Principles of ultrasound elastography

Elastography and Applications in the Musculoskeletal System in Veterinary Medicine: From Physical Basis to Image Formation

Musculoskeletal ultrasound is a versatile imaging technique, surpassing conventional radiographic examinations in detecting certain alterations in the musculoskeletal system and showing effectiveness comparable to magnetic resonance imaging in assessing articular and periarticular soft tissues. The objective of this review is to discuss the physical principles of ultrasound elastography and its applications in the musculoskeletal system of veterinary medicine. This bibliographic review compiles relevant studies exploring elastography's physical basis, its technological development, and its clinical applications in veterinary contexts. Elastography complements B-mode ultrasound by assessing tissue stiffness, offering unique diagnostic insights beyond acoustic impedance and flow properties. Studies have demonstrated the potential of elastography in evaluating tendon injuries, muscle disorders, and bone healing, with promising results in dogs, horses and experimental models like sheep. Techniques such as compression elastography and shear wave elastography provide qualitative and quantitative data, enhancing the assessment of pathological changes. Shear wave elastography enables precise measurements of tissue elasticity, aiding the diagnosis, monitoring of healing and evaluation of therapeutic interventions. Despite technical challenges, elastography is a valuable tool that can optimize musculoskeletal diagnostics and treatment planning. Its expanding use in veterinary medicine underscores its clinical relevance and potential for widespread adoption as a complementary imaging modality.

Placental elasticity in trisomy 21: prenatal assessment with shear-wave elastography

OBJECTIVES

To quantitatively examine placental tissue elasticity in Trisomy 21 (T21) pregnancies using shear wave elastography (SWE) and to evaluate the potential contribution of placental SWE measurements in predicting T21 fetuses.

METHODS

This prospective case-control study was conducted at tertiary centers between January 2022 and January 2024. The study included 30 pregnant women who underwent invasive prenatal diagnostic testing and were found to have T21, along with 30 pregnant women with a normal karyotype. Central placental elasticity measurements were performed from the middle of the thickest part of the placenta, avoiding vascular areas and lacunae, and peripheral measurements were performed two centimeter (cm) medial to the lateral border of the placenta.

RESULTS

The mean gestational week at measurement was 16 ± 2 weeks. Peripheral placental SWE velocity was significantly higher in the T21 group (7.4 ± 3.7 kPa vs. 4.8 ± 3.6 kPa, p=0.004). Similarly, central placental SWE velocity was also significantly higher in the T21 group (6.5 ± 2.1 kPa vs. 4.1 ± 2.6 kPa, p<0.001). In predicting T21, central placental SWE velocity had 76.7 % sensitivity and 73.3 % specificity with a cut-off value of ≥4.35 kPa (p<0.001), and peripheral had 70 % sensitivity and 66.7 % specificity with a cut-off value of ≥4.65 kPa (p=0.004). When central placental SWE velocity was ≥4.35 kPa, the risk of T21 was increased 6.64-fold, even after adjusting for maternal age, which is a well-known risk factor for T21.

CONCLUSIONS

Placental stiffness was significantly higher in T21 in both central and peripheral areas. Placental elasticity, especially in the central part, may be a potential marker for T21.

The pulsing brain: state of the art and an interdisciplinary perspective

Understanding the pulsing dynamics of tissue and fluids in the intracranial environment is an evolving research theme aimed at gaining new insights into brain physiology and disease progression. This article provides an overview of related research in magnetic resonance imaging, ultrasound medical diagnostics and mathematical modelling of biological tissues and fluids. It highlights recent developments, illustrates current research goals and emphasizes the importance of collaboration between these fields.

Ultrasound innovations in abdominal radiology: techniques and clinical applications in pediatric imaging

Contrast-enhanced ultrasound, microvascular imaging, elastography, and fat quantification have varying degrees of utility, with some applications in the pediatric setting mirroring that in adults and having unique uses when applied to children in others. This review will present novel ultrasound technologies and the clinical context in which they are applied to the pediatric abdomen. New ultrasound technologies have a broad range of applications in clinical practice and represent a powerful diagnostic tool with the potential to replace other imaging modalities, such as magnetic resonance imaging and computed tomography, in specific cases.

Elastography in Reproductive Medicine, a Game-Changer for Diagnosing Polycystic Ovary Syndrome, Predicting Intrauterine Insemination Success, and Enhancing In Vitro Fertilization Outcomes: A Systematic Review

Background: Elastography is an ultrasound-based imaging technology that allows for quantitative measurement of tissue stiffness and elasticity. In reproductive medicine, it is a potential non-invasive method for assessing ovarian activity, uterine contractility, and endometrial receptivity. While conventional ultrasound provides anatomical and vascular information, it does not assess biomechanical properties, which are important for understanding polycystic ovary syndrome (PCOS), predicting intrauterine insemination (IUI) success, and determining endometrial receptivity in in vitro fertilization (IVF). Methods: A systematic review was conducted in accordance with the PRISMA principles, and the protocol was recorded in PROSPERO. A comprehensive literature search was conducted across several databases to uncover studies that used real-time elastography (RTE) or shear wave elastography (SWE) for PCOS diagnosis, IUI result prediction, or endometrial receptivity evaluation in IVF. The risk of bias was assessed using the ROBINS-I technique. Results: Four studies fulfilled the inclusion criteria. One study indicated that PCOS patients had considerably increased ovarian stiffness, which supports elastography as a diagnostic marker. Another study found that increased uterine flexibility and decreased contractility were related with better IUI outcomes. A retrospective cohort research discovered that non-uniform endometrial echogenicity had no influence on IVF results. Furthermore, SWE successfully evaluated endometrial receptivity in unexplained infertility, with higher stiffness being related to reduced implantation potential. Conclusions: Elastography gives real-time, quantitative insights into reproductive biomechanics, with potential applications in infertility diagnosis and ART improvement. However, the absence of defined imaging procedures and confirmed clinical criteria prevent its broad use. More large-scale prospective investigations are required to improve elastographic parameters and define diagnostic cutoffs for clinical use.

Extracellular Matrix Stiffness: Mechanotransduction and Mechanobiological Response-Driven Strategies for Biomedical Applications Targeting Fibroblast Inflammation

The extracellular matrix (ECM) is a dynamic network providing mechanical and biochemical cues that regulate cellular behavior. ECM stiffness critically influences fibroblasts, the primary ECM producers, particularly in inflammation and fibrosis. This review explores the role of ECM stiffness in fibroblast-driven inflammation and tissue remodeling, focusing on the physicochemical and biological mechanisms involved. Engineered materials, hydrogels, and polydimethylsiloxane (PDMS) are highlighted for replicating tissue-specific stiffness, enabling precise control over cell-matrix interactions. The surface functionalization of substrate materials, including collagen, polydopamine, and fibronectin, enhances bioactivity and fibroblast adhesion. Key mechanotransduction pathways, such as integrin signaling and YAP/TAZ activation, are related to regulating fibroblast behaviors and inflammatory responses. The role of fibroblasts in driving chronic inflammatory diseases emphasizes their therapeutic potentials. Advances in ECM-modifying strategies, including tunable biomaterials and hydrogel-based therapies, are explored for applications in tissue engineering, drug delivery, anti-inflammatory treatments, and diagnostic tools for the accurate diagnosis and prognosis of ECM stiffness-related inflammatory diseases. This review integrates mechanobiology with biomedical innovations, providing a comprehensive prognosis of fibroblast responses to ECM stiffness and outlining future directions for targeted therapies.

Utilization of lymph node elastography in the axillary staging of breast cancer

Background

The differential diagnosis of lymphadenopathy is an important determinant of prognosis in patients with breast cancer (BC). Invasive, fine needle aspiration (FNA) biopsy has been long considered as the gold standard for differentiating malignant lymph nodes (LN) from benign ones. Ultrasonography (USG) evaluation is a useful, rapid, and user-friendly imaging tool for LN assessment due to its high resolution. Compared to USG, ultrasound elastography is a relatively novel non-invasive method to differentiate benign and malignant lesions based on the stiffness heterogeneity of the tissue. The purpose of our study was to compare non-invasive imaging techniques, conventional USG, and strain elastography, to differentiate benign and malignant LNs lesions in a cohort of patients with early BC.

Methods

In total, 50 patients (48 women and 2 men) with histologically confirmed early BC were evaluated by conventional USG in B-mode followed by strain elastography (using parameters: pattern, strain ratio, hue histogram) for assessment of axillary LNs status. The surgical treatment included surgery of regional LNs (sentinel LN biopsy or axillary dissection), which served as the gold standard in statistical processing.

