Clinical Trials Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Cardiol. Sep 26, 2018; 10(9): 110-118
Published online Sep 26, 2018. doi: 10.4330/wjc.v10.i9.110
Accuracy of myocardial viability imaging by cardiac MRI and PET depending on left ventricular function
Peter Hunold, Heinz Jakob, Raimund Erbel, Jörg Barkhausen, Christina Heilmaier
Peter Hunold, Jörg Barkhausen, Clinic for Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck 23538, Germany
Heinz Jakob, Department of Thoracic and Cardiovascular Surgery, West German Heart Center, University of Duisburg-Essen, University Hospital Essen, Essen 45122, Germany
Raimund Erbel, Department of Cardiology, West German Heart Center, University of Duisburg-Essen, University Hospital Essen, Essen 45122, Germany
Christina Heilmaier, Department of Radiology and Nuclear Medicine, Stadtspital Triemli, Zürich 8063, Switzerland
Author contributions: Hunold P and Heilmaier C designed research; Hunold P, Heilmaier C, Barkhausen J, Erbel R and Jakob H acquired data; Hunold P, Heilmaier C and Barkhausen J analyzed data; Heilmaier C and Hunold P wrote the paper; Barkhausen J, Erbel R and Jakob H revised and approved final manuscript version
Institutional review board statement: This study was reviewed and approved by the Institutional review board of the Medical Faculty of the University Essen, Germany (No. 00-142-1497).
Clinical trial registration statement: N/A.
Informed consent statement: All patients gave written informed consent to participate in the study prior to study inclusion and agreed to the evaluation and publication of their anonymized data.
Conflict-of-interest statement: None of the authors states a conflict of interest concerning firms and products reported in this study.
Open-Access: This article is an open-access article which selected by an in-house editor and fully peer-reviewed by external reviewers. It 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: Peter Hunold, MD, Assistant Professor, Vice Chairman, Clinic for Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, Lübeck 23538, Germany. peterhunold@icloud.com
Telephone: +49-451-50017010 Fax: +49-451-50017004
Received: March 29, 2018
Peer-review started: March 29, 2018
First decision: April 23, 2018
Revised: June 28, 2018
Accepted: August 5, 2018
Article in press: August 5, 2018
Published online: September 26, 2018
Processing time: 185 Days and 8.2 Hours
Abstract
AIM

To compare myocardial viability assessment accuracy of cardiac magnetic resonance imaging (CMR) compared to [18F]-fluorodeoxyglucose (FDG)- positron emission tomography (PET) depending on left ventricular (LV) function.

METHODS

One-hundred-five patients with known obstructive coronary artery disease (CAD) and anticipated coronary revascularization were included in the study and examined by CMR on a 1.5T scanner. The CMR protocol consisted of cine-sequences for function analysis and late gadolinium enhancement (LGE) imaging for viability assessment in 8 mm long and contiguous short axis slices. All patients underwent PET using [18F]-FDG. Myocardial scars were rated in both CMR and PET on a segmental basis by a 4-point-scale: Score 1 = no LGE, normal FDG-uptake; score 2 = LGE enhancement < 50% of wall thickness, reduced FDG-uptake ( ≥ 50% of maximum); score 3 = LGE ≥ 50%, reduced FDG-uptake (< 50% of maximum); score 4 = transmural LGE, no FDG-uptake. Segments with score 1 and 2 were categorized “viable”, scores 3 and 4 were categorized as “non-viable”. Patients were divided into three groups based on LV function as determined by CMR: Ejection fraction (EF), < 30%: n = 45; EF: 30%-50%: n = 44; EF > 50%: n = 16). On a segmental basis, the accuracy of CMR in detecting myocardial scar was compared to PET in the total collective and in the three different patient groups.

RESULTS

CMR and PET data of all 105 patients were sufficient for evaluation and 5508 segments were compared in total. In all patients, CMR detected significantly more scars (score 2-4) than PET: 45% vs 40% of all segments (P < 0.0001). In the different LV function groups, CMR found more scar segments than PET in subjects with EF< 30% (55% vs 46%; P < 0.0001) and EF 30%-50% (44% vs 40%; P < 0.005). However, CMR revealed less scars than PET in patients with EF > 50% (15% vs 23%; P < 0.0001). In terms of functional improvement estimation, i.e., expected improvement after revascularization, CMR identified “viable” segments (score 1 and 2) in 72% of segments across all groups, PET in 80% (P < 0.0001). Also in all LV function subgroups, CMR judged less segments viable than PET: EF < 30%, 66% vs 75%; EF = 30%-50%, 72% vs 80%; EF > 50%, 91% vs 94%.

CONCLUSION

CMR and PET reveal different diagnostic accuracy in myocardial viability assessment depending on LV function state. CMR, in general, is less optimistic in functional recovery prediction.

Keywords: Magnetic resonance imaging, Positron-emission tomography, Myocardial infarction, Coronary artery disease, Myocardium, Ventricular dysfunction

Core tip: Both cardiac magnetic resonance imaging (CMR) and [18F]-fluorodeoxyglucose-positron emission tomography (PET) are considered standard methods and reliable in myocardial viability imaging in coronary artery disease. However, CMR in general detects more scar and is, therefore, less optimistic in functional recovery prediction. Moreover, CMR and PET reveal different diagnostic accuracy depending on left ventricular (LV) function state: Particularly in severe and moderate LV function impairment, where revascularization is performed to improve function, CMR detects more scar and less viable myocardium - most probably due to higher spatial resolution. This aspect has not been reported, yet. Irrespective of LV function, PET might overestimate the improvement of regional and global function after revascularization.