Tissue Elasticity Measurement Research Articles

Diagnostic role of gray-scale and shear-wave elastography in pediatric patients with undescended testes: a prospective controlled study.

Ultrasound elastography is a simple non-invasive method for measuring tissue elasticity in relation to tissue fibrosis. The aim of this study was to compare echogenicity, volume and shear wave velocities of undescended vs normally descended testes. Sixty-six boys with undescended testes were included in this study. The median age range was 35.5 (10-118) months old. The cases included in this prospective study consisted of 66 patients with non-operated undescended testes, with 51 of them being affected unilaterally and 15 affected bilaterally, as diagnosed by physical examination. The control group consisted of 31 healthy boys without any particular health problems. This prospective study was performed by gray-scale ultrasonography and shear wave elastography in boys with undescended testes and healthy testes. The testicular volumes were established by ultrasound measurement, the echogenicity and shear wave elastography values were measured in boys with unilateral and bilateral undescended testes, and the results were compared with healthy boys' testes and their contralateral testes. The stiffness values were recorded for speed (m/s) and elasticity (kPa), and the stiffness values of undescended testes were compared with the healthy control group. Echogenicity values were lower in the bilateral undescended testes group than in the healthy group, and the healthy group's echogenicity was normal (p <0.001). The ROC curve was used to identify a cut-off shear wave elastography value for predicting decreased testicular echogenicity by using average shear wave elastography values. The area under the curve for the undescended testes was 0.78 (95% CI: 0.70-0.85, sensitivity 83.7%, specificity 68.7%, p <0.001), with an average shear wave elastography value of 2.32 (m/s) for above the cut-off point indicates. This was found to be significantly associated with reduced echogenicity on gray-scale ultrasonography, suggesting that it may be correlated with fibrosis developing in patients with undescended testes. The study provides interesting findings in that it proposes an alternative non-invasive method for the assessment of testicular tissue in undescended testes. We used shear wave elastography to compare the stiffness of normal testes in both heathy patients and in the contralateral healthy testes of boys with undescended testes, with the values obtained for the undescended testes reflecting the level of fibrosis of the parenchyma. Another outcome of this study was observed in patients with unilateral undescended testes, where the normally descended testes showed increased shear wave elastography values, which could be an early indication of parenchymal change.

Ultrasound shear wave speeds reduced following hamstring strain injury but not after returning to sport

ObjectivesThe purpose of the study was to investigate differences in ultrasound shear wave speed (SWS) between uninjured and injured limbs following hamstring strain injury (HSI) at time of injury (TOI), return to sport (RTS), and 12 weeks after RTS (12wks).MethodsThis observational, prospective, cross-sectional design included male and female collegiate athletes who sustained an HSI. SWS imaging was performed at TOI, RTS, and 12wks with magnetic resonance imaging. SWS maps were acquired by a musculoskeletal-trained sonographer at the injury location of the injured limb and location-matched on the contralateral limb. The average SWS from three 5 mm diameter Q-boxes on each limb were used for analysis. A linear mixed effects model was performed to determine differences in SWS between limbs across the study time points.ResultsSWS was lower in the injured limb compared to the contralateral limb at TOI (uninjured – injured limb difference: 0.23 [0.05, 0.41] m/s, p = 0.006). No between-limb differences in SWS were observed at RTS (0.15 [-0.05, 0.36] m/s, p = 0.23) or 12wks (-0.11 [-0.41, 0.18] m/s, p = 0.84).ConclusionsThe SWS in the injured limb of collegiate athletes after HSI was lower compared to the uninjured limb at TOI but not at RTS or 12 weeks after RTS.Critical relevance statementHamstring strain injury with structural disruption can be detected by lower injured limb shear wave speed compared to the uninjured limb. Lack of between-limb differences at return to sport may demonstrate changes consistent with healing. Shear wave speed may complement traditional ultrasound or MRI for monitoring muscle injury.Key points• Ultrasound shear wave speed can non-invasively measure tissue elasticity in muscle injury locations.• Injured limb time of injury shear wave speeds were lower versus uninjured limb but not thereafter.• Null return to sport shear wave speed differences may correspond to structural changes associated with healing.• Shear wave speed may provide quantitative measures for monitoring muscle elasticity during recovery.Graphical

Quantitative and qualitative evaluation of the masseter muscle by ultrasonography and correlation with whole body health status.