Results

The USG B-mode was found to have a sensitivity of 68.75% and a specificity of 61.54%. Among strain elastography parameters, the elastographic pattern showed the highest specificity (66.67%) while the sensitivity was 83.3%. The strain ratio showed 100% sensitivity and 55.6% specificity, followed by a hue histogram with a sensitivity of 72.2%, but specificity was only 25.9%.

Conclusion

Despite promising data, monitored parameters currently cannot reliably replace sentinel LN biopsy. However, the monitored parameters represent an appropriate additional tool that can be used to refine preoperative staging, better targeting of FNA biopsy, and more accurate assessment of LNs in follow-up patients within the dispensary.

A finite element analysis model for magnetomotive ultrasound elastometry magnet design with experimental validation

Objective. Magnetomotive ultrasound (MMUS) using magnetic nanoparticle contrast agents has shown promise for thrombosis imaging and quantitative elastometry via magnetomotive resonant acoustic spectroscopy (MRAS). Young's modulus measurements of smaller, stiffer thrombi require an MRAS system capable of generating forces at higher temporal frequencies. Solenoids with fewer turns, and thus less inductance, could improve high frequency performance, but the reduced force may compromise results. In this work, a computational model capable of assessing the effectiveness of MRAS elastometry magnet configurations is presented and validated.Approach. Finite element analysis (FEA) was used to model the force and inductance of MRAS systems. The simulations incorporated both solenoid electromagnets and permanent magnets in three-dimensional steady-state, frequency domain, and time domain studies.Main results. The model successfully predicted that a configuration in which permanent magnets were added to an existing MRAS system could be used to increase the force supplied. Accordingly, the displacement measured in a magnetically labeled validation phantom increased by a factor of 2.2 ± 0.3 when the force was predicted to increase by a factor of 2.2 ± 0.2. The model additionally identified a new solenoid configuration consisting of four smaller coils capable of providing sufficient force at higher driving frequencies.Significance. These results indicate two methods by which MRAS systems could be designed to deliver higher frequency magnetic forces without the need for experimental trial and error. Either the number of turns within each solenoid could be reduced while permanent magnets are added at precise locations, or a larger number of smaller solenoids could be used. These findings overcome a key challenge toward the goal of MMUS thrombosis elastometry, and simulation files are provided online for broader experimentation.

Assessment of skin fibrosis in a murine model of systemic sclerosis with multifunctional optical coherence tomography

Significance

Systemic sclerosis (SSc) is a chronic idiopathic disease that causes immune dysregulation, vasculopathy, and organ fibrosis that affects more than 3 million people in the US alone. The modified Rodnan skin score (mRSS) is the current gold standard for diagnosing and staging skin fibrosis in SSc. However, mRSS is subjective, requires extensive training, and has high observer variability.

Aim

We aim to provide a quantitative method for the assessment of fibrosis.

Approach

We utilized optical coherence tomography (OCT), its extensions, optical coherence elastography (OCE), and OCT angiography (OCTA) to evaluate SSc-like fibrosis and therapy response in a mouse model.

Results

We showed stiffness differences between fibrotic and normal mouse skin by week 4 ( p = 0.02 ) during the longitudinal study. In the treatment response study, OCE recorded higher elastic wave velocity in untreated fibrotic skin ( p = 0.04 ). Treated fibrotic skin stiffness was between normal and fibrotic levels. OCTA indicated significantly dilated microvasculature in fibrotic skin versus control ( p ≪ 0.01 ), with more dilation in the treatment group ( p ≪ 0.01 ) than in normal skin.

Conclusions

Our results indicate that OCT and its extensions effectively analyze dermal fibrosis. OCE revealed increased stiffness in fibrotic skin, OCTA showed vessel dilation, and OCT noted morphological changes in fibrosis tissue.

A review of multiparametric ultrasound imaging in the clinical setting: scrotal contents

The innovative techniques in ultrasound have added a new dimension to investigating superficially located areas such as the contents of the scrotal sac. High frequency transducers, improved technology with the addition of elastography, contrast enhanced ultrasound and microvascular imaging has resulted in a further improvement in diagnostic capabilities. The ability to clearly demonstrate the presence or absence of vascularity within the area under investigation adds an additional dimension to operator confidence in establishing the presence of infarction, global or segmental, or the walls and cavity of an abscess in the testis or epididymis. Increased vascularity of a tumor aids the differential diagnosis based on the flow dynamics of the microbubble contrast, benign lesions likely to retain contrast. Elastography has the ability to ascertain the stiffness of tissue, and when used in conjunction with other ultrasound methods adds to the understanding of the likelihood of a malignant abnormality being present. All the different techniques come under the umbrella term 'multiparametric ultrasound', with the application in the scrotal sac detailed in this article.

A Finite Element Analysis Model for Magnetomotive Ultrasound Elastometry Magnet Design with Experimental Validation

Objective

Magnetomotive ultrasound (MMUS) using magnetic nanoparticle contrast agents has shown promise for thrombosis imaging and quantitative elastometry via magnetomotive resonant acoustic spectroscopy (MRAS). Young's modulus measurements of smaller, stiffer thrombi require an MRAS system capable of generating forces at higher temporal frequencies. Solenoids with fewer turns, and thus less inductance, could improve high frequency performance, but the reduced force may compromise results. In this work, a computational model capable of assessing the effectiveness of MRAS elastometry magnet configurations is presented and validated.

Approach

Finite element analysis (FEA) was used to model the force and inductance of MRAS systems. The simulations incorporated both solenoid electromagnets and permanent magnets in three-dimensional steady-state, frequency domain, and time domain studies.

Main results

The model successfully predicted that a configuration in which permanent magnets were added to an existing MRAS system could be used to increase the force supplied. Accordingly, the displacement measured in a magnetically labeled validation phantom increased by a factor of 2.2 ± 0.3 when the force was predicted to increase by a factor of 2.2 ± 0.2. The model additionally identified a new solenoid configuration consisting of four smaller coils capable of providing sufficient force at higher driving frequencies.

Significance

These results indicate two methods by which MRAS systems could be designed to deliver higher frequency magnetic forces without the need for experimental trial and error. Either the number of turns within each solenoid could be reduced while permanent magnets are added at precise locations, or a larger number of smaller solenoids could be used. These findings overcome a key challenge toward the goal of MMUS thrombosis elastometry, and simulation files are provided online for broader experimentation.

Comparison Between Strain and 2D Shear Wave Elastography of Testes in Healthy Dogs

Sonoelastography is a rapid and non-invasive ultrasound-based technique to assess tissue elasticity. Interest in this technique's application in veterinary medicine is progressively increasing, with preliminary reports also available to assess canine testicular parenchyma abnormalities. Since elastographic techniques are different and it is of paramount importance to standardize procedures, this work aimed to compare two different elastographic techniques, SE and 2D SWE, on the same testes and compare the data with the current literature. Thirty healthy canine testes were included, and complete B-mode, color and power Doppler examinations were performed on each one. SE was performed qualitatively through an elastogram evaluation and semiquantitatively comparing the parenchyma with peripheral skin. 2D SWE was performed and m/s measurements were taken. Each measurement was collected in the cranial, middle and caudal portions, considering the sections above and below the mediastinum separately. The healthy testes appeared to be intermediate in stiffness with differences in the various portions for SE and expressed a mean value from 1.3 m/s to 1.4 m/s for 2D SWE, consistent with the previous literature. Considering the technical specifics of the software for the two elastography methods, both of them are valuable in assessing canine testis stiffness and are potentially clinically appliable.

Evaluation of Usability and Efficacy of Strain Elastography Method Concurrently with Preoperative Ultrasonography in Cases of Hydatid Cyst

Background

Hydatid cysts (HCs), which are among the cystic lesions of the liver, are frequently encountered in endemic areas. Routine imaging modalities are sometimes insufficient to differentiate HC types, and ultrasound (US) elastography has just begun to be used for this purpose. In this study, the effectiveness of the strain elastography (SE) method in preoperative HC cases was investigated, and the relationship between HC types and elastography values was evaluated.

Methods

HC cases that underwent SE simultaneously with preoperative US between January 2019 and February 2021 were evaluated retrospectively, and 75 cases were included in the study. In addition to elastography data, cyst typing according to the World Health Organization (WHO) classification was also available.

