is aimed at evaluating the feasibility of SWE in carotid plaque risk stratification in relation to ischemic stroke (PROSPERO registration: CRD42022309709). 18 studies, obtained via search on PubMed, Cochrane, and Embase from inception until November 1, 2022, assessed SWE’s feasibility in carotid plaque risk stratification in humans (13 studies) and phantom models (5 studies). Human studies showed heterogeneity with respect to SWE devices, acquisition settings, and methodology, which consequently reflected in the between-study variability of YM values used for distinguishing vulnerable/symptomatic (27–52 kPa) and stable/asymptomatic (28–115 kPa) carotid plaques. However, within-study assessment of all human studies indicated SWE’s feasibility in carotid plaque risk stratification. Furthermore, four out of five carotid plaque phantom studies showed the potential of SWE to discriminate tissues of different stiffness comparable to the carotid vessel wall, soft and hard plaques, and with good reproducibility. SWE may potentially offer a bedside risk stratification tool for identifying patients with vulnerable carotid plaques, who may benefit from carotid surgery, stenting, or prolonged dual antiplatelet therapy. Patients with stable carotid plaques could be spared the risks of potentially harmful treatments and complications. However, available data are not enough to facilitate the immediate clinical application of SWE, and therefore, larger prospective clinical are warranted.

Impact of Ventricular Geometric Characteristics on Myocardial Stiffness Assessment Using Shear-Wave Velocity in Healthy Children and Young Adults

Diastolic myocardial stiffness (MS) can serve as a key diagnostic parameter for congenital or acquired heart diseases. Using shear modulus and shear-wave velocity (SWV), shear-wave elastography (SWE) is an emerging ultrasound-based technique that can allow noninvasive assessment of MS. However, MS extrinsic parameters such as left ventricular geometric characteristics could affect shear-wave propagation. The aims of this study were to determine a range of normal values of MS using SWE in age groups of healthy children and young adults and to explore the impact of left ventricular geometric characteristics on SWE. Sixty healthy volunteers were recruited in the study and divided into 2 groups: neonates (0-1 months old, n=15) and >1month old (1month to 45years of age, n=45). SWE was performed using the Verasonics Vantage systems with a phased-array ultrasound probe. The anteroseptal basal segment was assessed in two views. SWE was electrocardiographically triggered during the end-diastolic phase. Conventional echocardiography was performed to assess ventricular function and anatomy. Results are presented as stiffness values along with mean velocity measurements and SDs. Simple and multivariate linear regression analyses were performed. For neonates, mean MS was 1.87±0.79kPa (range, 0.59-2.91kPa; mean SWV, 1.37±0.57m/sec), with high variability and no correlation with age (P=.239). For this age group, no statistically significant correlation was found between MS and any demographic or echocardiographic parameters (P>.05). For the >1month old group, a mean MS value of 1.67±0.53kPa was observed (range, 0.6-3kPa; mean SWV, 1.29±0.49m/sec) for healthy volunteers. When paired for age, no sex-related difference was observed (P=.55). In univariate linear regression analysis, age (r=0.83, P<.01), diastolic interventricular septal thickness (r=0.72, P<.01), and left ventricular end-diastolic diameter (r=0.67, P<.01) were the parameters with the highest correlation coefficients with MS. In a multiple linear regression analysis incorporating these three parameters as cofounding factors, age was the only statistically significant parameters (r=0.81, P=.02). Diastolic MS increases linearly in children and young adults. Diastolic MS correlates more robustly with age than with myocardial and left ventricular geometric characteristics. However, the geometry affects SWV, implying the need to determine well-established boundaries in future studies for the clinical application of SWE.

Clinical study of the value of shear wave elastography in evaluating the degree of liver fibrosis in children.

