Mean Shear Wave Velocity Research Articles

Shear wave elastography of lymph nodes in dogs with head and neck cancer: A pilot study.

Shear wave elastography (SWE) is a novel ultrasound imaging technique, used in human medicine to differentiate metastatic from non-metastatic lymph nodes (LNs) based on higher tissue stiffness. The objective of this pilot study was to evaluate whether canine metastatic LNs were stiffer compared to non-metastatic LNs. SWE of sentinel or regional LNs in dogs with head and neck cancer was performed. Ten elastograms of each LN were acquired. In each elastogram, mean, median, and maximum shear wave velocities (SWVs) were calculated in the most elastic region, the stiffest region, and the entire LN. The means of those SWVs for each region of each LN were subsequently calculated. Furthermore, a stepwise subsampling was performed to assess the effect of the number of acquired elastograms on the consistency of the classification of a LN as metastatic or not. Twenty-four LNs in 15 dogs with head and neck cancer were included, of which 10 LNs were metastatic. Metastatic medial retropharyngeal and mandibular LNs were successfully distinguished from non-metastatic LNs based on higher mean and median SWVs in the stiffest region and higher maximum SWVs in entire LNs. Furthermore, maximum SWVs in the stiffest region of mandibular LNs were higher in metastatic LNs compared to non-metastatic LNs. Downstream analyses demonstrated that at least eight elastograms were necessary to perform reliable analyses. This pilot trial demonstrated that SWE has potential to discriminate metastatic from non-metastatic LNs; however, LN status should be based on at least eight elastograms in future clinical trials.

Shear wave elastography and Doppler ultrasound in kidney transplant recipients.

ObjectiveTo evaluate the association between shear wave elastography parameters and arterial resistance in kidney transplant recipients.Materials and MethodsThis was a prospective cross-sectional study involving consecutive adult kidney transplant recipients. All patients underwent color Doppler to evaluate the resistive index (RI) and ultrasound shear wave elastography for the quantification of renal allograft stiffness.ResultsWe evaluated 55 patients, of whom 9 (16.4%) had an RI defined as abnormal (≥ 0.79) and 46 (83.6%) had an RI defined as normal (< 0.79). The mean age was higher in the abnormal RI group than in the normal RI group (68.0 ± 8.6 years vs. 42.6 ± 14.1 years; p < 0.001), as was the mean shear wave velocity (2.6 ± 0.4 m/s vs. 2.2 ± 0.4 m/s; p = 0.013). Multivariate analysis identified two independent predictors of arterial resistance: age (OR = 1.169; 95% CI: 1.056 to 1.294; p = 0.003) and shear wave velocity (OR = 17.1; 95% CI: 1.137 to 257.83; p = 0.040).ConclusionWe observed an association between rigidity in the cortex of the transplanted kidney, as evaluated by shear wave elastography, and arterial resistance, as evaluated by color Doppler, in kidney transplant recipients.

A Comparison of Shear Wave Elastography between Normal Myometrium, Uterine Fibroids, and Adenomyosis: A Cross-Sectional Study.

BackgroundThe differential diagnosis between uterine fibroid and adenomyosis is sometimes difficult; a precise diagnosis is required in women with infertility because of the different choice of treatments. Ultrasound elastography (UE) is a novel technique to evaluate the elasticity or the stiffness of the tissue of interest. The present study aims to compare UE shear wave velocity (SWV) among normal uterine myometrium, uterine fibroid, and adenomyosis, and assess the accuracy of shear wave elastography in the diagnosis of adenomyosis.Materials and MethodsThis cross-sectional study recruited 25 subjects for each group (control, adenomyosis, and fibroid) from April 2019 to April 2020. Transvaginal UE using an Aplio 500 (Toshiba Medical Systems, Japan) with ultrasound mapping for point of tissue biopsy was performed for all subjects. The diagnosis was confirmed by histology. Masson’s trichrome staining for collagen was performed and quantifiedResultsThe mean ± standard deviation (SD) for SWV was 3.44 ± 0.95 m/seconds (control group), 4.63 ± 1.45 m/seconds (adenomyosis group), and 4.53 ± 1.07 m/seconds (fibroid group). The mean SWV differed when comparing normal myometrium and adenomyosis after adjustments for age and endometrial pathology (P=0.019). The cut-off point of SWV at 3.465 m/seconds could differentiate adenomyosis from the normal uterus with an 80% sensitivity, 80% specificity, and an area under the curve (AUC) of 0.80 (95% confidence interval [CI]: 0.68-0.93) (P<0.001). No significant difference in SWV between the adenomyosis and fibroid groups was detected.ConclusionShear wave elastography could be an alternative tool to distinguish between normal myometrium and adenomyosis; however, it could not differentiate adenomyosis from uterine fibroid or uterine fibroid from normal myometrium.

