MRI-Compatible Injection System for Magnetic Microparticle Embolization

Li, Ning; Michaud, François; Nosrati, Zeynab; Loghin, Dumitru; Tremblay, Christine; Plantefève, Rosalie; Saatchi, Katayoun; Häfeli, Urs O.; Soulez, Gilles

doi:10.1109/tbme.2018.2889000

Cited by 14 publications

(15 citation statements)

References 36 publications

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“…In particular, magnetic microspheres (MMS) are considered advantageous for biomedical applications due to their chemical stability, 15 biocompatibility 15,16 and ease of transport within blood vessels, if they can be produced at a size (o3 mm) suitable for flow inside hepatic arteries. 17 Magnetite (Fe 3 O 4 ) microspheres and nanospheres have been investigated for magnetic-induced hyperthermia treatment of cancers 18 and have been employed successfully as contrast agents in magnetic resonance imaging (MRI), 15,19 whilst targeted magnetic drug-delivery systems are currently at the pre-clinical stage. 15 MMP have also proved beneficial for environmental remediation, including the removal of heavy metals and radionuclides from contaminated soil and water, and phosphates from wastewater, 15,20 along with oils and chemicals/toxins from the environment.…”

Section: Introductionmentioning

confidence: 99%

Flame spheroidisation of dense and porous Ca₂Fe₂O₅ microspheres

et al. 2020

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Section: Introductionmentioning

confidence: 99%

Flame spheroidisation of dense and porous Ca₂Fe₂O₅ microspheres

et al. 2020

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“…When the aggregate has reached a predetermined size as shown by an infrared optical sensor, the flow in the MMP suspension tube is stopped, the magnet is pulled away from the aggregation area, and the aggregate is pushed into the catheter by a fluid injection from a second tubing. This device was successfully used to controllably and reproducibly inject aggregates of 25 ± 6 MMPs …”

Section: Methodsmentioning

confidence: 99%

“…An MR-compatible injector which can controllably form and release MDEBs aggregates has been proposed. 22 The first objective of this study was to determine if a slow laminar flow compatible with MRN could be achieved by occlusion of the proper hepatic artery with injection of saline distally to a balloon catheter in an animal model. The second objective was to assess the feasibility of MRN for selective embolization with magnetized microparticle (MMP) aggregates in a vascular phantom replicating physiological conditions.…”

Section: Magneticmentioning

confidence: 99%

“…This device was successfully used to controllably and reproducibly inject aggregates of 25 AE 6 MMPs. 22…”

Section: D Automated Mmp Injectormentioning

confidence: 99%

“…Furthermore, studies using small microbeads were performed with continuous injection of microbeads aggregates, an approach that is not compatible with particle navigation across two‐branch divisions since steering gradients must be applied in a timely fashion to steer particles successively in different directions. An MR‐compatible injector which can controllably form and release MDEBs aggregates has been proposed …”

Section: Introductionmentioning

confidence: 99%

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Selective embolization with magnetized microbeads using magnetic resonance navigation in a controlled‐flow liver model

Michaud

Plantefève

et al. 2018

Medical Physics

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Purpose The purpose of this study was to demonstrate the feasibility of using a custom gradient sequence on an unmodified 3T magnetic resonance imaging (MRI) scanner to perform magnetic resonance navigation (MRN) by investigating the blood flow control method in vivo, reproducing the obtained rheology in a phantom mimicking porcine hepatic arterial anatomy, injecting magnetized microbead aggregates through an implantable catheter, and steering the aggregates across arterial bifurcations for selective tumor embolization. Materials and Methods In the first phase, arterial hepatic velocity was measured using cine phase‐contrast imaging in seven pigs under free‐flow conditions and controlled‐flow conditions, whereby a balloon catheter is used to occlude arterial flow and saline is injected at different rates. Three of the seven pigs previously underwent selective lobe embolization to simulate a chemoembolization procedure. In the second phase, the measured in vivo controlled‐flow velocities were approximately reproduced in a Y‐shaped vascular bifurcation phantom by injecting saline at an average rate of 0.6 mL/s with a pulsatile component. Aggregates of 200‐μm magnetized particles were steered toward the right or left hepatic branch using a 20‐mT/m MRN gradient. The phantom was oriented at 0°, 45°, and 90° with respect to the B0 magnetic field. The steering differences between left–right gradient and baseline were calculated using Fisher's exact test. A theoretical model of the trajectory of the aggregate within the main phantom branch taking into account gravity, magnetic force, and hydrodynamic drag was also designed, solved, and validated against the experimental results to characterize the physical limitations of the method. Results At an injection rate of 0.5 mL/s, the average flow velocity decreased from 20 ± 15 to 8.4 ± 5.0 cm/s after occlusion in nonembolized pigs and from 13.6 ± 2.0 to 5.4 ± 3.0 cm/s in previously embolized pigs. The pulsatility index measured to be 1.7 ± 1.8 and 1.1 ± 0.1 for nonembolized and embolized pigs, respectively, decreased to 0.6 ± 0.4 and 0.7 ± 0.3 after occlusion. For MRN performed at each orientation, the left–right distribution of aggregates was 55%, 25%, and 75% on baseline and 100%, 100%, and 100% (P < 0.001, P = 0.003, P = 0.003) after the application of MRN, respectively. According to the theoretical model, the aggregate reaches a stable transverse position located toward the direction of the gradient at a distance equal to 5.8% of the radius away from the centerline within 0.11 s, at which point the aggregate will have transited through a longitudinal distance of 1.0 mm from its release position. Conclusion In this study, we showed that the use of a balloon catheter reduces arterial hepatic flow magnitude and variation with the aim to reduce steering failures caused by fast blood flow rates and low magnetic steering forces. A mathematical model confirmed that the reduced flow rate is low enough to maximize steering ratio. After reproducing the flow rate in a vascular bifur...

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