Principles of ultrasound elastography.
Ontology highlight
ABSTRACT:
SUBMITTER: Ozturk A
PROVIDER: S-EPMC5973820 | biostudies-literature | 2018 Apr
REPOSITORIES: biostudies-literature
Publications
Principles of ultrasound elastography.
Ozturk Arinc A Grajo Joseph R JR Dhyani Manish M Anthony Brian W BW Samir Anthony E AE
Abdominal radiology (New York) 20180401 4
Tissue stiffness has long been known to be a biomarker of tissue pathology. Ultrasound elastography measures tissue mechanical properties by monitoring the response of tissue to acoustic energy. Different elastographic techniques have been applied to many different tissues and diseases. Depending on the pathology, patient-based factors, and ultrasound operator-based factors, these techniques vary in accuracy and reliability. In this review, we discuss the physical principles of ultrasound elasto ...[more]
Similar Datasets
Project description:ObjectiveThe purpose of this article is to provide an overview of ultrasound and MR elastography, including a glossary of relevant terminology, a classification of elastography techniques, and a discussion of their respective strengths and limitations.ConclusionElastography is an emerging technique for the noninvasive assessment of mechanical tissue properties. These techniques report metrics related to tissue stiffness, such as shear-wave speed, magnitude of the complex shear modulus, and the Young modulus.
| S-EPMC4819982 | biostudies-literature
Project description:Background:Piriformis muscle syndrome (PMS) is relatively less known and underestimated because it is confused with other clinical pathological conditions. Delays in its diagnosis may lead to chronic somatic dysfunction and muscle weakness. Objective:Here, we aimed to evaluate the diagnostic performance of the ultrasound elastography (UE) as an easy, less-invasive, and cost-effective method for early diagnosis of PMS. Materials and Methods:Twenty-eight cases clinically diagnosed as PMS at the outpatient clinic were evaluated by UE. The elastographic strain ratio was calculated by dividing the strain value of the subcutaneous fat tissue by the mean stress value of the muscle beneath. The diagnostic performances of the strain rate measures were compared using the receiver operating characteristic curve analysis. Results:Twenty-one (N = 21) cases were female, and seven (N = 7) of the cases were male. The mean age was 45 years (ranged 24-62 years). The strain rates of piriformis muscle (PM) and gluteus maximus (GM) muscles were significantly higher on the PMS-diagnosed side (P < 0.001). The cutoff value of UE strain ratio for the PM and GM were 0.878 [95% confidence interval (CI) 0.774-0.981] and 0.768 (95% CI 0.622-0.913), respectively, and the sensitivity and specificity values were, respectively, 80.95% and 85.71% for the PM, and they were, respectively, 85.71% and 66.67% for the GM. Conclusion:We showed that the muscle elasticity and tissue hardening increased on the problematic side both on PM and GM. UE may provide early diagnosis of PMS, thereby increasing the possibility of treatment with less invasive methods.
| S-EPMC6319104 | biostudies-other
Project description:Thromboembolism in a cerebral blood vessel is associated with high morbidity and mortality. Mechanical thrombectomy (MT) is one of the emergenc proceduresperformed to remove emboli. However, the interventional approaches such as aspiration catheters or stent retriever are empirically selected. An inappropriate selection of surgical devices can influence the success rate during embolectomy, which can lead to an increase in brain damage. There has been growing interest in the study of clot composition and using a priori knowledge of clot composition to provide guidance for an appropriate treatment strategy for interventional physicians. Developing imaging tools which can allow interventionalists to understand clot composition could affect management and device strategy. In this study, we investigated how clots of different compositions can be characterized by using acoustic radiation force optical coherence elastography (ARF-OCE) and compared with ultrasound shear wave elastography (SWE). Five different clots compositions using human blood were fabricated into cylindrical forms from fibrin-rich (21% red blood cells, RBCs) to RBC-rich (95% RBCs). Using the ARF-OCE and SWE, we characterized the wave velocities measured in the time-domain. In addition, the semi-analytical finite element model was used to explore the relationship between the phase velocities with various frequency ranges and diameters of the clots. The study demonstrated that the wave group velocities generally decrease as RBC content increases in ARF-OCE and SWE. The correlation of the group velocities from the OCE and SWE methods represented a good agreement as RBC composition is larger than 39%. Using the phase velocity dispersion analysis applied to ARF-OCE data, we estimated the shear wave velocities decoupling the effects of the geometry and material properties of the clots. The study demonstrated that the composition of the clots can be characterized by elastographic methods using ARF-OCE and SWE, and OCE demonstrated better ability to discriminate between clots of different RBC compositions, compared to the ultrasound-based approach, especially in clots with low RBC compositions.