Identifying the effects of excess weight, metabolic syndrome and insulin resistance on liver stiffness using ultrasound elastography in children.

Metabolic syndrome (MetS) and insulin resistance (IR) are known predictors of nonalcoholic fatty liver disease (NAFLD) which is one of the significant comorbidities of obesity. Obese children with MetS and IR are reported to be more likely to have advanced liver fibrosis compared to those without MetS or IR. The aim of this study is to determine the effects of excess weight, MetS and IR on liver fibrosis assessing liver stiffness in children using ultrasound elastography and compare gray scale ultrasonographic findings of hepatic steatosis (HS) with liver fibrosis. The study group involved 131 overweight/obese children. The control group involved 50 healthy lean children. Groups were adjusted according to body mass index (BMI) and BMI-standard deviation scores (SDS). Liver stiffness measurements which are expressed by shear wave velocity (SWV) were performed for each individual. The study group was further subgrouped as children with MetS and without MetS, with IR and without IR. The mean SWV of liver was 1,07 ± 0,12 m/s in the control group and 1,15 ± 0,51 m/s in the study group. The difference was significant (p=0,047). SWV of liver was weakly correlated with age, BMI, BMI-SDS, Homeostatic Model Assessment-Insulin Resistance and high-density lipoprotein cholesterol. The mean SWV of the liver in the study group for children without MetS was 1,1 ± 0,44 m/s, with MetS was 1,23 ± 0,70 m/s. The difference was not significant (p=0,719). The mean SWV of the liver in the study group for children without IR was 1,02 ± 0,29 m/s, with IR was 1,24 ± 0,61 m/s. The difference was not significant (p=0,101). In multivariate regression analysis, the only independent factor affecting liver stiffness was BMI-SDS (OR:2,584, 95% CI: 1,255- 5,318, p=0,010). Obesity itself, regardless of MetS or IR seems to be the major problem affecting liver stiffness in this study. However, large scale longitudinal studies might clarify this issue.

Evaluation of the relationship between placental stiffness measured by shear wave elastography and perinatal outcomes in women with gestational diabetes mellitus.

Recently, studies on placental elastography in high-risk pregnancies continue to increase. The shear wave technique can contribute to the management of gestational diabetes mellitus (GDM) and improve perinatal outcomes by measuring placental stiffness.Purpose: To evaluate the relationship between placental stiffness measured by shear wave elastography (SWE) and perinatal outcomes in women with GDM.Material and Methods: This prospective cross-sectional study was conducted at our hospital between March and October 2020. The participants were divided into three groups: GDM-A1 group (regulated by dietary modifications); GDM-A2 group (needed pharmacologic treatment); and low-risk pregnancy (LRP) group. Both SWE and shear wave velocity (SWV) were measured in the placenta during pregnancy. In total, 111 women were included in the study. The mean SWE (kPa) values for the GDM-A1, GDM-A2, and LRP groups were 10.4 (range 3.1-23.3), 13 (range 4.3-29.6), and 8.3 (range 3.2-15.1), respectively. The mean HbA1c and fasting glucose values of diabetes groups showed strongly positive correlation with mean SWE and SWV values (P < 0.001, r=0.875; P < 0.001, r=0.856; P < 0.001, r=0.791; P < 0.001, r=0.740), respectively. The SWE values of central maternal and fetal surfaces of the placenta (P=0.01, r=0.242; P < 0.001, r=0.333) showed a moderately positive correlation with admission to the neonatal intensive care unit. Placental stiffness has increased in the GDM-A2 group when compared to the GDM-A1 and LRP groups. We also observed a strong positive correlation between HbA1c, fasting glucose values, and increased elasticity values in diabetic patients with metabolic dysregulation that may have clinical value.

