Document Detail

Velocity navigator for motion compensated thermometry.
MedLine Citation:
PMID:  21373916     Owner:  NLM     Status:  MEDLINE    
OBJECT: Proton resonance frequency shift thermometry is sensitive to breathing motion that leads to incorrect phase differences. In this work, a novel velocity-sensitive navigator technique for triggering MR thermometry image acquisition is presented.
MATERIALS AND METHODS: A segmented echo planar imaging pulse sequence was modified for velocity-triggered temperature mapping. Trigger events were generated when the estimated velocity value was less than 0.2 cm/s during the slowdown phase in parallel to the velocity-encoding direction. To remove remaining high-frequency spikes from pulsation in real time, a Kalman filter was applied to the velocity navigator data. A phantom experiment with heating and an initial volunteer experiment without heating were performed to show the applicability of this technique. Additionally, a breath-hold experiment was conducted for comparison.
RESULTS: A temperature rise of ΔT = +37.3°C was seen in the phantom experiment, and a root mean square error (RMSE) outside the heated region of 2.3°C could be obtained for periodic motion. In the volunteer experiment, a RMSE of 2.7°C/2.9°C (triggered vs. breath hold) was measured.
CONCLUSION: A novel velocity navigator with Kalman filter postprocessing in real time significantly improves the temperature accuracy over non-triggered acquisitions and suggests being comparable to a breath-held acquisition. The proposed technique might be clinically applied for monitoring of thermal ablations in abdominal organs.
Florian Maier; Axel J Krafft; Joshua P Yung; R Jason Stafford; Andrew Elliott; Rüdiger Dillmann; Wolfhard Semmler; Michael Bock
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Publication Detail:
Type:  Journal Article     Date:  2011-03-04
Journal Detail:
Title:  Magma (New York, N.Y.)     Volume:  25     ISSN:  1352-8661     ISO Abbreviation:  MAGMA     Publication Date:  2012 Feb 
Date Detail:
Created Date:  2012-02-03     Completed Date:  2012-07-10     Revised Date:  2014-01-20    
Medline Journal Info:
Nlm Unique ID:  9310752     Medline TA:  MAGMA     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  15-22     Citation Subset:  IM    
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MeSH Terms
Body Temperature
Echo-Planar Imaging / methods
Equipment Design
Hot Temperature
Image Processing, Computer-Assisted
Magnetic Resonance Imaging / methods*
Models, Statistical
Phantoms, Imaging
Time Factors
Reg. No./Substance:

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

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