Safety of MRI‐guided endovascular guidewire applications

Liu, Chia-Ying; Farahani, Keyvan; Lu, David; Duckwiler, Gary; Oppelt, A

doi:10.1002/1522-2586(200007)12:1<75::aid-jmri8>3.0.co;2-#

Cited by 81 publications

(56 citation statements)

References 14 publications

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“…During MRI scanning, radiofrequency energy deposition on long conductive devices such as guidewires may cause heating. 27,53 We used an FDA-approved active guidewire coil designed to prevent heating by decoupling the device during radiofrequency excitation. This study shows a significant improvement in visualization, tracking, and procedure time with such active devices compared with passive guidewires.…”

Section: Discussionmentioning

confidence: 99%

Real-Time Magnetic Resonance Imaging–Guided Stenting of Aortic Coarctation With Commercially Available Catheter Devices in Swine

et al. 2005

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Background-Real-time MR imaging (rtMRI) is now technically capable of guiding catheter-based cardiovascular interventions. Compared with x-ray, rtMRI offers superior tissue imaging in any orientation without ionizing radiation. Translation to clinical trials has awaited the availability of clinical-grade catheter devices that are both MRI visible and safe. We report a preclinical safety and feasibility study of rtMRI-guided stenting in a porcine model of aortic coarctation using only commercially available catheter devices. Method and Results-Coarctation stenting was performed wholly under rtMRI guidance in 13 swine. rtMRI permitted procedure planning, device tracking, and accurate stent deployment. "Active" guidewires, incorporating MRI antennas, improved device visualization compared with unmodified "passive" nitinol guidewires and shortened procedure time (26Ϯ11 versus 106Ϯ42 minutes; Pϭ0.008). Follow-up catheterization and necropsy showed accurate stent deployment, durable gradient reduction, and appropriate neointimal formation. MRI immediately identified aortic rupture when oversized devices were tested. Conclusions-This experience demonstrates preclinical safety and feasibility of rtMRI-guided aortic coarctation stenting using commercially available catheter devices. Patients may benefit from rtMRI in the future because of combined device and tissue imaging, freedom from ionizing radiation, and the ability to identify serious complications promptly. Key Words: angioplasty Ⅲ catheterization Ⅲ coarctation Ⅲ heart defects, congenital Ⅲ stents E ndovascular stenting effectively relieves focal native and recurrent aortic coarctation in children and adults. 1-3 X-ray fluoroscopy (XRF) is used in these procedures with intermittent boluses of iodinated radiocontrast to define anatomic targets and to guide devices. This approach is limited because XRF does not visualize soft tissue, lacks depth perspective, and exposes patients to ionizing radiation.MRI displays soft tissue detail in any spatial orientation, requires no ionizing radiation, and can provide hemodynamic information. Real-time MRI (rtMRI) is now technically feasible and has enabled transcatheter treatment of congenital 4 -7 and acquired 8 -20 cardiovascular disease in animal models and humans.Razavi and colleagues 21 demonstrated safety and feasibility of cardiovascular catheterization in children and adults using a combined XRF and MRI suite. MRI-guided therapeutic human procedures will require conspicuous clinical-grade catheter devices. Our aim was to test the safety and feasibility of wholly MRI-guided stenting of aortic coarctation in swine using commercially available clinical devices. Specifically, we hypothesize that rtMRI can (1) provide safe and accurate device navigation, positioning, and deployment; (2) provide immediate preprocedural and postprocedural anatomic and hemodynamic assessment; (3) provide early recognition of significant complications; and (4) be conducted with catheter devices commercially available in the United States. Me...

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Section: Discussionmentioning

confidence: 99%

Real-Time Magnetic Resonance Imaging–Guided Stenting of Aortic Coarctation With Commercially Available Catheter Devices in Swine

et al. 2005

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“…The second process, induced by the electric component of the RF pulse, is the so-called "antenna effect" (8,9). The electric field couples into a linear conductive wire (the leads) and causes a voltage along the wire according to Maxwell's equations, given by…”

