高速スピンエコー法を用いたT1・T2同時計測MRI

The purpose of our study is to develop and to assess a method to calculate T1 and T2 relaxation times using fast spin-echo (FSE) sequences with two echoes per excitation. On a 1.5-T MRI, dual-echo FSE sequences with different repetition times (TR:TR2=2TR1, i.e., TR1=400ms and TR2=800ms) were performed in MnCl2 phantom. Then, we assessed effects of the echo train length (ETL) , effective echo time (TE) , and T2 correction for T1 measurement, when changed each imaging parameter. Besides, we evaluated with comparison between the dual-echo FSE method and mixed sequence. With optimizing FSE imaging parameters, i.e., effective TE, TR, and low ETL, the measurement values of T1 and T2 revealed significantly higher correlation between the dual FSE method and mixed sequence. Moreover, the T2 correction to calculate T1 value could be omitted by shortening first effective TE. The dual-echo FSE method makes it possible to measure T1 and T2 fast and easily and to obtain more detailed information of organizations in human