Evidence map›Paper›PMID 35940379›Full record

ArticleMagnetic resonance imaging2022

Parallel transmission 2D RARE imaging at 7T with transmit field inhomogeneity mitigation and local SAR control.

Filiz Yetisir, Benedikt A Poser, P Ellen Grant, Elfar Adalsteinsson, Lawrence L Wald, Bastien Guerin

Abstract read
PubMed Full text at PMC Publisher
In one paragraph

Article in Magnetic resonance imaging, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.

0numbers the graph read from it
0cells of the map it votes in
4citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

4 citing papers in PubMed.

  1. Article
  2. Review
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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

6 authors.

Filiz YetisirFetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA. Electronic address: filiz.yetisir@childrens.harvard.edu.
Benedikt A PoserDepartment of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Universiteitssingel 40, 6229 ER Maastricht, the Netherlands.
P Ellen GrantFetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA; Department of Radiology, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA.
Elfar AdalsteinssonDepartment of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 MA Avenue, Cambridge, MA 02139, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, 77 MA Avenue, Cambridge, MA 02139, USA; Institute for Medical Engineering and Science, Massachusetts Institute of Technology, 77 MA Avenue, Cambridge, MA 02139, USA.
Lawrence L WaldDepartment of Radiology, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, 77 MA Avenue, Cambridge, MA 02139, USA; Athinoula A. Martinos Center for Biomedical Imaging, MA General Hospital, 149 13th Street, Charlestown, MA 02129, USA.
Bastien GuerinDepartment of Radiology, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA; Athinoula A. Martinos Center for Biomedical Imaging, MA General Hospital, 149 13th Street, Charlestown, MA 02129, USA.

Funding

Project 4P41EB015896 · NIBIB · MASSACHUSETTS GENERAL HOSPITAL · PI ROSEN, BRUCE R · 2012 to 2018
$9.8M
Advanced Fetal ImagingR01EB017337 · NIBIB · BOSTON CHILDREN'S HOSPITAL · PI ADALSTEINSSON, ELFAR, GRANT, PATRICIA ELLEN · 2014 to 2018
$6.2M
Parallel Excitation Methods for High Field MRIR01EB006847 · NIBIB · MASSACHUSETTS GENERAL HOSPITAL · PI WALD, LAWRENCE L · 2007 to 2020
$5.4M
Foundations of MRI Corticography for mesoscale organization and neuronal circuitryR01MH111444 · NIMH · UNIVERSITY OF CALIFORNIA BERKELEY · PI FEINBERG, DAVID ALAN · 2016 to 2020
$5.1M
Noninvasive Realtime Assessment of Placental Structure and Function with Novel MR Imaging MethodsU01HD087211 · NICHD · BOSTON CHILDREN'S HOSPITAL · PI GRANT, PATRICIA ELLEN, WALD, LAWRENCE L · 2015 to 2015
$4.9M
NIBIB NIH HHS P41 EB015896NIBIB NIH HHS R01 EB006847NIBIB NIH HHS R01 EB017337NICHD NIH HHS U01 HD087211NIMH NIH HHS R01 MH111444
6 · The paper itself

Abstract

purposeWe develop and test a parallel transmit (pTx) pulse design framework to mitigate transmit field inhomogeneity with control of local specific absorption rate (SAR) in 2D rapid acquisition with relaxation enhancement (RARE) imaging at 7T.

methodsWe design large flip angle RF pulses with explicit local SAR constraints by numerical simulation of the Bloch equations. Parallel computation and analytical expressions for the Jacobian and the Hessian matrices are employed to reduce pulse design time. The refocusing-excitation "spokes" pulse pairs are designed to satisfy the Carr-Purcell-Meiboom-Gill (CPMG) condition using a combined magnitude least squares-least squares approach.

resultsIn a simulated dataset, the proposed approach reduced peak local SAR by up to 56% for the same level of refocusing uniformity error and reduced refocusing uniformity error by up to 59% (from 32% to 7%) for the same level of peak local SAR compared to the circularly polarized birdcage mode of the pTx array. Using explicit local SAR constraints also reduced peak local SAR by up to 46% compared to an RF peak power constrained design. The excitation and refocusing uniformity error were reduced from 20%-33% to 4%-6% in single slice phantom experiments. Phantom experiments demonstrated good agreement between the simulated excitation and refocusing uniformity profiles and experimental image shading.

conclusionPTx-designed excitation and refocusing CPMG pulse pairs can mitigate transmit field inhomogeneity in the 2D RARE sequence. Moreover, local SAR can be decreased significantly using pTx, potentially leading to better slice coverage, enabling larger flip angles or faster imaging.

Indexed as

AlgorithmsMagnetic Resonance ImagingBrainImage Interpretation, Computer-AssistedPhantoms, ImagingLocal SARParallel transmissionRARERF pulse designturbo spin echoUltra-high field MRI

Identifiers

PMID35940379
PMCPMC9789791

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.