Diagnostic value of shear wave velocity in polycystic ovarian syndrome.

Aim: In polycystic ovarian syndrome, the ovaries become stiffer due to chronic anovulation. We aimed to compare tissue elasticity in terms of shear wave velocities measured using acoustic radiation force impulse imaging technique between the ovaries of polycystic ovarian syndrome women and non-polycystic ovarian syndrome women. Material and methods: The study was designed as a retrospective data analysis of women who underwent transvaginal ultrasound and acoustic radiation force impulse imaging in a university hospital between July 2014 and March 2015, for various reasons. There were 32 polycystic ovarian syndrome patients and 32 patients without a diagnosis of polycystic ovarian syndrome. Age, body mass index, fasting glucose levels, cycle day 3 follicle stimulating hormone, luteinizing hormone, thyroid stimulating hormone, prolactin, antimullerian hormone levels, and menstrual patterns with clinical hyperandrogenism were evaluated. On the menstrual cycle days 2–4, by performing a transvaginal ultrasound scan, the ovarian volumes and antral follicle counts in both ovaries were recorded for each woman. The ultrasound system was converted into the elastography mode, and acoustic radiation force impulse imaging was performed. Shear wave velocity (m/sec) was measured at least 5 times for each ovary, and the mean value was calculated for each polycystic ovarian syndrome and non-polycystic ovarian syndrome woman. Results: Age, body mass index, fasting glucose levels, cycle day 3 follicle stimulating hormone, luteinizing hormone, thyroid stimulating hormone, and prolactin levels were similar between the groups (p >0,05). Antimullerian hormone levels, antral follicle counts, and mean ovarian volumes were statistically different between the groups (p <0,05). Mean shear wave velocity values for both ovaries were 2.12 ± 0.82 (0.78–4.9) m/sec in the polycystic ovarian syndrome group, and 1.18 ± 0.41 (0.77–2.0) m/sec in the non-polycystic ovarian syndrome group, which was statistically significantly different (p = 0.016). Conclusion: In our study, we found significantly higher shear wave velocity levels in polycystic ovarian syndrome women than non-polycystic ovarian syndrome women, which indicates an impact of the condition on shear wave velocity. The increased acoustic frequencies cause a decreased response in time to transition, and motion becomes out of phase; in other words, scattered waves are faster in stiffer ovaries. Our results are thus compatible with the pathophysiology of the disease. Shear wave velocity is a beneficial tool for evaluating ovarian elasticity in polycystic ovarian syndrome patients in whom the levels are found to be significantly higher than non-polycystic ovarian syndrome women. In light of these findings, shear wave velocity is expected to be slower than polycystic ovarian syndrome levels in ovulatory women.

Profiling the Quito basin (Ecuador) using seismic ambient noise

SUMMARY Quito, the capital of Ecuador, with more than 2.5 M inhabitants, is exposed to a high seismic hazard due to its proximity to the Pacific subduction zone and active crustal faults, both capable of generating significant earthquakes. Furthermore, the city is located in an intermontane piggy-back basin prone to seismic wave amplification. To understand the basin’s seismic response and characterize its geological structure, 20 broad and medium frequency band seismic stations were deployed in Quito’s urban area between May 2016 and July 2018 that continuously recorded ambient seismic noise. We first compute horizontal-to-vertical spectral ratios to determine the resonant frequency distribution in the entire basin. Secondly, we cross-correlate seismic stations operating simultaneously to retrieve interstations surface-wave Green’s functions in the frequency range of 0.1–2 Hz. We find that Love waves travelling in the basin’s longitudinal direction (NNE–SSW) show much clearer correlograms than those from Rayleigh waves. We then compute Love wave phase-velocity dispersion curves and invert them in conjunction with the HVSR curves to obtain shear-wave velocity profiles throughout the city. The inversions highlight a clear difference in the basin’s structure between its northern and southern parts. In the centre and northern areas, the estimated basin depth and mean shear-wave velocity are about 200 m and 1800 ms−1, respectively, showing resonance frequency values between 0.6 and 0.7 Hz. On the contrary, the basement’s depth and shear-wave velocity in the southern part are about 900 m and 2500 ms−1, having a low resonance frequency value of around 0.3 Hz. This difference in structure between the centre-north and the south of the basin explains the spatial distribution of low-frequency seismic amplifications observed during the Mw 7.8 Pedernales earthquake in April 2016 in Quito.