Section: Induced Voltagementioning

confidence: 99%

Active deep brain stimulation during MRI: A feasibility study

Georgi¹,

Stippich²,

Tronnier³

et al. 2004

Magnetic Resonance in Med

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The goal of this study was to evaluate the feasibility of active deep brain stimulation (DBS) during the application of standard clinical sequences for functional MRI (fMRI) in phantom measurements. During active DBS, we investigated induced voltage, temperature at the electrode tips and lead, forces on the electrode and lead, consequences of defective leads and loose connections, proper operation of the neurostimulator, and image quality. Sequences for diffusion-and perfusion-weighted imaging, fMRI, and morphologic MRI were used. The DBS electrode and lead were placed in a NaCl solution-filled phantom. Over the past decade, deep brain stimulation (DBS) has become an established technique in the neurosurgical treatment of patients suffering from medically intractable, chronic pain, Parkinson's disease, or seizures. However, about 30% of the patients in whom electrodes were implanted did not improve clinically (1,2).MRI examinations to map activity, perfusion, and cellular integrity in the human brain (e.g., fMRI, perfusionweighted imaging, and diffusion-weighted imaging) have become an integral part of clinical radiodiagnostics. If these techniques were also feasible in patients undergoing DBS, they could be used as powerful tools to distinguish between responders and nonresponders to DBS, and to investigate possible causes of treatment success or failure (3). During fMRI, a periodic switching between active and inactive DBS can serve as a stimulation paradigm to map brain activity and assess therapeutic effects.Recent studies (3-7) have suggested that in patients undergoing examination with inactive or disconnected implanted neurostimulators, MRI does not appear to be hazardous because the induced voltage is in the range of a few volts. Given the high frequency of the sinusoidal induced voltage, it was assumed that an action potential could not be evoked in neurons. The temperature increase at the electrodes and the implanted pulse generator (IPG) did not exceed 3.7°C for commonly used positioning and specific absorption rate (SAR) values (4). When the stimulators were switched off during imaging, they worked properly after they were switched on again. Imaging was not affected by the electrodes, except for an MR signal loss near the electrode due to susceptibility artifacts.The results obtained with inactive IPGs and disconnected electrodes cannot be applied to the setup required for fMRI, where the electrodes are connected to an active extracorporeal pulse generator that is switched on and off during the examination. The aim of this study was to investigate the feasibility of fMRI techniques using such an experimental setup. We focused on the question of whether the safety and feasibility of MRI are influenced by 1) the sequences used for the examinations (i.e., diffusionweighted spin-echo EPI, T* 2 gradient-echo EPI for perfusion MRI, and BOLD imaging); 2) the periodic switching (on/off) of the pulse generator during measurements; and 3) the localization of the pulse generator outside the scanning room. THEOR...

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“…The position of these coils along the catheter can be detected simultaneously without penalty in imaging time if each coil is connected to a separate receive channel of the MR system (9). A disadvantage of this method is the cable between the MR system and the coils, which can cause severe RF heating (51)(52)(53).…”

Section: Tracking and Profiling Rf Coilsmentioning

confidence: 99%

MR‐guided intravascular interventions: Techniques and applications

Bock

Wacker

2008

Magnetic Resonance Imaging

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Magnetic resonance imaging (MRI) offers several advantages over other imaging modalities that make it an attractive imaging tool for diagnostic and therapeutic procedures. This tremendous potential of MRI has provided the rationale for increased attention toward MR-guided endovascular interventions. MR guidance has been used recently to navigate endovascular catheters and deliver stents, vena cava filters, embolization materials, and septum closure devices. However, its potential goes beyond just copying existing procedures toward the development of new minimally invasive techniques that cannot be performed with conventional guiding techniques. Because of technical limitations and safety issues associated with some of the currently available devices, a limited number of clinical studies have been performed so far. The overall success for this developing field requires considerable interdisciplinary research within both the interventional and the MR community. Only through a combined effort can this complex technology find its way into clinical practice. This review discusses the hardware and software improvements that have helped to advance endovascular interventions under MR imaging guidance from a pure research tool to become a clinical reality. In addition, technical and safety issues specific to endovascular MR image guidance will be described and practical applications will be shown that take advantage of the benefits of MR for endovascular interventions.

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Safety of MRI‐guided endovascular guidewire applications

Cited by 81 publications

References 14 publications

Real-Time Magnetic Resonance Imaging–Guided Stenting of Aortic Coarctation With Commercially Available Catheter Devices in Swine

Real-Time Magnetic Resonance Imaging–Guided Stenting of Aortic Coarctation With Commercially Available Catheter Devices in Swine

Active deep brain stimulation during MRI: A feasibility study

MR‐guided intravascular interventions: Techniques and applications

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