To explore the clinical application of shear wave elastography (SWE) in evaluating the degree of liver fibrosis in children. To explore the value of SWE in assessing liver fibrosis in children, the correlation between elastography values and the METAVIR grade of liver fibrosis in children with biliary system or liver diseases was studied. Children with significant liver enlargement were enrolled, and the fibrosis grade was analyzed to explore the value of SWE in assessing the degree of liver fibrosis in the presence of significant liver enlargement. A total of 160 children with bile system or liver diseases were recruited. The areas under the receiver operating characteristic curve (AUROCs) for liver biopsy from stage F1 to F4 were 0.990, 0.923, 0.819, and 0.884. According to the degree of liver fibrosis at liver biopsy, there was a high correlation between the SWE value and the degree of liver fibrosis (correlation coefficient 0.74). There was no significant correlation between the Young's modulus value of the liver and the degree of liver fibrosis (correlation coefficient 0.16). Supersonic SWE can generally accurately evaluate the degree of liver fibrosis in children with liver disease. However, When the liver is significantly enlarged, SWE can only evaluate liver stiffness based on Young's modulus values, and the degree of liver fibrosis must still be determined by pathologic biopsy.

Applicability of shear wave elastography for lacrimal gland evaluation in primary Sjögren syndrome.

Primary Sjögren syndrome (pSS) is a systemic autoimmune disease that mainly affects the salivary and lacrimal glands, leading to their progressive destruction. The primary aim of this study was to verify whether shear wave elastography (SWE) of the lacrimal glands can be used to differentiate patients with pSS from healthy controls. The secondary aim was to assess whether there are any associations between SWE values, results of other ocular tests included in pSS diagnosis (the Schirmer test, ocular staining score [OSS]), and subjective symptoms of eye dryness. The study included 45 patients with pSS (41 women, 4 men) and 108 healthy controls (104 women, 4 men). All pSS patients met the 2016 American College of Rheumatology / European League Against Rheumatism pSS classification criteria. The participants underwent bilateral SWE of the lacrimal glands with the results expressed in kilopascals (kPa). The Schirmer test was performed in all patients, and OSS was calculated only in the pSS group. The patients with pSS had significantly higher SWE values for the lacrimal glands than the controls. No significant differences in SWE results were observed between the groups of pSS patients with or without eye dryness confirmed by the Schirmer test and OSS, or the pSS patients with or without subjective symptoms of eye dryness. The optimal cutoff point for the diagnosis of pSS for the mean result of left and right lacrimal gland elastography was 7.2 kPa (sensitivity, 88.9%; specificity, 88%). Lacrimal gland SWE values may be a good classifier for the diagnosis of pSS, with an area under the receiver operating characteristic curve of 89.8 (95% CI, 81.5-98.1). SWE of the lacrimal glands is a noninvasive, quantitative method that seems to be a reliable additional examination tool to support the diagnosis of pSS. Its role among the functional tests has not yet been well defined. To confirm the usefulness of SWE for pSS diagnosis, a standardized and widely accepted study protocol should be defined first.

Application of Shear-Wave Elastography in the Evaluation of Hamstring Stiffness in Young Basketball Athletes.

Previous literature has postulated a relationship between greater hamstring stiffness and a higher risk of sustaining injury. Shear wave elastography (SWE) presents a relatively new means for non-invasive evaluation of soft tissue elasticity pre- and post- injury or intervention. 1. To establish baseline hamstring stiffness measures for young competitive athletes and (2) determine effect of targeted neuromuscular training (TNMT) on shear wave stiffness of the hamstring. Un-blinded, prospective, non-randomized, cohort study. Six-hundred forty-two lower extremities from 321 high school and collegiate basketball athletes (177 F: 139 M) were examined for hamstring stiffness prior to the start of their competitive basketball season. Teams were cluster assigned to either the control or intervention (TNMT) group. Subjects in the control group underwent regular season activities as directed, with no influence from the research team. For the TNMT group, the research team introduced a hamstring targeted dynamic warm-up program as an intervention focused on activating the hamstring musculature. Collegiate status was significant to hamstring stiffness for both sexes (p ≤ 0.02), but hamstring stiffness did not correlate to age or sex (r2 ≤ 0.08). Intervention was a significant factor to hamstring stiffness when the hip was positioned in extension (p ≤ 0.01), but not in deeper flexion (p = 0.12). This effect was sex-specific as TNMT influenced hamstring stiffness in females (p = 0.03), but not in males (p ≥ 0.13). Control athletes suffered three HAM injuries; TNMT athletes suffered 0 hamstring injuries. Higher SWE measurements correlated with increased risk of injury, male sex, and collegiate athletics. TNMT intervention can lessen muscle stiffness which may reduce relate to injury incidence. Intervention effectiveness may be sex specific. II.