Shear wave velocity measurements obtained in different regions are repeatable for presumed normal canine lymph nodes: A pilot study.

Shear wave elastography (SWE) has been applied as a noninvasive method for predicting regional lymph node (LN) metastases in human and veterinary patients. However, published studies describing standardized protocols and repeatability of this technique are currently lacking. The objective of this prospective, pilot, observer agreement study was to determine whether different shear wave velocity (SWV) measurements obtained in different regions of presumed normal canine LNs would be repeatable. Two imagers consecutively performed shear wave elastography of submandibular, superficial inguinal, and popliteal LNs in 10, clinically healthy adult dogs. Ten elastograms of each LN were acquired by each imager. In each adequate elastogram, three regions of interest (ROIs) were placed in the softest and stiffest region of the LN. Additionally, one ROI was drawn covering the entire LN. In each ROI, mean, median, and maximum SWVs were calculated. Mean values for the mean, median, and maximum SWVs varied from 2.33 to 3.10 m/s, 2.32 to 3.10 m/s, and 2.61 to 4.09 m/s, respectively. Intra- and interobserver agreements were acceptable. Superficial inguinal LNs demonstrated the highest intra- and interobserver agreement, followed by the popliteal and the submandibular LNs, respectively. Using the different measurements (mean, median, or maximum SWVs) had no significant effect on the intra- and interobserver variability, neither did the region (softest, stiffest, or entire LN). Findings indicated that all evaluated measurements and regions could be used to obtain reliable elastography data of presumed normal canine LNs. Clinical trials in dogs with cancer are necessary to compare SWVs of metastatic LNs with the reported SWVs and evaluate whether various measurements and regions can also be used in metastatic LNs.

Role of transabdominal ultrasound in the diagnosis of autoimmune pancreatitis

The most important thing in the diagnosis of autoimmune pancreatitis (AIP) is to suspect the possibility of AIP. In the acute phase, diffuse pancreatic enlargement is a highly specific finding of AIP compared to focal enlargement. Though the sensitivity is low, high-frequency transducers can detect the capsule-like rim sign and penetrating duct sign. Those findings are characteristic of AIP and useful for differential diagnosis with pancreatic carcinoma. In focal AIP, both contrast-enhanced US showing iso/hypervascularity and elastography showing increased stiffness not only in the focal enlargement but also in the surrounding parenchyma are also useful for differential diagnosis. Furthermore, changes over time after the two-week steroid trial, such as resolution or measurable reduction in parenchymal enlargement and a decrease in the mean shear-wave velocity on elastography, are also cardinal features of AIP. Since AIP is a pancreatic manifestation in immunoglobulin G4-related disease, evaluation of other organs, including the biliary tract and salivary glands, is particularly useful in focal AIP. A characteristic US finding of bile ducts is three-layered (high-low-high pattern) wall thickening with a markedly thickened middle layer. US can also detect wall thickening of bile ducts, which show no abnormalities on cholangiography. These findings are useful for differential diagnosis with cholangiocarcinoma. Multiple hypoechoic areas in submandibular glands are characteristic US findings of sialadenitis in type 1 AIP, and the sensitivity is higher than that of physical examination. US can further contribute to the diagnosis of AIP by employing elastography and contrast-enhanced US in addition to high-frequency transducers.

