Experimental identification of high order Lamb waves and estimation of the mechanical properties of a dry human skull

Mazzotti, Matteo; Sugino, Christopher; Kohtanen, Eetu; Ertürk, Alper; Ruzzene, Massimo

doi:10.1016/j.ultras.2020.106343

Cited by 22 publications

(6 citation statements)

References 27 publications

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“…In this previous study, pore‐free compact plates (aluminum and Plexiglas) were investigated in both simulations and experimentally, while a skull segment of unknown porosity was investigated experimentally. Separately, researchers have also demonstrated the potential for using oblique incidence‐based Lamb waves for characterizing the skull 22,23 . Studies also indicate that transmission at large incidence angles might facilitate aberration reduction, given that the speed of the shear wave is similar to that (i.e., ∼1540 m/s) of ultrasound in soft tissue 18,19,24,25 …”

Section: Introductionmentioning

confidence: 99%

“…Separately, researchers have also demonstrated the potential for using oblique incidence-based Lamb waves for characterizing the skull. 22,23 Studies also indicate that transmission at large incidence angles might facilitate aberration reduction, given that the speed of the shear wave is similar to that (i.e., ∼1540 m/s) of ultrasound in soft tissue. 18,19,24,25 Conversely, other studies indicate that transmitting through the skull at large incidence angles should be avoided in transcranial focused ultrasound therapy due to the substantially higher attenuation of the shear wave relative to that of the longitudinal wave.…”

Section: Introductionmentioning

confidence: 99%

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Effect of skull porosity on ultrasound transmission and wave mode conversion at large incidence angles

2023

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Background Transcranial ultrasound imaging and therapy depend on the efficient transmission of acoustic energy through the skull. Multiple previous studies have concluded that a large incidence angle should be avoided during transcranial‐focused ultrasound therapy to ensure transmission through the skull. Alternatively, some other studies have shown that longitudinal‐to‐shear wave mode conversion might improve transmission through the skull when the incidence angle is increased above the critical angle (i.e., 25° to 30°). Purpose The effect of skull porosity on the transmission of ultrasound through the skull at varying incidence angles was investigated for the first time to elucidate why transmission through the skull at large angles of incidence is decreased in some cases but improved in other cases. Methods Transcranial ultrasound transmission at varying incidence angles (0°–50°) was investigated in phantoms and ex vivo skull samples with varying bone porosity (0% to 28.54% ± 3.36%) using both numerical and experimental methods. First, the elastic acoustic wave transmission through the skull was simulated using micro‐computed tomography data of ex vivo skull samples. The trans‐skull pressure was compared between skull segments having three levels of porosity, that is, low porosity (2.65% ± 0.03%), medium porosity (13.41% ± 0.12%), and high porosity (26.9%). Next, transmission through two 3D‐printed resin skull phantoms (compact vs. porous phantoms) was experimentally measured to test the effect of porous microstructure alone on ultrasound transmission through flat plates. Finally, the effect of skull porosity on ultrasound transmission was investigated experimentally by comparing transmission through two ex vivo human skull segments having similar thicknesses but different porosities (13.78% ± 2.05% vs. 28.54% ± 3.36%). Results Numerical simulations indicated that an increase in transmission pressure occurs at large incidence angles for skull segments having low porosities but not for those with high porosity. In experimental studies, a similar phenomenon was observed. Specifically, for the low porosity skull sample (13.78% ± 2.05%), the normalized pressure was 0.25 when the incidence angle increased to 35°. However, for the high porosity sample (28.54% ± 3.36%), the pressure was no more than 0.1 at large incidence angles. Conclusions These results indicate that the skull porosity has an evident effect on the transmission of ultrasound at large incidence angles. The wave mode conversion at large, oblique incidence angles could enhance the transmission of ultrasound through parts of the skull having lower porosity in the trabecular layer. However, for transcranial ultrasound therapy in the presence of highly porous trabecular bone, transmission at a normal incidence angle is preferable relative to oblique incidence angles due to the higher transmission efficiency.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of skull porosity on ultrasound transmission and wave mode conversion at large incidence angles