| S-EPMC7880883 | biostudies-literature
Project description:Ultrasound (US) elastography has been introduced as a noninvasive imaging technique for evaluating cervical lymph nodes. US elastography techniques include strain elastography and shear wave-based elastography. The application of this technique is based on the fact that stiff tissues tend to deform less and show less strain than compliant tissues when the same force is applied. In general, metastatic lymph nodes demonstrate higher stiffness than benign lymph nodes. Overall, preliminary studies suggest that US elastography may be useful in differentiating benign and malignant cervical lymph nodes, thereby informing decisions to perform a biopsy and facilitating follow-up. For US elastography to be accepted into clinical practice, however, its techniques, associated diagnostic criteria, and reliability need to be further refined.
| S-EPMC4484291 | biostudies-other
Project description:BackgroundThyroid nodular disease is a common disorder. Ultrasonography has emerged as a powerful tool for the diagnosis of thyroid disease owing to its high operational simplicity, non-invasiveness and reproducibility. This study aimed to systematically evaluate the value of ultrasound elastography and conventional ultrasound for the diagnosis of thyroid nodules.MethodsThe PubMed, EMBASE, Cochrane Library, China National Knowledge Infrastructure, Wanfang and VIP databases were searched systematically. RevMan 5.3 software was used to draw a risk bias map, and Stata 16.0 was used to plot a sensitivity and specificity forest map. A summary receiver operating characteristics (SROC) curve was plotted, and the area under the curve (AUC) was calculated. Meta-regression was used to explore the sources of heterogeneity.ResultsThe sensitivity of conventional ultrasonography for detecting thyroid nodules was 0.55 [95% confidence interval (CI): 0.45-0.65], the specificity was 0.90 (95% CI: 0.87-0.93), the positive likelihood ratio was 5.8 (95% CI: 3.8-8.9), the negative likelihood ratio was 0.49 (95% CI: 0.39-0.6), and the AUC was 0.86 (95% CI: 0.82-0.88). The sensitivity of ultrasonic elastography for detecting thyroid nodules was 0.67 (95% CI: 0.60-0.73), the specificity was 0.93 (95% CI: 0.90-0.95), the positive likelihood ratio was 9.1 (95% CI: 6.3-13.3), the negative likelihood ratio was 0.36 (95% CI: 0.29-0.44), and the AUC was 0.89 (95% CI: 0.86-0.91). The sensitivity of conventional ultrasound combined with ultrasonic elastography for detecting thyroid nodules was 0.88 (95% CI: 0.84-0.90), the specificity of the combined approach was 0.96 (95% CI: 0.93-0.98), the positive likelihood ratio was 23.3 (95% CI: 12.4-43.6), the negative likelihood ratio was 0.13 (95% CI: 0.10-0.17), and the AUC was 0.92 (95% CI: 0.90-0.94). Age, region, research type, conventional ultrasound evaluation criteria and elastography evaluation criteria had specific effects on sensitivity and specificity when detecting thyroid nodules.ConclusionsConventional ultrasound can be used as a routine examination technique for the differential diagnosis of benign and malignant thyroid nodules, while ultrasound elastography can improve the sensitivity and specificity of the diagnosis. The diagnostic value of conventional ultrasound combined with ultrasound elastography is higher than that of a single diagnostic method.
| S-EPMC10006152 | biostudies-literature
Project description:Functionally graded soft materials (FGSMs) with microstructures and mechanical properties exhibiting gradients across a spatial volume to satisfy specific functions have received interests in recent years. How to characterize the mechanical properties of these FGSMs in vivo/in situ and/or in a non-destructive manner is a great challenge. This paper investigates the use of ultrasound elastography in the mechanical characterization of FGSMs. An efficient finite-element model was built to calculate the dispersion relation for surface waves in FGSMs. For FGSMs with large elastic gradients, the measured dispersion relation can be used to identify mechanical parameters. In the case where the elastic gradient is smaller than a certain critical value calculated here, our analysis on transient wave motion in FGSMs shows that the group velocities measured at different depths can infer the local mechanical properties. Experiments have been performed on polyvinyl alcohol (PVA) cryogel to demonstrate the usefulness of the method. Our analysis and the results may not only find broad applications in mechanical characterization of FGSMs but also facilitate the use of shear wave elastography in clinics because many diseases change the local elastic properties of soft tissues and lead to different material gradients. This article is part of the theme issue 'Rivlin's legacy in continuum mechanics and applied mathematics'.