The Applicability of Shear Wave Elastography to Assess Myotendinous Stiffness of Lower Limbs during an Incremental Isometric Strength Test.

The aim of the study was to describe the applicability of shear wave elastography to assess muscular and tendinous stiffness of the lower limbs during an incremental isometric strength test and to differentiate the stiffness evolution between superficial and deep muscle regions. Dominant rectus femoris and patellar tendons of 30 physically active people (28.3 ± 9.2 years, 173.2 ± 7.7 cm, 76.2 ± 12.6 kg) were measured in different isometric strength conditions (relaxed muscle, and at 10%, 20%, 30%, 40%, 50% and 60% of maximal voluntary contraction (MVC)). The percentage of success was &gt;85% at all muscle contraction intensities for rectus femoris muscles but only in a relaxed condition for patellar tendons. Rectus femoris stiffness significantly increased compared to the relaxed condition from 30% to 60% MVC (p ≤ 0.011) in superficial muscle regions, and from 10% to 60% MVC (p ≤ 0.002) in deep muscle regions. Deep muscle regions showed higher stiffness values than superficial muscle regions at 30% MVC (51.46 ± 38.17 vs. 31.83 ± 17.05 kPa; p = 0.019), 40% MVC (75.21 ± 42.27 vs. 51.25 ± 28.90 kPa; p = 0.018), 50% MCV (85.34 ± 45.05 vs. 61.16 ± 37.03 kPa; p = 0.034) and 60% MVC (109.29 ± 40.04 vs. 76.67 ± 36.07 kPa; p = 0.002). Rectus femoris stiffness increased during the incremental isometric contraction test, and inter-region differences were found at 30% MVC.

Clinical Application of Shear Wave Elastography With Shear Wave Dispersion Imaging in the Preoperative Evaluation of Hepatic Parenchyma in Patients With Liver Tumors.

This study aimed to compare the diagnostic accuracy of shear wave elastography (SWE) with that of shear wave dispersion (SWD) in evaluation of hepatic parenchyma in patients with liver tumors before resection. A total of 174 patients with liver tumors were prospectively enrolled. SWE and SWD examinations were performed. Fibrosis stage and necroinflammatory activity were determined histopathologically according to the Scheuer standard. We compared the diagnostic accuracy of SWE and SWD. Both SWE and SWD values of the liver were highly correlated with liver fibrosis stage (P < .05, respectively). Both SWE and SWD values of the liver were moderately correlated with necroinflammatory activity (P < .05, respectively). Both SWE and SWD values of the liver were not correlated with steatosis (P > .05, respectively). Both SWE and SWD values were significantly different among the patients with different stages of liver fibrosis (P < .001, respectively). The area under the receiver operating characteristic (ROC) curve of SWE value was 0.982, 0.977, 0.969, and 0.984 for predicting S ≥ 1, S ≥ 2, S ≥ 3, and S=4, respectively. The optimal cutoff SWE values were 6.9, 7.9, 8.7, and 10.6kPa for S ≥ 1, S ≥ 2, S ≥ 3, and S=4, respectively. The area under the ROC curve of SWD value was 0.967, 0.960, 0.925, and 0.954 for predicting S ≥ 1, S ≥ 2, S ≥ 3, and S=4, respectively. The optimal cutoff SWD values were 11.2, 12.0, 13.2, and 16.0 m/s/kHz for S ≥ 1, S ≥ 2, S ≥ 3, and S=4, respectively. SWE and SWD could be noninvasive and accurate for predicting the stage of liver fibrosis in patients with liver tumors before surgery. SWE was more accurate than SWD in predicting severe fibrosis (S ≥ 3) and cirrhosis (S=4).

Analysis of the Influence of Thyroid Nodule Characteristics on the Results of Shear Wave Elastography.

