Interventional MRI - Devices

1351054 - Feasibility of MRI-Guided Cardiac Catheterization, Angioplasty, and Stenting in a 0.55T Scanner with Limited Gradient Performance

Wednesday, January 25, 2023

Location: E-POSTER

Presenting Author(s)

Aimee K. Armstrong, MD

Director, Cardiac Catheterization & Interventional Therapies
Nationwide Children's Hospital
Columbus, Ohio, United States

Primary Author(s)

Aimee K. Armstrong, MD

Director, Cardiac Catheterization & Interventional Therapies
Nationwide Children's Hospital
Columbus, Ohio, United States

Co-Author(s)

RK

Ramkumar Krishnamurthy, PhD

PhD
3Medical and Scientific Affairs, Icon Clinical Research, Ohio, United States
JS

Jason Swinning, RT

RT(R)(CI) RCIS
Nationwide Children's Hospital, United States
YL

Yingmin Liu, PhD

Research Associate
The Ohio State University
Columbus, Ohio, United States
MJ

Matthew Joseph, BS

Technician
The Ohio State University
Columbus, Ohio, United States
NJ

Ning Jin, PhD

Senior Key Expert
Siemens Medical Solutions USA, Inc., Ohio, United States
JP

Jianing Pang, PhD

Staff Scientist
Siemens Medical Solutions USA, Inc., United States
FM

Florian Maier, PhD

Senior Application Developer
Siemens Healthcare GmbH
Erlangen, Bayern, Germany
AK

Axel J. Krafft, PhD

PhD
Siemens Healthcare GmbH
Erlangen, Bayern, Germany
JA

Jalil Ahmed, MSc

M.Sc.
Nano4Imaging GmbH, Germany
PB

Paul Borm, PhD

PhD
Nano4Imaging GmbH, Germany
Orlando P. Simonetti, PhD

Professor, Medicine and Radiology
The Ohio State University
Columbus, Ohio, United States

Disclosure(s):

Orlando P. Simonetti, PhD: No relevant disclosure to display

Background: Low-field (0.55T) magnetic resonance imaging (MRI) may allow MRI-guided intervention using available equipment, as radiofrequency-induced heating of devices is reduced. We tested the feasibility of performing right and left heart catheterization (R&LHC), inferior vena cava (IVC) angioplasty, and IVC stenting with realtime imaging in a 0.55T MAGNETOM Free.Max MRI system (Siemens Healthcare, Erlangen, Germany) with maximum gradient amplitude and slew rate of 26 mT/m and 45 mT/m/ms, respectively. We also evaluated 3 sizes and 2 locations of proprietary MagnaFy MR-visible markers (Nano4Imaging GmbH, Dusseldorf, Germany) on Z-Med balloons (NuMED Inc., Hopkinton, NY).

Methods: Eight juvenile Yorkshire pigs (60.9 ± 9.1kg) underwent catheterization. Arrow balloon wedge catheters (Teleflex, Wayne, PA) with CO2-filled balloons were used for RHC, and Judkins Right catheters (Cook Medical, Bloomington, IN) were used for LHC. The EmeryGlide guidewire (Nano4imaging) was used for both. Ferumoxytol (2 mg/kg) was infused prior to realtime visualization using a prototype interactive spoiled gradient echo sequence (iMRI WIP) with different temporal and spatial resolution settings: 7 frames/sec, TE/TR = 2.8ms/6.0ms, Rate 3 GRAPPA, 3.5 x 3.5 x 10mm voxels; 2.2 frames/sec, TE/TR = 2.8ms/6.2ms, Rate 2 GRAPPA, 1.8 x 1.8 x 9.5mm voxels. IVC angioplasty used 20mm x 3cm Z-Med balloons with 2 MR markers of 0.25mm, 0.5mm, and 1mm widths and 1% gadolinium in the balloon. Mega and Max LD stainless steel stents (Medtronic, Dublin, Ireland) were deployed on Z-Med balloons, and a Covered Mounted CP stent (NuMed) was implanted.

Results: One pig expired during ferumoxytol infusion, but catheterization was performed. RHC was successful in 7/7 pigs with the balloon tip seen well in all realtime protocols (Fig 1). LHC was attempted and successful in 2 pigs, with the EmeryGlide entering the left ventricle. IVC angioplasty was attempted and successful in 4 pigs. Implantation of 6 stainless steel stents and one platinum-iridium stent was successful in all attempts. The 0.5 and 1mm wide markers were more easily seen than the 0.25mm markers. Markers placed 5.5cm apart at the balloon ends (Fig 2 white arrows), as opposed to 3cm apart at the balloon shoulders, were more easily distinguished from the crimped stent (Fig 2 red arrows). The stainless steel stents were seen well before and after deployment, but the platinum-iridium stent caused significant artifact and inability to assess wall apposition. For IVC stenting, the higher resolution, lower frame rate imaging yielded optimal visualization.

Conclusion: This study is the first to show the technical feasibility of R&LHC, IVC angioplasty, and IVC stenting using realtime MRI with a commercially available low field scanner with limited gradient performance. Marking conventional catheters with available passive marker technology (Nano4Imaging) shows conspicuity to allow angioplasty and stenting. For IVC stenting, a higher resolution, lower frame rate image was optimal.