[Purpose] Ultrasonography can be used to non-invasively analyze any cross-section of the human body and to measure tissue elasticity, thickness, and brightness. This study was performed to examine the quantitative and qualitative changes in the masseter muscle at rest and at maximal occlusion, and to evaluate the relationship between these changes and the general health of the individual. [Participants and Methods] The study cohort comprised 30 healthy adults. Correlations between basic participant information (sex, age, height, body weight, body mass index, body fat, maximum bite force, handgrip strength, and tongue pressure) and masseter muscle ultrasonographic data were examined. [Results] Masseter muscle thickness was significantly greater in males than in females. Body weight and body mass index correlated positively with masseter muscle thickness. Body mass index and body fat percentage correlated positively with masseter muscle brightness. Tongue pressure correlated positively with handgrip strength. [Conclusion] Our analyses of muscle thickness and brightness suggest that ultrasonography may be useful in evaluating masseter muscle quantity and quality, and that the condition of the masseter muscle may correlate with the overall health status of the individual.

Evaluation of meniscal elasticity using shear wave elastography in obese children and adolescents: a preliminary cross-sectional study.

Musculoskeletal problems such as pain, joint pathology, increased risk of fracture, and the development of structural deformities are common in childhood obesity. Increased mechanical stress on the knee joint leads to degenerative changes in the cartilage and meniscus. Meniscal elasticity values increase in meniscal degeneration. Shear wave elastography (SWE) is an ultrasound-based imaging technique based on the principle of measuring tissue elasticity. We aimed to investigate the changes in meniscal stiffness and thickness that can be caused by obesity in children and adolescents using SWE. In this prospective cross-sectional study, the menisci of obese (n=44) and age- and sex-matched healthy weight (n=44) children and adolescents were assessed by SWE. Meniscal elasticity was measured in kPa on the coronal plane. Independent samples t-test was used to compare meniscal elasticity values between groups. Additionally, Pearson's correlation test was used to examine the relationships between elasticity values and age, height, weight, and body mass index (BMI). Meniscal elasticity values were significantly higher in the obese group than in the control group (P<0.001). In both groups, there was no significant difference in meniscal stiffness between the boys and girls or between the right and left sides. In the obese group, there were weak and moderate positive correlations between meniscal elasticity values and age, weight, and BMI (P<0.05). There was no significant difference in meniscal thickness between the obese and control groups. Meniscal stiffness is increased in obese children and adolescents.

Multi-Frequency 3D Shear Wave Absolute Vibro-Elastography (S-WAVE) System for the Prostate.

This article describes a novel system for quantitative and volumetric measurement of tissue elasticity in the prostate using simultaneous multi-frequency tissue excitation. Elasticity is computed by using a local frequency estimator to measure the three-dimensional local wavelengths of steady-state shear waves within the prostate gland. The shear wave is created using a mechanical voice coil shaker which transmits simultaneous multi-frequency vibrations transperineally. Radio frequency data is streamed directly from a BK Medical 8848 transrectal ultrasound transducer to an external computer where tissue displacement due to the excitation is measured using a speckle tracking algorithm. Bandpass sampling is used that eliminates the need for an ultra-fast frame rate to track the tissue motion and allows for accurate reconstruction at a sampling frequency that is below the Nyquist rate. A roll motor with computer control is used to rotate the transducer and obtain 3D data. Two commercially available phantoms were used to validate both the accuracy of the elasticity measurements as well as the functional feasibility of using the system for in vivo prostate imaging. The phantom measurements were compared with 3D Magnetic Resonance Elastography (MRE), where a high correlation of 96% was achieved. In addition, the system has been used in two separate clinical studies as a method for cancer identification. Qualitative and quantitative results of 11 patients from these clinical studies are presented here. Furthermore, an AUC of 0.87±0.12 was achieved for malignant vs. benign classification using a binary support vector machine classifier trained with data from the latest clinical study with leave one patient out cross-validation.