ObjectiveTo analyze the ultrasonic characteristics of false-negative and false-positive results of shear wave elastography (SWE) in the diagnosis of thyroid nodules to clarify the influence of nodular characteristics on SWE and to guide the clinical application of SWE.MethodsA total of 435 thyroid nodules from 343 patients with the diagnosis confirmed by surgical pathology were analyzed. Preoperative ultrasonography and SWE were conducted. The conventional ultrasound characteristics of thyroid nodules and the maximum Young’s modulus were recorded. The false negativity and false positivity of SWE for the diagnosis of thyroid nodules were calculated. The ultrasonic characteristics of thyroid nodules with SWE false results were analyzed, and logistic regression analysis was adopted to determine the ultrasonic characteristics associated with SWE false results of thyroid nodules.ResultsAmong 323 malignant nodules, the SWE false negativity was 27.2% (88/323). The false positivity of SWE in 112 benign nodules was 19.6% (22/112). Regression analysis showed that an increase in the nodule volume increased the risk of SWE false-positive results (odds ratio [OR] 3.286; 95% confidence interval [CI]: 1.572–6.871; P = 0.002) and decreased the risk of false-negative results (OR 0.238; 95% CI: 0.115–0.493; P < 0.001). Nodules with coarse calcification had an increased risk of SWE false-positive results compared with those without calcification (OR 5.303; 95% CI: 1.098–25.619; P = 0.038). However, nodules with scattered hyperechoic foci had a reduced risk of SWE false-negative results (OR 0.515; 95% CI: 0.280–0.951; P = 0.034).ConclusionNodular size and calcification were correlated with SWE false results, and the clinical application of SWE should be combined with conventional ultrasound features. Fine needle aspiration or a puncture biopsy should be conducted if necessary.

Assessment of ultrasound shear wave elastography within muscles using different region of interest sizes, manufacturers, probes and acquisition angles: an ex vivo study.

The application of shear wave elastography (SWE) in assessment of the musculoskeletal system is affected by various factors. This study aimed to explore the influence of machines, probes, region of interest (ROI) sizes, and the acquisition angles on muscle shear wave speed (SWS). The SWS of ex vivo isolated muscles were acquired using 3 different machines (Aixplorer system, SuperSonic Imagine; Acuson S3000, Siemens Healthcare; Resona 7, Mindray) and 2 linear probes (Aixplorer system, SL 10-2 and SL 15-4). Also, 4 different ROI sizes (diameter 1-10 mm) and 9 different acquisition angles (0-40°) were tested. The SWS acquired under different conditions were compared, and the intra-class correlation coefficients (ICC) were used to evaluate reproducibility. There was a significant difference in SWS acquired using the 3 different machines (P<0.001) or with 9 different angles (P=0.008). There was no significant difference in SWS acquired using 2 probes (P=0.053) or 4 different ROI sizes (P=0.874, 0.778, and 0.865 for 3 operators, respectively). All machines produced substantial intra-system reproducibility (ICC, 0.61-0.80). Both probes demonstrated an almost perfect degree of intra-system agreement (ICC, >0.80), and nearly all ROI sizes demonstrated an almost perfect degree of intra- and inter-operator agreement (ICC, >0.80). The measurement reliability was higher when the acquisition angles were no more than 20°. The 3 machines had different SWS values. Attention should be paid when comparing SWS results using different machines. For the Aixplorer system, the ROI size had no effect on the SWS values. Angles larger than 25° will lead to SWS measurements with greater variability compared to smaller angles (≤20°).

Shear wave elastography: the relationship of the cervical stiffness with gestational age and cervical length- a feasibility study

Objectives To standardize the measurement of shear wave elastography for assessment of cervical stiffness and its relationship with gestational age and cervical length. Methods A prospective cross-sectional study was conducted from September 2017 to March 2019. Data from 125 unselected women (at 11–13 + 6, 18–22 and 24–28 weeks’ gestation) and 55 high-risk women were analyzed for the study. Six regions of interest were evaluated for cervical elastography in the mid-sagittal position by transvaginal ultrasound. Statistical analyses were performed using R statistical language in R-studio. Delivery outcomes were recorded for each patient. Results The shear wave elastography was feasible with good intraoperator and interoperator reproducibility. The endocervical canal and anterior lip internal position had the highest reproducibility (ICC-0.82, 0.75). Shear wave speed was significantly higher in all internal os regions than the external os. There was a statistically significant negative linear relationship of shear wave speed with the gestational age. There was a weak positive relationship between shear wave speed and cervical length. There was no difference between pregnancies with and without spontaneous preterm delivery in shear wave speed measurements and cervical length, although numbers were small for statistical analysis. The internal os of the large loop excision of the transformation zone group was stiffer than the normal population. Conclusion Cervical elastography is feasible and effectively evaluates the tensile properties of the cervix during pregnancy. The most reproducible measurements were obtained at the anterior lip of the internal cervical os. Combining evaluation of cervical elasticity and length might further improve the identification of women at risk of preterm delivery. Currently, technical issues hinder the practical application of shear wave elastography in the clinical setting and require further research and development of the imaging modality.

