Imperial College London
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DrJamesChoi

Faculty of Engineering, Department of Bioengineering

Senior Lecturer
 
 
 
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Contact

 

+44 (0)20 7594 1777j.choi Website

 
 
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Location

 

RSM 4.06Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

72 results found

Coviello C, Kozick R, Choi J, Gyoengy M, Jensen C, Smith PP, Coussios C-Cet al., 2015, Passive acoustic mapping utilizing optimal beamforming in ultrasound therapy monitoring, JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, Vol: 137, Pages: 2573-2585, ISSN: 0001-4966

Journal article

Pouliopoulos AN, Bonaccorsi S, Choi JJ, 2014, Exploiting flow to control the <i>in vitro</i> spatiotemporal distribution of microbubble-seeded acoustic cavitation activity in ultrasound therapy, PHYSICS IN MEDICINE AND BIOLOGY, Vol: 59, Pages: 6941-6957, ISSN: 0031-9155

Journal article

Choi JJ, Carlisle RC, Coviello C, Seymour L, Coussios C-Cet al., 2014, Non-invasive and real-time passive acoustic mapping of ultrasound-mediated drug delivery, Physics in Medicine and Biology, Vol: 59, Pages: 4861-4877, ISSN: 0031-9155

New classes of biologically active materials, such as viruses, siRNA, antibodies and a wide range of engineered nanoparticles have emerged as potent agents for diagnosing and treating diseases, yet many of these agents fail because there is no effective route of delivery to their intended targets. Focused ultrasound and its ability to drive microbubble-seeded cavitation have been shown to facilitate drug delivery. However, cavitation is difficult to control temporally and spatially, making prediction of therapeutic outcomes deep in the body difficult. Here, we utilized passive acoustic mapping in vivo to understand how ultrasound parameters influence cavitation dynamics and to correlate spatial maps of cavitation to drug delivery. Focused ultrasound (center frequency: 0.5 MHz, peak-rarefactional pressure: 1.2 MPa, pulse length: 25 cycles or 50,000 cycles, pulse repetition interval: 0.02, 0.2, 1 or 3 s, number of pulses: 80 pulses) was applied to murine xenograft-model tumors in vivo during systemic injection of microbubbles with and without cavitation-sensitive liposomes or type 5 adenoviruses. Analysis of in vivo cavitation dynamics through several pulses revealed that cavitation was more efficiently produced at a lower pulse repetition frequency of 1 Hz than at 50 Hz. Within a pulse, inertial cavitation activity was shown to persist but reduced to 50% and 25% of its initial magnitude in 4.3 and 29.3 ms, respectively. Both through several pulses and within a pulse, the spatial distribution of cavitation was shown to change in time due to variations in microbubble distribution present in tumors. Finally, we demonstrated that the centroid of the mapped cavitation activity was within 1.33  ±  0.6 mm and 0.36 mm from the centroid location of drug release from liposomes and expression of the reporter gene encoded by the adenovirus, respectively. Thus passive acoustic mapping not only unraveled

Journal article

Graham SM, Carlisle R, Choi JJ, Stevenson M, Shah AR, Myers RS, Fisher K, Peregrino M-B, Seymour L, Coussios CCet al., 2014, Inertial cavitation to non-invasively trigger and monitor intratumoral release of drug from intravenously delivered liposomes, JOURNAL OF CONTROLLED RELEASE, Vol: 178, Pages: 101-107, ISSN: 0168-3659

Journal article

Carlisle R, Choi J, Bazan-Peregrino M, Laga R, Subr V, Kostka L, Ulbrich K, Coussios C-C, Seymour LWet al., 2013, Enhanced Tumor Uptake and Penetration of Virotherapy Using Polymer Stealthing and Focused Ultrasound, JNCI-JOURNAL OF THE NATIONAL CANCER INSTITUTE, Vol: 105, Pages: 1701-1710, ISSN: 0027-8874

Journal article

Graham SM, Myers RS, Choi J, Bazan-Peregrino M, Seymour L, Carlisle R, Coussios CCet al., 2013, Use of micro- and nano-sized inertial cavitation nuclei to trigger and map drug release from cavitation-sensitive liposomes.

