Enhancement and Passive Acoustic Mapping of Cavitation from Fluorescently Tagged Magnetic Resonance-Visible Magnetic Microbubbles In Vivo

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• 作者：Calum Crake^&lowast ; ; Joshua Owen^&lowast ; ; Sean Smart^&dagger ; ; Christian Coviello^&lowast ; ; Constantin-C. Coussios^&lowast ; ; Robert Carlisle^&lowast ; ; Eleanor Stride^&lowast ; ; ^{eleanor.stride@eng.ox.ac.uk" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Ultrasound ; Magnetic microbubbles ; Passive acoustic mapping ; Cavitation ; Drug delivery ; Fluorescence ; Magnetic resonance imaging
• 刊名：Ultrasound in Medicine & Biology
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：42
• 期：12
• 页码：3022-3036
• 全文大小：3175 K

文摘

Previous work has indicated the potential of magnetically functionalized microbubbles to localize and enhance cavitation activity under focused ultrasound exposure in vitro. The aim of this study was to investigate magnetic targeting of microbubbles for promotion of cavitation in vivo. Fluorescently labelled magnetic microbubbles were administered intravenously in a murine xenograft model. Cavitation was induced using a 0.5-MHz focused ultrasound transducer at peak negative focal pressures of 1.2–2.0 MPa and monitored in real-time using B-mode imaging and passive acoustic mapping. Magnetic targeting was found to increase the amplitude of the cavitation signal by approximately 50% compared with untargeted bubbles. Post-exposure magnetic resonance imaging indicated deposition of magnetic nanoparticles in tumours. Magnetic targeting was similarly associated with increased fluorescence intensity in the tumours after the experiments. These results suggest that magnetic targeting could potentially be used to improve delivery of cavitation-mediated therapy and that passive acoustic mapping could be used for real-time monitoring of this process.