Ultrasound Elastography in Children.

Ultrasound elastography is a novel ultrasound technique, being extensively researched in children in the last decade. It measures tissue elasticity with the observation of tissue response after an external stimulus. From research to clinical practice, ultrasound elastography has evolved significantly in liver fibrosis evaluation in children; however, several other applications of the technique are available in both clinical practice and research environments. Practically, in children any organ can be assessed, including the brain in early ages, along with muscle and connective tissue elasticity evaluation, spleen, kidney, skin, lymphatic tissue, etc. The elastography method, age, body mass index and technical points should be considered when performing ultrasound elastography. This review highlights its vast potential as a diagnostic tool in the pediatric population, where ultrasound is a dominant imaging tool; however, the indications and exam protocol for its clinical use in several fields in pediatrics have yet to be elucidated.

Shear wave elastography correlates to degeneration and stiffness of the long head of the biceps tendon in patients undergoing tenodesis with arthroscopic shoulder surgery

Tendinopathy of the long head of the biceps (LHB) tendon causes degeneration and changes its stiffness. However, a reliable means of diagnosis has not been established. Shear wave elastography (SWE) provides quantitative tissue elasticity measurements. In this study, the relationship of preoperative SWE values with biomechanically measured stiffness and degeneration of the LHB tendon tissue was investigated. LHB tendons were obtained from 18 patients who underwent arthroscopic tenodesis. SWE values were measured preoperatively at 2 sites, proximal to and within the bicipital groove of the LHB tendon. The LHB tendons were detached immediately proximal to the fixed sites and at their superior labrum insertion. Tissue degeneration was histologically quantified using the modified Bonar score. Tendon stiffness was determined using a tensile testing machine. The SWE values of the LHB tendon were 502.1±113.6kPa proximal to the groove and 439.4±123.3kPa within the groove. The stiffness was 39.3±19.2N/mm. The SWE values displayed a moderate positive correlation with the stiffness proximal to the groove (r=0.80) and within it (r=0.72). The SWE value of the LHB tendon within the groove showed a moderate negative correlation with the modified Bonar score (r=-0.74). These findings suggest that preoperative SWE values of the LHB tendon correlate moderately positively with stiffness and moderately negatively with tissue degeneration. Therefore, SWE may predict LHB tendon tissue degeneration and changes in stiffness caused by tendinopathy.

Magnetomotive Ultrasound Shear Wave Elastography (MMUS-SWE): A Validation Study From Simulations to Experiments.

Ultrasound elastography is a functional imaging method that enables the measurement of soft tissue elasticity, which is associated with the pathological process of many diseases. However, the measurement area of the conventional elastography method is subjectively selected. Inspired by the targeted imaging technology, we propose a method of magnetomotive ultrasound shear wave elastography (MMUS-SWE). This method utilizes the magnetic force between the magnetic nanoparticles (MNPs) and the external magnetic field to generate shear waves. Then, it can detect the distribution of MNPs and the elasticity of the tissue around the MNPs. As MNPs have been widely used for targeted labeling, the strategy to induce local vibration by MNPs will be more specific than that of the conventional SWE. In this study, the theoretical feasibility was verified by the finite element simulation model. Then, an experimental system was built, and the experimental feasibility of the method was demonstrated through phantom experiments, in vitro tissue experiments, and in vivo experiments. The results show that the distribution of the MNPs and the elastic information of tissues surrounding the MNPs can be detected simultaneously. This technology is expected to realize targeted elasticity measurement based on the MNPs and has potential applications for disease diagnosis.

