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Relaxation Mechanism

2 of 106. ????? (relaxation) ?. ?? : evolution of magnetization T1 = longitudinal T2 = transverse?????????. 3 of 106. T2 ???????. ?? (dephasing) ????? ??????? ????? .... 4 of 106. . ???????? ??????. . . . . z'. y'. x'. . . . M. . . . . . . ????? ????. ????? ????. 5 of 106. . ?????????????

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Relaxation Mechanism

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    1. 1 of 106 ??????? Relaxation Mechanism ??? ?? ????? ?????????

    2. 2 of 106 ????? (relaxation) ? ?? : evolution of magnetization T1 = longitudinal T2 = transverse ?????????

    3. 3 of 106 T2 ??????? ?? (dephasing) ????? ??????? ????? ...

    4. 4 of 106 ???????? ??????

    5. 5 of 106 ?????????????? ?????????

    6. 6 of 106 ??????? ???? = ??? ?????????????? ????????????? ????? = ?? = ???

    7. 7 of 106 ???? H2O ??????? ~ 0.16 nm ???? ~ +/- 10 Gauss ! w = g Bo ?????? ~ 85,200 Hz

    8. 8 of 106 ????? 1 / 85,200 Hz ~ 0.012 msec 0.01 msec ??,?????? ??? : T1WI ? TE ~ 10 msec Lung MRI : TE ~ 1.2 msec

    9. 9 of 106 ??????????????? ???????? ? T2 ~ 0.01 msec

    10. 10 of 106 0.01 msec ? T2 ???????????? “??” : ??? 0.01 msec ?? ???? (?,????? ...) ??????????? MRI ??

    11. 11 of 106 ?????? ? ???? : 0 ~ 105 Hz ?? : 0 ~ 1012 Hz ??? : 0 ~ 109 Hz ??? : ??,?????

    12. 12 of 106 ????????? ??????????? ???????? ??????????????? T2 ? (motion narrowing)

    13. 13 of 106 ??????????????? ????????? ?????????

    14. 14 of 106 ??????? T2 ????????,???? ?????, T2 ?? T2 ?? ? ?????? ? ????????

    15. 15 of 106 ??? T2 T1 ??? ? T1 : longitudinal relaxation ??????? transition ????????????? ?

    16. 16 of 106 ???? ???? M ????? z ?

    17. 17 of 106 T1 ????? ?????? : ??????? ????????????? ????????? 63.87 MHz ??????,??? T1 ??

    18. 18 of 106 ??????? ???? = ??? ??????? (??) ????? ? ????

    19. 19 of 106 ??????????????? ??????????? ???? RF ??

    20. 20 of 106 ????????? ??? Larmor frequency ?? ??????????? ???????,????? T1 ???????

    21. 21 of 106 ???????? ???? : 0 ~ 105 Hz ?? : 0 ~ 1012 Hz ??? : 0 ~ 109 Hz ?? : 63.87 MHz ~ 108 Hz

    22. 22 of 106 ??????? T1 ?? ?????? ???? (T1 ??)

    23. 23 of 106 ??????? T1 ? 108 Hz ?????????,??? RF ??,???? ??? T1 ?? T1 ?? ? ????????

    24. 24 of 106 ?????? (????) ? T1 ?? ????????? T1 ??

    25. 25 of 106 ?? ? ????? Dipole-dipole coupling ?? : ?? T2 ?? ?? : ?? T1 ? T2 ?? ?? T1 ??? T2 ?

    26. 26 of 106 ??????? …

    27. 27 of 106 BPP Theory (1948) Bloembergen-Purcell-Pound ?? ?????????????????? ???? T1?T2 ???????

    28. 28 of 106 T1 ? T2 ?????????? Bloembergen-Purcell-Pound theory

    29. 29 of 106 ?????????? ? ?? … ???????? ! 7.5 ? vs. 29.5 ? 28 slides vs. 19 slides ????,????????

    30. 30 of 106 ?????????? ? ?? ~ ??? 1.5T ??,??????? ???????????? ?????????? ...

    31. 31 of 106 ??????? (??)

