Dispersion presents both a challenge and a diagnostic opportunity in shear wave elastography (SWE).(SWR) is an inversion technique for processing SWE data acquired using an acoustic radiation force impulse (ARFI) excitation. The main advantage of SWR is that it can characterize the shear properties of homogeneous soft media over a wide frequency range. Assumptions associated with SWR include tissue homogeneity, tissue isotropy, and axisymmetry of the ARFI excitation).Evaluate the validity of the SWR assumptions in ex vivo bovine liver.SWR was used to measure the shear properties of bovine liver tissue as function of frequency over a large frequency range. Assumptions associated with SWR (tissue homogeneity, tissue isotropy, and axisymmetry of the ARFI excitation) were evaluated through measurements performed at multiple locations and probe orientations. Measurements focused on quantities that would reveal violations of the assumptions.Measurements of shear properties were obtained over the 25-250 Hz range, and showed a 4-fold increase in shear storage modulus (from 1 to 4 kPa) and over a 10-fold increase in the loss modulus (from 0.2 to 3 kPa) over that decade-wide frequency range. Measurements under different conditions were highly repeatable, and model error was low in all cases.SWR depends on modeling the ARFI-induced shear wave as a full vector viscoelastic shear wave resulting from an axisymmetric source; it is agnostic to any specific rheological model. Despite this generality, the model makes three main simplifying assumptions. These results show that the modeling assumptions used in SWR are valid in bovine liver over a wide frequency band.
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http://dx.doi.org/10.1088/2057-1976/ad6b31 | DOI Listing |
Magn Reson Med
January 2025
MRI Research Centre, Physics, University of New Brunswick, Fredericton, New Brunswick, Canada.
Purpose: Magnetic resonance elastography (MRE) provides detailed maps of tissue stiffness, helping to diagnose various health conditions, but requires the use of expensive clinical MRI scanners. Our approach utilizes compact, cost-effective portable MR sensors that offer bulk characterization of material properties in a region of interest close to the surface (within 1-2 cm). This accessible instrument could enable routine monitoring and prevention of diseases not readily evaluated with conventional tools.
View Article and Find Full Text PDFJ Ultrasound Med
January 2025
Department of Radiodiagnosis, Government Medical College and Hospital, Chandigarh, India.
Objectives: To determine the efficacy of quantitative shear wave elastography in differentiating benign and malignant axillary lymph nodes (ALN).
Methods: Exactly 127 lymph nodes from 127 patients with clinically palpable axillary swelling were examined by both B-mode sonography and elastography from November 2022 to March 2024. Gray-scale sonograms were evaluated based on: the short-axis diameter, shape, hilum, maximum cortical thickness, and border of the ALN.
J Appl Physiol (1985)
January 2025
Experimental Biomechanics Group, Institute of Structural Mechanics and Dynamics in Aerospace Engineering, Faculty of Aerospace Engineering and Geodesy, University of Stuttgart, Germany.
Characterizing individual muscle behavior is crucial for understanding joint function and adaptations to exercise, diseases, or aging. Shear wave elastography (SWE) is a promising tool for measuring the intrinsic material properties of muscle. This study assessed the passive and active shear modulus of the triceps surae muscle group in 14 volunteers (7 females, 25.
View Article and Find Full Text PDFZhonghua Yi Xue Za Zhi
January 2025
Department of Urology, Henan Joint International Pediatric Urodynamic Laboratory, the First Affiliated Hospital of Zhengzhou University, Zhengzhou450002, China.
To comprehensively evaluate the structure and function of the bladder wall in children using multi-modal ultrasound (MMU). A total of 110 children without urinary symptoms admitted to the First Affiliated Hospital of Zhengzhou University from January 2022 to June 2023 were included prospectively. MMU was performed and the vesical volume (VV), bladder wall thickness (BWT), shear wave velocity (SWV) of the anterior wall, resistance index (RI) and vascularization index (VI) were measured in the filled and emptied bladder respectively, and the ultrasound bladder compliance (UBC) was also calculated.
View Article and Find Full Text PDFUltrasound Med Biol
January 2025
School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan ROC; Center of Physical Therapy, National Taiwan University Hospital, Taipei, Taiwan ROC. Electronic address:
Objective: This study aimed to validate the ultrasound speckle tracking (UST) algorithm, determine the optimal probe location by comparing normalized cross-correlation (NCC) values of muscle displacement at two locations (proximal vs. middle) of the biceps femoris long head (BFlh) using the UST, and investigate the effects of Nordic hamstring curl exercise (NHE) training on BFlh displacement.
Methods: UST efficacy was verified with ex vivo uniaxial testing of porcine leg muscles.
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