Basha, Tamer

Botnar, Rene M

Jang, Jihye

Nezafat, Maryam

Roujol, Sébastien

Journal of Cardiovascular Magnetic Resonance

Harvard University - DASH 

Myocardial T1 mapping withspectrally-selective inversionpulse to reduce the influence of fatThe Harvard community has made thisarticle openly available.  Please share  howthis access benefits you. Your story mattersCitation Nezafat, Maryam, Sébastien Roujol, Jihye Jang, Tamer Basha,and Rene M Botnar. 2016. “Myocardial T1 mapping withspectrally-selective inversion pulse to reduce the influenceof fat.” Journal of Cardiovascular Magnetic Resonance 18(Suppl 1): P19. doi:10.1186/1532-429X-18-S1-P19. http://dx.doi.org/10.1186/1532-429X-18-S1-P19.Published Version doi:10.1186/1532-429X-18-S1-P19Citable link http://nrs.harvard.edu/urn-3:HUL.InstRepos:29407636Terms of Use This article was downloaded from Harvard University’s DASHrepository, and is made available under the terms and conditionsapplicable to Other Posted Material, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#LAAPOSTER PRESENTATION Open AccessMyocardial T1 mapping with spectrally-selectiveinversion pulse to reduce the influence of fatMaryam Nezafat1,2*, Sébastien Roujol2, Jihye Jang3, Tamer Basha2,4, Rene M Botnar1From 19th Annual SCMR Scientific SessionsLos Angeles, CA, USA. 27-30 January 2016BackgroundChanges in the longitudinal relaxation time (T1) of themyocardium are considered an important imaging-basedbiomarker to detect and quantify diffuse fibrosis. Severalsequences have been suggested to measure myocardialT1 values [1]. However, T1 measurements are ofteninfluenced by the presence of intramyocardial or epicar-dial fat [2,3,4]. The aim of this study was to minimizethe effect of fat in T1 mapping by the use of a waterselective inversion pulse and to investigate the impact ofthis spectrally-selective inversion pulse on T1 measure-ments in the presence of field inhomogeneities.MethodsWe used the recently proposed STONE T1 mappingsequence [5] using a gradient echo imaging readout. Awater selective inversion pulse (f0 = 42.5 MHz, duration= 7 ms) was used instead of the adiabatic inversionpulse to only invert the water signal, and therefore,maintains signal from fat. This combination (WS-STONE) allows to perform T1 mapping of 5 slices andto evaluate the T1 relaxation time of the myocardiumwithout the effect of the fat signal in vivo. The sche-matic of the proposed sequence is shown in Fig 1A.Numerical simulations were performed to study theeffect of B0 and B1 inhomogeneities on the efficiency ofthe inversion pulse and thus on the T1 measurements ofthe sequence. The feasibility of the proposed sequencehas been reported previously in a T1 mapping phantomand healthy volunteers [2]. Phantom imaging was per-formed using butter immerged in a bottle of Gd-dopedwater to evaluate the efficiency of the sequence in voxelscontaining both fat and water. In vivo images were alsoacquired in 9 healthy subjects using a 1.5T PhilipsAchieva scanner equipped with a 32-element cardiaccoil. Scans were performed using free-breathing multi-slice T1 mapping sequence with a respiratory navigator.The imaging parameters included TR/TE = 4.5/2.2 ms,flip angle = 10°, FOV = 300 × 300 mm2, voxel size =2 × 2 mm2, slice thickness = 8 mm and SENSE factor = 2.To generate the T1 map, a 3-parameter fit model wasused.ResultsA representative T1 map of the butter phantomacquired with STONE and WS-STONE is shown inFigure 1B. The measured T1 of butter with theWS-STONE is infinity due to the fact that the fat signalis not disturbed during the magnetization preparationwith the water selective inversion pulse. Results ofnumerical simulations incorporating the effect of the B0and B1 inhomogeneity on the flip angle and measuredT1 are shown in Fig 2, demonstrating only little changesin the flip angle for the clinically expected inhomogene-ities. In vivo T1 mapping of the heart demonstratedgood agreement between the two T1 mapping methods(1125 ± 27 ms for STONE vs. 1115 ± 26 ms forWS-STONE, p = 0.2).ConclusionsWe demonstrate the feasibility of a water selective RFinversion pulse to reduce the fat impact on cardiac T1measurements within the clinically expected range offield inhomogeneities.Authors’ details1Division of Imaging Sciences & Biomedical Engineering, King’s CollegeLondon, London, UK. 2Department of Medicine, Beth Israel DeaconessMedical Center and Harvard Medical School, Boston, MA, USA. 3ComputerAided Medical Procedures, Technische Universität München, Munich,Germany. 4Biomedical Engineering Department, Cairo University, Giza, Egypt.1Division of Imaging Sciences & Biomedical Engineering, King’s CollegeLondon, London, UKFull list of author information is available at the end of the articleNezafat et al. Journal of Cardiovascular MagneticResonance 2016, 18(Suppl 1):P19http://www.jcmr-online.com/content/18/S1/P19© 2016 Nezafat et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided theoriginal work is properly cited. 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.Figure 1 A) Schematic of the STONE sequence with water selective RF pulse. After a water selective inversion pulse 5 slices are acquired(TI1: first Inversion time). Subsequently, the slice order is changed to sampling of all 5 heartbeats for each slice. The same experiment isrepeated with TI2. 11 images acquired for each slice. WS INV: water selective inversion pulse. B) The phantom consists of butter in Gd-dopedwater. The T1 of the water with Gd is 1061 ms and butter is 50 ms.Figure 2 Numerical simulation results for the effect of B0 and B1 off-resonance on A) the inversion flip angle, and B) the measured T1value for a typical myocardial T1 value of 1100 ms.Nezafat et al. Journal of Cardiovascular MagneticResonance 2016, 18(Suppl 1):P19http://www.jcmr-online.com/content/18/S1/P19Page 2 of 3Published: 27 January 2016doi:10.1186/1532-429X-18-S1-P19Cite this article as: Nezafat et al.: Myocardial T1 mapping withspectrally-selective inversion pulse to reduce the influence of fat.Journal of Cardiovascular Magnetic Resonance 2016 18(Suppl 1):P19.Submit your next manuscript to BioMed Centraland take full advantage of: • Convenient online submission• Thorough peer review• No space constraints or color figure charges• Immediate publication on acceptance• Inclusion in PubMed, CAS, Scopus and Google Scholar• Research which is freely available for redistributionSubmit your manuscript at www.biomedcentral.com/submitNezafat et al. Journal of Cardiovascular MagneticResonance 2016, 18(Suppl 1):P19http://www.jcmr-online.com/content/18/S1/P19Page 3 of 3

Myocardial T1 mapping with spectrally-selective inversion pulse to reduce the influence of fat

Maryam Nezafat

Sébastien Roujol

Jihye Jang

Tamer Basha

Rene M Botnar

Springer - Publisher Connector

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Myocardial T1 mapping with spectrally-selective inversion pulse to reduce the influence of fat

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