Encapsulation of cytotoxic drugs into liposomes enhances pharmacokinetics and improves passive accumulation in tumors. However, stable liposomes have limited drug release, and thus action, at the target site. This inefficient and unpredictable drug release is compounded by a lack of low-cost, non-invasive methods to map release in real time. We present a new liposomal vehicle that is exclusively triggered by inertial cavitation. Ultrasound exposure of these liposomes in the absence of SonoVue® provided no increase in drug release, whilst with SonoVue® at inertial cavitation pressure levels a substantial (30%) and significant (p < 0.001) increase was observed in vitro. A 16-fold increase in the level of drug release within tumors was similarly observed in the presence of inertial cavitation following intravenous delivery. Passive acoustic mapping of inertial cavitation sources during delivery was also found to correlate strongly with the presence of release. However, variability in tumor perfusion indicated that uneven distribution of micron-sized SonoVue® may limit this approach. Nano-scale cavitation nuclei, which may more readily co-localize with 140 nm liposomes, were thus developed and showed similar cavitation energies to SonoVue® in vitro. These nano-nuclei may ultimately provide a more reliable and uniform way to trigger drug release in vivo.

Conference paper

Bazan-Peregrino M, Rifai B, Carlisle RC, Choi J, Arvanitis CD, Seymour LW, Coussios CCet al., 2013, Cavitation-enhanced delivery of a replicating oncolytic adenovirus to tumors using focused ultrasound, JOURNAL OF CONTROLLED RELEASE, Vol: 169, Pages: 40-47, ISSN: 0168-3659

Journal article

Coviello C, Kozick RJ, Choi JJ, Gyöngy M, Collin J, Jensen C, Smith PP, Coussios CCet al., 2013, Passive acoustic mapping using optimal beamforming for real-time monitoring of ultrasound therapy, ISSN: 1939-800X

In ultrasound therapy, passive acoustic mapping (PAM) has been shown to be an effective method for imaging the acoustic emissions generated during treatment providing the potential for real-time therapy monitoring. In both high intensity ultrasound (HIFU) ablative surgery and targeted drug delivery, imaging artefacts at higher amplitude exposure conditions have been observed which make the localization and dosimetry of therapeutically relevant cavitation activity a challenge. Due to these artefacts, correlating drug release or lesion volumes to the PAMs is hindered for many exposures. It is proposed that incorporating optimal beamforming techniques into the PAM framework can reduce and remove these artefacts allowing determination of the extent of cavitation activity during ultrasound therapy. Additionally, optimal beaforming is found to yield improved resolution, good interference suppression, and robustness against steering vector errors. A description of the origin of the artefacts as well as reduction of them by implementing optimal beamforming within PAM will be demonstrated in the context of targeted drug delivery. © 2013 Acoustical Society of America.

Conference paper

Choi JJ, Coussios C-C, 2012, Spatiotemporal evolution of cavitation dynamics exhibited by flowing microbubbles during ultrasound exposure, JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, Vol: 132, Pages: 3538-3549, ISSN: 0001-4966

Journal article

Konofagou EE, Tung Y-S, Choi J, Deffieux T, Baseri B, Vlachos Fet al., 2012, Ultrasound-Induced Blood-Brain Barrier Opening, CURRENT PHARMACEUTICAL BIOTECHNOLOGY, Vol: 13, Pages: 1332-1345, ISSN: 1389-2010

Journal article

Baseri B, Choi JJ, Deffieux T, Samiotaki G, Tung Y-S, Olumolade O, Small SA, Morrison B, Konofagou EEet al., 2012, Activation of signaling pathways following localized delivery of systemically administered neurotrophic factors across the blood-brain barrier using focused ultrasound and microbubbles, PHYSICS IN MEDICINE AND BIOLOGY, Vol: 57, Pages: N65-N81, ISSN: 0031-9155

Journal article

Choi J, Konofagou E, Borden M, 2011, Systems and methods for opening a tissue, US20110295105 A1

Systems and methods for opening a tissue to a target value are disclosed herein. In an exemplary method, a region of the tissue is targeted for opening, a size range of microbubbles corresponding to the target value is determined, microbubbles of the size range are positioned in proximity to the targeted region, and an ultrasound beam is applied to the targeted region such that the tissue is opened with the assistance of the microbubbles to the target value.

