Passive Directivity Detection Using Individual Biaxial Ultrasound Transducers

Meulenbroek, Nathan; Delgado, Sagid; Curiel, Laura; Waspe, Adam C.; Pichardo, Samuel

doi:10.1109/tuffc.2022.3211484

Cited by 2 publications

(2 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Of further interest is the ability of biaxial transducers to passively detect directivity or the direction of arrival of incident waves based on the amplitude ratio and phase difference of the responses of the P-and L-electrodes (Meulenbroek et al 2023), which could enable acoustic feedback control with a spatially coherent map of microbubble activity. Typical single-element acoustic receivers can provide information about the magnitude and time of an event, but cannot provide spatial information about the event's origin.…”

Section: Discussionmentioning

confidence: 99%

“…Typical single-element acoustic receivers can provide information about the magnitude and time of an event, but cannot provide spatial information about the event's origin. Arrays are therefore utilized to spatially localize sources based on delay-and-sum beamforming and time-of-flight information, though complex geometry can induce reflection, refraction, and scattering with the same time-of-flight information for multiple wave paths (Meulenbroek et al 2023). The ability of biaxial transducers to passively detect directivity with single-element transducers has the potential to distinguish between true signals and reflections (Meulenbroek et al 2023) to enable more consistent effects on blood-brain barrier permeability over large volumes, controlling for spatial variance in vasculature and microbubble response, warranting future investigation.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Biaxial ultrasound driving technique for small animal blood–brain barrier opening

Pellow,

Li,

Delgado

et al. 2023

Phys. Med. Biol.

Self Cite

View full text Add to dashboard Cite

Biaxial driving can more efficiently convert electrical power to forward acoustic power in piezoelectric materials, and the interaction between the orthogonal electric fields can produce a combination of extensional and shear deformations as a function of the phase difference between them to allow dynamic steering of the beam with a single-element. In this study, we demonstrate for the first time the application of a single-element biaxially driven ring transducer in vivo for blood–brain barrier opening in mice, and compare it to that achieved with a conventional single-element highly focused (F# = 0.7) spherical transducer operating at a similar frequency. Transcranial focused ultrasound (0.45 MPa, 10 ms pulse length, 1 Hz repetition frequency, 30 s duration) was applied bilaterally to mice with a 40 μl/kg bolus of DefinityTM microbubbles, employing either a single-element biaxial ring (1.482 MHz, 10 mm inner diameter, 13.75 mm outer diameter) or spherical (1.5 MHz, 35 mm diameter, F# = 0.7; RK50, FUS Instruments) transducer on each side. Follow-up MRI scans (T1 pre- and post- 0.2 mmol/kg Gd injection, T2) were acquired to assess blood–brain barrier opening volume and potential damage. Compared to blood–brain barrier opening achieved with a conventional single-element spherical focused transducer, the opening volume achieved with a single-element biaxial ring transducer was 35% smaller (p = 0.002) with a device of a ring diameter of 40% the aperture size. Axial refocusing was further demonstrated with the single-element biaxial ring transducer, yielding a 1.63 mm deeper, five-fold larger opening volume (p = 0.048) relative to its small-focus mode. The biaxial ring transducer achieved a more localized opening compared to the spherical focused transducer under the same parameters, and further enabled dynamic axial refocusing with a single-element transducer with a smaller fabrication footprint.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%