Application of Shear Wave Elastography and Contrast-Enhanced Ultrasound in Transrectal Prostate Biopsy.

To explore the clinical value of ultrasound shear wave elastography (SWE) and contrast-enhanced ultrasound (CEUS) in transrectal prostate biopsy. A total of 54 patients (average age: 67.79±12.01 years) in the experimental group underwent transrectal prostate biopsy under the guidance of SWE, while 46 patients (average age: 69.22±11.54 years) in the control group underwent transrectal prostate biopsy guided by CEUS. There were a total of 451 needles, with an average of 8.35±1.67 needles per patient in the experimental group, and a total of 462 needles, with an average of 10.04±1.33 needles per patient in the control group. The difference in puncture times between the two groups was statistically significant (P<0.05). There was no significant difference in the positive detection rate, sensitivity or specificity between the two groups (P>0.05), but there was a significant difference in the diagnostic accuracy between the two groups (P<0.05). The Emean and Emax of prostate cancer were significantly higher in the experimental group than in benign prostatic hyperplasia (P<0.05). The receiver operating characteristic curve (ROC) analysis showed that the area under the ROC curve (AUC) of Emean was 0.752 (S.E. =0.072, 95% CI=0.611-0.894, P=0.007), and the best cutoff value was 47.005 kPa. In summary, both SWE- and CEUS-guided transrectal prostate biopsy can help find the focus and guide the puncture, and improve the positive detection rate.

Role of shear wave elastography ultrasound in patients with systemic sclerosis.

A study of shear wave elastography (SWE) for evaluation of skin stiffness in systemic sclerosis (SSc) patients. The purpose of this study was to measure the skin stiffness and thickness in patients with scleroderma using shear wave elastography. Prospective data collections of skin stiffness and thickness using SWE in SSc and control groups. Skin stiffness and thickness were done in 29 patients with SSc and a 29 control population using SWE on bilateral forearms. The SSc patients had thicker skin and higher stiffnesses than the control group. The mean of skin thickness and stiffness using SWE of SSc are 1.74mm and 47.32kPa while normal subjects were 1.5mm and 19.5kPa. Mean differences were 0.023mm (95% CI 0.15-0.3, p < 0.001) and 27.82kPa (95% CI 22.63-33.01, p < 0.001). The dorsal forearms tend to have a higher SWE than the volar forearms in SSc. No statistically significant differences between gender, age or dominancy of skin stiffness were found. SWE has a good correlation with clinical manual palpation of forearms (mRSS) with Spearman rho's of 0.550 (p = 0.002) and 0.508 (p = 0.005) of dominant and non-dominant forearms. The application of SWE can be used for evaluation of skin involvement in scleroderma patients with good correlations with the mRSS that was used in the current patients. Furthermore, SWE is a safe technique for either diagnosis or follow up.

Muscle elasticity is different in individuals with diastasis recti abdominis than healthy volunteers