Results

Thirty cases were male and 45 cases were female, the median age was 48 years, and the interquartile range was 41 years. According to the WHO classification, 15 cases were Type I, 27 cases were Type II, and 33 cases were Type III HC. Median strain ratio (SR) values were 5.69 (4.07-14.47) for Type I, median 1.49 (1.26-1.74) for Type II, and median 0.21 (0.13-0.30) for Type III, and there was a highly significant relationship between HC types and SR values (P < 0.001). There was also a very strong (-) directional correlation between HC type and strain rate (P < 0.001, Spemann rho (ρ): -0.928).

Conclusion

US elastography is a new modality in the diagnosis of HC types, and there are few studies available. In this study, unlike the literature, it is the first time that HC typing and discrimination have been used using the SE technique, which is remarkable.

Two-Dimensional Shear-Wave Elastography: Accuracy in Liver Fibrosis Staging Using Magnetic Resonance Elastography as the Reference Standard

Background: The accurate staging of liver fibrosis is crucial for managing chronic liver disease (CLD). Although magnetic resonance elastography (MRE) is the reference standard for noninvasive fibrosis assessment, its cost, specialized hardware, and operational demands restrict accessibility. In contrast, two-dimensional shear-wave elastography (2D-SWE) is more affordable, accessible, and widely integrated into routine ultrasound systems. Objective: Our aim was to determine the optimal 2D-SWE cut-offs for detecting significant fibrosis (≥F2) and evaluate its diagnostic performance across fibrosis stages. Methods: In this prospective study, 71 patients with suspected CLD underwent same-day MRE and 2D-SWE. MRE-defined cut-offs categorized fibrosis stages (≥3.5 kPa for significant fibrosis). Sensitivity, specificity, area under the receiver operating characteristic curve (AUROC), and likelihood ratios were calculated for various 2D-SWE thresholds. Results: At a 2D-SWE cut-off of 7.0 kPa, sensitivity for detecting ≥F2 fibrosis was 100% with a specificity of 85.7% and a positive likelihood ratio (LR+) of 7.0. Increasing the threshold to 8.0 kPa improved specificity to 91.8% while maintaining a sensitivity of 86.4% and achieving an AUROC of 0.89. For cirrhosis, a cut-off of 11.0 kPa achieved 100% sensitivity and 96.9% specificity. A 5.0 kPa cut-off reliably excluded abnormal stiffness with 89.1% sensitivity. Conclusions: Two-dimensional SWE is a reliable method for staging liver fibrosis. Thresholds of 7.0 kPa for screening significant fibrosis, 8.0 kPa for confirmation, and 11.0 kPa for diagnosing cirrhosis demonstrate high diagnostic accuracy. A 5.0 kPa cut-off effectively excludes abnormal liver stiffness.

The diagnostic value of two-dimensional ultrasound Su-RADS combined with shear wave elastography for benign and malignant lesions of the gastric wall

OBJECTIVE

This study explored the value of stomach ultrasound reporting and data system (Su-RADS) and two-dimensional shear wave elastography (2D-SWE) in the diagnosis of benign and malignant lesions of the gastric wall, evaluating the feasibility of combining the two methods for the diagnosis of gastric wall lesions.

METHODS

113 patients with gastric wall lesions were examined after oral gastric ultrasound contrast agent, and the grades of the gastric wall lesions were classified according to Su-RADS. Moreover, 2D-SWE was performed to measure the E value of the lesions. ROC curves were constructed to evaluate the diagnostic efficacy of Su-RADS, 2D-SWE and their combination for gastric wall lesions.

RESULTS

The cutoff values for Emean and Emax were 8.01 kPa and 11.08 kPa, respectively. The sensitivity and specificity of 2D-SWE were 70.59%, 93.67% and 85.69%, 88.61%, respectively. The diagnostic sensitivity and specificity of Su-RADS were 91.18% and 82.28%, respectively. The AUC of combination of two methods was 0.951, which was greater than that of Su-RADS (0.940) or 2D-SWE alone (0.853, 0.903), and the sensitivity and specificity were 82.35% and 94.94%. The sensitivity and specificity of the combination of the two methods for the diagnosis of malignant gastric lesions were 82.35% and 94.94%, respectively. The AUC was 0.951, and the Youden index was 0.8064. The DeLong test was used to determine the AUC between the combination of two methods and 2D-SWE was P < 0.05.

CONCLUSION

Compared with Su-RADS or 2D-SWE alone, the combination of the two methods is more effective at diagnosing of gastric wall.And improved the specificity in the diagnosis of gastric wall lesions.

Can Multiparametric Ultrasound Analysis Predict Malignancy in Testes? An 11-Year Single Center Experience with Testicular Masses

Introduction/Objective: Contrast-enhanced ultrasound (CEUS) is a promising modality for differentiating benign and malignant lesions in various organs, including the testis. Testicular tumors, common in young men, are often treated with radical orchiectomy, which can have significant consequences. This study aimed to analyze CEUS parameters and their association with malignant testicular tumors. Materials and Methods: Between May 2009 and September 2020, 342 patients with suspected testicular lesions underwent CEUS at a tertiary referral center. Multiparametric ultrasound, including B-mode, Color Doppler, CEUS, and elastography, was performed. Exclusion criteria were the absence of a testicular lesion in the CEUS examination. Histological results, CEUS parameters, and elastography data were analyzed, and statistical correlations were evaluated using chi-square and Mann-Whitney U tests, with multivariate logistic regression for significant findings. Results: Of the 342 patients, 114 (33.3%) had suspicious CEUS findings, and 84 underwent surgical exploration. Malignancy was confirmed in 48 cases (57.1%). The sensitivity and specificity of CEUS for detecting malignancy were 93.8% and 85.2%, respectively. Contrast enhancement was observed in 93.3% of malignant tumors, but not statistically significant compared to benign lesions (p = 0.107). However, elastography revealed higher tissue stiffness in 77.8% of malignant tumors versus 41.0% in benign lesions (p = 0.009). Multivariate analysis indicated that tissue stiffness was significantly associated with malignancy (HR 8.29, 95%CI 1.26-54.58, p = 0.028). Conclusions: CEUS is a valuable tool for testicular lesion evaluation, with elastography showing strong potential in predicting malignancy through tissue stiffness. However, contrast enhancement and "wash-in/-out" were not reliable malignancy indicators. Further research is needed to standardize CEUS and elastography techniques for routine clinical use.

Two-Dimensional and Point Shear-Wave Elastography to Predict Esophageal Varices and Clinically Significant Portal Hypertension in Patients with Chronic Liver Disease

Introduction: The non-invasive assessment of disease severity remains pivotal in patients with chronic liver disease (CLD) as it has wide implications in predicting liver-related complications or death. Shear-wave elastography (SWE) is an emerging ultrasound-based method to non-invasively measure liver stiffness. The aim of our study was to evaluate two-dimensional (2D) and point (p) SWE to predict the presence of esophageal varices (EV) or clinically significant portal hypertension (CSPH). Methods: This was a retrospective analysis of a prospectively performed cohort study of patients with CLD treated in the outpatient clinic of the Frankfurt University Hospital. PSWE using the Hitachi HI Vision ASCENDUS system and the Siemens ACUSON S2000TM system or 2D-SWE using the Toshiba APLIO500 system were analyzed at baseline and during follow-up to predict EV or surrogate parameters of CSPH. ROC curves were calculated for pooled liver stiffness measurements (LSMs) using a bootstrap approach. A combined model of SWE and platelet count was created and a mixed-effect logistic regression analysis using log-transformed values was performed. Results: Overall, 511 patients with CLD and 919 consecutive LSMs were included and 315 patients (61.6%) had signs of CSPH. 2D-SWE performed best to predict EV and CSPH, and the addition of platelet count to the predictive model significantly increased test results for EV (AUC 0.83, 95%-CI: 0.76-0.89; difference in AUC 0.11, 95%-CI: 0.03-0.19, p = 0.004), but only marginally for CSPH (AUC 0.75, 95%-CI: 0.64-0.85; difference in AUC 0.06, 95%-CI: 0.02-0.14, p = 0.150). LSM > 18.5 and >20 kPa were indicative of CSPH and EV, while LSM < 10 kPa and <11 kPa ruled out CSPH and EV, respectively. Conclusions: Our study found that 2D-SWE in combination with platelet count performed best (in comparison to the other SWE methods) to predict EV or CSPH in patients with CLD. Future prospective trials are needed to validate our results.

Soft tissue elasticity at teeth and implant sites. A novel outcome measure of the soft tissue phenotype

AIM

To assess ultrasonographic tissue elasticity at teeth and implant sites and its variation after peri-implant soft tissue augmentation with a connective tissue graft (CTG).