Role of Ultrasound Elastography in Patient Selection for Prostatic Artery Embolization

PurposeTo determine the effects of prostatic artery embolization (PAE) on prostate elasticity as assessed using ultrasound elastography (US-E) and to describe baseline US-E's potential role in patient selection. Materials and MethodsThis was a prospective investigation that included 20 patients undergoing PAE to treat lower urinary tract symptoms attributed to benign prostatic hyperplasia (BPH). US-E with measurement of the prostatic elastic modulus (EM) and shear wave velocity (SWV) was performed before PAE and at 1-month follow-up. Baseline, 3-month, and 1-year follow-up evaluations included prostate-specific antigen, uroflowmetry, pelvic magnetic resonance imaging, and clinical assessment using the International Prostate Symptom Score (IPSS) and quality of life (QoL) metrics. ResultsSeventeen patients entered statistical analysis. US-E showed a significant reduction in mean prostatic EM (34.4 kPa vs 46.3 kPa, −24.7%, P < .0001) and SWV (3.55 m/s vs 4.46 m/s, −20.0%, P < .0001) after PAE. There were moderate positive correlations between baseline EM and 1-year IPSS (R = 0.62, P = .007) and between baseline SWV and 1-year IPSS (R = 0.68, P = .002). Baseline SWV ≥ 5.59 m/s and baseline EM ≥ 50.14 kPa were associated with suboptimal IPSS and QoL outcomes after PAE with high degrees of sensitivity (100%) and specificity (69-100%). ConclusionsPAE led to a positive effect on the BPH dynamic component related to prostatic elasticity. There was a moderate positive correlation between baseline prostatic elastographic parameters and 12-month IPSS. Measurement of baseline elastographic characteristics may become useful for the evaluation and selection of patients for PAE.

Acoustic radiation force impulse elastography findings of achilles tendon in patients with hypothyroidism

Introduction&#x0D; The aim of our study was to investigate the effect of thyroid dysfunction on tendons and the contribution of Acoustic Radiation Force Impulse (ARFI) elastography to the diagnosis of tendinopathy.&#x0D; Methods&#x0D; Eighty Achilles tendons of 40 patients under levothyroxine treatment, who had previously known hypothyroidism but high serum thyroid stimulating hormone levels, and 80 Achilles tendons of 40 healthy individuals were evaluated with ARFI (Virtual Touch Quantification®). 19 of 40 of the patients with hypotiroidism’ Achilles tendons were re-evaluated after thyroid stimulating hormone levels reached to normal limits following the adjustments in thyroid hormone replacement therapy. The middle portion of the each Achilles tendon was chosen for the examination. Every examination consisted of three to five independent measurements (shear wave velocity- meters per second). The mean shear wave velocity value was calculated for each tendon, and used for statistical analysis.&#x0D; Results&#x0D; The stiffness values of both left and right Achilles tendons, represented as shear wave velocity, were similar in patients with hypothyroidism and control group. There was no significant difference between the Achilles tendon shear wave velocity measurements of 19 of 40 hypothyroidism patients who were re-evaluated after the adjustments in thyroid hormone replacement therapy.&#x0D; Conclusions&#x0D; The lack of significant difference in Achilles tendon stiffness between non-naive hypothyroid patients and the control group may be explained as a positive clinical effect of thyroid hormone replacement therapy.

Quantifying Lower Limb Muscle Stiffness as Ambulation Function Declines in Duchenne Muscular Dystrophy with Acoustic Radiation Force Impulse Shear Wave Elastography

Duchenne muscular dystrophy (DMD) is a progressive muscular disease, but validated imaging tools to quantify muscle microstructure alteration as mobility declines are lacking. We aimed to determine the feasibility of using acoustic radiation force impulse shear-wave elastography (ARFI/SWE) in the quantitative assessment of lower limb muscle stiffness in DMD patients. Shear wave velocities (SWVs) of lower limbs were measured in 39 DMD patients and 36 healthy controls aged 3–20 y. Mean SWV values of the controls and of the DMD patients at different ambulatory stages were compared using analysis of variance with Bonferroni correction. The DMD group had increased lower limb muscle stiffness compared with controls. Stiffness of the tibialis anterior and medial gastrocnemius muscle decreased from ambulatory to early non-ambulatory stages, whereas stiffness of the rectus femoris muscle increased from ambulatory to late non-ambulatory stages. We describe how SWV changes in lower limb muscles have the potential to predict ambulatory decline in DMD.