2023

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“…occurring far from typical working conditions. Ultrasonic techniques, in particular resonant ultrasound spectroscopy (RUS) [27,28], have successfully helped to determine and investigate the macroscopic mechanical properties on several biological samples including wood [29,30], bones [31,32], or the human skull [33], also in combination with micro-computed tomography (μCT) scans and finite element analysis (FEA) [34], while nano and microscale characterizations are also fundamental to address the same properties at smaller length scales [35][36][37][38][39].…”

Section: Introductionmentioning

confidence: 99%

Multiscale static and dynamic mechanical study of the Turritella terebra and Turritellinella tricarinata seashells

Liu

Lott

et al. 2023

J. R. Soc. Interface.

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Marine shells are designed by nature to ensure mechanical protection from predators and shelter for molluscs living inside them. A large amount of work has been done to study the multiscale mechanical properties of their complex microstructure and to draw inspiration for the design of impact-resistant biomimetic materials. Less is known regarding the dynamic behaviour related to their structure at multiple scales. Here, we present a combined experimental and numerical study of the shells of two different species of gastropod sea snail belonging to the Turritellidae family, featuring a peculiar helicoconic shape with hierarchical spiral elements. The proposed procedure involves the use of micro-computed tomography scans for the accurate determination of geometry, atomic force microscopy and nanoindentation to evaluate local mechanical properties, surface morphology and heterogeneity, as well as resonant ultrasound spectroscopy coupled with finite element analysis simulations to determine global modal behaviour. Results indicate that the specific features of the considered shells, in particular their helicoconic and hierarchical structure, can also be linked to their vibration attenuation behaviour. Moreover, the proposed investigation method can be extended to the study of other natural systems, to determine their structure-related dynamic properties, ultimately aiding the design of bioinspired metamaterials and of structures with advanced vibration control.

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“…[ 5 ], while various aspects of QUS studies with both bio-mimicking samples and ex vivo samples can be found in Refs. [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

Study of Ultrasonic Guided Wave Propagation in Bone Composite Structures for Revealing Osteoporosis Diagnostic Indicators

Glushkov,

Glushkova,

Ermolenko

et al. 2023

Materials

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Tubular bones are layered waveguide structures composed of soft tissue, cortical and porous bone tissue, and bone marrow. Ultrasound diagnostics of such biocomposites are based on the guided wave excitation and registration by piezoelectric transducers applied to the waveguide surface. Meanwhile, the upper sublayers shield the diseased interior, creating difficulties in extracting information about its weakening from the surface signals. To overcome these difficulties, we exploit the advantages of the Green’s matrix-based approach and adopt the methods and algorithms developed for the guided wave structural health monitoring of industrial composites. Based on the computer models implementing this approach and experimental measurements performed on bone phantoms, we analyze the feasibility of using different wave characteristics to detect hidden diagnostic signs of developing osteoporosis. It is shown that, despite the poor excitability of the most useful modes associated with the diseased inner layers, the use of the improved matrix pencil method combined with objective functions based on the Green’s matrix allows for effective monitoring of changes in the elastic moduli of the deeper sublayers. We also note the sensitivity and monotonic dependence of the resonance response frequencies on the degradation of elastic properties, making them a promising indicator for osteoporosis diagnostics.

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Experimental identification of high order Lamb waves and estimation of the mechanical properties of a dry human skull

Cited by 22 publications

References 27 publications

Effect of skull porosity on ultrasound transmission and wave mode conversion at large incidence angles

Effect of skull porosity on ultrasound transmission and wave mode conversion at large incidence angles

Multiscale static and dynamic mechanical study of the Turritella terebra and Turritellinella tricarinata seashells

Study of Ultrasonic Guided Wave Propagation in Bone Composite Structures for Revealing Osteoporosis Diagnostic Indicators

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