15分で分かる（？）MRI - 新潟大学歯学部

1 15 MRI MRI Part 3-21 15 Part 3-2 2009/10/30 2022/01/12 ~ ~ 30 2021/01/02 MRI TR TE Part 1 4 Part 1 T1 T2 ~ --- MRI Part 2 ~ 2 --- Part 3-1 ~ TE SE GRE UTE etc. Part 3-2 ~ T1 T2 NMR/MRI MRI Part 4 ~ Part 3-2. MRI T1 T2 MRI 5 6 30 CHESS ppm CHESS Chemical Shift Selective GRE Gradient Echo In-phase Out-of-phase Dixon Bp r B0 Bq B1=Bq (3cos2 -1) B0+B1 B0B1 2 Bq 0 B1 Bq 90 B1 0 55 Magic Angle 55 3cos2 -1 = 0 B1 Bq (3cos2 -1)

2 BpBqBqBqBq55 55 Magic Angle B0 0= B0 0 0 150Hz 0 B0 0 0 0 SE 0 90 90 0 SE 90 T1 1 STIR IR Inversion Recovery STIR Short-TI Inversion Recovery SE Spin Echo 90 180 IR Inversion Recovery 180 TI: Inversion Time T1 2 STIRIR(Inversion Recovery) Null Point Null Point PD PD180 0 T1 70% TI InversionTime T1 220msec TI 150msec 12=1 exp 1 1=log 12 = 1 log 2= 1 1 3 STIRTI 90 SE TI PD PD0TI SE Spin Echo 90 180 TI Inversion Time 90 MRI Fat Suppression CHESS STIR TI T1 T2 LB0 c 10-12 (free water) c 10-9 structured water) (Fullerton, 1986)

3 50nm (Drost-Hansen, 1982) c 10-7 10-6 bound water T1 T2 ( c) ( L) T1 1/ c L T2 c L T1 SE 180 T2 T2 T1 T2* 180 c LB0 T1 T2 BPP theory of water proton(Bloembergen, Purcell, Pound) + + + c(sec)T1,T2(sec)T1( )T2( )T1(3T)T2(3T) T1 T2 T1 T2 T1 T T2 T2 T2 T2 T1 T1 A T2 pi T2 T2i = 1 2 = 2 =1 (Beltons ) T2 T2 T2 100% T2 T2 1 = 1 2 T2 y = = = (msec) :short :middle :long ( :short) ( :middle) ( :long) T2= T2= T2= 100% T2 Short:20msec Middle:20-40msec Long.

4 40msec = 2 Magic Angle Bp r B0 Bq B1=Bq (3cos2 -1) B0B1 Bq 0 B1 1 Bq 90 B1 0 55 Magic Angle 55 3cos2 -1 = 0 B1 Bq (3cos2 -1) BpBqBqBqBq55 55 B1 B0 B1= ( 0/4 ) (3cos2 -1)/r3 3 cos2 1 = 55 ) B1= 0 T2 (B1) 55 T2 magneticdipoleBoB1 55 55 B1 B0 B1 B0 B0 z B0 B1 B1 xy Magic angle effect TR=2000, TE=15B0 55 55 MR ExchangeSurface of Collagen fibersB0 Bound waterOHHBulk water T2 Evenlyspacedbindingsitesappearedonthesur faceofthetriplehelixofcollagenfibers.

5 T2 1/T2( ) = 1/T2(90 ) (3cos2 -1)2+ 1/T2 (55 ) + cc SI( ) = a exp[-TE/T2 ( )]= a exp[-TE {1/ T2 (90 ) (3cos2 -1)2+ 1/T2 (55 ) + c}]a =0 =55 =90 spin echo Bovine tendon . , , Peter BENEDEK, , , 39 (1):27-34, 1999 , Tadashi Sasai, , Signal intensity change in pseudodynamicMR imaging of TMJ, Oral and Maxillofacial RadiolgyToday, ExceptaMedicaInternational Congress Series 1199 Radiology, 2000, Signal intensity ratio of the intermediate zoneR2 = between the disk and the static magnetic field (degree)Signal intensity ratio(Im/Ab)03006009001200 Signal intensity of bovinetendon(SE 2000/15 TR/TE)Im/AbBovine tendonQuartic regression curve55 26 , Tadashi Sasai, , Signal intensity change in pseudodynamicMR imaging of TMJ, Oral and Maxillofacial RadiolgyToday, ExceptaMedicaInternational Congress Series 1199 Radiology, 2000, 26 , Tadashi Sasai, , Signal intensity change in pseudodynamicMR imaging of TMJ, Oral and Maxillofacial RadiolgyToday, ExceptaMedicaInternational Congress Series 1199 Radiology, 2000, / MT MTC(Magnetization Transfer Contrast)effect 2 1 ppm MT MTC cross-relaxation saturationplus.

6 Off-resonanceplus CEST MTC MT MTC CEST CEST Chemical exchange saturation transfer -NH -OH APT Amide proton transfer -NH MT, CEST Z ppm SIsat/SI01 (SI) 0 ppm+ ppm- ppmMT, CEST - ppm 0 SISISICEST effect + =CEST - ppm + ppm SI- SI+ SI0 NMR/MRI MRI/NMR MRI/NMR MRI/NMR N N/2 MRI CPU MRI ( ), ( ) 3,500 URL MRIsimulationsInc.

7 CPU GPU by KouheiSugimoto (id:radmodel) 2020-03-10 MRI MRI 2020-05-10 Python k-space [ ] MRI T1 SE 400/10 T2 SE 4000/100 Zipper noise MRI 2 ( ), ( ),WilliamG., ( ), 6,500 MRI Q&A ( ), ( ) 5,800 MRI MEDICALVIEW 6,000 NMR RayFreeman( ) 8,400 NMR ( ) ( ), ( ) ( ) ( ), , , , ( ) 5,200 NMR 2,200 12,000 MRI 6,500 MRI MedicalView 7,500 :2022 1 12 PDF CT/MRI - -3 CT/MRI 3-3 AmideProtonTransfer APT , , , , , 59 2 ,2014 spinecho Bovinetendon.

8 , ,PeterBENEDEK, , , 39(1):27-34,1999 Part 1 4 Part 1 T1 T2 ~ --- MRI Part 2 ~ 2 --- Part 3-1 ~ TE SE GRE UTE etc. Part 3-2 ~ T1 T2 NMR/MRI MRI Part 4 ~