ObjectiveTo determine the value of shear wave elastography (SWE) in assessing abdominal wall muscles, including rectus abdominis (RA), external oblique muscle (EO), internal oblique muscle, and transversus abdominis (TrA) in patients with diastasis recti abdominis (DRA) and healthy controls.MethodsFrom October 2018 to December 2019, 36 postpartum DRA patients and 24 nulliparous healthy women were identified. Inter-rectus distance (IRD) measurements were taken by B-mode ultrasound. Shear wave speed (SWS) values were acquired by one operator at ten specific locations. Clinical and ultrasound variables, including demographics, IRD, muscle thickness, and muscle SWS, were compared between the two groups using Student’s t test or Fisher's exact test. Pearson correlation analyses were conducted for the variables of IRD, muscle thickness, and SWS in the 36 DRA patients.ResultsThe maximum diameter of recti abdominus separation was located at the umbilicus in DRA patients (4.59 ± 1.14 cm). The SWS value was significantly lower in the RA (p = 0.003) and higher in the TrA muscle (p < 0.001) in DRA patients compared with the age-matched controls. However, SWS in both muscles (RA and TrA) showed a statistically positive correlation with IRD (p < 0.05). In addition, the SWS value in EO statistically decreased in DRA patients compared with the healthy controls (1.65 ± 0.15 vs. 1.79 ± 0.14, p = 0.001).ConclusionsThe application of SWE to abdominal wall muscles in DRA patients is feasible. The correlation between SWS value and IRD in RA should be interpreted with caution.

Clinical Application of Shear Wave Elastography for Assisting Brain Tumor Resection.

BackgroundThe clinical outcomes for brain tumor resection have been shown to be significantly improved with increased extent of resection. To achieve this, neurosurgeons employ different intra-operative tools to improve the extent of resection of brain tumors, including ultrasound, CT, and MRI. Young’s modulus (YM) of brain tumors have been shown to be different from normal brain but the accuracy of SWE in assisting brain tumor resection has not been reported.AimsTo determine the accuracy of SWE in detecting brain tumor residual using post-operative MRI scan as “gold standard”.MethodsThirty-four patients (aged 1–62 years, M:F = 15:20) with brain tumors were recruited into the study. The intraoperative SWE scans were performed using Aixplorer® (SuperSonic Imagine, France) using a sector transducer (SE12-3) and a linear transducer (SL15-4) with a bandwidth of 3 to 12 MHz and 4 to 15 MHz, respectively, using the SWE mode. The scans were performed prior, during and after brain tumor resection. The presence of residual tumor was determined by the surgeon, ultrasound (US) B-mode and SWE. This was compared with the presence of residual tumor on post-operative MRI scan.ResultsThe YM of the brain tumors correlated significantly with surgeons’ findings (ρ = 0.845, p < 0.001). The sensitivities of residual tumor detection by the surgeon, US B-mode and SWE were 36%, 73%, and 94%, respectively, while their specificities were 100%, 63%, and 77%, respectively. There was no significant difference between detection of residual tumor by SWE, US B-mode, and MRI. SWE and MRI were significantly better than the surgeon’s detection of residual tumor (p = 0.001 and p < 0.001, respectively).ConclusionsSWE had a higher sensitivity in detecting residual tumor than the surgeons (94% vs. 36%). However, the surgeons had a higher specificity than SWE (100% vs. 77%). Therefore, using SWE in combination with surgeon’s opinion may optimize the detection of residual tumor, and hence improve the extent of brain tumor resection.

Clinical applicability of shear wave elastography for the evaluation of medial epicondylitis.

To evaluate the ability of shear wave elastography (SWE) in diagnosing medial epicondylitis and to compare the diagnostic performance of SWE with that of grey-scale ultrasound (GSU) and strain elastography (SE). GSU, SE, and SWE were performed on 61 elbows of 54 patients from March 2018 to April 2019. An experienced radiologist evaluated the GSU findings (swelling, cortical irregularity, hypoechogenicity, calcification, and tear), colour Doppler findings (hyperaemia), SE findings (strain ratio [SR]), and SWE findings (stiffness and shear wave velocity [SWV]). Participants were divided in two groups: patients with clinically diagnosed medial epicondylitis and patients without medial elbow pain. Findings from the two groups were compared, and the receiver operating characteristic (ROC) curves were calculated for significant features. Of the 54 patients, 25 patients with 28 imaged elbows were clinically diagnosed with medial epicondylitis and 29 patients with 33 imaged elbows had no medial elbow pain. Cortical irregularity, hypoechogenicity, calcification, hyperaemia, SR, stiffness, and SWV were significantly different between the two groups. The areas under the ROC curves were 0.838 for hypoechogenicity, 0.948 for SR, 0.999 for stiffness, and 0.999 for SWV. The diagnostic performances of SR, stiffness, and SWV were significantly superior compared to that of hypoechogenicity. However, there were no significant differences among SR, stiffness, and SWV. SWE can obtain both stiffness and SWV, which are valuable diagnostic tools in the diagnosis of medial epicondylitis. The diagnostic performance of SWE and SE is similar in detecting medial epicondylitis. • Shear wave elastography providing stiffness and shear wave velocity showed excellent performance in the diagnosis of medial epicondylitis. • There was no significant difference in the ability of SE and SWE for diagnosing medial epicondylitis.

