The new insight into the inflammatory response following focused ultrasound-mediated blood-brain barrier disruption.

Background: Despite the great potential of FUS-BBB disruption (FUS-BBBD), it is still controversial whether FUS-BBBD acts as an inducing factor of neuro-inflammation or not, and the biological responses after FUS-BBBD triggers the inflammatory process are poorly understood. The aim of this study is to investigate the safety window for FUS levels based on a comprehensive safety assessment.

Methods: The mice were treated with two different ultrasound parameters (0.

Verification of Blood-Brain Barrier Disruption Based on the Clinical Validation Platform Using a Rat Model with Human Skull.

Methods to improve drug delivery efficiency through blood-brain barrier disruption (BBBD) based on microbubbles and focused ultrasound (FUS) are continuously being studied. However, most studies are being conducted in preclinical trial environments using small animals. The use of the human skull shows differences between the clinical and preclinical trials.

Polarization Inverted Ultrasound Transducer Based on Composite Structure for Tissue Harmonic and Frequency Compound Imaging.

Ultrasound transducer with polarization inversion technique (PIT) can provide dual-frequency feature for tissue harmonic imaging (THI) and frequency compound imaging (FCI). However, in the conventional PIT, the ultrasound intensity is reduced due to the multiple resonance characteristics of the combined piezoelectric element, and it is challenging to handle the thin piezoelectric layer required to make a PIT-based acoustic stack. In this study, an improved PIT using a piezo-composite layer was proposed to compensate for those problems simultaneously.

Interleaved Array Transducer with Polarization Inversion Technique to Implement Ultrasound Tissue Harmonic Imaging.

In ultrasound tissue harmonic imaging (THI), it is preferred that the bandwidth of the array transducer covers at least the fundamental frequency f for transmission and the second harmonic frequency 2f for reception. However, it is challenging to develop an array transducer with a broad bandwidth due to the single resonance characteristics of piezoelectric materials. In this study, we present an improved interleaved array transducer suitable for THI and a dedicated transducer fabrication scheme.

A Phase-Canceled Backing Layer for Ultrasound Linear Array Transducer: Modeling and Experimental Verification.

In this study, a phase-canceled backing layer for ultrasound linear array transducer is presented. The proposed backing layer is composed of multiple blocks operated by a phase inversion technique. Inside the proposed backing layer, the phase of the reflected signals can be canceled by adjusting acoustic impedance, piezoelectric layer contact area, and thickness of each block constituting the backing layer.

Phase-Inverted Multifrequency HIFU Transducer for Lesion Expansion: A Simulation Study.

It has been well known that the treatment time of high-intensity focused ultrasound (HIFU) surgery can be reduced by expanding the focal area per sonication. Previously, a dual-concentric transducer using phase-inverted signals was proposed to axially extend the focal area, but it has suffered from the deep notch point between two focal lobes. In this paper, we propose the improved HIFU transducer with dual-concentric aperture driven by phase-inverted multifrequency signals based on an inversion layer technique.