Proceedings of the KOSOMBE Conference (대한의용생체공학회:학술대회논문집)

The Korean Society of Medical and Biological Engineering (대한의용생체공학회)
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Turbo FLASH NRI Using Optimized Flip Angle Pattern: Application to Inversion-Recovery T1-Weighted Imaging

최적화된 Flip Angle Pattern을 사용한 Turbo FLASH MRI: Inversion-Recovery T1-Weighted Imaging에의 응용

  • Oh, C.H. (Department of Electronics & Information Engineering, Korea University) ;
  • Choi, H.J. (Department of Electronics & Information Engineering, Korea University) ;
  • Yang, Y.J. (Department of Electronics & Information Engineering, Korea University) ;
  • Lee, D.R. (Department of Electronics & Information Engineering, Korea University) ;
  • Ryu, Y.C. (Department of Electronics & Information Engineering, Korea University) ;
  • Hyun, J.H. (Department of Electronics & Information Engineering, Korea University) ;
  • Kim, S.R. (Department of Electronics & Information Engineering, Korea University) ;
  • Yi, Y. (Department of Electronics & Information Engineering, Korea University) ;
  • Jung, K.J. (Medison MRI Institute) ;
  • Ahn, C.B. (Kwangwoon University)
  • 오창현 (고려대학교 전자및정보공학부) ;
  • 최환준 (고려대학교 전자및정보공학부) ;
  • 양윤정 (고려대학교 전자및정보공학부) ;
  • 이덕래 (고려대학교 전자및정보공학부) ;
  • 류연철 (고려대학교 전자및정보공학부) ;
  • 현정호 (고려대학교 전자및정보공학부) ;
  • 김사라 (고려대학교 전자및정보공학부) ;
  • 이윤 (고려대학교 전자및정보공학부) ;
  • 정관진 (메디슨 MRI 연구소) ;
  • 안창범 (광운대학교)
  • Published : 1998.11.20
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Abstract

The 3-D Fast Gradient Echo (Turbo FLASH, Turbo Fast Low Angle Shot) sequence is optimized to achieve a good T1 contrast using variable excitation flip angles. In Turbo FLASH sequence, depending on the contrast preparation scheme, various types of image contrast can be established. While proton density contrast is obtained when using a short repetition time with a short echo time and small flip angles, T1 or T2 weighting can be obtained with proper contrast preparation sequences applied before the above proton density Turbo FLASH sequence. To maximize the contrast to noise ratio while retaining a sharp impulse response (smooth frequency domain response), the excitation flip-angle pattern is optimized through simulation and experiments. The TI (the delay after the preparation sequence which is a 180 degree inversion RF pulse in the IR T1 weighted imaging case), TD (the delay time between the Turbo FLASH sequence and the next preparation), and TR are also optimized fur the best image quality. The proposed 3-D Turbo FLASH provides $1mm\times1mm\times1.5mm$ high resolution images within a reasonable 5-8 minutes of imaging time. The proposed imaging sequence has been implemented in a Medison's Magnum 1.0T system and verified through simulations as well as human volunteer imaging. The experimental results show the utility of the proposed method.

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