Chirp- and random-based coded ultrasonic excitation for localized blood-brain barrier opening

Autor(es)

Kamimura, H. A. S. ^{[1, 2]} ; Wang, S. ^[2] ; Wu, S-Y ^[2] ; Karakatsani, M. E. ^[2] ; Acosta, C. ^[2] ; Carneiro, A. A. O. ^[1] ; Konofagou, E. E. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Phys, Ribeirao Preto, SP - Brazil

^[2] Columbia Univ, Dept Biomed Engn, New York, NY 10027 - USA

• Tipo de documento: Artigo Científico
• Fonte: Physics in Medicine and Biology; v. 60, n. 19, p. 7695-7712, OCT 7 2015.
• Citações Web of Science: 11

Resumo

Chirp- and random-based coded excitation methods have been proposed to reduce standing wave formation and improve focusing of transcranial ultrasound. However, no clear evidence has been shown to support the benefits of these ultrasonic excitation sequences in vivo. This study evaluates the chirp and periodic selection of random frequency (PSRF) coded-excitation methods for opening the blood-brain barrier (BBB) in mice. Three groups of mice (n = 15) were injected with polydisperse microbubbles and sonicated in the caudate putamen using the chirp/PSRF coded (bandwidth: 1.5-1.9 MHz, peak negative pressure: 0.52 MPa, duration: 30 s) or standard ultrasound (frequency: 1.5 MHz, pressure: 0.52 MPa, burst duration: 20 ms, duration: 5 min) sequences. T1-weighted contrast-enhanced MRI scans were performed to quantitatively analyze focused ultrasound induced BBB opening. The mean opening volumes evaluated from the MRI were 9.38 +/- 5.71 mm(3), 8.91 +/- 3.91 mm(3) and 35.47 +/- 5.10 mm(3) for the chirp, random and regular sonications, respectively. The mean cavitation levels were 55.40 +/- 28.43 V.s, 63.87 +/- 29.97 V.s and 356.52 +/- 257.15 V.s for the chirp, random and regular sonications, respectively. The chirp and PSRF coded pulsing sequences improved the BBB opening localization by inducing lower cavitation levels and smaller opening volumes compared to results of the regular sonication technique. Larger bandwidths were associated with more focused targeting but were limited by the frequency response of the transducer, the skull attenuation and the microbubbles optimal frequency range. The coded methods could therefore facilitate highly localized drug delivery as well as benefit other transcranial ultrasound techniques that use higher pressure levels and higher precision to induce the necessary bioeffects in a brain region while avoiding damage to the surrounding healthy tissue. (AU)

• Processo FAPESP: 11/10809-6 - Sonotrombólise por força de radiação acústica focalizada e modulada por duplo feixe
• Beneficiário: Hermes Arytto Salles Kamimura
• Linha de fomento: Bolsas no Brasil - Doutorado
• Processo FAPESP: 13/08116-8 - Fornecimento de energia acústica através de excitação ultrassônica multifrequencial para o tratamento de acidente vascular cerebral isquêmico e os seus efeitos térmicos e eficiência com microbolhas
• Beneficiário: Hermes Arytto Salles Kamimura
• Linha de fomento: Bolsas no Exterior - Estágio de Pesquisa - Doutorado