Quantitative assessment of normal middle deltoid muscle elasticity at various arm abduction using ultrasound shear wave elastography

The objective of this study is to assess the change in the normal MD elasticity using shear wave elastography (SWE) through measuring the middle deltoid (MD) elasticity in healthy participants at various arm abduction (with bilateral arms at 0 degrees abduction and 90 degrees active abduction) and analyzing the factors affecting normal MD elasticity. Mean shear wave velocity (SWV) of the MD in healthy right-handed participants were evaluated using SWE at different arm abduction, and potential factors (gender, MD thickness, age, body mass index) affecting MD elasticity were analyzed. Different arm abduction positions of each participant were as follows: (i) 0° abduction of bilateral arm (L0° and R0°), (ii) 90° active abduction of bilateral arm (L90° and R90°). Mean SWV was significantly higher at L90° than L0°, higher at R90° than R0°, higher at R0° than L0°, and higher at R90° than L90° (all P < 0.0001). SWV was significantly higher in males at both L0° (P < 0.05) and R0° (P < 0.01) than in females. Neither MD thickness, age nor body mass index influenced MD elasticity. Reference ranges of normal MD elasticity were 2.4–3.1 m/s in males and 2.2–2.9 m/s in females at L0° and 2.5–3.3 m/s in males and 2.4–3.2 m/s in females at R0°, and were 4.9–6.7 m/s at L90°, 5.2–7.1 m/s at R90° for both males and females. SWE is a feasible technique to assess normal MD elasticity at various arm abduction. Our results suggest that normal MD elasticity at L0°, R0°, L90°, and R90° with SWE are different. Moreover, these reference ranges may serve as quantitative baseline measurements for assessment of normal MD elasticity in the future.

Using shear wave elasticity in normal terminal ileum of a healthy southwest Chinese population: a pilot study of reference elasticity ranges.

Elastography has not been widely applied to the gastrointestinal tract. The bowel wall's normal elasticity values are still unknown and are necessary for studies of gastrointestinal diseases. This study explores the feasibility of using shear wave elastography (SWE) to measure the terminal ileum wall stiffness in healthy subjects and establish the corresponding normal ranges of elasticity values. This observational study recruited 139 healthy adult volunteers from April to July 2020. All examinations were performed in the anterior terminal ileum wall. Shear wave velocity (SWV) and Young's modulus (E) values were measured in the midline on longitudinal sections and replicated different operators' obtained data. Also, bowel wall thickness (BWT) and depth were recorded. Subgroups were classified according to the volunteers' gender, age, body mass index (BMI), BWT, and depth. The intra-class correlation coefficient was calculated to analyze inter- and intra-operator consistency, and independent t-tests and one-way analysis of variance were used to explore the differences in variables. The inter- and intra-operator agreements were good to excellent by different operators and in the replicated measurements (intra-operator consistency: 0.963; inter-operator consistency: 0.842). In all volunteers, the mean SWV was 1.08±0.25 m/s, the mean E value was 3.84±1.84 kPa, and the median BWT was 2 mm. SWV and E did not show significant differences according to gender (P=0.589), age (P=0.738), BMI (P=0.678), depth (P=0.375), or BWT (P=0.410). BWT did not show significant differences according to age (P=0.142), BMI (P=0.863), or depth (P=0.368). SWE can be used in terminal ileum wall stiffness measurements with good reliability, and the SWE values do not appear to vary significantly according to different physiological factors. The corresponding elasticity ranges of the terminal ileum in normal adults were acquired.

Shear Wave Elastography of the Plantar Fascia: Comparison between Patients with Plantar Fasciitis and Healthy Control Subjects.

