Magnetic Resonance–Guided Passive Catheter Tracking for Endovascular Therapy

Abstract

Synopsis The use of MR guidance for endovascular intervention is appealing due to its lack of ionizing radiation, high-contrast visualization of vessel walls and adjacent soft tissues, multiplanar capabilities, and potential to incorporate functional information such as flow, fluid dynamics, perfusion, or cardiac motion. Concurrent advances in the design of “real-time” MR fluoroscopy pulse sequences and the development of MR compatible endovascular devices have facilitated progress from initial in vitro and animal feasibility studies of the initial use of MR guidance for endovascular interventions to human clinical applications. This review highlights current state-of-the-art imaging techniques and hardware used for passive tracking of endovascular devices in interventional MRI, including negative contrast, passive contrast, non-proton multispectral, and direct current techniques. The advantages and disadvantages of passive tracking relative to active tracking are also summarized.

A 20‐gauge active needle design with thin‐film printed circuitry for interventional MRI at 0.55T

“…The active needle prototypes were well visualized even when using relatively thick 8 mm slices (Figure 9). The in vivo visualization performance was found acceptable and comparable to previously reviewed iMRI devices 12,17,27 by the interventional cardiologists and MRI technologists in our group when using a validated acquisition strategy. Hence, we believe that clinical translation of the needle prototype is feasible.…”

Real-time CMR guidance for intracardiac and great vessel pressure mapping in patients with congenital heart disease using an MR conditional guidewire—results of 25 patients

“…An MR-certified guidewire could be useful for most of these catheterization procedures. The availability of certified equipment has long been a major bottleneck in the iCMR community (10,26 (27). Knight et al showed that CMR-right heart catheterization can be incorporated into clinical practice for testing of pulmonary hypertension (24).…”

X-ray to MR: the progress of flexible instruments for endovascular navigation

“…In order to visualise the previously described guidewires, passive negative markers are commonly employed. In the negative contrast approach, the incorporated materials or added markers make guidewires visible by introducing localised magnetic field inhomogeneities which lead to the dephasing of adjacent proton spins and a local signal void (susceptibility artefact) on an MR image [136,137]. The common method adopted by research groups and guidewire manufacturers involves the gluing or adhering (super)paramagnetic iron oxide microparticles embedded in curable resin at different (discrete) points along the length of the guidewire to provide better MR visibility.…”

“…An image is considered T 1 -weighted when the signal acquisition parameters are chosen to reflect the variations in T 1 (same applies to T 2 -weighted images). Passive markers can be further classified into negative contrast, positive contrast, and non-proton multispectral contrast [136].…”

“…In the negative contrast approach, the incorporated materials or added markers make instruments visible by introducing localised magnetic field inhomogeneities which lead to the dephasing of adjacent proton spins and a local signal void (susceptibility artefact) on an MR image [136,137]. From the previously described steerable catheters, the ones which make use of the negative contrast effect are constructed from the following materials: nitinol hypotubes [141,142], ferromagnetic spheres [162][163][164][165], and SMA wires [192].…”