MRIの原理と実際 - FrontPage

1 1 MRI X MRI: Magnetic Resonance Imaging X-Ray CT: Computed Tomography 2 MRI MR H15 1984 NCVC 1 = 10000 N. 3 .. 1988 H15 NMR 1 NMR 2 NMR 5 MR 6 / / 3 4 / 7 4E1E2 NMR RF / NMR (1946) ( 1952) (1971) NMR( 1991) / NMR 2003)F. R. P. 5B0 SSNNNNSS paramagnetic diamagnetic m 1. 2. ( ) 3. 1 -100 1000 1236 MRI 19F13C23Na31P14N1H MRI S/N xB SSB0NN / (1H) /T (31P) 7 NMR E1E2E1E2 (RF) SSNNB0B0 MMMB1B1M: 8 NMR RF E2E2E1E1 B0MM M T1 T2 T1 100 T2 10 100 -1 - 9 NMR T2 T2* (FID) FID: free induction decay T2*.

2 T2 star 15 1ppm/ 10mT/m - / 10 / - 1H 31P (ppm) (ppm) 11 NMR 1 NMR 2 NMR 5 MR 6 / / 3 4 / 7 NSNSNS RF NMR 12 MRI RF-1RF-2RF-3 ABCDEA B C D: E MRI FID GRE SE STE1 RF 1 RF+ 2 RF 3 RF GRE SE 13RF: TR M0 1T1T2*MzMxyMM0 MMM TE: RF: TRTE (z)(y)(x) 10mT/m SE GSSGPEGRO14 GSSRFRF zyxzB0 GSS sinc rect B0 GRO x xzGRO x 15B0B0 GPE GPE bacdabcdabcd0 0 0 0 10 20 0 30 xxxxxx(=0)zzyyyyyy B0B0 GPE GPE abcdabcd20 40 0 60 30 60 0 90 zxyzxyxyxyxyxy16abcd0 0 0 0 abcdabcdabcd30 20 10 0 60 40 20 0 90 60 30 0 xx x xxxx xyyyyyyyy TR GPE PE RO PE RO RO PE MR 2 1 17 RF.

3 TR TE (z)(y)(x) 10mT/m SE GSSGPEGRO - 2D-FT MRI 18 2D vs 3D - - NMR 1 NMR 2 NMR 5 MR 6 / / 3 4 / 7 19RF: TR M0 1T1T2*MzMxyMM0 MMM TE: sin T1 T2 T2* 20 O 65 C H N .. 60 65 .. 15 20 + 18 7 .. + + 60 70 40 45 20 25 + 8 5+3 15 21 c T1T2 T1 T2 T1 T2 MRI 1.

4 2. 3. 4. T1 T2 65 20 1234 22 A. B. C. D. E. T1 T2 T1T2 ABCDENMR 1 NMR 2 NMR 5 MR 6 / / 3 4 / 7 23 90 RF180 RF90 RF180 RFT2*T2 180 1234 RadioGraphics4: 1984 24 sin T1 T2 T2* e-TE / T2S xx( 1 - e ) -TR / T1 TR>>TE T1, T2 , TR, TE , 25 MRI T1 T2 X CTTR +T2 TE +T1 T1 T2 X T1 TR T2 TE T1 TR T1 +TE T2 T2 TR T1 +TE T2 TR T1 +TE T2 26 RFT2*T2 GRE GRE FLASH / / # GRE TR / SSFP steady-state free precession RF RF RF.

5 FID/SE/STE SE/STE T2/T1 T2 FISP / true FISP / balanced TFE SSFP / FIDSE/STE 27 MRI AoAoAo TR / TE / FA:100ms / 27ms / 30 TR / TE / FA:1900ms / 30ms / 90 GRE GRE MR 28 180 RF 180 RF vs.