METHODS

Twenty-eight patients, each contributing with one clinically healthy dental implant exhibiting a soft tissue dehiscence (PSTD), were included. Implant sites were augmented with CTG and monitored over 12 months. Ultrasonographic strain elastography, expressed as strain ratios (SR1, SR2, and SR3, respectively) was assessed at baseline, 6-, and 12-month, and compared with the corresponding contralateral homologous natural tooth. SR1 assessed the strain/elasticity of the midfacial coronal portion of the soft tissue in comparison to the natural tooth crown/implant-supported crown, SR2 evaluated the strain of the midfacial coronal soft tissue in relation to the one of the alveolar mucosa, while SR3 depicted the strain of the midfacial soft tissue in relation to the interproximal soft tissue on the transverse ultrasound scan.

RESULTS

SR1 in natural dentition and at implant sites was 0.20 ± 0.08 and 0.30 ± 0.14, respectively (p = .002), indicating that the coronal portion of the soft tissue around teeth is generally more elastic than its counterpart around dental implants. Soft tissue augmentation with CTG promoted an increased stiffness of the midfacial coronal portion of the soft tissue over 12 months (p < .001 for SR1, SR2, and SR3). Strain ratios at the 12-month time points were significantly higher than the values observed at 6 months (p < .001). Regression analysis demonstrated that strain elastography ratios in natural dentition were significantly associated with keratinized gingiva width, and gingival thickness. At implant sites, SR1 was significantly associated with keratinized mucosa width and mucosal thickness (p < .001 for both correlations), SR2 was significantly associated with keratinized mucosa width (p = .013), and SR3 was significantly associated with the surgical technique performed in combination with CTG (p = .022).

CONCLUSION

Ultrasound strain elastography captures and quantifies tissue elasticity and its changes after soft tissue augmentation. A different baseline tissue elasticity was observed between teeth and dental implants in the most coronal aspect of the soft tissue. The main factors affecting tissue elasticity-related outcomes were the keratinized tissue width, and mucosal thickness.

Reproducibility of Anterior Scalene Stiffness Measurement with Shear Wave Elastography: An Inter-Examiner Reliability Study

PURPOSE

Although previous studies have highlighted the clinical relevance of the anterior scalene muscle (AS) in patients with neck pain or nerve compressive syndromes, evidence reporting the diagnostic accuracy of shear wave elastography (SWE) for assessing the AS stiffness properties is lacking. This study aimed to analyze the SWE inter-examiner reliability for calculating the Young's modulus and shear wave speed of the AS muscle in asymptomatic subjects.

MATERIALS AND METHODS

Using a linear transducer, ultrasound images of the antero-lateral neck region at the C7 level were acquired in 35 healthy volunteers by one experienced examiner and one novice examiner. After codifying the images to blind the participants' identity, the trial, and the side, Young's modulus and shear wave speed were obtained by an independent experienced rater in randomized order. Intra-class correlation coefficients (ICC), standard error of measurement (SEM), minimal detectable changes (MDC), and coefficient of variation (CV%) were calculated.

RESULTS

The assessed AS metrics showed no side-to-side differences (p>0.05). Sex differences were found for muscle size (p=0.002), but muscle brightness and stiffness were similar (p>0.05). Inter-examiner reliability was good for determining the AS muscle stiffness (ICC = 0.881 for Young's modulus and 0.850 for shear wave speed).

CONCLUSION

The obtained results suggest that assessing the AS stiffness properties in asymptomatic subjects is a reliable procedure. Further studies should verify the SWE capacity for discriminating healthy and clinical populations and identify potential factors contributing to the variance of measurement errors.

Ultrasound elastography in dogs: Physical principles and application in intestinal evaluation

Ultrasound elastography provides diagnostic information based on tissue elasticity. There is a lack of specific studies on the application of elastography in canine intestinal assessment. Therefore, we reviewed comparative medicine studies and those referring to the literature listed in the databases. Static and dynamic elastography techniques are widely applied in human intestinal diseases, especially Chron's disease, but few studies have investigated the application of these modalities in canine enteropathies. This case raises questions about the use of new diagnostic imaging techniques in veterinary gastroenterology and highlights the need for further research. Hence, this study aimed to review the literature on the physical principles of elastography and its clinical application in the intestinal evaluation of dogs.

Ex vivo SIM-AFM measurements reveal the spatial correlation of stiffness and molecular distributions in 3D living tissue

Living tissues each exhibit a distinct stiffness, which provides cells with key environmental cues that regulate their behaviors. Despite this significance, our understanding of the spatiotemporal dynamics and the biological roles of stiffness in three-dimensional tissues is currently limited due to a lack of appropriate measurement techniques. To address this issue, we propose a new method combining upright structured illumination microscopy (USIM) and atomic force microscopy (AFM) to obtain precisely coordinated stiffness maps and biomolecular fluorescence images of thick living tissue slices. Using mouse embryonic and adult skin as a representative tissue with mechanically heterogeneous structures inside, we validate the measurement principle of USIM-AFM. Live measurement of tissue stiffness distributions revealed the highly heterogeneous mechanical nature of skin, including nucleated/enucleated epithelium, mesenchyme, and hair follicle, as well as the role of collagens in maintaining its integrity. Furthermore, quantitative analysis comparing stiffness distributions in live tissue samples with those in preserved tissues, including formalin-fixed and cryopreserved tissue samples, unveiled the distinct impacts of preservation processes on tissue stiffness patterns. This series of experiments highlights the importance of live mechanical testing of tissue-scale samples to accurately capture the true spatiotemporal variations in mechanical properties. Our USIM-AFM technique provides a new methodology to reveal the dynamic nature of tissue stiffness and its correlation with biomolecular distributions in live tissues and thus could serve as a technical basis for exploring tissue-scale mechanobiology. STATEMENT OF SIGNIFICANCE: Stiffness, a simple mechanical parameter, has drawn attention in understanding the mechanobiological principles underlying the homeostasis and pathology of living tissues. To explore tissue-scale mechanobiology, we propose a technique integrating an upright structured illumination microscope and an atomic force microscope. This technique enables live measurements of stiffness distribution and fluorescent observation of thick living tissue slices. Experiments revealed the highly heterogeneous mechanical nature of mouse embryonic and adult skin in three dimensions and the previously unnoticed influences of preservation techniques on the mechanical properties of tissue at microscopic resolution. This study provides a new technical platform for live stiffness measurement and biomolecular observation of tissue-scale samples with micron-scale resolution, thus contributing to future studies of tissue- and organ-scale mechanobiology.

Current and Future Directions of Technology in Assessment of Peyronie's Disease

PURPOSE OF REVIEW

This review assesses the effectiveness of various imaging modalities for diagnosing and managing Peyronie's disease (PD), exploring their clinical utility and limitations.

RECENT FINDINGS

Ultrasonography, currently the only modality endorsed by the American Urological Association, effectively detects calcifications and assesses vascular status but struggles with identifying non-palpable plaques. Computed tomography and magnetic resonance imaging provide detailed anatomical views but are costly along with other deterring factors. Autophotography and 3-dimensional imaging offer convenient home assessments but with variable accuracy. Elastography improves upon traditional ultrasonography, while emerging AI technologies show promise for automating precise curvature assessments, pending further validation. A combined approach tailored to each individual patient based on their needs enhances diagnostic accuracy. Supplementing ultrasonography with elastography and potentially AI could improve diagnostic outcomes and better guide treatment decisions. Continued research is vital to integrate these advancements into standard clinical practice and develop updated standardized protocols.

