magnetic resonance imaging,MRI

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??????? magnetic resonance imaging,MRI  
????????????? ? ?
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MRI?????--???????????????? ????? ?? 1. ??????
?????---??? ??--- ??(??,??) 2. ??????????
???????????
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3. ???M????
????B0???------???M0(???) ??????? gt
??????? ( ???1 H) (
???1 H)
1 H
1 H
1 H
1 H
1 H
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 4. MRI?????? M0 ?????B?
Larmor?? ???? ???? 1H ??
? ?????
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???????? 1????? 2?????B0??? ???M0
---- ??????B0
??-????
??-????
3?????(RF) ?????(RF?) M0??RF??? ????MXY
???
MXY
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4??????(MRS) MXY????B0(?)??????(???? MRS)

5. ??????MR
??RF????(??) ???1 H
???1 H
????(??,MRS)
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????(Relaxation) ???????
 1. ????(T1??) M0(MZ)??? ,??
???1 H ? ???1 H MRS???(H2O)???
(Brown?????)? ??????????
??RF????(??) ???1 H
???1 H
????(??,MRS)
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T1???? MZ??? M0?2/3?????
T1???M0???? H2O???(Brown??) gtgt? T1?
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2. ????(T2??) MXY ????(dephasing),?? 90oRF?
??,?1 H?????????(?????),MXY??-- 1
H???????????????? ??--????, BO???,
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T2???? MXY ??2/3????? T2????????? MXY??????
???MXY ?????(?) T2?
MXY?S
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????T1 gtgt T2?
CSF ?? ??
T1 1155 235 600
T2 145 80 100
MXY???????M0??
???,???
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3?T1?T2?????,?????? ???MXY??,
T2????MXY, T1 --- M0 --- MXY
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 ?? ??T1?T2????? H2O???(Brown??)gtgt ?
,T1? 1?????? ???--- H2O????--- ??? ---
T1? 2???????? ??H2O ---
??? --- Brown?? gtgt ? ?1H -? ?1H ?? ????
--- ??? --- Brown?? ltlt ? T1??M0????
???H2O,???,???? --- ???
--- Brown?? ? ?1H ? ?1H ??T1??M0????
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3. ?????-- Fe3 Gd(?) T1 ???,T1 ??
?B0?????, ???????? ?
?1H
?1H ? ?B0?????, ?????????
??M0???
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???????--???????,????? ??????MRI??? (?)????? 1.
MXY??(1H??)?? RF ??B0 2. ????Z(GZ)
GZ?B0?? ?????RF ????1H????? 3.
??????? RF??? ? GZ??? ? ???
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lt?gt??????? 1?????
2????? M0?--GZ?RF? ????MXY
---------- GY??Y??1H????
?1H??? MXY??????
???
?????? ? GX? ?X??1H????
?Y????1H ?MXY
MXY?????? ????(????)
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lt?gt?????????? GZ----??????MXY
GX----MXY?????? GY----MXY??????
(???MXY??) ?
?????????, ???????? MRS(FID)
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???????????----??????
???? ????
X-ray ?? KV?mAS
MRI 1H?T1?T2??? ??(TR?TE??)
????(pulse sequence) RF?????M0???MXY?,????S
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(?) ????????
--TR(time of repetition)-- 900RF
?M0 900RF
MXY? ?M0 ---- MXY?--- - ---

?M0 MXY?
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(?) ???????? --TI(time
of inversion)-- 1800RF
M00 900RF
MXY0 ?M0 ---- ?M0---- -----

