Optimization of self-reference thermometry using complex field estimation
Article first published online: 30 AUG 2006
Copyright © 2006 Wiley-Liss, Inc.
Magnetic Resonance in Medicine
Volume 56, Issue 4, pages 835–843, October 2006
How to Cite
Kuroda, K., Kokuryo, D., Kumamoto, E., Suzuki, K., Matsuoka, Y. and Keserci, B. (2006), Optimization of self-reference thermometry using complex field estimation. Magn Reson Med, 56: 835–843. doi: 10.1002/mrm.21016
- Issue published online: 21 SEP 2006
- Article first published online: 30 AUG 2006
- Manuscript Accepted: 15 JUN 2006
- Manuscript Revised: 10 JUN 2006
- Manuscript Received: 25 AUG 2005
- Ministry of Education, Sciences and Culture of Japan. Grant Number: 15500325
- chemical shift;
- resonance frequency
Referenceless, or self-reference, thermometry is a technique for mapping temperature differences in the region of interest (ROI) using the baseline phase estimated by extrapolating the field in the surrounding region for estimation (RFE) and subtracting the estimated baseline from the measured field. In the present work a self-reference technique based on complex field estimation using 2D polynomials comprising complex-valued coefficients was proposed and optimized. Numerical simulations with a Gaussian-profiled phase distribution demonstrated that the ROI radius had to be 2.3–2.5 times the standard deviation (SD) of the Gaussian function in order to keep the error below 8% of the peak phase change. The area ratio between the ROI and the RFE had to be larger than 2.0 to maintain the error level. Based on the simulations, and phantom and volunteer experiments, the complex-based method with independently optimized polynomial orders for the two spatial dimensions was compared with the phase-based method using the similar-order optimization strategy. The complex-based method appeared to be useful when phase unwrapping was not removed. Otherwise, the phase-based method yielded equivalent results with less polynomial orders. Magn Reson Med, 2006. © 2006 Wiley-Liss, Inc.