Point Shear Wave Elastography for Assessment of Liver Stiffness in Normal Individuals and in Patients With Non-alcoholic Fatty Liver Disease

Background Non-alcoholic fatty liver disease (NAFLD) is an increasing health issue worldwide, driven by rising rates of diabetes, obesity, and hypertriglyceridemia. Often asymptomatic, NAFLD is diagnosed through blood tests, imaging, and sometimes liver biopsy. Some cases advance to non-alcoholic steatohepatitis (NASH), which can lead to complications like liver cirrhosis and liver failure. While liver biopsy is the standard test for diagnosis, non-invasive methods such as shear wave elastography (SWE) offer a simpler and more reproducible alternative for diagnosing NAFLD. This is crucial for early intervention and preventing the progression of liver damage. Objectives The objectives of the study were to measure and compare liver stiffness in healthy individuals and patients with NAFLD using point shear wave elastography (pSWE), as well as to correlate liver stiffness in NAFLD patients with the ultrasonographic grades of fatty liver. Materials and methods This observational study was carried out at Dr. D. Y. Patil Medical College, Hospital and Research Centre in Pune, India, from December 2022 to April 2024. The study involved 82 participants in total, with 41 patients diagnosed with NAFLD (cases) and 41 healthy individuals with a sonographically normal liver (controls). pSWE was performed on each participant to measure liver stiffness, with results expressed in kilopascals (kPa). The procedure was conducted using a Samsung HS70A ultrasound machine (Samsung Electronics Pvt. Ltd., Seoul, South Korea). Data analysis was performed using IBM SPSS Statistics for Windows, Version 26.0 (Released 2019; IBM Corp., Armonk, New York, USA). Non-parametric tests, such as the Mann-Whitney test and Kruskal-Wallis test, were used to evaluate the significance of differences. A p-value of less than 0.05 was considered statistically significant. Results The mean liver stiffness, measured in kilopascals (kPa), was higher in NAFLD patients (cases) (10±5.1 kPa) than in normal individuals (controls) (4.4±0.7 kPa). This difference was statistically significant, with a p-value of less than 0.001. A positive correlation (rho=0.848, p<0.001) was found between the ultrasonographic grade of fatty liver and liver stiffness in NAFLD patients. Conclusion Our study demonstrated that individuals with NAFLD exhibited significantly higher liver stiffness compared to healthy individuals, as measured by ultrasound SWE. These findings suggest that pSWE could serve as a valuable, non-invasive diagnostic tool for assessing liver stiffness in NAFLD patients. Additionally, pSWE holds the potential for evaluating and monitoring the progression of the disease. However, further research with larger sample sizes is necessary to determine the prognostic significance of liver stiffness in these patients.

Quantification of Cervical Elasticity During Pregnancy Based on Transvaginal Ultrasound Imaging and Stress Measurement

Strain elastography and shear wave elastography are commonly used to quantify cervical elasticity. However, the absence of stress information in strain elastography causes difficulty in inter-session elasticity comparison, and the robustness of shear wave elastography is compromised by cervical tissue's high inhomogeneity.

OBJECTIVE

To overcome these limitations, we develop a quantitative cervical elastography system by adding a stress sensor to a clinically used transvaginal ultrasound imaging system.

METHODS

We record the cervical deformation in B-mode images and measure the probe-surface stress through the sensor. Then we quantify the strain using a customized algorithm and estimate the cervical Young's modulus through stress-strain linear regression.

RESULTS

In phantom experiments, we demonstrate the system's high accuracy (alignment with the quasi-static compression method, p-value = 0.369 > 0.05), robustness (alignment between 60°- and 90°-contact measurements, p-value = 0.638 > 0.05), repeatability (consistency of single sonographers' measurements, coefficient of variation < 0.06), and reproducibility (alignment between two sonographers' measurements, Pearson correlation coefficient = 0.981). Applying it to pregnant participants, we observe significant cervical softening (p-value < 0.001): Young's modulus decreases 3.95% weekly and its geometric mean value during the first (11 to 13 weeks), second, and third trimesters are 13.07 kPa, 7.59 kPa, and 4.40 kPa, respectively.

CONCLUSION

The proposed system is accurate, robust, and safe, and enables longitudinal and inter-examiner comparisons.

SIGNIFICANCE

The system applies to different ultrasound machines with minor software updates, which allows for studies of cervical softening patterns in pregnancy for larger populations, facilitating insights into conditions such as preterm birth.

Application of Strain Elastography in Dentistry: A Systematic Review

Strain elastography, a non-invasive imaging technique complements traditional diagnostic methods by offering quantitative and qualitative information about soft and hard tissues within the oral cavity. The article aimed to provide an overview of the currently available data on the use of strain elastography in dentistry. To support the review of strain elastography applications in dentistry, a wide range of articles was searched using both online and offline databases. Inclusion and exclusion criteria were defined according to the Population, Intervention, Comparison, Outcomes, and Study Design (PICOS) approach. The results show that 12 of the 107 papers found to be eligible for inclusion in a qualitative examination of the use of strain elastography in dentistry satisfied the PICOS criteria. Elastography is a promising tool for diagnosing various dental diseased conditions, but sufficient evidence is not available. More studies on a larger population should be performed to determine its accuracy in diagnosis.

Extended Review and Updates of Nonalcoholic Fatty Pancreas Disease

Non-alcoholic fatty pancreatic disease (NAFPD), also known as pancreatic steatosis, is a benign condition characterized by deposition of lipids in the pancreas and is associated with insulin resistance, malnutrition, obesity, metabolic syndrome, aging, and absence of heavy alcohol intake or infection. Similar to nonalcoholic fatty liver disease, NAFPD is a phenotypic entity that includes fat buildup in the pancreas, pancreatic inflammation, and subsequent fibrosis. The extent to which pancreatic fat infiltration is clinically important remains unclear. Despite these clinical associations, most of the clinical effects of NAFPD are not known. NAFPD may be identified by transabdominal and elastography ultrasound, computed tomography scan, or magnetic resonance imaging modalities, but a confirmatory diagnosis can only be made through tissue histology. In addition to complications such as acute and chronic pancreatitis, NAFPD may progress to pancreatic ductal adenocarcinoma. However, further research is required to fully understand the associations, pathophysiology, and effects of NAFPD. This review provides a narrative synthesis of the current literature on the epidemiology, pathophysiology, complications, diagnostic and imaging tools, and management of NAFPD.

Shear-wave elastographic imaging in choroidal melanomas: clinical and hemodynamic correlations

PURPOSE

This study evaluated the role of shear wave elastography imaging (SWEΙ) in uveal melanomas and the associations between SWEI and clinical and hemodynamic findings.

STUDY DESIGN

Prospective, clinical study METHODS: Twelve patients with uveal melanomas, scheduled to undergo Ru-106 brachytherapy, were prospectively recruited from the Department of Ophthalmology of the University Hospital of Heraklion (September-December 2022). B-mode, hemodynamic and SWEI ultrasonography examinations were performed with the HiScan (OPTIKON 2000) and the LOGIQ E9 (GE Healthcare) sonographic systems, respectively. Differences in SWEI scores (kPa) between tumor (TS) and adjacent non-affected choroid (CS), as well as between TS and orbital fat (FS) were examined. Correlations between SWEI and intra-tumoral hemodynamic parameters, including peak systolic and end diastolic velocities and resistivity index (RI) were also examined.

RESULTS

TS was significantly correlated with intra-tumoral RI (Pearson's bivariate correlation coefficient 0.681, p=0.015) and with maximal tumor height (Pearson's bivariate correlation coefficient 0.620, p=0.031). TS was significantly higher than both FS and CS scores (paired-samples t-test, p=0.003 and p=0.006, respectively).

CONCLUSIONS

SWEI score is applicable as a quantitative biomechanical marker in the assessment of choroidal melanoma. Choroidal melanomas are stiffer than both adjacent choroid and orbital fat. Moreover, choroidal melanomas with higher RI as well as those with higher apical elevations display higher SWEI scores.

The value of real-time shear wave elastography in spontaneous preterm birth

This study aimed to investigate the predictive value of real-time shear wave elastography (SWE) for spontaneous preterm birth (SPB). This study prospectively selected 175 women with singleton pregnancies at 16 to 36 weeks of gestation. Cervical length (CL) and uterocervical angle (UCA) were measured using transvaginal ultrasonography. Real-time shear wave elastography was used to measure Young's modulus values, including the average Young's modulus (Emean) and the maximum Young's modulus (Emax) at 4 points: point A on the inner lip of the cervical os, point B on the outer lip of the cervical os, point C on the inner lip of the external os, and point D on the outer lip of the external os. Receiver operating characteristic (ROC) curve analysis was performed to compare the accuracy of Young's modulus values at the 4 points, CL, and UCA in predicting SPB. Significant variables were used to construct a binary logistic regression model to predict the multifactorial predictive value of SPB, which was evaluated using an ROC curve. A total 176 valid cases, including 160 full-term pregnancies and 16 SPB, were included in this study. Receiver operating characteristic curve analysis revealed that Emean at point A, as well as Emean and Emax at point D, had a relatively high accuracy in diagnosing SPB, with area under the curve values of 0.704, 0.708, and 0.706, respectively followed by CL (0.670), SWE at point C (Emean 0.615, Emax 0.565), SWE at point B (Emean 0.577, Emax 0.584), and UCA (0.476). Binary logistic regression analysis showed that comorbidities during pregnancy (including diabetes mellitus, hypertension, cholestasis and thyroid dysfunction), CL, and Emean at point A were independent predictors of preterm birth. In addition, the AUC value of the logistic regression model's ROC curve was 0.892 (95% CI: 0.804-0.981), with a sensitivity of 0.867, specificity of 0.792, and Youden's index of 0.659, indicating that the regression model has good predictive ability for SPB. Real-time shear wave elastography showed a higher predictive value for SPB than CL and UCA. The SWE combined with CL and comorbidities during pregnancy model has a good predictive ability for SPB.