Background: The purpose of this study was to evaluate plantar fasciae of healthy subjects and patients with plantar fasciitis by shear wave velocity (SWV) and stiffness with correlation to B-Mode and color Doppler ultrasonography (CDUS) and to establish cut-off values. Methods: This observational study was conducted with the approval of the Institutional Review Boards (IRBs) of our institution. 108 unilateral plantar fasciae were evaluated by including 87 consecutive patients (mean age 51.7; range: 29–82) (66 women and 21 men) with plantar fasciitis and 21 asymptomatic age matched healthy volunteers (mean age 47.3; range: 32–58) (15 women and 6 men). All patients were prospectively imaged between July 2018 and March 2019. B-mode US was used to measure thickness and CDUS to grade vascularity. SWE measurements were repeated 3 times and mean was used for statistical analysis. Results: Mean SWV value in healthy subjects was 6.94 m/s and in patients 4.98 m/s with a mean stiffness value of 152.88 kPa and 93.54 kPa respectively (p < 0.001). For SWV a cut-off value of 6.16 m/s had a specificity of 80.95% and sensitivity of 79.31%. For stiffness a cut-off value of 125.57 kPa had a specificity of 80.95% and sensitivity of 80.46%. No correlation to CDUS was found. The mean thickness of healthy fascias was 3.3 mm (range 2.4–3.9) compared to 6.1 mm (range 2.0–22.0) in plantar fasciitis (p < 0.001) with no correlation to SWV or to stiffness (r² = 0.02, p = 0.06). Conclusion: SWE allows quantitative assessment of plantar fascia stiffness, which decreases in patients with plantar fasciitis. No correlation to the thickness of the plantar fascia was found, therefore it represents an independent factor for the diagnosis of plantar fasciitis and could be helpful in addition to thickness measurement in unclear cases.

The Utility of Shear-Wave Elastography in the Evaluation of Myositis

Changes in muscle elasticity are expected in patients with untreated myositis. The purpose of this study was to define the accuracy of shear-wave elastography (SWE) in diagnosing myositis. This case control study included 21 patients (mean age, 49.4 y; 12 women) with myositis who underwent SWE, magnetic resonance imaging (MRI) and biopsy of the involved muscle group. SWE was performed accordingly in a control group (n = 24; mean age, 51.2 y; 8 women). Blood tests consisted of creatine kinase (CK) and aldolase. Two operators performed SWE in longitudinal and transverse planes of muscular fibers, quantifying the mean shear-wave velocity (SWV) and the pattern of stiffness. On MRI, short-TI inversion recovery (STIR) signal hyperintensity and T1 contrast enhancement of muscle was considered diagnostic for myositis. The patient group suffered from different types of myositis (nine patients with polymyositis, eight with dermatomyositis and four with other types of myositis). Blood tests showed significantly increased CK and aldolase values in patients with myositis (p < 0.001 and p < 0.0001). MRI showed a sensitivity of 0.95. In the patient group, the mean SWVs of longitudinal and transverse measurements were 2.8 ± 1.4 m/s and 3.1 ± 1.2 m/s, respectively. In the control group, SWVs were 2.3 ± 0.5 m/s and 2.4 ± 0.5 m/s, respectively. The difference between transverse measurements was significant (p = 0.02). Increased heterogeneity as a marker for myositis in transverse SWE showed a sensitivity of 0.8, specificity of 0.79, positive predictive value (PPV) of 0.76 and negative predictive value (NPV) of 0.82. Inter-observer difference was very low (κ = 0.92). Increased heterogeneity in both planes compared with histologic results showed a sensitivity of 0.56, specificity of 0.93, PPV of 0.91 and NPV of 0.62. Spearman correlation between CK <1000 U/L and SWE was 0.54. In conclusion, transverse orientation SWE may serve as an imaging biomarker for the diagnosis of myositis through the display of a heterogeneous pattern and increased absolute SWV values of inflamed muscles.

Identification of Subsurface Structures and Dynamic Modulus Determination Based on Downhole Seismic Surveys (Case Study)

Seismic features of the site are studied in earthquake prone areas. In these studies, the seismic design parameters of the site are determined based on geological and geotechnical engineering features. In this regard, part of the building regulations (European Standard) is related to site classification. In order to classify the land, the bylaws provide various methods such as mean shear wave velocity up to 30 m depth. In the present study, the values of the dynamic modulus of layers are calculated using conventional relationships based on the values of wave velocities for different depths. In this study, data from 22 boreholes, in which Downhole Seismic surveys were performed, were identified and implemented to identify subsurface layers and to determine the dynamic modulus in the area. The results of these studies in land classification were used to evaluate the site effect based on European Standard. The results show that the area under study is classified in class B according to this standard.

Quantitative assessment of temporomandibular disc and masseter muscle with shear wave elastography.

