Accelerated free-breathing 3D T1ρ cardiovascular magnetic resonance using multicoil compressed sensing

Abstract

Background

Endogenous contrast T1ρ cardiovascular magnetic resonance (CMR) can detect scar or infiltrative fibrosis in patients with ischemic or non-ischemic cardiomyopathy. Existing 2D T1ρ techniques have limited spatial coverage or require multiple breath-holds. The purpose of this project was to develop an accelerated, free-breathing 3D T1ρ mapping sequence with whole left ventricle coverage using a multicoil, compressed sensing (CS) reconstruction technique for rapid reconstruction of undersampled k-space data.

Methods

We developed a cardiac- and respiratory-gated, free-breathing 3D T1ρ sequence and acquired data using a variable-density k-space sampling pattern (A = 3). The effect of the transient magnetization trajectory, incomplete recovery of magnetization between T1ρ-preparations (heart rate dependence), and k-space sampling pattern on T1ρ relaxation time error and edge blurring was analyzed using Bloch simulations for normal and chronically infarcted myocardium. Sequence accuracy and repeatability was evaluated using MnCl ₂ phantoms with different T1ρ relaxation times and compared to 2D measurements. We further assessed accuracy and repeatability in healthy subjects and compared these results to 2D breath-held measurements.

Results

The error in T1ρ due to incomplete recovery of magnetization between T1ρ-preparations was T1ρ _healthy = 6.1% and T1ρ _infarct = 10.8% at 60 bpm and T1ρ _healthy = 13.2% and T1ρ _infarct = 19.6% at 90 bpm. At a heart rate of 60 bpm, error from the combined effects of readout-dependent magnetization transients, k-space undersampling and reordering was T1ρ _healthy = 12.6% and T1ρ _infarct = 5.8%. CS reconstructions had improved edge sharpness (blur metric = 0.15) compared to inverse Fourier transform reconstructions (blur metric = 0.48). There was strong agreement between the mean T1ρ estimated from the 2D and accelerated 3D data ( R ² = 0.99; P < 0.05) acquired on the MnCl ₂ phantoms. The mean R1ρ estimated from the accelerated 3D sequence was highly correlated with MnCl ₂ concentration (R ² = 0.99; P < 0.05). 3D T1ρ acquisitions were successful in all human subjects. There was no significant bias between undersampled 3D T1ρ and breath-held 2D T1ρ (mean bias = 0.87) and the measurements had good repeatability (COV _2D = 6.4% and COV _3D = 7.1%).

Conclusions

This is the first report of an accelerated, free-breathing 3D T1ρ mapping of the left ventricle. This technique may improve non-contrast myocardial tissue characterization in patients with heart disease in a scan time appropriate for patients.

Electronic supplementary material

The online version of this article (10.1186/s12968-018-0507-2) contains supplementary material, which is available to authorized users.

Affiliations

[1 ]ISNI 0000 0004 1936 8972, GRID grid.25879.31, Department of Radiology, , Perelman School of Medicine, University of Pennsylvania, ; Philadelphia, PA 19104 USA

[2 ]ISNI 0000 0004 1936 8972, GRID grid.25879.31, Department of Bioengineering, , University of Pennsylvania, ; Philadelphia, PA 19104 USA

[3 ]ISNI 0000 0004 1936 8972, GRID grid.25879.31, Department of Medicine, , University of Pennsylvania, ; Philadelphia, PA 19104 USA

Contributors

Srikant Kamesh Iyer: [e-mail]

Brianna Moon: [e-mail]

Eileen Hwuang: [e-mail]

Yuchi Han: [e-mail]

Michael Solomon: [e-mail]

Harold Litt: [e-mail]

Walter R. Witschey: [e-mail]

Journal

Journal ID (nlm-ta): J Cardiovasc Magn Reson

Journal ID (iso-abbrev): J Cardiovasc Magn Reson

Title: Journal of Cardiovascular Magnetic Resonance

Publisher: BioMed Central (London )

ISSN (Print): 1097-6647

ISSN (Electronic): 1532-429X

Publication date (Electronic): 10 January 2019

Publication date PMC-release 10 January 2019

Publication date Collection 2019

Volume: 21

PubMed ID: 30626437

PMC ID: 6327532

Publisher ID: 507

DOI: 10.1186/s12968-018-0507-2

Copyright statement: © The Author(s). 2019

License:

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License ( http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Funding

Funded by: FundRef http://dx.doi.org/10.13039/100000050, National Heart, Lung, and Blood Institute;

Award ID: R00-HL108157

Award Recipient : Walter R. Witschey

Funded by: FundRef http://dx.doi.org/10.13039/100000002, National Institutes of Health;

Award ID: UL1TR001878

Award Recipient : Walter R. Witschey

Categories

Subject: Research

Custom metadata

issue-copyright-statement © The Author(s) 2019