Research progress of ultrasound in accurate evaluation of cartilage injury in osteoarthritis

Osteoarthritis (OA) is a prevalent cause of joint algesia, loss of function, and disability in adults, with cartilage injury being its core pathological manifestation. Since cartilage damage is non-renewable, the treatment outcome in the middle and late stages of OA is unsatisfactory, which can be minimized by changing lifestyle and other treatment modalities if diagnosed and managed in the early stages, indicating the importance of early diagnosis and monitoring of cartilage injury. Ultrasound technology has been used for timely diagnosis and even cartilage injury treatment, which is convenient and safe for the patient owing to no radiation exposure. Studies have demonstrated the effectiveness of ultrasound and its various quantitative ultrasound parameters, like ultrasound roughness index (URI), reflection coefficient (R), apparent integrated backscatter (AIB), thickness, and ultrasound elastography, in the early and accurate assessment of OA cartilage pathological changes, including surface and internal tissue, hardness, and thickness. Although many challenges are faced in the clinical application of this technology in diagnosis, ultrasound and ultrasound-assisted techniques offer a lot of promise for detecting early cartilage damage in OA. In this review, we have discussed the evaluation of ultrasonic cartilage quantitative parameters for early pathological cartilage changes.

Assessment of the utility of two-dimensional shear wave elastography and superb microvascular imaging in postoperative patients with biliary atresia

PURPOSE

We aimed to investigate whether prediction of liver fibrosis using two-dimensional shear wave elastography (2D-SWE) and vascular tree grading using superb microvascular imaging (SMI) are useful for postoperative follow-up in patients with biliary atresia (BA).

METHODS

We retrospectively collected data from medical records of 134 patients who underwent ultrasound examination with 2D-SWE or SMI, including 13 postoperative patients with BA and 121 non-BA patients. We investigated the distribution of liver stiffness values with SWE and vascular tree grading with SMI and evaluated correlations between these findings and biochemical indices of liver fibrosis in postoperative BA patients.

RESULTS

The SWE values of the BA group were not significantly different from that of any other disease groups in non-BA patients. In postoperative BA patients, SWE values correlated significantly with aspartate aminotransferase to platelet ratio index (Spearman rank correlation coefficient [rs] = 0.6380, p = 0.0256) and with the Fib-4 index (rs = 0.6526, p = 0.0214). SMI vascular tree grading of the BA group was significantly higher than that of the choledochal cyst group (p = 0.0008) and other hepatobiliary disorder group (p = 0.0030). In postoperative BA patients, SMI vascular tree grading was not positively correlated with any biochemical marker of fibrosis.

CONCLUSION

2D-SWE appears to be useful for follow-up in postoperative BA patients.

Metabolic Pathways in Hydrocephalus: Profiling with Proteomics and Advanced Imaging

Hemorrhagic hydrocephalus is a common pathology in neonates with high mortality and morbidity. Current imaging approaches fail to capture the mechanisms behind its pathogenesis. Here, we discuss the processes underlying this pathology, the metabolic dysfunction that occurs as a result, and the ways in which these metabolic changes inform novel methods of clinical imaging. The imaging advances described allow earlier detection of the cellular and metabolic changes, leading to better outcomes for affected neonates.

Viscoelasticity in 3D Cell Culture and Regenerative Medicine: Measurement Techniques and Biological Relevance

The field of mechanobiology is gaining prominence due to recent findings that show cells sense and respond to the mechanical properties of their environment through a process called mechanotransduction. The mechanical properties of cells, cell organelles, and the extracellular matrix are understood to be viscoelastic. Various technologies have been researched and developed for measuring the viscoelasticity of biological materials, which may provide insight into both the cellular mechanisms and the biological functions of mechanotransduction. Here, we explain the concept of viscoelasticity and introduce the major techniques that have been used to measure the viscoelasticity of various soft materials in different length- and timescale frames. The topology of the material undergoing testing, the geometry of the probe, the magnitude of the exerted stress, and the resulting deformation should be carefully considered to choose a proper technique for each application. Lastly, we discuss several applications of viscoelasticity in 3D cell culture and tissue models for regenerative medicine, including organoids, organ-on-a-chip systems, engineered tissue constructs, and tunable viscoelastic hydrogels for 3D bioprinting and cell-based therapies.

Effect of proteinuria at relapse on shear wave velocity assessed using ultrasound elastography in children with idiopathic nephrotic syndrome

PURPOSE

Shear wave velocity (SWV) is an ultrasound elastography technique that provides much information for kidney disease assessment. However, the factors that alter SWV are not fully understood; it is unclear whether the variation in SWV seen in proteinuria associated with disease progression is due to tissue or proteinuria. This study investigated the effect of proteinuria on SWV.

METHODS

This prospective observational study compared SWV at remission with SWV at relapse in children treated for idiopathic nephrotic syndrome (INS) between April 2020 and December 2023. All relapses without oral steroids during the observation period were measured. SWV at remission was defined as the date closest to relapse during which repeated measurements were taken approximately every 3 months after steroid discontinuation.

RESULTS

Eight patients were treated for INS with a median observation period of 21.9 months (11.8-27.1). Of the 15 relapses, five that met the definition were considered for the study. The median interval between the measurement at relapse and remission was 40 days (11-55). SWV was significantly lower at relapse than remission (2.40 ± 0.20 m/s vs. 2.14 ± 0.15 m/s, P < 0.01).

CONCLUSIONS

SWV decreased in the presence of severe proteinuria at relapse compared to the remission measurements. Although more cases need to be studied, the decrease in SWV may reflect the mechanism by which protein leaks into the urine, not just a direct change caused by the presence of proteinuria.

Effectiveness of two-dimensional shear-wave sonoelastography in the diagnosis and follow-up of infantile hypertrophic pyloric stenosis

INTRODUCTION

We sought to determine the effectiveness and utility of two-dimensional shear-wave sonoelastography (2D-SW-SE) in the diagnosis and postoperative follow-up of infantile hypertrophic pyloric stenosis (IHPS).

MATERIALS AND METHODS

Twenty-three infants were included in the study, 13 in the IHPS group and 10 in the control group (CG). Preoperative B-mode ultrasonography measurements (longitudinal length and single-wall thickness of the pylorus) and 2D-SW-SE measurements (pylorus tissue stiffness and shear-wave propagation speed) were compared between the groups. The infants with IHPS then underwent Ramstedt pyloromyotomy and were invited for follow-ups on the tenth day and the first, third, and sixth months postoperatively. Measurements taken at the follow-ups were compared with the preoperative values.

RESULTS

No differences were found between the groups regarding age, gender, body weight, or week of birth. The pyloric lengths in the IHPS group were longer than in the CG (p < 0.001), and the single-wall thicknesses were thicker (p < 0.001). The pylorus in the IHPS group was four times stiffer than in the CG (27.4 kPa versus 7.66 kPa), and the shear-wave propagation speed in the tissue was higher (1.34 m/s versus 2.69 m/s; p < 0.001). Both values decreased over time in the IHPS group and were normal by the third postoperative month.

CONCLUSIONS

2D-SW-SE can be used as an assistive imaging tool alongside B-mode ultrasound for diagnosing IHPS. It can also be used to identify inadequate surgery by detecting whether the pyloric tissue has softened at follow-up.

Ultrasound Shear Wave Elastography Evaluation of the Liver and Implications for Perioperative Medicine

Ultrasound shear wave elastography (SWE) is a non-invasive, low risk technology allowing the assessment of tissue stiffness. Used clinically for nearly two decades to diagnose and stage liver fibrosis and cirrhosis, it has recently been appreciated for its ability to differentiate between more subtle forms of liver dysfunction. In this review, we will discuss the principle of ultrasound shear wave elastography, its traditional utilization in grading liver cirrhosis, as well as its evolving role in identifying more subtle degrees of liver injury. Finally, we will show how this capacity to distinguish nuanced changes may provide an opportunity for its use in perioperative risk stratification.