    32. 32 of 106 ??????????? ??????????? ????,???? ??????????? MR contrast agent !

    33. 33 of 106 ???????????? Bound water ?????

    34. 34 of 106 ???????? ??????????????? ????????,????????? (bound water) ??? T1 ? T2 ??

    35. 35 of 106 ?? ? Bound Water ???????????? ??????

    36. 36 of 106 ???????? Bound ? free water ????? ??????????????????? R1 = A x R1a + B x R1b T1 ???????????

    37. 37 of 106 ???? (Chemical Exchange) ??????

    38. 38 of 106 ???????????? Bound water ?????

    39. 39 of 106 ??????? ? ??????????? T1 ?????????? ????,???????

    40. 40 of 106 ???? (Chemical Exchange) ??????

    41. 41 of 106 ??????? T1 ???? ??????

    42. 42 of 106 Relaxation ??????? ???????? ?????????????? ??????? ???? (chemical exchange) ??

    43. 43 of 106 ????????? ???????? bound water ????

    44. 44 of 106 ? : Cytolysis ???? ? ???? ???????????? Bound water ??,free water ?? ???? T1 ? T2 ??

    45. 45 of 106 ?? : ???????? ??????????????? ??????????? … ????????? (? T2) ... ????,?????????

    46. 46 of 106 ???????????? ??????

    47. 47 of 106 ??????????? (6000 ?) ??????? ???????????

    48. 48 of 106 ???????????? ???? T1WI ? T2WI ????????? T1 ? T2 ?????? ??????????

    49. 49 of 106 MRI ???? Contrast Agent for MRI ??? ?? ????? ?????????

    50. 50 of 106 ??????????? ??????????? ????,???? ??????????? MR contrast agent !

    51. 51 of 106 ??? FDA ?????? ????? T1 ???? ? T1 ??????? (?) ??????? T1 ? ????? T2(*) ????

    52. 52 of 106 T1 ????? (????) ?????? : ??????? ????????????? ????????? 63.87 MHz ??????,??? T1 ??

    53. 53 of 106 ??????? T1 ?? ?????? ???? (T1 ??)

    54. 54 of 106 ?????????? ?? = ????? ?????? 658 ? ! ????????????? ?????? ? ???? ?

    55. 55 of 106 ???????? 658 ? ??????????????

    56. 56 of 106 ????? ??????????????? ????????????? ?? (???)???? (???) ?????? (???????)

    57. 57 of 106 ??????? ???????

    58. 58 of 106 ????? ??? (free radicals) ????? (????????) ??????????? Cu+2 (1), Mn+2 (5), Gd+3 (7) ...

    59. 59 of 106 ? “?????” ?? ?? “???” (paramagnetic) ??????????? ????? T1 ?????? ???? ? T1 ?????

    60. 60 of 106 ???????????????? ??????????? ????? RF ??

    61. 61 of 106 ??????? T1 ?? ??????????? ?? T1 ?? (T1 ?)

    62. 62 of 106 ??????? T1 ??? ????????? ???????? ??? T1 ???????? T1 ?? ? T1WI ??

    63. 63 of 106 ???????????????? Weinman et al., AJR 142:619, 1984

    64. 64 of 106 ????????? Gd+3 (Gadolinium; ?) 7 ??????,??? ?? T1 ????????

    65. 65 of 106 ???????? Patient dies (?????) Protein or oxygen binding ????? “??” ??????????????

    66. 66 of 106 FDA ????? Gd ??? ??? multi-arm organic ligand ??

    67. 67 of 106 ??? MRI T1 ??? Magnevist (Schering) ProHance (Bracco) OmniScan (Nycomed) Dotarem (Guerbet)

    68. 68 of 106 Gd-DTPA (Magnevist) ????? ?????????

    69. 69 of 106 ????????? ???????? enhance ? ??????

    70. 70 of 106 ???? MRA Peripheral Arteries

    71. 71 of 106 ????? Gd-DTPA ?????????? ??????????? (4%) ???????????? BBB ?????? enhance !

    72. 72 of 106 ??? Tumor ? Boundary Pre-contrast Post-contrast

    73. 73 of 106 Multiple Sclerosis (Sub)acute : ???????? BBB ????? Chronic : gliosis, demyelination ??? Gd enhance ??

