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Investigation of proton density for measuring tissue temperature
Author(s) -
Chen Jing,
Daniel Bruce L.,
Pauly Kim Butts
Publication year - 2006
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.20516
Subject(s) - adipose tissue , muscle tissue , boltzmann constant , nuclear magnetic resonance , linear regression , materials science , chemistry , physics , anatomy , thermodynamics , mathematics , medicine , biochemistry , statistics
Abstract Purpose To examine the temperature dependence of the proton density (PD) in both adipose and muscle tissues, and the application of the PD as a thermometry parameter in breast tissues. Materials and Methods Porcine fat samples and bovine muscle samples were successively heated to temperatures ranging from 30°C to 76°C and then cooled. They were then imaged with a dual‐echo spin‐echo sequence. T1 and T2 effects were carefully corrected from the images. The apparent PD (APD) in regions of interest (ROIs) and the sum of the APD in all pixels (Sum_APD) were measured and analyzed by linear regression. Results APD in adipose tissue is linear and reversible, and changes with a 0.3%/°C to 0.45%/°C temperature variation. The temperature coefficient of Sum_APD in adipose tissue is approximately 0.29%/°C, as predicted from the Boltzmann distribution. However, the results in muscle tissue are more variable. There is an offset in both APD and Sum_APD between heating and cooling phases, as well as different temperature coefficients between these two phases. Conclusion The Sum_APD in adipose tissue validates the 1/ T dependence on temperature. The APD is a potentially useful parameter for fat thermometry; however, its application in muscle tissue requires further investigation. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.