Patent

Choi JJ, Selert K, Vlachos F, Wong A, Konofagou EEet al., 2011, Noninvasive and localized neuronal delivery using short ultrasonic pulses and microbubbles, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Vol: 108, Pages: 16539-16544, ISSN: 0027-8424

Journal article

Carlisle R, Choi J, Kostka L, Bazan-Peregrino M, Ulbrich K, Coussios C, Seymour Let al., 2011, Ultrasound-enhanced delivery of polymer-coated oncolytic adenovirus for tumour growth inhibition, Publisher: MARY ANN LIEBERT INC, Pages: A36-A36, ISSN: 1043-0342

Conference paper

Choi JJ, Selert K, Gao Z, Samiotaki G, Baseri B, Konofagou EEet al., 2011, Noninvasive and localized blood-brain barrier disruption using focused ultrasound can be achieved at short pulse lengths and low pulse repetition frequencies, JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM, Vol: 31, Pages: 725-737, ISSN: 0271-678X

Journal article

Tung YS, Vlachos F, Choi JJ, Deffieux T, Selert K, Konofagou EEet al., 2010, In vivo transcranial cavitation detection during ultrasound-inducedblood- brain barrier opening, Pages: 1518-1521, ISSN: 1051-0117

The blood-brain barrier (BBB) has been shown capable being openednoninvasively through the combined application of focused ultrasound (FUS) andmicrobubbles. In order to better identify the underlying mechanism responsiblefor BBB opening as well as associated safety, the in vivo noninvasive andtranscranial cavitation detection associated with FUS-induced BBB opening wasstudied. A cylindrically focused hydrophone, confocal with the FUS transducer,was used as a passive cavitation detector (PCD) to identify the threshold ofinertial cavitation (IC) in the presence of Definity microbubbles. AfterDefinity were injected intravenously, pulsed FUS was applied (frequency: 1.525and 1.5 MHz, peak-negative pressure: 0.15-0.60 MPa, duty cycle: 20%, PRF: 10 Hz,duration: 1 min with 30s interval) on the right hippocampus in twenty-six micein vivo through their intact scalp and skull. T1-weighted MRI was used to verifythe BBB opening. A spectrogram was generated at each pressure in order todetect the inertial cavitation onset and duration. The bubble behavior was showndetectable in vivo through the intact scalp and skull. We demonstrated that: 1)the inertial cavitation response could be detected transcranially during BBBopening; 2) the inertial cavitation pressure threshold lied at 0.45 MPa but theBBB was opened at 0.30 MPa so the BBB can be opened without requiring inertialcavitation; 3) the BBB could be opened without any cellular damage. © 2010IEEE.

Conference paper

Tung Y-S, Vlachos F, Choi JJ, Deffieux T, Selert K, Konofagou EEet al., 2010, <i>In vivo</i> transcranial cavitation threshold detection during ultrasound-induced blood-brain barrier opening in mice, PHYSICS IN MEDICINE AND BIOLOGY, Vol: 55, Pages: 6141-6155, ISSN: 0031-9155

Journal article

Baseri B, Choi JJ, Tung Y-S, Konofagou EEet al., 2010, MULTI-MODALITY SAFETY ASSESSMENT OF BLOOD-BRAIN BARRIER OPENING USING FOCUSED ULTRASOUND AND DEFINITY MICROBUBBLES: A SHORT-TERM STUDY, ULTRASOUND IN MEDICINE AND BIOLOGY, Vol: 36, Pages: 1445-1459, ISSN: 0301-5629

Journal article

Tung Y-S, Choi JJ, Baseri B, Konofagou EEet al., 2010, IDENTIFYING THE INERTIAL CAVITATION THRESHOLD AND SKULL EFFECTS IN A VESSEL PHANTOM USING FOCUSED ULTRASOUND AND MICROBUBBLES, ULTRASOUND IN MEDICINE AND BIOLOGY, Vol: 36, Pages: 840-852, ISSN: 0301-5629