The diagnostic value of shear-wave elastography in the salivary glands of patients with primary Sjögren syndrome.

We aimed to quantify the extent of salivary gland fibrosis using shear-wave elastography (SWE) to assess its diagnostic value for primary Sjögren syndrome (pSS). A total of 58 pSS patients and 44 controls underwent SWE ultrasound evaluation of the parotid and submandibular glands. We measured the degree of salivary gland fibrosis in all participants and investigated the diagnostic accuracy of SWE for pSS and its relationship to disease progression. The diagnostic sensitivity, specificity, and accuracy of pSS were highest when the critical Young's modulus values of the parotid and submandibular glands were 18.4 and 15.9 kPa, respectively, effectively improving the diagnostic value of pSS. The area under the SWE curve of the submandibular gland was higher than that of the parotid gland (z = 2.292, P = 0.02), suggesting that the submandibular gland was damaged earlier. The mean parotid gland thickness of pSS patients was thicker than in healthy controls (mean ± standard deviation 2.5 ± 0.3 vs 2.4 ± 0.2, P = 0.013]. SWE had a 70.3% sensitivity for diagnosing pSS patients with a disease duration of 5 years, but this did not differ significantly from pSS patients with a longer disease duration. SWE is a valid diagnostic method for pSS. The degree of salivary gland fibrosis related to secretory function and pathological progression, and quantitative measurements of tissue elasticity provide objective criteria for predicting damage in pSS.

Liver and kidney ultrasound elastography in children and young adults with hypertension or chronic kidney disease.

Ultrasoundelastography is a research method increasingly used to measure tissue elasticity. The aim of the study was to assess its usability in pediatric patients with either chronic kidney disease (CKD)or hypertension. A total of 46 patients with CKD (group 1), 50 patients with hypertension (group 2), and 33 healthy participants as the control group were included. In all, we performed studies assessing their cardiovascular risk along with liver and kidney elastography. Liver elastography parameters were increased compared to those in the control group (1.49m/s, p = 0.007, in group 1 and 1.52m/s, p < 0.001, in group 2, vs. 1.41m/s among controls). Kidney elastography parameters were significantly higher in group 2 (1.9m/s, p = 0.001, and 1.9m/s, p = 0.003, in each kidney) when compared to group 1 (1.79m/s and 1.81m/s). Additionally, all participants were divided according to overweight/obesity and normal weight status, where both liver (1.53m/s vs. 1.45m/s, p < 0.001) and kidney parameters (1.96m/s and 1.92m/s vs. 1.81m/s and 1.84m/s, p = 0.002) were significantly higher in the group of overweight/obese subjects. Ultrasound elastography of the liver and kidney is feasible in pediatric patients with either CKD or hypertension, showing increased liver stiffness parameters in both groups, further aggravated by obesity. In obese patients with CKD, kidney stiffness also increased indicating a negative effect of clustering cardiovascular risk factors leading to decreased kidney elasticity. Further research is warranted. A higher resolution version of the Graphical abstract is available as Supplementary information.

Quantitative Tissue Elasticity Measurement of Human Cadaver Oesophagus by Using Vibrational Optical Coherence Elastography

