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Water-suppression cycling 3-T cardiac 1 H-MRS detects altered creatine and choline in patients with aortic or mitral stenosis.

Accepted version
Peer-reviewed

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Authors

Peterzan, Mark 
Rider, Oliver J 
Valkovič, Ladislav 

Abstract

Cardiac proton spectroscopy (1 H-MRS) is widely used to quantify lipids. Other metabolites (e.g. creatine and choline) are clinically relevant but more challenging to quantify because of their low concentrations (approximately 10 mmol/L) and because of cardiac motion. To quantify cardiac creatine and choline, we added water-suppression cycling (WSC) to two single-voxel spectroscopy sequences (STEAM and PRESS). WSC introduces controlled residual water signals that alternate between positive and negative phases from transient to transient, enabling robust phase and frequency correction. Moreover, a particular weighted sum of transients eliminates residual water signals without baseline distortion. We compared WSC and the vendor's standard 'WET' water suppression in phantoms. Next, we tested repeatability in 10 volunteers (seven males, three females; age 29.3 ± 4.0 years; body mass index [BMI] 23.7 ± 4.1 kg/m2 ). Fat fraction, creatine concentration and choline concentration when quantified by STEAM-WET were 0.30% ± 0.11%, 29.6 ± 7.0 μmol/g and 7.9 ± 6.7 μmol/g, respectively; and when quantified by PRESS-WSC they were 0.30% ± 0.15%, 31.5 ± 3.1 μmol/g and 8.3 ± 4.4 μmol/g, respectively. Compared with STEAM-WET, PRESS-WSC gave spectra whose fitting quality expressed by Cramér-Rao lower bounds improved by 26% for creatine and 32% for choline. Repeatability of metabolite concentration measurements improved by 72% for creatine and 40% for choline. We also compared STEAM-WET and PRESS-WSC in 13 patients with severe symptomatic aortic or mitral stenosis indicated for valve replacement surgery (10 males, three females; age 75.9 ± 6.3 years; BMI 27.4 ± 4.3 kg/m2 ). Spectra were of analysable quality in eight patients for STEAM-WET, and in nine for PRESS-WSC. We observed comparable lipid concentrations with those in healthy volunteers, significantly reduced creatine concentrations, and a trend towards decreased choline concentrations. We conclude that PRESS-WSC offers improved performance and reproducibility for the quantification of cardiac lipids, creatine and choline concentrations in healthy volunteers at 3 T. It also offers improved performance compared with STEAM-WET for detecting altered creatine and choline concentrations in patients with valve disease.

Description

Keywords

1H-MRS, 3 T, PRESS, STEAM, cardiac, heart, human, water-suppression cycling, Adult, Aged, Aortic Valve Stenosis, Choline, Cohort Studies, Creatine, Female, Healthy Volunteers, Humans, Male, Metabolome, Middle Aged, Mitral Valve Stenosis, Myocardium, Phantoms, Imaging, Proton Magnetic Resonance Spectroscopy, Reproducibility of Results, Signal-To-Noise Ratio, Water, Young Adult

Journal Title

NMR Biomed

Conference Name

Journal ISSN

0952-3480
1099-1492

Volume Title

34

Publisher

Wiley

Rights

All rights reserved
Sponsorship
Wellcome Trust (Unknown)
Wellcome Trust (098436/Z/12/B)
Medical Research Council (MR/M008983/1)
BD is currently funded by Gates Cambridge Trust. MAP was supported by a British Heart Foundation Clinical Research Training Fellowship [FS/15/80/31803]. FEM was funded by a UK Medical Research Council Doctoral Training Award (MR/K501256/1), a Scatcherd European Scholarship and the RDM Scholars Programme. OR is supported by a British Heart Foundation Intermediate Fellowship. LV acknowledges support of the Slovak Grant Agencies VEGA [2/0003/20] and APVV [#19-0032]. CTR is funded by a Sir Henry Dale Fellowship from the Wellcome Trust and the Royal Society [098436/Z/12/B]. We acknowledge support from the Oxford NIHR BRC, and the Cambridge NIHR BRC (BRC-1215-20014). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.