| S-EPMC6452040 | biostudies-literature
Project description:BACKGROUND:Ultrasound elastography is an imaging procedure that can assess the biomechanical characteristics of different tissues. The aim of this study was to define the diagnostic value of the endobronchial ultrasound (EBUS) elastography strain ratio of mediastinal lymph nodes in patients with a suspicion of lung cancer. The diagnostic values of the strain ratios were compared with the EBUS brightness mode (B-mode) features of selected mediastinal lymph nodes and with their cytological diagnoses. PATIENTS AND METHODS:This prospective, single-centre study enrolled patients with an indication for biopsy and mediastinal staging after a non-invasive diagnostic workup of a lung tumour. EBUS with standard B-mode evaluation and elastography with strain ratio measurement were performed before endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). RESULTS:Thirty-three patients with 80 suspicious mediastinal lymph nodes were included. Malignant infiltration was confirmed in 34 (42.5%) lymph nodes. The area under the receiver operating characteristic curve for the strain ratio was 0.87 (p < 0.0001). At a strain ratio ? 8, the accuracy for malignancy prediction was 86.25% (sensitivity 88.24%, specificity 84.78%, positive predictive value [PPV] 81.08%, negative predictive value [NPV] 90.70%). The strain ratio is more accurate than conventional B-mode EBUS modalities for differentiating between malignant and benign lymph nodes. CONCLUSIONS:EBUS-guided elastography with strain ratio assessment can distinguish malignant from benign mediastinal lymph nodes with greater accuracy than conventional EBUS modalities. This new method may reduce the number of mediastinal EBUS-TBNAs and thus reduce the invasiveness and expense of mediastinal staging in patients with non-small lung cancer (NSCLC).
| S-EPMC4722923 | biostudies-literature
Project description:BACKGROUND:In lung cancer staging, mediastinal lymph nodes are currently aspirated using endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) based on size and FDG-PET avidity. EBUS strain elastography (SE) is a new technique that may help predict the presence of malignancy. However, a standardized assessment strategy for EBUS-SE measurement is lacking. OBJECTIVES:The aim of this study was to determine the optimal assessment strategy for investigating the predictive value of EBUS-SE in mediastinal lymph nodes. METHODS:Two qualitative visual analogue scale strain scores and two semiquantitative strain elastography measurements (a strain histogram and strain ratio) were acquired in 120 lymph nodes of 63 patients with (suspected) lung cancer. The dataset was randomized into an 80% training dataset to determine cut-off values. Performance was consecutively tested on the remaining 20% and the overall dataset. RESULTS:The semiquantitative mean histogram scoring strategy with a cut-off value of 78 (range 0-255) showed the best and most reproducible performance in prediction of malignancy with 93% overall sensitivity, 75% specificity, 69% positive predictive value, 95% negative predictive value, and 82% accuracy. Combining the EBUS-SE mean histogram scoring outcome with PET-CT information increased the post-test probability of disease in relevant clinical scenarios, having a positive test likelihood ratio of 4.16 (95% CI 2.98-8.13) and a negative test likelihood ratio of 0.14 (95% CI 0.04-2.81) in suspicious lymph nodes based on FDG-PET or CT imaging. CONCLUSIONS:EBUS-SE can potentially help predict lymph node malignancy in patients with lung cancer. The best semiquantitative assessment method is the mean strain histogram technique.
| S-EPMC6492606 | biostudies-literature
Project description:Introduction: Identifying the HER2 status of breast cancer patients is important for treatment options. Previous studies have shown that ultrasound features are closely related to the subtype of breast cancer. Methods: In this study, we used features of conventional ultrasound and ultrasound elastography to predict HER2 status. Results and Discussion: The performance of model (AUROC) with features of conventional ultrasound and ultrasound elastography is higher than that of the model with features of conventional ultrasound (0.82 vs. 0.53). The SHAP method was used to explore the interpretability of the models. Compared with HER2- tumors, HER2+ tumors usually have greater elastic modulus parameters and microcalcifications. Therefore, we concluded that the features of conventional ultrasound combined with ultrasound elastography could improve the accuracy for predicting HER2 status.
| S-EPMC10369848 | biostudies-literature
Project description:Obtaining accurate displacement estimates along both axial (parallel to the acoustic beam) and lateral (perpendicular to the beam) directions is an important task for several clinical applications such as shear strain imaging, modulus reconstruction and temperature imaging, where a full description of the two or three-dimensional (2D/3D) deformation field is required. In this study we propose an improved speckle tracking algorithm where axial and lateral motion estimations are simultaneously performed to enhance motion tracking accuracy. More specifically, using conventional ultrasound echo data, this algorithm first finds an iso-contour in the vicinity of the peak correlation between two segments of the pre- and post-deformation ultrasound radiofrequency echo data. The algorithm then attempts to find the center of the iso-contour of the correlation function that corresponds to the unknown (sub-sample) motion vector between these two segments of echo data. This algorithm has been tested using computer-simulated data, studies with a tissue-mimicking phantom, and in vivo breast lesion data. Computer simulation results show that the method improves the accuracy of both lateral and axial tracking. Such improvements are more significant when the deformation is small or along the lateral direction. Results from the tissue-mimicking phantom study are consistent with findings observed in computer simulations. Using in vivo breast lesion data we found that, compared to the 2D quadratic subsample displacement estimation methods, higher quality axial strain and shear strain images (e.g. 18.6% improvement in contrast-to-noise ratio for shear strain images) can be obtained for large deformations (up to 5% frame-to-frame and 15% local strains) in a multi-compression technique. Our initial results demonstrated that this conceptually and computationally simple method could improve the image quality of ultrasound-based strain elastography with current clinical equipment.
| S-EPMC4729314 | biostudies-literature