Publications by authors named "Nicolas Asquier"
Exposure to ultrasound combined with intravenous injection of microbubbles is a technique that can be used to temporarily disrupt the blood-brain barrier. Transcranial monitoring of cavitation can be done with one or more passive cavitation detectors (PCDs). However, the positioning of the PCDs relative to the cavitation site and the attenuation of these signals by the skull are two sources of error in the quantification of cavitation activity.
View Article and Find Full Text PDFPurpose: The blood-brain barrier (BBB) limits the efficacy of drug therapies for glioblastoma (GBM). Preclinical data indicate that low-intensity pulsed ultrasound (LIPU) can transiently disrupt the BBB and increase intracerebral drug concentrations.
Patients And Methods: A first-in-man, single-arm, single-center trial (NCT02253212) was initiated to investigate the transient disruption of the BBB in patients with recurrent GBM.
Article Synopsis
- The study aimed to develop a semiautomatic method to estimate disruption of the blood-brain barrier in glioblastoma patients using an implantable ultrasound device, while also analyzing the correlation between ultrasound-induced signal enhancement (SUISE) and local acoustic pressure in the brain.!* -
- Gd-enhanced MRI images were analyzed to evaluate contrast enhancement before and after ultrasound treatments, with volumes of SUISE calculated and compared against qualitative grades given by clinicians for validation purposes.!* -
- The algorithm demonstrated high accuracy in predicting blood-brain barrier openings and showed a strong correlation between SUISE probability and local acoustic pressure, especially indicating greater enhancement in gray matter than in white matter, paving the way for future clinical
Evaluation of a Three Hydrophones Method for 2-Dimensional Cavitation Localization.
IEEE Trans Ultrason Ferroelectr Freq Control
April 2018
Cavitation is a critical parameter in various therapeutic applications involving ultrasound (US) such as histotrispy, lithothripsy, drug delivery, and cavitation-enhanced hyperthermia. A cavitation exposure outside the region of interest may lead to suboptimal treatment efficacy or in a worse case, to safety issues. Current methods of localizing cavitation are based on imaging approaches, such as beamforming the cavitation signals received passively by a US imager.
View Article and Find Full Text PDFEvaluation of a Three-Hydrophone Method for 2-D Cavitation Localization.
IEEE Trans Ultrason Ferroelectr Freq Control
July 2018
Article Synopsis
- - Cavitation plays a significant role in ultrasound therapies like histotripsy and drug delivery, where proper localization is essential to ensure treatment effectiveness and safety.
- - Current localization techniques rely on expensive imaging methods, prompting the need for a more accessible solution.
- - A new three-hydrophone approach measures delays between sensors to accurately track cavitation sources, achieving similar precision as the cavitation cloud size (2-4 mm) and allowing real-time 3-D localization.