Document Detail

Method for in situ characterization of radiofrequency heating in parallel transmit MRI.
MedLine Citation:
PMID:  22714806     Owner:  NLM     Status:  MEDLINE    
In ultra-high-field magnetic resonance imaging, parallel radiofrequency (RF) transmission presents both opportunities and challenges for specific absorption rate management. On one hand, parallel transmission provides flexibility in tailoring electric fields in the body while facilitating magnetization profile control. On the other hand, it increases the complexity of energy deposition as well as possibly exacerbating local specific absorption rate by improper design or delivery of RF pulses. This study shows that the information needed to characterize RF heating in parallel transmission is contained within a local power correlation matrix. Building upon a calibration scheme involving a finite number of magnetic resonance thermometry measurements, this work establishes a way of estimating the local power correlation matrix. Determination of this matrix allows prediction of temperature change for an arbitrary parallel transmit RF pulse. In the case of a three transmit coil MR experiment in a phantom, determination and validation of the power correlation matrix were conducted in less than 200 min with induced temperature changes of <4°C. Further optimization and adaptation are possible, and simulations evaluating potential feasibility for in vivo use are presented. The method allows general characteristics indicative of RF coil/pulse safety determined in situ.
Leeor Alon; Cem Murat Deniz; Ryan Brown; Daniel K Sodickson; Yudong Zhu
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2012-06-19
Journal Detail:
Title:  Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine     Volume:  69     ISSN:  1522-2594     ISO Abbreviation:  Magn Reson Med     Publication Date:  2013 May 
Date Detail:
Created Date:  2013-04-18     Completed Date:  2013-11-04     Revised Date:  2014-05-09    
Medline Journal Info:
Nlm Unique ID:  8505245     Medline TA:  Magn Reson Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1457-65     Citation Subset:  IM    
Copyright Information:
Copyright © 2012 Wiley Periodicals, Inc.
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MeSH Terms
Body Temperature / physiology*,  radiation effects*
Computer Simulation
Dose-Response Relationship, Radiation
Heating / methods
Image Interpretation, Computer-Assisted / methods*
Magnetic Fields
Magnetic Resonance Imaging / instrumentation,  methods*
Models, Biological*
Phantoms, Imaging
Radiation Dosage
Reproducibility of Results
Sensitivity and Specificity
Thermography / methods*
Grant Support

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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