?M0 ?M0 MXY?
TI????T1?,????????????STIR
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(?)????????(spin echo, SE)
???????
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(?)????????(spin echo, SE)
-------------TR-------------
------TE(time of echo) -----
900RF
1800RF
S 900RF ?M0
-------------- MXY? ------------ MXY0
-------------- MXY? - - - - - ?M0 ---------
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??SE
??SE
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lt?gt??????
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MRI????? ?????MR?? ---- 1H?T1?T2??
???? ????
X-ray ?? KV?mAS
MRI 1H?T1?T2??? ??(TR?TE??)
???? ------ sequence,??
weighted image, WI,??
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(?)????N(H) 1.
??????N(H)??---????? ,N(H)WI M0?---
MXY? -------------------- M0?--- MXY?
RF S
RF S
TE
TE
---------TR-------
?TR--- ??T1??,???RF???M0???,T1???? ?TE---
??T2??,?????MXY????,T2???? ( S--MXY???--
M0?--N(H))
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2. N(H)?????? ???????????????????
N(H)---- M0?---- MXY?? ?????????(?)
T2W I
T1WI
T2WI
T1W I
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(?)T1????---T1??? ,T1WI M0??MXY?
--------- M0??MXY?
RF S RF S
TE
TE
----TR---- ?TE---??T2??,?????MXY????,??T2??
?TR---???RF? T1??????M0????(M0??)?M
XY???S? T1??????M0????(M0??)?MXY??
?S? (T1??---- M0???---- MXY???)
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?T1????????? ??? ????????? ?T1???????(T1??)?????
????(????)
--??
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(?)T2???? ---T2??? ,T2WI M0??MXY? - - - - MXY
------- - - - ------- M0??MXY? - - - - MXY
RF S
RF S
--TE--
--TE--
--------TR------- ?TR---
??T1??,???RF???m0???,??T1?? ?TE---
??S?T2??????MXY???S?
T2??????MXY???S?
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?T2???????(T2??)?????
????????(????),???????
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(?)?? SE?? TR?TE???????N(H)?T1?T2 ?????
?TR--- ?????T1??
?TR--- ?T1?,M0??,MXY??,S?
?T1?,M0??,MXY??,S? ?TE--- ?????T2??
?TE--- ?T2?,MXY??????,S?
?T2?,MXY??????,S?
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?????MR??
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??????(flow-effect, flow void effect) (?)????? 1.
????(?10cm/s)???? 1H???----???????????,1H??????
?
900RF
1800???? MXY?T2
???MXY ??
?????M0
2??? 1H???????
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lt?gt???(MRA)--??????(flow-related
enhancement) TOF(time of flight,?????)??????TR?
1??????1H(M0?)????,??????RF?S?? 2????????RF
??TR,M0????
M0
??900RF
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PCA(phase contrast angiography,?????) ????????????
??????, MXY????, ??????????
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????(artifact) lt?gt???? 1????? ????---- ????
????---- ???? ?????
??? 2????CSF???? lt?gt???? 1????? 2???
lt?gtMR??????? 1???????(chemical shift
artifact) 2?????(wrap-around artifact) 3??????(low
-intensity artifact) ????(Gating Control)
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??MR???(CONTRAST) ?????(paramagnetic
substance) ????????? godolinium-DTPA
(Gd-DTPA) 1?????3 Gd,????????????????
??T1?? 2??????CT??
? ????????
? Gd-DTPA??????BBB ??????(superparamagnetic)-
-????? ??????,??dephasing,??T2 ??????(SPIO)--Kupff
er????,????S??
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MRI??? ???????????? 1. ??(Magnet) ???B0 ( Tesla,
T )??????M0
???(permanent
magnet) ???(resistive magnet)
???(superconducting magnet)
????(magnet shielding) 2. ????(gradient coil)
??X?Y?Z?????? ?????? 3. ???? (radio-frequen
ce system, RF ) MR???? ????????????
????????,??
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MRI????? 1????????(??????) 2?????? 3?????(????) 4?
????? 5??????,???? 6??????????
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MRI????????? 1.??? ?????????
???????????????????????????
????????????????
??????,????,???????
2. ?? ????????
??????(??,???CT) ????
??MR???????
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• ??MRI???
• ?????????
• ?????? ???????????????(AVM)?
• ??????? ?????????????
• ????? ????????????????????
• ?????????? ?????(MS)?
• ????? ??????????????????

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?????MRI??? 1. ????? ?????(????????????),
????(???????) 2. ?????
?????????????????????
????????? 3. ?? ??????????????????????? 4.
???????????? ??????????????,

????????,????, 5. ?????????? 6.
???????(?MS),???? 7. ?????
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• ??MRI???
• ????
• ?????????????,?????????CT?
• ??????????????
• ????????????????
• ?? ?CT??????
• ??????
• ????? ????????????
• ???????,??????
• ??(??????????)?????????,????

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• ??MRI???
• ?????????????????
• ??????,??????
• ????,?????????????
• ??????????????,????
• ?????(???????)???
• ??????????,MRCP,MRU
• ????

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????MRI??? X??CT???????--??????????? ???????? 1.
?????????(????????,?????? ????????????) 2.
?????????(?????) 3. ?????????(??????)