    74. 74 of 106 Multiple Sclerosis Pre-contrast Post-contrast

    75. 75 of 106 ???? (Kidney Cyst) Pre-contrast Post-contrast

    76. 76 of 106 ????? ???? : 0.1 mmol/Kg ???????? enhance ?? ????????????

    77. 77 of 106 ????? (metastasis) Single dose Triple dose

    78. 78 of 106 ????? 3T … ???? ? ?????? ?? T1 ??? 3T ?? Gd ????? 1.5T ?????????????

    79. 79 of 106 MRI ??????? ??? : ??????????? ?????????? (??) ???? LD50 study 50% ?????????

    80. 80 of 106 LD50 Study

    81. 81 of 106 ????????? ???????? Biodistribution Excretion pathway ?????????

    82. 82 of 106 ??? MRI ?????? ????? Gd ???????? Enhance ????? ???????? ?

    83. 83 of 106 ?? intravascular ??? ????? ??????? (1994) : Magnevist : 13 in 5,900,000 ??????? coma

    84. 84 of 106 ????????? LD50 ?????????? ?????????? ???? : OmniScan ? NSF ??????????

    85. 85 of 106 Nephrogenic Systemic Fibrosis

    86. 86 of 106 ???? NSF ????? CE-MR,????????? (?????) ????????????? ???? biopsy ??? Gd

    87. 87 of 106 ???? ????? Gd ?? (??? ?) ?????????????? ??????? (RSNA, ISMRM, FDA, ??? …)

    88. 88 of 106 MRI ?????? ? Gd ? ????? T1,???? ? chelate ? ???????,????

    89. 89 of 106 ??????? Vasovist (Schering, MS-325) Blood pool agents ? bind ? serum albumin ?,???? enhancement

    90. 90 of 106 MS-325 ? Phase II Trial (ICA) 5 ??? 50 ???

    91. 91 of 106 MS-325 ? Phase II Trial (ICA) 5 ??? ?? DSA

    92. 92 of 106 ??????? Liver-specific (??????) Gd : Primovist (Schering), MultiHance (Bracco) Mn : Teslascan (GE, MnDPDP)

    93. 93 of 106 ???????? T2 ???? T1 ? T1 ??? T2 ????? ? ?? ! ??? T2 << T1,?????

    94. 94 of 106 ???????? Gd ?????? -- ??? ?????????? ? ?? ! T2* ?? ! Brain perfusion MRI !

    95. 95 of 106 ??? FDA ?????? ????? T1 ???? ? T1 ??????? (?) ??????? T1 ? ????? T2(*) ????

    96. 96 of 106 FDA ??? T2 ??? ??????? SuperParamagnetic Iron Oxide ??????????????? T2* ? T2 ?????

    97. 97 of 106 Liver Metastasis ? T2 ??? Resovist ????????? T2 ??????????

    98. 98 of 106 SPIO T2(*) ??? Resovist (Schering), Endorem (Guerbet), Feridex (Berlex) ????????? (???) ?????? ($6,000 + ?? …) ???????

    99. 99 of 106 ? : ??????? (’03) ????? (blood-pool) ??? Hepatobiliary chelate ??? Oral ??? (GI tract) ??????? (????) ...

    100. 100 of 106 ?????? T1 ??? (MnCl2) Pre-contrast Post-contrast

    101. 101 of 106 ??????? T1 ??? (?????) Pre-contrast Post-contrast

    102. 102 of 106 Oral Contrast Agent ????? : ????? (Mn) Mn+2 : ????????? T1, T2 ?????????? 250 cc ???

    103. 103 of 106 ????????? T2 ?? (MRCP) ! Pre-contrast Post-contrast

    104. 104 of 106 ??????????? ????????????????????? … ???? ? MRI 2006; 24(2): 195-200. ????????

    105. 105 of 106 ?? : ????? ?????????????? ?? relaxation ????????,??????? !

    106. 106 of 106 Relaxation Mechanism & Contrast Agent for MRI ??? ?? ????? ?????????

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