Application of shear wave elastography as a diagnostic method for esophageal varices.

To evaluate the value of shear wave elastic imaging (SWE) in the classification of esophageal varices (EV) and detection of rupture hemorrhage. A total of 120 patients with clinically diagnosed cirrhosis were selected from October 2017 to October 2018 and underwent ultrasonography, endoscopy, and laboratory examinations. Several factors, including gender, age, body mass index (BMI), aspartate aminotransferase (AST), AST to platelet count ratio index (APRI), portal vein diameter, platelet count, spleen thickness, liver stiffness (LS), and spleen stiffness (SS), were evaluated for their diagnostic value for EV classification and detection of rupture hemorrhage. Correlation analyses were also conducted. The APRI, portal vein diameter, platelet count, spleen thickness, LS, and SS had areas under the curve (AUCs) of 0.76, 0.81, 0.82, 0.89, 0.84, and 0.91, respectively, indicating their potential use as indices for the diagnosis of EV (all P<0.05). The platelet count and APRI could not distinguish low-risk EV from high-risk EV (P=0.301, P=0.564), but EV with or without rupture hemorrhage was identified by SS (P<0.001). Therefore, SS is a valuable factor for the identification of low-risk EV and high-risk EV, as well as for the identification of EV with or without rupture hemorrhage. Spearman's correlation analysis indicated that the occurrence of EV is moderately correlated with APRI, portal vein diameter, platelet count, and LS (r=0.41, 0.49, 0.51, 0.54, P<0.05) and highly correlated with spleen thickness and SS (r=0.63, 0.65, P<0.05). SWE demonstrated a high diagnostic value, supporting its application as a non-invasive method for predicting EV classification and rupture hemorrhage.

Layer-specific ultrasound elastography using a multi-layered shear wave dispersion model for assessing the viscoelastic properties

Mechanical properties of biological tissues are significant biomarkers for diagnosing various diseases. Assessing the viscoelastic properties of multi-layer tissues has remained challenging for a long time. Some shear wave models have been proposed to estimate thin-layer tissues’ viscoelasticity recently. However, the potential applications of these models are highly restricted since few biological tissues are single-layered. Here we proposed a multi-layer model for layer-specific viscoelasticity estimation of biological tissues. Integrating the theoretical model and ultrasonic micro-elastography imaging system, the viscoelasticity of both layers was assessed. Dual-layer phantoms and ex vivo porcine eyes were used to verify the proposed model. Results obtained from the mechanical test and shear wave rheological model using bulk phantoms were provided as validation criteria. The representative phantom had two layers with elastic moduli of 1.6 ± 0.2 kPa and 18.3 ± 1.1 kPa, and viscosity moduli of 0.56 ± 0.16 Pa·s and 2.11 ± 0.28 Pa·s, respectively. The estimated moduli using the proposed model were 1.3 ± 0.2 kPa and 16.20 ± 1.8 kPa, and 0.80 ± 0.31 Pa·s and 1.87 ± 0.67 Pa·s, more consistent with the criteria (one-tailed t-test, p < 0.1). By contrast, other methods, including the group velocity method and single-layer Rayleigh–Lamb model, generate significant errors in their estimates. For the ex vivo porcine eye, the estimated viscoelasticity was 23.2 ± 8.3 kPa and 1.0 ± 0.4 Pa·s in the retina, and 158.0 ± 17.6 kPa and 1.2 ± 0.4 Pa·s in the sclera. This study demonstrated the potential of the proposed method to significantly improve accuracy and expand clinical applications of shear wave elastography.