King's College London

Research portal

Extended RF shimming: Sequence-level parallel transmission optimization applied to steady-state free precession MRI of the heart

Research output: Contribution to journalArticle

Standard

Extended RF shimming : Sequence-level parallel transmission optimization applied to steady-state free precession MRI of the heart. / Beqiri, Arian; Price, Anthony N.; Padormo, Francesco; Hajnal, Joseph V.; Malik, Shaihan J.

In: NMR in Biomedicine, 06.2017.

Research output: Contribution to journalArticle

Harvard

Beqiri, A, Price, AN, Padormo, F, Hajnal, JV & Malik, SJ 2017, 'Extended RF shimming: Sequence-level parallel transmission optimization applied to steady-state free precession MRI of the heart', NMR in Biomedicine. https://doi.org/10.1002/nbm.3701

APA

Beqiri, A., Price, A. N., Padormo, F., Hajnal, J. V., & Malik, S. J. (2017). Extended RF shimming: Sequence-level parallel transmission optimization applied to steady-state free precession MRI of the heart. NMR in Biomedicine, [e3701]. https://doi.org/10.1002/nbm.3701

Vancouver

Beqiri A, Price AN, Padormo F, Hajnal JV, Malik SJ. Extended RF shimming: Sequence-level parallel transmission optimization applied to steady-state free precession MRI of the heart. NMR in Biomedicine. 2017 Jun. e3701. https://doi.org/10.1002/nbm.3701

Author

Beqiri, Arian ; Price, Anthony N. ; Padormo, Francesco ; Hajnal, Joseph V. ; Malik, Shaihan J. / Extended RF shimming : Sequence-level parallel transmission optimization applied to steady-state free precession MRI of the heart. In: NMR in Biomedicine. 2017.

Bibtex Download

@article{92df9b3de5ad4cb5bfaaa38c841c38e4,
title = "Extended RF shimming: Sequence-level parallel transmission optimization applied to steady-state free precession MRI of the heart",
abstract = "Cardiac magnetic resonance imaging (MRI) at high field presents challenges because of the high specific absorption rate and significant transmit field (B1 +) inhomogeneities. Parallel transmission MRI offers the ability to correct for both issues at the level of individual radiofrequency (RF) pulses, but must operate within strict hardware and safety constraints. The constraints are themselves affected by sequence parameters, such as the RF pulse duration and TR, meaning that an overall optimal operating point exists for a given sequence. This work seeks to obtain optimal performance by performing a 'sequence-level' optimization in which pulse sequence parameters are included as part of an RF shimming calculation. The method is applied to balanced steady-state free precession cardiac MRI with the objective of minimizing TR, hence reducing the imaging duration. Results are demonstrated using an eight-channel parallel transmit system operating at 3 T, with an in vivo study carried out on seven male subjects of varying body mass index (BMI). Compared with single-channel operation, a mean-squared-error shimming approach leads to reduced imaging durations of 32 ± 3{\%} with simultaneous improvement in flip angle homogeneity of 32 ± 8{\%} within the myocardium.",
keywords = "Cardiac, Parallel transmission MRI, RF shimming, SAR",
author = "Arian Beqiri and Price, {Anthony N.} and Francesco Padormo and Hajnal, {Joseph V.} and Malik, {Shaihan J.}",
note = "{\circledC} 2017 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.",
year = "2017",
month = "6",
doi = "10.1002/nbm.3701",
language = "English",
journal = "NMR in Biomedicine",
issn = "0952-3480",

}

RIS (suitable for import to EndNote) Download

TY - JOUR

T1 - Extended RF shimming

T2 - Sequence-level parallel transmission optimization applied to steady-state free precession MRI of the heart

AU - Beqiri, Arian

AU - Price, Anthony N.

AU - Padormo, Francesco

AU - Hajnal, Joseph V.

AU - Malik, Shaihan J.

N1 - © 2017 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.

PY - 2017/6

Y1 - 2017/6

N2 - Cardiac magnetic resonance imaging (MRI) at high field presents challenges because of the high specific absorption rate and significant transmit field (B1 +) inhomogeneities. Parallel transmission MRI offers the ability to correct for both issues at the level of individual radiofrequency (RF) pulses, but must operate within strict hardware and safety constraints. The constraints are themselves affected by sequence parameters, such as the RF pulse duration and TR, meaning that an overall optimal operating point exists for a given sequence. This work seeks to obtain optimal performance by performing a 'sequence-level' optimization in which pulse sequence parameters are included as part of an RF shimming calculation. The method is applied to balanced steady-state free precession cardiac MRI with the objective of minimizing TR, hence reducing the imaging duration. Results are demonstrated using an eight-channel parallel transmit system operating at 3 T, with an in vivo study carried out on seven male subjects of varying body mass index (BMI). Compared with single-channel operation, a mean-squared-error shimming approach leads to reduced imaging durations of 32 ± 3% with simultaneous improvement in flip angle homogeneity of 32 ± 8% within the myocardium.

AB - Cardiac magnetic resonance imaging (MRI) at high field presents challenges because of the high specific absorption rate and significant transmit field (B1 +) inhomogeneities. Parallel transmission MRI offers the ability to correct for both issues at the level of individual radiofrequency (RF) pulses, but must operate within strict hardware and safety constraints. The constraints are themselves affected by sequence parameters, such as the RF pulse duration and TR, meaning that an overall optimal operating point exists for a given sequence. This work seeks to obtain optimal performance by performing a 'sequence-level' optimization in which pulse sequence parameters are included as part of an RF shimming calculation. The method is applied to balanced steady-state free precession cardiac MRI with the objective of minimizing TR, hence reducing the imaging duration. Results are demonstrated using an eight-channel parallel transmit system operating at 3 T, with an in vivo study carried out on seven male subjects of varying body mass index (BMI). Compared with single-channel operation, a mean-squared-error shimming approach leads to reduced imaging durations of 32 ± 3% with simultaneous improvement in flip angle homogeneity of 32 ± 8% within the myocardium.

KW - Cardiac

KW - Parallel transmission MRI

KW - RF shimming

KW - SAR

UR - http://www.scopus.com/inward/record.url?scp=85013127219&partnerID=8YFLogxK

U2 - 10.1002/nbm.3701

DO - 10.1002/nbm.3701

M3 - Article

C2 - 28195684

JO - NMR in Biomedicine

JF - NMR in Biomedicine

SN - 0952-3480

M1 - e3701

ER -

View graph of relations

© 2018 King's College London | Strand | London WC2R 2LS | England | United Kingdom | Tel +44 (0)20 7836 5454