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KMID : 1001220130150020063
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Journal of the Korean Society of Digital Medical Imaging Technology
2013 Volume.15 No. 2 p.63 ~ p.68
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Effect of Temperature on T1 and T2 Relaxation Time in 3.0T MRI
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Kim Ho-Hyun
Kwon Soon-Yong
Kang Chung-Hwan
Kim Kyung-Soo
Kim Sun-Bae
Baek Moon-Young
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Abstract
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Purpose : The relaxation times of tissue in MRI depend on strength of magnetic field, morphology of nuclear, viscosity, size of molecules and temperature. This study intended to analyze quantitatively that materials’ temperatures have effects on T1 and T2 relaxation times without changing of other conditions.
Materials and Methods : The equipment was used MAGNETOM SKYRA of 3.0T(SIEMENS, Erlagen, Germany), 32 channel spine coil and Gd-DTPA water concentration phantom. To find out T1 relaxation time, Inversion Recovery Spin Echo sequences were used at 50, 400, 1100, 2500 ms of TI. To find out T2 relaxation time, Multi Echo Spin Echo sequences were used at 30, 60, 90, 120, 150, 180, 210, 240, 270 ms of TE. This experiment was scanned with 5 steps from 25 to 45°C. next, using MRmap(Messroghli, BMC Medical Imaging, 2012) T1 and T2 relaxation times were mapped. on the Piview STAR v5.0(Infinitt, Seoul, Korea) 5 steps were measured as the same ROI, and then mean values were calculated. Correlation between the temperatures and relaxation times were analyzed by SPSS(version 17.0, Chicago, IL, USA).
Results : According to increase of temperatures, T1 relaxation times were 214.39±0.25, 236.02±0.87, 267.47±0.48, 299.44±0.64, 330.19±1.72 ㎳. T2 relaxation times were 180.17±0.27, 197.17±0.44, 217.92±0.39, 239.89±0.53, 257.40±1.77 ㎳. With the correlation analysis, the correlation coefficients of T1 and T2 relaxation times were statistically significant at 0.998 and 0.999 (p<0.05).
Conclusion : T1 and T2 relaxation times are increased as temperature of tissue goes up. In conclusion, we suggest to recognize errors of relaxation time caused local temperature’s differences, and consider external factors as well in the quantitative analysis of relaxation time or clinical tests.
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KEYWORD
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Temperature, Molecular tumbling, Relaxation time, Mapping, Correlation analysis
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