The mechanical properties and structure alteration (e.g., layer morphology and thickness) of the oesophagus wall can reflect its pathological conditions. Hence, quantitative measurement of the above-mentioned properties can play a significant role in aiding the disease diagnosis in clinical application. As a fast and non-invasive imaging modality, Optical coherence tomography (OCT) and vibrational elastography can provide high resolution (&lt;10 µm) structural and mechanical mapping of soft tissue. This study is a preliminary study to explore the potential of OCT and VOCE to evaluate both structural and mechanical properties of the oesophagus wall. Jn total, 52 oesophageal tissue samples were acquired from seven human Thiel-embalmed cadavers and were examined by the vibrational OCE. Both the OCT structure image and quantitative elasticity of each sample layer were obtained. In the OCT structure image, the averaged thickness for each sample layer was measured and corresponded with the histological image. Lamina propria has the largest thickness of 158.14 ± 8.75 µm, submucosa is the thinnest with a thickness of 143.19 ± 10.11 µm, and the thickness of muscularis mucosa is 149.49 ± 10.85 µm. Averaged intensity of back-scattered light from each sample layer was evaluated. Intensity of lamina propria layer, muscularis mucosa layer, and submucosa layer have an average value of 79.27 ± 0.51 dB, 69.83 ± 0.56 dB, and 76.10 ± 0.55 dB, respectively. The quantitative elasticity of each sample layer was evaluated in OCE. Elasticity of the lamina propria layer, muscularis mucosa layer, and submucosa layer were estimated as 115.64 ± 8.80 kPa, 60.28 ± 5.27 kPa, and 205.25 ± 19.03 kPa, respectively. The quantitative elasticity results obtained by vibrational OCE corresponded with the collagen distribution trend in each sample layer. This study demonstrates the ability of OCT and vibrational OCE in the characterisation and quantitative evaluation of human cadaver oesophagus wall-structure properties and mechanical properties. The feasibility of applying OCT and vibrational OCE in clinical diagnosis of oesophageal disease is also discussed.

In Vivo Longitudinal Monitoring of Cardiac Remodeling in Murine Ischemia Models With Adaptive Bayesian Regularized Cardiac Strain Imaging: Validation Against Histology.

Adaptive Bayesian regularized cardiac strain imaging (ABR-CSI) uses raw radiofrequency signals to estimate myocardial wall contractility as a surrogate measure of relative tissue elasticity incorporating regularization in the Bayesian sense. We determined the feasibility of using ABR-CSI -derived strain for in vivo longitudinal monitoring of cardiac remodeling in a murine ischemic injury model (myocardial infarction [MI] and ischemia-reperfusion [IR]) and validated the findings against ground truth histology. We randomly stratified 30 BALB/CJ mice (17 females, 13 males, median age=10 wk) into three surgical groups (MI=10, IR=12, sham=8) and imaged pre-surgery (baseline) and 1, 2, 7 and 14 d post-surgery using a pre-clinical high-frequency ultrasound system (VisualSonics Vevo 2100). We then used ABR-CSI to estimate end-systolic and peak radial (er) and longitudinal (el) strain estimates. ABR-CSI was found to have the ability to serially monitor non-uniform cardiac remodeling associated with murine MI and IR non-invasively through temporal variation of strain estimates post-surgery. Furthermore, radial end-systole (ES) strain images and segmental strain curves exhibited improved discrimination among infarct, border and remote regions around the myocardium compared with longitudinal strain results. For example, the MI group had significantly lower (Friedman's with Bonferroni-Dunn test, p=0.002) ES er values in the anterior middle (infarcted) region at day 14 (n=9, 9.23 ± 7.39%) compared with the BL group (n=9, 44.32 ± 5.49). In contrast, anterior basal (remote region) mean ES er values did not differ significantly (non-significant Friedman's test, χ2=8.93, p=0.06) at day 14 (n=6, 33.05 ± 6.99%) compared with baseline (n=6, 34.02 ± 6.75%). Histology slides stained with Masson's trichrome (MT) together with a machine learning model (random forest classifier) were used to derive the ground truth cardiac fibrosis parameter termed histology percentage of myocardial fibrosis (PMF). Both radial and longitudinal strain were found to have strong statistically significant correlations with the PMF parameter. However, radial strain had a higher Spearman's correlation value (εresρ=-0.67, n=172, p < 0.001) compared with longitudinal strain (εlesρ=-0.60, n=172, p < 0.001). Overall, the results of this study indicate that ABR-CSI can reliably perform non-invasive detection of infarcted and remote myocardium in small animal studies.

Quantitative Assessment of Breast-Tumor Stiffness Using Shear-Wave Elastography Histograms.