Journal article

Choi JJ, Feshitan JA, Baseri B, Wang S, Tung Y-S, Borden MA, Konofagou EEet al., 2010, Microbubble-Size Dependence of Focused Ultrasound-Induced Blood-Brain Barrier Opening in Mice <i>In Vivo</i>, IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, Vol: 57, Pages: 145-154, ISSN: 0018-9294

Journal article

Choi JJ, Wang S, Tung Y-S, Morrison B, Konofagou EEet al., 2010, MOLECULES OF VARIOUS PHARMACOLOGICALLY-RELEVANT SIZES CAN CROSS THE ULTRASOUND-INDUCED BLOOD-BRAIN BARRIER OPENING <i>IN VIVO</i>, ULTRASOUND IN MEDICINE AND BIOLOGY, Vol: 36, Pages: 58-67, ISSN: 0301-5629

Journal article

Samiotaki G, Vlachos F, Choi JJ, Tung YS, Konofagou EEet al., 2010, Quantitative assessment of <i>in vivo</i> Focused Ultrasound induced Blood-Brain Barrier Opening using Magnetic Resonance Imaging, 2010 IEEE 36th Annual Northeast Bioengineering Conference, Publisher: IEEE, ISSN: 0277-1063

Conference paper

Tung YS, Choi JJ, Konofagou EE, 2010, Identifying the Skull Effects to the Inertial Cavitation Threshold of Microbubbles in a Vessel Phantom, 2010 IEEE 36th Annual Northeast Bioengineering Conference, Publisher: IEEE, ISSN: 0277-1063

Conference paper

Tung Y-S, Choi JJ, Konofagou EE, 2010, Identifying the Inertial Cavitation Pressure Threshold and Skull Effects in a Vessel Phantom Using Focused Ultrasound and Microbubbles, 9th International Symposium on Therapeutic Ultrasound, Publisher: AMER INST PHYSICS, Pages: 186-189, ISSN: 0094-243X

Conference paper

Konofagou EE, Choi J, Baseri B, Selert K, Tung Y-Set al., 2010, Mechanism and Safety at the Threshold of the Blood-Brain Barrier Opening <i>In</i> <i>Vivo</i>, 9th International Symposium on Therapeutic Ultrasound, Publisher: AMER INST PHYSICS, Pages: 172-175, ISSN: 0094-243X

Conference paper

Choi J, Konofagou E, Pernot M, Small Set al., 2009, Systems and methods for opening of the blood-brain barrier of a subject using ultrasound, US20090005711 A1

A system and method for opening the blood-brain barrier in the brain of a subject is disclosed. In some embodiments, a region of the brain of a subject is targeted for opening; and a focused ultrasound beam is applied through the skull of the subject to the targeted region to open the blood-brain barrier in the brain of the subject.

Patent

Choi JJ, Feshitan JA, Wang S, Tung Y-S, Baseri B, Borden MA, Konofagou EEet al., 2009, The Dependence of the Ultrasound-Induced Blood-Brain Barrier Opening Characteristics on Microbubble Size <i>In Vivo</i>, 8th International Symposium on Therapeutic Ultras, Publisher: AMER INST PHYSICS, Pages: 58-+, ISSN: 0094-243X

Conference paper

Konofagou EE, Choi J, Baseri B, Lee Aet al., 2009, Characterization and Optimization of Trans-Blood-Brain Barrier Diffusion In Vivo, 8th International Symposium on Therapeutic Ultras, Publisher: AMER INST PHYSICS, Pages: 418-422, ISSN: 0094-243X

Conference paper

Konofagou EE, Choi J, Lee A, Baseri Bet al., 2009, MOLECULAR IMAGING THROUGH THE BLOOD-BRAIN BARRIER: SAFETY ASSESSMENT AND PARAMETER DEPENDENCE, IEEE International Symposium on Biomedical Imaging - From Nano to Macro, Publisher: IEEE, Pages: 771-+, ISSN: 1945-7928

Conference paper

Wang S, Baseri B, Choi JJ, Tung Y-S, Morrison B, Konofagou EEet al., 2009, Qualitative and Quantitative Analysis of Molecular Delivery Through the Ultrasound-Induced Blood-Brain Barrier Opening in Mice, 8th International Symposium on Therapeutic Ultras, Publisher: AMER INST PHYSICS, Pages: 408-+, ISSN: 0094-243X

Conference paper

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