Multifrequency Time-Harmonic Elastography for the Measurement of Liver Viscoelasticity in Large Tissue Windows

Tzschätzsch, Heiko; Ipek-Ugay, Selcan; Trong, Manh Nguyen; Guo, Jing; Eggers, Jonathan; Gentz, Enno; Fischer, Thomas; Schultz, Michael K.; Braun, Jürgen; Sack, Ingolf

doi:10.1016/j.ultrasmedbio.2014.11.009

Cited by 42 publications

(30 citation statements)

References 34 publications

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“…Shear wave speed as a surrogate of liver stiffness was measured by using a THE system consisting of a custom‐designed vibration bed connected to a standard ultrasound scanner and an elastography computer for online data transfer and processing (GAMPT Merseburg, Germany), operated by one experienced investigator as described previously (Fig. b) . Subjects were examined in a supine position with the right arm in maximal abduction.…”

Section: Methodsmentioning

confidence: 99%

“…Several ultrasound‐based techniques have emerged, among those are transient elastography (TE), point shear wave elastography, and 2D‐shear wave elastography . Time‐harmonic elastography (THE) with external acoustic stimulation was recently introduced for evaluation of shear wave speed (SWS) in large tissue windows at depths up to 13 cm . An improvement of 1D THE, the 2D THE, allows full field‐of‐view shear‐wave speed maps based on the clinical B‐mode ultrasound image .…”

Section: Introductionmentioning

confidence: 99%

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Non‐invasive structure–function assessment of the liver by 2D time‐harmonic elastography and the dynamic Liver MAximum capacity (LiMAx) test

Heucke

Wuensch

Mohr

et al. 2019

J of Gastro and Hepatol

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Background and Aim Accurate assessment of structural and functional characteristics of the liver could improve the diagnosis and the clinical management of patients with chronic liver diseases. However, the structure–function relationship in the progression of chronic liver disease remains elusive. The aim of this study is the combined measurement of liver function by the 13C‐methacetin Liver MAximum capacity (LiMAx) test and tissue‐structure related stiffness by 2D time‐harmonic elastography for the assessment of liver disease progression. Methods LiMAx test and time‐harmonic elastography were applied, and the serological scores fibrosis 4 index and aspartate aminotransferase to platelet ratio index were calculated in patients with chronic liver diseases (n = 75) and healthy control subjects (n = 22). In 47 patients who underwent surgery, fibrosis was graded by histological examination of the resected liver tissue. Results LiMAx values correlated negatively with liver stiffness (r = −0.747), aminotransferase to platelet ratio index (r = −0.604), and fibrosis 4 (r = −0.573). Median (interquartile range) LiMAx values decreased with fibrosis progression from 395 μg/kg/h (371–460 μg/kg/h) in participants with no fibrosis to 173 μg/kg/h (126–309 μg/kg/h) in patients with severe fibrosis. Median liver stiffness increased progressively with the stage of fibrosis from no fibrosis (1.56 m/s [1.52–1.63 m/s]) to moderate fibrosis (1.60 m/s [1.54–1.67 m/s]) to severe fibrosis (1.85 m/s [1.76–1.92 m/s]). Conclusion Our findings show that structural changes in the liver due to progressing liver diseases and reflected by increased tissue stiffness correlate with a functional decline of the organ as reflected by a decreased metabolic capacity of the liver.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Non‐invasive structure–function assessment of the liver by 2D time‐harmonic elastography and the dynamic Liver MAximum capacity (LiMAx) test

Heucke

Wuensch

Mohr

et al. 2019

J of Gastro and Hepatol

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“…Time‐harmonic elastography of the liver was performed with a commercially available elastography system (GAMPT mbH, Merseburg, Germany) consisting of a clinical B‐mode scanner, an actuator‐integrated vibration bed, and an online postprocessing unit for real‐time elastographic feedback . With this system, the liver was mechanically excited by a multifrequency waveform composed of 7 frequencies from 30 to 60 Hz (5‐Hz increments) applied to the back with the participant in the supine position . A single time‐harmonic elastographic shot through the intercostal spaces along an A‐line profile of approximately 14 cm in length and guided by B‐mode sonography took 1 second, during which the volunteers were instructed to either hold their breath in shallow expiration or to perform a 3‐second Valsalva maneuver as described above.…”

Section: Methodsmentioning

confidence: 99%

“…A single time‐harmonic elastographic shot through the intercostal spaces along an A‐line profile of approximately 14 cm in length and guided by B‐mode sonography took 1 second, during which the volunteers were instructed to either hold their breath in shallow expiration or to perform a 3‐second Valsalva maneuver as described above. Corresponding to the method proposed previously, we repeated the measurement 40 times with slightly changed views under both normal and Valsalva conditions in an interleaved fashion to retrieve 2 wave speed values (liver stiffness in meters per second), 1 for the measurement under normal conditions and 1 for the measurement during the Valsalva maneuver. Additionally, our algorithm recovered the slope of the wave speed over the drive frequency, as explained previously .…”

Section: Methodsmentioning

confidence: 99%

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Physiologic Reduction of Hepatic Venous Blood Flow by the Valsalva Maneuver Decreases Liver Stiffness

et al. 2017

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In vivo wideband multifrequency MR elastography of the human brain and liver

Dittmann

Hirsch

Tzschätzsch

et al. 2015

Magnetic Resonance in Med

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Purpose: To demonstrate the feasibility of in vivo wideband MR elastography (wMRE) using continuous, time-harmonic shear vibrations in the frequency range of 10-50 Hz. Theory and Methods: The method was tested in a gel phantom with marked mechanical loss. The brains and livers of eight volunteers were scanned by wMRE using multislice, single-shot MRE with optimized fractional encoding and synchronization of sequence acquisition to vibration. Multifrequency three-dimensional inversion was used to reconstruct compound maps of magnitude jG*j and phase u of the complex shear modulus. A new phase estimation, u*, was developed to avoid systematic bias due to noise. Results: In the phantom, G*-dispersion measured by wMRE agreed well with oscillatory shear rheometry. jG*j and u* measured at vibrations of 10-25 HZ, 25-35 HZ, and 40-50 HZ were 0.62 6 0.08, 1.56 6 0.16, 2.18 6 0.20 kPa and 0.09 6 0.17, 0.39 6 0.16, 0.20 6 0.13 rad in brain and 0.89 6 0.11, 1.67 6 0.20, 2.27 6 0.35 kPa and 0.15 6 0.10, 0.24 6 0.05, 0.26 6 0.05 rad in liver. Elastograms including all frequencies showed the best resolution of anatomical detail with jG*j ¼ 1.38 6 0.12 kPa, u* ¼ 0.24 6 0.10 rad (brain) and jG*j ¼ 1.79 6 0.23 kPa, u* ¼ 0.24 6 0.05 rad (liver). Conclusion: wMRE reveals highly dispersive G* properties of the brain and liver, and our results suggest that the influence of large-scale structures such as fluid-filled vessels and sulci on the MRE-measured parameters increases at low vibration frequencies.

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Multifrequency Time-Harmonic Elastography for the Measurement of Liver Viscoelasticity in Large Tissue Windows

Cited by 42 publications

References 34 publications

Non‐invasive structure–function assessment of the liver by 2D time‐harmonic elastography and the dynamic Liver MAximum capacity (LiMAx) test

Non‐invasive structure–function assessment of the liver by 2D time‐harmonic elastography and the dynamic Liver MAximum capacity (LiMAx) test

Physiologic Reduction of Hepatic Venous Blood Flow by the Valsalva Maneuver Decreases Liver Stiffness

In vivo wideband multifrequency MR elastography of the human brain and liver

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