Basic Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Radiol. Sep 28, 2018; 10(9): 100-107
Published online Sep 28, 2018. doi: 10.4329/wjr.v10.i9.100
Optimized cardiac magnetic resonance imaging inversion recovery sequence for metal artifact reduction and accurate myocardial scar assessment in patients with cardiac implantable electronic devices
El-Sayed H Ibrahim, Mason Runge, Jadranka Stojanovska, Prachi Agarwal, Maryam Ghadimi-Mahani, Anil Attili, Thomas Chenevert, Chiel den Harder, Frank Bogun
El-Sayed H Ibrahim, Department of Radiology, Medical College of Wisconsin, Milwaukee, WI 53226, United States
Mason Runge, Jadranka Stojanovska, Prachi Agarwal, Maryam Ghadimi-Mahani, Anil Attili, Thomas Chenevert, Frank Bogun, Department of Radiology, University of Michigan, Ann Arbor, MI 48109, United States
Chiel den Harder, Department of Medical Physics, Leiden University Medical Center, Leiden 2333ZA, The Netherlands
Author contributions: Ibrahim EH and Stojanovska J designed research; Ibrahim EH, Stojanovska J, Agarwal P, Ghadimi-Mahani M and Attili A performed research; Ibrahim EH, Stojanovska J and Bogun F analyzed data; Runge M, Chenevert T, den Harder C and Bogun F contributed with analytic tools; Ibrahim E wrote the paper.
Institutional review board statement: The study is approved by the University of Michigan Institutional Review Board.
Informed consent statement: All study participants provided informed written consent prior to study enrollment.
Conflict-of-interest statement: The authors do not have conflicts of interest to declare.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: El-Sayed H Ibrahim, PhD, Associate Professor, Department of Radiology, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226, United States. eibrahim@mcw.edu
Telephone: +1-414-9554663 Fax: +1-414-9556314
Received: April 26, 2018
Peer-review started: April 26, 2018
First decision: May 22, 2018
Revised: July 12, 2018
Accepted: July 14, 2018
Article in press: July 16, 2018
Published online: September 28, 2018
ARTICLE HIGHLIGHTS
Research background

Late gadolinium enhancement magnetic resonance imaging is typically used for myocardial viability imaging. An important application of the late gadolinium enhancement (LGE) technique is the assessment of myocardial scar in patients with ventricular tachycardia (VT) before the ablation procedure.

Research motivation

LGE imaging is challenging in patients with cardiac implantable electronic devices (CIEDs) due to device-generated metal hyperintensity artifacts, which compromise the effect of the IR pulse and obscure the region of interest.

Research objectives

To develop a modified inversion recovery (IR) technique that eliminates the LGE hyperintensity artifacts and improves diagnostic image quality.

Research methods

The modified pulse sequence developed in this study includes a wideband IR RF pulse with adjustable frequency offset and bandwidth, which allows for optimal myocardial signal nulling even in the presence of CIEDs. A phantom experiment was performed and twelve in vivo scans were conducted on patients with CIEDs. The imaging parameters were optimized to improve myocardial nulling and minimize metal artifacts.

Research results

The developed wideband IR sequence significantly minimized the hyperintensity artifacts, such that scar assessment could be confidently performed. Increasing the IR frequency BW results in better artifact reduction, although this improvement is achieved at the cost of incomplete myocardial nulling.

Research conclusions

The developed wideband IR technique minimizes the CIED-generated hyperintensity artifacts without increasing scan time, and allows for accurate identification of ablation targets in VT patients. The RF pulse BW should be set to the minimum value that eliminates the artifact. Further, proper setting of the frequency offset could allow for removing the artifact without the need to increase the frequency BW. Based on the studied cases, optimal BW is in the range of 2000-3000 Hz with optimal frequency shift up to 1000 Hz.

Research perspectives

The developed optimized IR technique allows MRI to play a larger role in treatment planning in VT patients with CIEDs. Future studies should investigate the clinical usefulness of the developed technique by implementing it on a large number of VT patients with different disease stages and CIED types.