Revisiting the standards of cancer detection and therapy alongside their comparison to modern methods

In accordance with the World Health Organization data, cancer remains at the forefront of fatal diseases. An upward trend in cancer incidence and mortality has been observed globally, emphasizing that efforts in developing detection and treatment methods should continue. The diagnostic path typically begins with learning the medical history of a patient; this is followed by basic blood tests and imaging tests to indicate where cancer may be located to schedule a needle biopsy. Prompt initiation of diagnosis is crucial since delayed cancer detection entails higher costs of treatment and hospitalization. Thus, there is a need for novel cancer detection methods such as liquid biopsy, elastography, synthetic biosensors, fluorescence imaging, and reflectance confocal microscopy. Conventional therapeutic methods, although still common in clinical practice, pose many limitations and are unsatisfactory. Nowadays, there is a dynamic advancement of clinical research and the development of more precise and effective methods such as oncolytic virotherapy, exosome-based therapy, nanotechnology, dendritic cells, chimeric antigen receptors, immune checkpoint inhibitors, natural product-based therapy, tumor-treating fields, and photodynamic therapy. The present paper compares available data on conventional and modern methods of cancer detection and therapy to facilitate an understanding of this rapidly advancing field and its future directions. As evidenced, modern methods are not without drawbacks; there is still a need to develop new detection strategies and therapeutic approaches to improve sensitivity, specificity, safety, and efficacy. Nevertheless, an appropriate route has been taken, as confirmed by the approval of some modern methods by the Food and Drug Administration.

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.

Diastolic Heart Failure Mechanisms and Assessment Revisited

The syndrome of heart failure (HF) with preserved ejection fraction (HFpEF) makes up about half of the HF population. The HF mechanisms in these patients are varied and not fully understood. In addition, the term "diastolic HF" was switched to HFpEF because of difficulties in measuring the left ventricular (LV) diastolic performance. In the late stages, HFpEF carries a prognosis that is as bad as or worse than that of HFrEF. Hence, it is important to recognize LV diastolic impairment at an earlier stage so that the causal mechanisms, if any, can be treated to retard its progression. Despite the availability of numerous disease-modifying agents for HFrEF, there are hardly any available treatments for HFpEF. With our aging population, there will be an epidemic of HFpEF and hence this entity needs attention and respect. In this paper, we review the fundamental mechanisms of HFpEF, the physiology of LV filling and how LV diastolic function can be comprehensively measured. We also speculate how this may help with the early recognition of diastolic HF and its treatment.

Ultrasonic surface acoustic wave elastography: A review of basic theories, technical developments, and medical applications

Physiological and pathological changes in tissues often cause changes in tissue mechanical properties, making tissue elastography an effective modality in medical imaging. Among the existing elastography methods, ultrasound elastography is of great interest due to the inherent advantages of ultrasound imaging technology, such as low cost, portability, safety, and wide availability. However, most current ultrasound elastography methods are based on the bulk shear wave; they can image deep tissues but cannot image superficial tissues. To address this challenge, ultrasonic elastography methods based on surface acoustic waves have been proposed. In this paper, we present a comprehensive review of ultrasound-based surface acoustic wave elastography techniques, including their theoretical foundations, technical implementations, and existing medical applications. The goal is to provide a concise summary of the state-of-the-art of this field, hoping to offer a reliable reference for the further development of these techniques and foster the expansion of their medical applications.

Elasticity of the Cervix in Relation to Uterus Position

Strain elastography allows the evaluation of tissue elasticity. Background/Objectives: Tissue elasticity depends on the content and distribution of collagen fibers and is shaped by the applied tensile forces that may differ in uteri with a different angle of flexion of the corpus on the cervix. The objective was to investigate whether the angle of uterine flexion is related to cervical tissue elasticity. Methods: The anterior angle between the longitudinal axis of the uterus corpus and that of the cervix was measured in 275 non-pregnant young women by transvaginal ultrasonography and considered both as an absolute value or categorized as ≤150°, between >150° and ≤210°, and >210°. Strain elastography was used to assess tissue elasticity by placing the probe in the anterior vaginal fornix. Tissue elasticity was evaluated in the middle of the anterior cervical compartment (ACC), in the middle of the posterior cervical compartment (PCC), in the middle portion of the cervical canal (MCC), and at the internal cervical os (ICO). In a sagittal plane MCC was evaluated across the cervical canal, and ACC and PCC at a distance equal between the cervical canal and the outer anterior or posterior part of the cervix. MCC, ACC and PCC were evaluated at equal distance between the ICO and the external cervical os. Elasticity was expressed as a color score ranging from 0.1 (low elasticity) to 3 (high elasticity). Results: The angle of uterine flexion show a negative linear relation with the elasticity of the ACC (p = 0.001) and MCC (p = 0.002) and a positive relation with the elasticity of the PCC (p = 0.054). In comparison to uteri with an angle of flexion of <150°, those with an angle of flexion of >210° had lower elasticity of the ACC (p = 0.001) and MCC (p = 0.001) and higher elasticity of the PCC (p = 0.004). The ACC/PCC and PCC/MCC elasticity ratios were also significantly different (p = 0.001). Conclusions: The angle of uterine flexion is associated with changes in cervix elasticity. Retroflexion is associated with stiffer ACC and MCC and a more elastic PCC. Differences in tissue elasticity suggest structural changes of the cervix that may have implication in variate obstetric and gynecological conditions.

Quantitative assessment of corneal elasticity distribution after FS-LASIK using optical coherence elastography

Quantifying corneal elasticity after femtosecond laser-assisted in situ keratomileusis (FS-LASIK) procedure plays an important role in improving surgical safety and quality, since some latent complications may occur ascribing to changes in postoperative corneal biomechanics. Nevertheless, it is suggested that current research has been severely constrained due to the lack of an accurate quantification method to obtain postoperative corneal elasticity distribution. In this paper, an acoustic radiation force optical coherence elastography system combined with the improved phase velocity algorithm was utilized to realize elasticity distribution images of the in vivo rabbit cornea after FS-LASIK under various intraocular pressure levels. As a result, elasticity variations within and between the regions of interest could be identified precisely. This is the first time that elasticity imaging of in vivo cornea after FS-LASIK surgery was demonstrated, and the results suggested that this technology may hold promise in further exploring corneal biomechanical properties after refractive surgery.

Resonance, Velocity, Dispersion, and Attenuation of Ultrasound-Induced Shear Wave Propagation in Blood Clot In Vitro Models

OBJECTIVE

Improve the characterization of mechanical properties of blood clots. Parameters derived from shear wave (SW) velocity and SW amplitude spectra were determined for gel phantoms and in vitro blood clots.

METHODS

Homogeneous phantoms and phantoms with gel or blood clot inclusions of different diameters and mechanical properties were analyzed. SW amplitude spectra were used to observe resonant peaks. Parameters derived from those resonant peaks were related to mimicked blood clot properties. Three regions of interest were tested to analyze where resonances occurred the most. For blood experiments, 20 samples from different pigs were analyzed over time during a 110-minute coagulation period using the Young modulus, SW frequency dispersion, and SW attenuation.

RESULTS

The mechanical resonance was manifested by an increase in the number of SW spectral peaks as the inclusion diameter was reduced (P < .001). In blood clot inclusions, the Young modulus increased over time during coagulation (P < .001). Descriptive spectral parameters (frequency peak, bandwidth, and distance between resonant peaks) were linearly correlated with clot elasticity values (P < .001) with R2  = .77 for the frequency peak, .60 for the bandwidth, and .48 for the distance between peaks. The SW dispersion and SW attenuation reflecting the viscous behavior of blood clots decreased over time (P < .001), mainly in the early stage of coagulation (first minutes).

CONCLUSION

The confined soft inclusion configuration favored SW mechanical resonances potentially challenging the computation of spectral-based parameters, such as the SW attenuation. The impact of resonances can be reduced by properly selecting the region of interest for data analysis.

Kidney cortex shear wave motion simulations based on segmented biopsy histology

BACKGROUND AND OBJECTIVE

Biopsy stands as the gold standard for kidney transplant assessment, yet its invasive nature restricts frequent use. Shear wave elastography (SWE) is emerging as a promising alternative for kidney transplant monitoring. A parametric study involving 12 biopsy data sets categorized by standard biopsy scores (3 with normal histology, 3 with interstitial inflammation (i), 3 with interstitial fibrosis (ci), and 3 with tubular atrophy (ct)), was conducted to evaluate the interdependence between microstructural variations triggered by chronic allograft rejection and corresponding alterations in SWE measurements.

