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Magnetic resonance imaging: basic principle

Magnetic resonance imaging: basic principle

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Magnetic resonance imaging: basic principle

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  1. Magnetic resonance imaging:basic principle Qiujianfeng 邱建峰 jfqiu100@tsmc.edu.cn 13082777550

  2. About me • Mri &the principle of medical imaging • Sorry for my english • Basic mri • Mri’s application

  3. 1、What’s the MRI? (Nuclear)Magnetic Resonance Imaging MRI(NMR CT) MRI NMR

  4. NMR • Digital signal processing(1D) • Chemical analysis

  5. MRI • imaging • Diagnosis the diseases

  6. MRI systems

  7. 2.brief history of MRI

  8. The discoverers of NMR 1952 Nobel Prize for Physics NMR Edward Mills Purcell 1912-1997 Felix Bloch 1905-1983 Stanford University MIT

  9. The discoverers of MRI 2003 Nobel Prize in Physiology or Medicine MRI Lauterbur, 1929 Mansfied 1933

  10. Paul C. Lauterbur – Prize Award Photo Sir Peter Mansfield – Prize Award Photo 10/6,2003

  11. The Shameful Wrong that must be righted Bypassed by nobel Prize Damadian Show the relaxation times of tissue and tumor differed

  12. 3、How to do a mri scan?

  13. Check in • Location to the mri center • Operating the computer • Waiting…… (a cup of tea) • Read the images

  14. Pacemaker! No! • Key! no! • metal filling! no!

  15. Coils around the body • Signal Source

  16. Earphone • Ear plugs • 30-60 minuters • Repetitive knocking sounds • Caused by electric currents in gradient fields

  17. 4、The safety of mri • Non-ionizing radiation • Dangers of Ferromagnetic object near the MRI magnet

  18. × • Claustrophobic Phobia fear of narrow space • Metal implants Pacemaker\dentures\bone screws…… • Pregnant women • Child × √ √

  19. 5.What’s the difference between the mri and other medical imaging technologies?

  20. Conventional imaging

  21. projection imaging

  22. Conventional imaging projection imaging

  23. MRI-brain

  24. MRI-vessel/body/l-spine/pelvis/kidney

  25. Multislices image

  26. MRI • Multi-dimension imaging(inclined plane ) • High quality soft tissue imaging • Non-ionizing radiation GE 3.0T mri scaner

  27. Beijing wandong i-open 0.36T mri scaner

  28. Multimodality imaging T1 Contrast TE = 14 ms TR = 400 ms T2 Contrast TE = 100 ms TR = 1500 ms Proton Density TE = 14 ms TR = 1500 ms

  29. Multi-dimension imaging T1 Contrast TE = 14 ms TR = 400 ms T2 Contrast TE = 100 ms TR = 1500 ms Proton Density TE = 14 ms TR = 1500 ms

  30. Sagittal plane Coronal plane Axial plane

  31. 3D Fusion from CT and MR MR CT

  32. 6.How the MRI work?

  33. Background knowledge

  34. Background knowledge Hydrogen atom 1H

  35. Background knowledge hydrogen atoms In the main magnetic field

  36. basic principle Magnetic Moment • H2O Hydrogen X 2 Oxygen X 1 Oxygen X 10

  37. 4.3 basic principle

  38. 4.3 basic principle

  39. 4.3 basic principle

  40. 4.3 basic principle

  41. 4.3 basic principle • E =  B, 是具有量子取向的。因此 角也具有不同取值,对于氢核,具有两种趋向。

  42. 4.3 basic principle • 为使核磁矩在磁场中的势能发生变化(即使μ与B夹角θ变化),必须外施能量或吸收能量。这可借与静磁场B的方向相垂直的平面(x-y平面)内加上一个在时间上交变的磁场

  43. 4.3 basic principle • θ增加,势能增加,能量增量由外加交变磁场提供; • θ减小,势能减小,能量交给外加交变磁场。 • 仅当交变磁场角频率满足ω=γB=ω0时才发生此种能量交换。 • 此时μ与B1_ 绕z轴同步旋转 —〉核磁共振现象

  44. 4.3 basic principle