Purpose: Shear-wave elastography (SWE) measures tissue elasticity using ultrasound waves. This study proposes a histogram-based SWE analysis to improve breast malignancy detection. Methods: N = 22/32 (patients/tumors) benign and n = 51/64 malignant breast tumors with histological ground truth. Colored SWE heatmaps were adjusted to a 0-180 kPa scale. Normalized, 250-binned RGB histograms were used as image descriptors based on skewness and area under curve (AUC). The histogram method was compared to conventional SWE metrics, such as (1) the qualitative 5-point scale classification and (2) average stiffness (SWEavg)/maximal tumor stiffness (SWEmax) within the tumor B-mode boundaries. Results: The SWEavg and SWEmax did not discriminate malignant lesions in this database, p &gt; 0.05, rank sum test. RGB histograms, however, differed between malignant and benign tumors, p &lt; 0.001, Kolmogorov-Smirnoff test. The AUC analysis of histograms revealed the reduction of soft-tissue components as a significant SWE biomarker (p = 0.03, rank sum). The diagnostic accuracy of the suggested method is still low (Se = 0.30 for Se = 0.90) and a subject for improvement in future studies. Conclusions: Histogram-based SWE quantitation improved the diagnostic accuracy for malignancy compared to conventional average SWE metrics. The sensitivity is a subject for improvement in future studies.

Practical Steps of Shear Wave Elastography for Nonalcoholic Fatty Liver Disease in an Adult Population

AbstractNonalcoholic fatty liver disease (NAFLD) is a growing epidemic worldwide and is widely prevalent in India with a community-based study in South India reporting a prevalence of 49.8%. Imaging modalities are used to screen for NAFLD, identify different stages of the disease from early to advanced stages, and to monitor the progress of the condition and responsiveness to therapy. Computed tomography and magnetic resonance imaging modalities are used to assess NAFLD but have limitations in availability and affordability. B-mode ultrasound provides a viable imaging alternative but only provides a gross assessment and the presence or absence of fibrosis. Shear wave elastography is a newer modality that allows for the measurement of tissue stiffness or elasticity in response to tissue deforming forces generated as shear waves. The changes in elasticity can usually be determined before obvious structural changes and can be used for early diagnosis of disease and to assess the progress of the condition. In this article, we present the practical steps to perform an ultrasound shear wave elastography for the assessment and staging of NAFLD.

Elastography as predictor for thyroid nodule malignancy

Background: Ultrasound elastography is a promising noninvasive technique that is still in its infancy. It uses tissue elasticity measurements to distinguish between benign (soft tissues) and malignant (hard tissues) nodules. Objectives: to see if elastography has diagnostic significance and if it may be used as a predictor of thyroid nodule malignancy Methods: An analytical cross-sectional study was done and data collected using Philips Epiq 7 linear transducer 8-12MHZ, strain type of elastography. A sample of 27 patients from Al-Hada Armed Forces Hospital, Taif, Saudi Arabia were included. Data about patients’ demographics, AP, TR, Echogenicity, Margin, Composition, Echogenic foci, FNA result, Elastography findings and TIRADs classification were collected. Results: According to FINA findings, the majority of patients (96.3 percent) had a benign tumour, and 81.5 percent had soft elastography. T2 was the most common TIRADs classification (55.6 percent). The percentage of patients with T2 (TIRADs) was significantly greater in patients with a younger mean age, and there was a non-significant association between TIRADs categorization and FINA findings. Females had a much higher percentage of benign diagnoses based on FINA results, with no significant link detected between FINA results and the demographic or clinical characteristics of the patients. Both TIRADs categorization and FINA results were shown to have no significant link with the elastography data. Conclusion: The elastography findings were found to have a non-significant link with both TIRADs categorization and FINA results. Future studies with larger samples should be conducted to clarify the study outcomes. Keywords: Elastography, predictor, thyroid, nodule, malignancy

Asynchronous magnetic resonance elastography: Shear wave speed reconstruction using noise correlation ofincoherent waves.

