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대구가톨릭대학병원 영상의학과 이 영 환

M. R. Basic Physics. 대구가톨릭대학병원 영상의학과 이 영 환. MR Signal T1-, T2-weighted TR, TE. MR Signal T1-, T2-weighted TR, TE. X-ray. Radiography, CT. Penetration. Ultrasound. Ultrasonography. Reflection. MRI. ?. RF Pulse. RF Pulse. H. 1 1. Surface Coil. Resonance. H.

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대구가톨릭대학병원 영상의학과 이 영 환

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  1. M R Basic Physics 대구가톨릭대학병원 영상의학과 이 영 환

  2. MR Signal T1-, T2-weighted TR, TE MR Signal T1-, T2-weighted TR, TE

  3. X-ray Radiography, CT Penetration

  4. Ultrasound Ultrasonography Reflection

  5. MRI ? RF Pulse

  6. RF Pulse H 1 1 Surface Coil Resonance

  7. H Magnetic Dipole 1 1 N S +

  8. N S Magnetization

  9. Magnetic Strength • Gauss • Tesla • 1 Tesla = 10,000 Gauss

  10. N S Precession

  11. N S Precession

  12.  =   =  B0 B0   Resonance Precession frequency Larmor frequency

  13. Electromagnetic Wave Frequency (MHz) -4 2 8 14 20 10 10 10 10 10 MR Radio X-rays Microwave Cosmic rays Visible light Gamma rays

  14. Surface Coil

  15. N N Z Y X S S

  16. N N Z Y X S S

  17. N N S S

  18. N Z Y X S Longitudinal Magnetization Transverse Magnetization N Z Y X S

  19. N Z Y X S Longitudinal Magnetization Transverse Magnetization N Z Y X S

  20. Effect of RF Pulse • Loss of longitudinal M. • Creation of transverse M. • In Phase

  21. Z Z Y Y X X MR Signal

  22. MR Signal T1-, T2-weighted TR, TE MR Signal T1-, T2-weighted TR, TE

  23. E2 Resonance ; Induction of transition between two energy states E1

  24. N S N S

  25. Relaxation N N S S

  26. Z Y X Relaxation Z Y X

  27. Relaxation ; Process determining return to equilibrium of both longitudinal & transverse magnetization • T1 Relaxation • T2 Relaxation

  28. N N S S T1 Relaxation

  29. N N Z Y X S S T1 Relaxation

  30. T1 Relaxation Longitudinal Magnetization Time

  31. N N S S T2 Relaxation

  32.  =  B0 

  33. T2 Relaxation Transverse magnetization Time

  34. Relaxation N N S S

  35. Relaxation Z Z Y Y X X

  36. T2 Relaxation Transverse magnetization Time

  37. T2 Relaxation Transverse magnetization Time TE

  38. T2 Contrast Long T2 Tissue Short T2 Tissue Time

  39. T2-weighted Long T2 Tissue Short T2 Tissue Time Long TE

  40. TE ; 28 msec TE ; 90 msec TE ; 230 msec TR ; 3000 msec

  41. Spatial Localization

  42. TE TR

  43. T1 Relaxation Longitudinal Magnetization Time

  44. T1 Contrast Short T1 Tissue Long T1 Tissue Time

  45. T1-weighted Short T1 Tissue Long T1 Tissue Time Short TR

  46. TR ; 150 msec TR ; 500 msec TR ; 1500 msec

  47. Spin Echo Poor contrast Poor S/N T2 120 - 60 TE (msec) T1 ? 40 - 10 300 - 800 1500 - 4000 TR (msec)

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