To assess the normal stiffness values of temporomandibular joint disc (TMJ) and masseter muscle by shear wave elastography (SWE) in a healthy adult population. This may be helpful in diagnosing and understanding the mechanism of temporomandibular disorders (TMD). This prospective study evaluated a total of 160 healthy adult volunteers (77 males, 83 females). The stiffness values of anterior, intermediate and posterior parts of the TMJ disc and masseter muscle were measured. Study cohort was classified into four groups based on age. Additionally, we investigated the changes in mean shear wave elasticity (kPa) and shear wave velocity(m/s) values of disc parts and masseter muscle in closed and open mouth positions, and the correlation of these SWE values with age and gender. Mean stiffness values of the disc were 37.02 ± 23.75kPa and 3.28 ± 1.09m/s in the anterior part, 30.47 ± 18.89kPa and 2.97 ± 1.04m/s in the intermediate part, 22.61 ± 13.97kPa and 2.55 ± 0.88m/s in the posterior part. Stiffness values showed significant decrease in the posterior part compared to the rest of the disc both in males and females. No significant differences in mean stiffness values of masseter muscle related to mouth position, age or gender. This study provides the normative quantitative elasticity values of disc and masseter muscle which could be a reference point for upcoming studies. Disc elasticity values are higher in women than men. Maybe this is one of the reason why TMD is more common in women. TMJ disc stiffness was significantly lower in the posterior part. SWE is a useful imaging method that can be used with routine ultrasonography in evaluation of the TMJ disc and masticatory muscles .

Effectiveness of ultrasonography and shear wave sonoelastography in Sjögren syndrome with salivary gland involvement.

PurposeThis study investigated the effectiveness of major salivary gland ultrasonography (MSGUS) using a new grading system and shear wave elastography (SWE) in evaluating the major salivary glands of patients with Sjögren syndrome (SjS).MethodsThis prospectively-designed cross-sectional study included 49 SjS patients and 49 healthy controls. Major salivary glands were examined with gray-scale ultrasonography and SWE. A new grading system for salivary glands was developed using MSGUS findings. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of MSGUS and shear wave velocity (SWV) values were investigated. The MSGUS grading system and SWV values were evaluated together by logistic regression analysis. A cutoff value of SWE for salivary glands was determined.ResultsThe sensitivity, specificity, PPV, and NPV of MSGUS were 69.4%, 73.5%, 72.3%, and 70.6% for the submandibular gland and 69.4%, 65.3%, 66.7%, and 68.1% for the parotid gland, respectively. The mean SWV values of the parotid and submandibular glands were significantly higher in SjS patients than in controls (P<0.05). The sensitivity, specificity, PPV, and NPV for the submandibular gland (cutoff, 1.95 m/s) and the parotid gland (cutoff, 2.39 m/s) were 69.4%, 52%, 59.1%, and 63% and 82.7%, 83.7%, 83.5%, and 82.8%, respectively. Adding SWE to the parotid gland grading system increased the sensitivity and specificity (sensitivity, 82.7%; specificity, 83.7%).ConclusionEvaluating the salivary glands using MSGUS with a new grading system and SWE may contribute to the diagnosis of SjS. The combination of MSGUS and SWE may be a promising tool for diagnosing SjS.

Determining the effects of excess weight on renal cortical stiffness in children and adolescents with point Shear Wave Elastography.

To determine the early effects of excess weight on renal cortical stiffness in children and adolescents using point shear wave elastography (pSWE). One hundred and forty-six overweight and obese children (43.2% male; mean age, 12.6±2.9 years: range 4.3-18) and 48 lean children (27.1% male: mean age, 12.4±3.4: range 4.8-18.9) were included in the study and control group, respectively. pSWE measurements of the two kidneys were performed. The mean value of shear wave velocity was compared between groups. The mean shear wave velocity was 2.79±0.53 m/s for the control subjects and 3.09±0.59 m/s for the overweight-obese subjects. The differences between the two groups were sta-tistically significant (p=0.001). There was no correlation between shear wave velocity and age or depth. A positive correlation was found between shear wave velocity and body mass index, body mass index-standard deviation score. Renal cortical stiffness was higher in children with excess weight than in lean children. This study is the first attempt at applying pSWE to investigate the early adverse effects of excess weight.