Attenuation measuring ultrasound shearwave elastography andin vivoapplication in post-transplant liver patients
Autor: | Ivan Z. Nenadic, Heng Zhao, William Sanchez, Bo Qiang, Shigao Chen, Matthew W. Urban, James F. Greenleaf |
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Rok vydání: | 2016 |
Předmět: |
Graft Rejection
Materials science Swine Quantitative Biology::Tissues and Organs Acoustics Physics::Medical Physics 01 natural sciences Article Viscoelasticity 030218 nuclear medicine & medical imaging 03 medical and health sciences Elasticity Imaging Techniques 0302 clinical medicine 0103 physical sciences medicine Animals Humans Radiology Nuclear Medicine and imaging Elasticity (economics) 010301 acoustics Ultrasonography Radiological and Ultrasound Technology medicine.diagnostic_test Phantoms Imaging Viscosity business.industry Liver Diseases Attenuation Ultrasound Soft tissue Liver Transplantation Magnetic resonance elastography Elastography business Biomedical engineering |
Zdroj: | Physics in Medicine and Biology. 62:484-500 |
ISSN: | 1361-6560 0031-9155 |
Popis: | Ultrasound and magnetic resonance elastography techniques are used to assess mechanical properties of soft tissues. Tissue stiffness is related to various pathologies such as fibrosis, loss of compliance, and cancer. One way to perform elastography is measuring shear wave velocity of propagating waves in tissue induced by intrinsic motion or an external source of vibration, and relating the shear wave velocity to tissue elasticity. All tissues are inherently viscoelastic and ignoring viscosity biases the velocity-based estimates of elasticity and ignores a potentially important parameter of tissue health. We present Attenuation Measuring Ultrasound Shearwave Elastography (AMUSE), a technique that independently measures both shear wave velocity and attenuation in tissue and therefore allows characterization of viscoelasticity without using a rheological model. The theoretical basis for AMUSE is first derived and validated in finite element simulations. AMUSE is validated against the traditional methods for assessing shear wave velocity (phase gradient) and attenuation (amplitude decay) in tissue mimicking phantoms and excised tissue. The results agreed within one standard deviation. AMUSE was used to measure shear wave velocity and attenuation in 15 transplanted livers in patients with potential acute rejection, and the results were compared with the biopsy findings in a preliminary study. The comparison showed excellent agreement and suggests that AMUSE can be used to separate transplanted livers with acute rejection from livers with no rejection. |
Databáze: | OpenAIRE |
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