The noninvasive measurement of biological tissue elasticity is an evolving technology that enables the robust characterization of soft tissue mechanics for a wide array of biomedical engineering and clinical applications. We propose, design, and implement here a new MRI technique termed asynchronous magnetic resonance elastography (aMRE) that pushes the measurement technology toward a driverless implementation. This technique can be added to clinical MRI scanners without any additional specialized hardware. Asynchronous MRE is founded on the theory of diffuse wavefields and noise correlation previously developed in ultrasound to reconstruct shear wave speeds using seemingly incoherent wavefields. Unlike conventional elastography methods that solve an inverse problem, aMRE directly reconstructs a pixel-wise mapping of wave speed using the spatial-temporal statistics of the measured wavefield. Incoherent finger tapping served as the wave-generating source for all aMRE measurements. Asynchronous MRE was performed on a phantom using a Siemens Prismafit as an experimental validation of the theory. It was further performed on thigh muscles as a proof-of-concept implementation of in vivo imaging using a Siemens Skyra scanner. Numerical and phantom experiments show an accurate reconstruction of wave speeds from seemingly noisy wavefields. The proof-of-concept thigh experiments also show that the aMRE protocol can reconstruct a pixel-wise mapping of wave speeds. Asynchronous MRE is shown to accurately reconstruct shear wave speeds in phantom experiments and remains at the proof-of-concept stage for in vivo imaging. After further validation and improvements, it has the potential to lower both the technical and monetary barriers of entry to measuring tissue elasticity.

Point Shear Wave Elastography and 2-Dimensional Shear Wave Elastography as a Non-Invasive Method in Differentiating Benign from Malignant Liver Lesions

Non-invasive, ultrasound-based methods for visualizing and measuring tissue elasticity are becoming more and more common in routine daily practice. An accurate diagnosis of malignant and benign tumors is essential for determining the appropriate treatment. Despite the wide use of imaging techniques, the investigation for assessing the elasticity of focal liver lesions and their differentiating is still continuing. Aim: To investigate the value of point shear wave elastography (pSWE) and two-dimensional shear wave elastography (2D-SWE) for the differential diagnosis of benign and malignant focal liver lesions. Materials and Methods: A total of 125 adult patients were included from the Clinic of Gastroenterology of University Hospital Kaspela, Plovdiv city, Bulgaria, in the period from January 2021 to July 2022. Participants were divided into two groups—with benign (hemangiomas) and malignant focal liver lesions (hepatocellular carcinoma). The group with benign lesions included 63 patients and the group with malignant focal liver lesions (FLLs)—62 patients. Point shear wave elastography (pSWE) and two-dimensional shear wave elastography (2D-SWE) integrated in the same ultrasound machine (Esaote MyLab™ 9Exp) were performed for each lesion. Results: Malignant FLLs have significantly higher stiffness in both pSWE (2.52–4.32 m/s, 90% CI: 2.37 to 2.68, 90% CI: 4.19 to 4.55) and 2d-SWE (2.52–4.43 m/s, 90% CI: 2.31 to 2.65, 90% CI: 4.27 to 4.61). Conclusion: 2D-SWE and pSWE could provide complementary data about FLLs. They enable us to conveniently and easily obtain accurate stiffness information of FLLs.

A Dual-Modal Imaging Method Combining Ultrasound and Electromagnetism for Simultaneous Measurement of Tissue Elasticity and Electrical Conductivity.

