Interventional cardiovascular magnetic resonance: state-of-the-art

Abstract

Transcatheter cardiovascular interventions increasingly rely on advanced imaging. X-ray fluoroscopy provides excellent visualization of catheters and devices, but poor visualization of anatomy. In contrast, magnetic resonance imaging (MRI) provides excellent visualization of anatomy and can generate real-time imaging with frame rates similar to X-ray fluoroscopy. Realization of MRI as a primary imaging modality for cardiovascular interventions has been slow, largely because existing guidewires, catheters and other devices create imaging artifacts and can heat dangerously. Nonetheless, numerous clinical centers have started interventional cardiovascular magnetic resonance (iCMR) programs for invasive hemodynamic studies or electrophysiology procedures to leverage the clear advantages of MRI tissue characterization, to quantify cardiac chamber function and flow, and to avoid ionizing radiation exposure. Clinical implementation of more complex cardiovascular interventions has been challenging because catheters and other tools require re-engineering for safety and conspicuity in the iCMR environment. However, recent innovations in scanner and interventional device technology, in particular availability of high performance low-field MRI scanners could be the inflection point, enabling a new generation of iCMR procedures. In this review we review these technical considerations, summarize contemporary clinical iCMR experience, and consider potential future applications.

Keywords: Cardiac catheterization; Electrophysiology; Interventional cardiovascular magnetic resonance; Invasive cardiovascular magnetic resonance; Magnetic resonance imaging; iCMR.

Fig. 1

Sites currently performing iCMR procedures. Orange pins: iCMR diagnostic catheterization sites; Purple pins: iCMR electrophysiology sites. iCMR, interventional cardiovascular magnetic resonance. Map data ©2023 Google

Fig. 2

iCMR atrial flutter ablation. Activation map superimposed on anatomic MR images during CMR-guided atrial flutter ablation. Image courtesy of Ivo van der Bilt, MD and the MRI Ablation Center at Haga Teaching Hospital, Netherlands. CMR, cardiovascular magnetic resonance, iCMR, interventional cardiovascular magnetic resonance

Fig. 3

CMR at low field. A Example cardiac MR images acquired using a high-performance 0.55 T imaging system illustrating the retained image quality. B Real-time bSSFP imaging used for patient right heart catheterization at 0.55 T. C Guidewire (180 cm × 0.035″ Glidewire, Terumo, Tokyo, Japan) heating in an ASTM gel phantom measured at 1.5 T and prototype 0.55 T (both MAGNETOM Aera, Siemens Healthcare, Erlangen, Germany). ASTM American Society for Testing and Materials, bSSFP balanced steady-state free precession, CMR cardiovascular magnetic resonance

Fig. 4

Commercially available non-metallic catheters for iCMR catheterization procedures. A Flow Directed Balloon Catheter, Cook, Model #: FDB5.3-35-80 (Cook, Bloomington, Indiana, United States); B Pulmonary Wedge Pressure Catheter, Model #150075 (Medtronic, Minneapolis, Minnesota, United States); C True Size Monitoring Catheter, Model #111F7 (Edwards Lifesciences, Irvine, California, United States); D Edwards, True Size Hi-Shore Monitoring "T" Tip Catheter, Model #T111F7 (Edwards); E Balloon Wedge Pressure Catheter, Model #AI-07127 (Teleflex, Wayne, Pennsylvania, United States); F True Size Monitoring “S” Tip Catheter, Model #S111F7 (Edwards). iCMR interventional cardiovascular magnetic resonance

Fig. 5

Real-time CMR. A Schematic diagram of real-time MRI fluoroscopy sequences for multi-planar interactive imaging. B Real-time bSSFP images with and without interactive saturation (“magnetization preparation”) pulses for gadolinium-filled balloon visualization from 1.5 T (MAGNETOM Aera, Siemens Healthcare, Erlangen Germany). Typical commercial real-time MRI parameters are 5–10 frames per second using bSSFP at 1.5 T (TE/TR = 1.3/2.6 ms, matrix = 192 × 144, acceleration factor = 2–4). bSSFP: balanced steady-state free precession

Fig. 6

Scar imaging. High-resolution 3D late gadolinium enhancement (LGE) imaging demonstrates heterogenous myocardium in swine 2 months post-myocardial infarction. Regions of tissue heterogeneity (red arrows) and viable tissue channels traversing scar (black arrows) both represent targets in the treatment of ventricular tachycardia. This animal was inducible for ventricular tachycardia. RF radiofrequency. All animal experiments performed according to institutional guidelines

Fig. 7

Visualization of radiofrequency ablations in swine. Top row: T1-weighted images identify coagulation necrosis and demonstrate that the lesion core remains relatively constant in size throughout the imaging period which includes encapsulation and scar deposition. One lesion is small, does not generate a necrotic core, and disappears after peripheral edema (green arrows) fades. Middle row: 3D T2-Mapping demonstrates that edema fades quickly before the 4th day. Bottom row: Late gadolinium enhancement (LGE) imaging can easily visualize two lesions (red arrows) applied on Day 0. On Day 21, a new lesion is applied (black arrows) creating new edema and a necrotic core. All animal experiments performed according to institutional guidelines

Fig. 8

iCMR guided endomyocardial biopsy. A Rapid frame-rate real-time MRI-guided navigation of an active visualization iCMR bioptome to target a focal lesion within the left ventricle, labeled with fluorescent microspheres. The jaws appear as a passive artifact (arrow). B After systemic gadolinium contrast administration, the lesion is visible using inversion-recovery real-time MRI (arrows). Real-time MRI-guided biopsy specimens viewed under (C) transmitted light and (D) ultraviolet light demonstrate higher diagnostic yield compared with X-ray fluoroscopy–guided biopsy specimens viewed under (E) transmitted light and (F) ultraviolet light. Reproduced from Rogers et al. JACC: Basic to Translational Science, 2016. iCMR interventional cardiovascular magnetic resonance