METHODS

Heterogeneous shear wave motion simulations from segmented kidney cortex sections were performed employing the staggered-grid finite difference (SGFD) method. The SGFD method allows the mechanical properties to be defined on a pixel-basis for shear wave motion simulation. Segmentation techniques enabled the isolation of four histological constituents: glomeruli, tubules, interstitium, and fluid. Baseline ex vivo Kelvin-Voigt mechanical properties for each constituent were drawn from established literature. The parametric evaluation was then performed by altering the baseline values individually. Shear wave velocity dispersion curves were measured with the generalized Stockwell transform in conjunction with slant frequency-wavenumber analysis (GST-SFK) algorithm. By fitting the curve within the 100-400 Hz range to the Kelvin-Voigt model, the rheological parameters, shear elasticity (µ1) and viscosity (µ2), were estimated. A time-to-peak algorithm was used to estimate the group velocity. The resultant in silico models emulated the heterogeneity of kidney cortex within the shear wave speed (SWS) reconstructions.

RESULTS

The presence of inflammation showed considerable spatial composition disparities compared to normal cases, featuring a 23 % increase in interstitial area and a 19 % increase in glomerular area. Concomitantly, there was a reduction of 12 % and 47 % in tubular and fluid areas, respectively. Consequently, mechanical changes induced by inflammation predominate in terms of rheological differentiation, evidenced by increased elasticity and viscosity. Mild tubular atrophy showed significant elevation in group velocity and µ1. Conversely, mild and moderate fibrosis exhibited negligible alterations across all parameters, compatible with relatively limited morphological impact.

CONCLUSIONS

This proposed model holds promise in enabling patient-specific simulations of the kidney cortex, thus facilitating exploration into how pathologies altering cortical morphology correlates to modifications in SWE-derived rheological measurements. We demonstrated that inflammation caused substantial changes in measured mechanical properties.

Liver fibrosis assessment in pediatric population - can ultrasound elastography be an alternative method to liver biopsy? A systematic review

Liver diseases of various etiologies are becoming increasingly common in the pediatric population. So far, the gold diagnostic standard in these disorders is liver biopsy. This procedure is invasive, painful and requires general anesthesia in this group of patients. Due to the continuous development of new research techniques, such as liver elastography, it is necessary to evaluate them in the context of their diagnostic usefulness. Ultrasound elastography, as a quick and effective method, is being used more and more often in the assessment and monitoring of liver dysfunction in both adults and children. There are several techniques of liver elastography, such as transient elastography, shear wave elastography consisting of various subtypes such as two-dimensional shear wave elastography, acoustic radiation force impulse and point shear wave elastography, which differ in terms of the measurement technique and the achieved results. The purpose of our review was to determine whether techniques of liver elastography could replace liver biopsy. Although now, based on the analyzed papers, elastography cannot replace liver biopsy, in our opinion, the role of this tool in monitoring pediatric patients with liver diseases will grow in the coming years.

An Emerging Era: Conformable Ultrasound Electronics

Conformable electronics are regarded as the next generation of personal healthcare monitoring and remote diagnosis devices. In recent years, piezoelectric-based conformable ultrasound electronics (cUSE) have been intensively studied due to their unique capabilities, including nonradiative monitoring, soft tissue imaging, deep signal decoding, wireless power transfer, portability, and compatibility. This review provides a comprehensive understanding of cUSE for use in biomedical and healthcare monitoring systems and a summary of their recent advancements. Following an introduction to the fundamentals of piezoelectrics and ultrasound transducers, the critical parameters for transducer design are discussed. Next, five types of cUSE with their advantages and limitations are highlighted, and the fabrication of cUSE using advanced technologies is discussed. In addition, the working function, acoustic performance, and accomplishments in various applications are thoroughly summarized. It is noted that application considerations must be given to the tradeoffs between material selection, manufacturing processes, acoustic performance, mechanical integrity, and the entire integrated system. Finally, current challenges and directions for the development of cUSE are highlighted, and research flow is provided as the roadmap for future research. In conclusion, these advances in the fields of piezoelectric materials, ultrasound transducers, and conformable electronics spark an emerging era of biomedicine and personal healthcare.

Feasibility and Measurement Value of Pancreatic 2-D Shear Wave Elastography in Healthy Adults: Evaluation, Influencing Factors, Reference Range, Measurement Stability and Reproducibility

OBJECTIVE

The present study was aimed at assessing the success rate and measurement value, determining the influencing factors and reference range and examining the intra-operator stability and inter-operator reproducibility of pancreatic 2-D shear wave elastography (SWE) measurement in healthy adults.

METHODS

In 2022, 387 healthy adults were prospectively recruited. Logistic regression and linear regression analyses were used to explore the factors influencing the success rate and the measurement value of pancreatic 2-D SWE measurement, respectively. A two-sided 95% reference range was estimated accordingly. The intraclass correlation coefficient was calculated to evaluate the intra-operator stability and inter-operator reproducibility of the pancreatic 2-D SWE measurement.

RESULTS

The pancreatic body (89.6%) bore the highest while the tail (72.8%) bore the lowest success rate of pancreatic 2-D SWE measurement. Sex and body mass index (BMI) were the independent factors influencing measurement success rate in all three parts of the pancreas. Mean measurement values (Emean) were not the same in the three parts of the pancreas of the same participant. BMI and image depth were the independent factors influencing Emean in the pancreatic body, while region of interest depth and BMI were the only independent factors influencing Emean in the pancreatic head and tail, respectively. The intra-operator stability of pancreatic 2-D SWE measurement was found to be excellent, whereas its inter-operator reproducibility was poor to good.

CONCLUSION

Pancreatic 2-D SWE is a reliable technique for evaluating pancreatic stiffness in healthy adults, but its success rate and measurement value are influenced by multiple factors.

Levator Scapulae Stiffness Measurement Reliability in Individuals with and without Chronic Neck Pain by Experienced and Novel Examiners

The levator scapulae muscle is a key structure in the etiopathology of neck and shoulder musculoskeletal pain. Although previous studies used shear-wave elastography (SWE) for characterizing this muscle elasticity, limited evidence assessed the inter-examiner reliability of this procedure. This study aimed to analyze the inter-examiner reliability for calculating Young's modulus and shear wave speed in a cohort of participants with and without chronic neck pain. A diagnostic accuracy study was conducted, acquiring a set of SWE images at the C5 level in participants with and without neck pain (n = 34 and 33, respectively) by two examiners (one experienced and one novel). After blinding the participants' identity, examiner involved, and side, the stiffness indicators were calculated by an independent rater in a randomized order. Intra-class correlation coefficients (ICC), standard error of measurement, minimal detectable changes, and coefficient of variation were calculated. Both cohorts had comparable sociodemographic characteristics (p > 0.05). No significant levator scapulae elasticity differences were found between genders, sides, or cohorts (all, p > 0.05). Inter-examiner reliability for calculating Young's modulus and shear wave speed was moderate-to-good for assessing asymptomatic individuals (ICC = 0.714 and 0.779, respectively), while poor-to-moderate in patients with neck pain (ICC = 0.461 and 0.546, respectively). The results obtained in this study support the use of this procedure for assessing asymptomatic individuals. However, reliability estimates were unacceptable to support its use for assessing elasticity in patients with chronic neck pain. Future studies might consider that the shear wave speed is more sensitive to detect real changes in comparison with Young's modulus.

[Compression elastography as a new method of ultrasound imaging in the differential diagnosis of chronic tonsillitis]

Chronic tonsillitis remains as an urgent problem in modern otorhinolaryngological practice, which requires improving the diagnostic methods of this pathology.

OBJECTIVE

To increase the diagnostic information content of objective methods for differential diagnosis of different forms of chronic tonsillitis.

MATERIAL AND METHODS

The study involved 97 patients who were divided into two groups: the 1st group (39 patients) - with a simple form; the 2nd group (58 patients) - with a toxic-allergic form of chronic tonsillitis. To assess the structure of the palatine tonsils, patients underwent ultrasound in the compression elastography mode.

RESULTS

According to results, patient with simple form of chronic tonsillitis in 64.1±7.68% cases had rigid structure of palatine tonsils, while toxic-allergic form is characterized by an elastic structure of the tonsils (58.62±6.47%).

CONCLUSION

The ultrasound compression elastography helps to value efficiently the pathology of the palatine tonsils and conduct a differential diagnosis of clinical forms of chronic tonsillitis.