The mechanical and electrical properties of soft tissues are relative to soft tissues' pathological state. Modern medical imaging devices have shown a trend to multi-modal imaging, which will provide complementary functional information to improve the accuracy of disease diagnosis. However, no method or system can simultaneously measure the mechanical and electrical properties of the soft tissue. In this study, we proposed a novel dual-modal imaging method integrated by shear wave elasticity imaging (SWEI) and Magneto-acousto-electrical tomography (MAET) to measure soft tissue's elasticity and conductivity simultaneously. A dual-modal imaging system based on a linear array transducer is built, and the imaging performances of MAET and SWEI were respectively evaluated by phantoms experiment and in vitro experiment. Conductivity phantom experiments show that the MAET in this dual-modal system can image conductivity gradient as low as 0.4 S/m. The phantom experiments show that the reconstructed 2-D elasticity maps of the phantoms with inclusions with a diameter larger than 5 mm are relatively accurate. In vitro experiments show that the elasticity parameter can significantly distinguish the changes in tissue before and after heating. This study first proposes a method that can simultaneously obtain tissue elasticity and electrical conductivity to the best of our knowledge. Although this paper just carried out the proof of concept experiments of the new method, it demonstrates great potential for disease diagnosis in the future.

Lower Limb Lipedema-Superficial Lymph Flow, Skin Water Concentration, Skin and Subcutaneous Tissue Elasticity.

Background: Lipedema of lower limbs is characterized by bilateral accumulations of excess adipose tissue starting from the ankle to the hips and buttocks. The studies with lymphoscintigraphy (LSC) and magnetic resonance (MR) lymphography show altered transport index and enlarged lymphatic vessels (LVs). Our studies aimed to investigate the superficial lymph flow, water accumulation, skin and subcutaneous tissue elasticity, and the possibility of using this information to diagnose lipedema. Methods and Results: Fifty patients with lipedema and 50 control subjects (women) were included. The Indocyanine Green (ICG) lymphography, LSC, skin water measurement, skin durometry, and deep tissue tonometry were done in all participants. ICG lymphography revealed: (1) Slower lymph flow in lipedema patients; after 3 minutes of feet movement in a horizontal position, the ICG-dyed lymph reached the upper calf level in 8% of lipedema patients compared with 56% in the control group (p ˂ 0.0001). (2) More than three LVs were noticed more often in lipedema patients. (3) The higher number of abnormal LV images at all limb levels and during each observation stage with a statistically significant number of foggy and dilated. (4) Statistically significant higher fluorescent intensity in all limb levels. Skin water concentration was higher in the feet in lipedema (p = 0.000189). Conclusion: Our studies have shown the differences in superficial lymph flow and water concentration between lipedema and normal limbs. Data proove the usefulness of ICG lymphography, skin water concentration and skin and subcutaneous tissue elasticity measurements in diagnosing lipedema.

High-Frequency Ultrasound Elastography for Assessing Elastic Properties of Skin and Scars.

Scars are a type of fibrous tissue that typically forms during the wound healing process to replace damaged skin. Because studies have indicated a high correlation between scar stiffness and clinical symptoms, assessing the mechanical properties of scar is crucial for determining an appropriate treatment strategy and evaluating the treatment's efficacy. Shear wave elastography (SWE) is a common technique for measuring tissue elasticity. Because scars are typically a few millimeters thick, they are thin-layer tissues, and therefore, the dispersion effect must be considered to accurately estimate their elasticity. In this study, high-frequency ultrasound (HFUS) elastography was proposed for estimating the elastic properties of scars by using the Lamb wave model (LWM). An external vibrator was used to generate elastic waves in scar tissue and skin, and the propagation of the elastic waves was tracked through 40-MHz ultrafast ultrasound imaging. The elasticity was estimated through shear wave models (SWMs) and LWMs. The effectiveness of using HFUS elastography was verified through phantom and human studies. The phantom experiments involved bulk phantoms with gelatin concentrations of 7% and 15% and 2-4-mm-thick thin-layer 15% gelatin phantoms. The studies of three patients with eight cases of scarring were also conducted. The phantom experimental results demonstrated that the elasticity estimation biases for the thin-layer mediums were approximately -36% to -50% and 3% to -9% in the SWMs and LWMs, respectively, and the estimated shear moduli were 12.8 ± 5.4 kPa and 74.8 ± 26.8 kPa for healthy skin and scar tissue, respectively. All the results demonstrated that the proposed HFUS elastography has a great potential for improving the accuracy of elasticity estimations in clinical dermatological diagnoses.