Real‐time MRI guidance of cardiac interventions

Abstract

Cardiac MR is appealing to guide complex cardiac procedures because it is ionizing radiation free and offers flexible soft tissue contrast. Interventional cardiac MR promises to improve existing procedures and enable new ones for complex arrhythmias, as well as congenital and structural heart disease. Guiding invasive procedures demands faster image acquisition, reconstruction and analysis, as well as intuitive intra-procedural display of imaging data. Standard cardiac MR techniques such as 3D anatomical imaging, cardiac function and flow, parameter mapping and late-gadolinium enhancement can be used to gather valuable clinical data at various procedural stages. Rapid intraprocedural image analysis can extract and highlight critical information about interventional targets and outcomes. In some cases, real-time interactive imaging is used to provide a continuous stream of images displayed to interventionalists for dynamic device navigation. Alternatively, devices are navigated relative to a roadmap of major cardiac structures generated through fast segmentation and registration. Interventional devices can be visualized and tracked throughout a procedure with specialized imaging methods. In a clinical setting, advanced imaging must be integrated with other clinical tools and patient data. In order to perform these complex procedures, interventional cardiac MR relies on customized equipment, such as interactive imaging environments, in-room image display, audio communication, hemodynamic monitoring and recording systems, and electroanatomical mapping and ablation systems. Operating in this sophisticated environment requires coordination and planning. This review will provide an overview of the imaging technology used in MRI-guided cardiac interventions. Specifically, this review will outline clinical targets, standard image acquisition and analysis tools, and the integration of these tools into clinical workflow.

Safe guidewire visualization using the modes of a PTx transmit array MR system

“…Catheter‐based procedures in cardiovascular interventions are typically guided under X‐ray fluoroscopy to visualize the guidewire‐catheter system within the surrounding anatomical structures. The use of MRI for guidance leads to both improved soft tissue contrast and elimination of radiation dose . However, many existing interventional devices used under X‐ray guidance are made of metal or contain metal and thus are electrically conductive and may be ferrous.…”

“…The use of MRI for guidance leads to both improved soft tissue contrast and elimination of radiation dose. 1,2 However, many existing interventional devices used under X-ray guidance are made of metal or contain metal and thus are electrically conductive and may be ferrous. Ferrous devices are contraindicated for use in MRI systems either because of excessive forces or production of unacceptable levels of artifact.…”

X‐ray fused with MRI guidance of pre‐selected transcatheter congenital heart disease interventions

“…Ultimately, if soft tissue visualization is necessary to guide interventions, rather than use a 3D image acquired before the intervention and then overlaid onto live fluoroscopy, it would be ideal to perform cases under real‐time 3D soft tissue MRI‐guidance. The clinical translation of real‐time MRI procedures has until recently been limited by lack of available MRI‐compatible and visible catheterization equipment for clinical use; recent progress is promising …”

MSU-Net: Multiscale Statistical U-Net for Real-Time 3D Cardiac MRI Video Segmentation

“…The duration of cardiac surgery (e.g., prosthetic valve implantation in the correct location at the aortic annulus) has been significantly shortened since interactive real-time MRI was getting applied [6]. Interventional real-time MRI has also been adopted for congenital, ischemic, and structural heart disease for its capacity of visualizing 3D anatomy and assessing myocardial tissue as well as local hemodynamics [2]. To achieve real-time MRI guidance, the images need to be segmented on-the-fly, at a speed of at least 30, preferably up to 100 frames per second (FPS) [9,3].…”