FSP MRI Spins

  1. T1 Conventional MRI scan (SE)
       - term
       - TR-TE
       - what primarily controls the contrast?
       - NMV in what direction
       - ?-? relaxsation
       - energy given to...
       - ... time contrast
       - shows...
       - what is bright
       - relation to field strength






    • - time to get to a point where longitudinal magnetization has returned to 63% of its final value
    • - TR­­↧ - TE↧
    • - TR primarily controls the contrast
    • - NMV in longitudinal (Z) direction
    • - spin-lattice relaxation
    • - energy given to surrounding tissue (other lattice)
    • - tissue-specific time constant
    • - shows anatomy (bone)
    • - fat is bright
    • - T1 longer at higher field strengths
    • Image Upload 1

    • Image Upload 2
    • Image Upload 3
  2. T2 Conventional MRI scan (SE)
       - term
       - TR-TE
       - what primarily controls the contrast?
       - NMV in what direction
       - ?-? relaxation
       - energy is exchanged to...
       - ... time contrast
       - shows...
       - what is bright
       - relation to field strength






    • - time to get to a point where transverse magnetization decay to 37% of its original value
    • - TR↥ - TE↥
    • - TE primarily controls the contrast
    • - NMV in transverse (X-Z) plane
    • - spin-spin interaction
    • - energy is exchanged to other spin of the same lattice
    • - tissue-specific time contrast and is always shorter than T1
    • - shows pathology (fluid)
    • - fluid is bright
    • - unrelated to field strength
    • Image Upload 4
    • Image Upload 5
    • Image Upload 6
  3. Time to get to a point where longitudinal magnetization has returned to 63% of its final value
    T1
  4. In what MRI scan TR↧ - TE↧?
    T1
  5. In T1 Conventional MRI scan what controls contrast?
    TR primarily controls the contrast
  6. T1 Conventional MRI scan NMV in what direction?
    NMV in longitudinal (Z) direction
  7. In T1 Conventional MRI scan energy given to...
    ?-? relaxation
    • - energy given to surrounding tissue (other lattice)
    • - spin-lattice relaxation
  8. T1 Conventional MRI scan shows...
    - shows anatomy (bone)
  9. In T1 Conventional MRI scan what is bright?
    - fat is bright
  10. How T1 Conventional MRI scan related to field strength?
    - T1 longer at higher field strengths
  11. Time to get to a point where transverse magnetization decay to 37% of its original value
    T2
  12. In what MRI scan TR↥ - TE↥?
    T2
  13. In T2 Conventional MRI scan what controls contrast?
    TE primarily controls the contrast
  14. In T2 Conventional MRI scan NMV in what direction?
    NMV in transverse (X-Z) plane
  15. In T2 Conventional MRI scan energy given to...
    ?-? relaxation
    • - energy is exchanged to other spin of the same lattice
    • - spin-spin interaction
  16. T2 Conventional MRI scan shows...
    - shows pathology (fluid)
  17. In T2 Conventional MRI scan what is bright?
    - fluid is bright
  18. How T2 Conventional MRI scan related to field strength?
    - T2 unrelated to field strength
  19. spin-spin interaction?
    T2
  20. spin-lattice relaxation?
    T1
  21. shows pathology
    T2
  22. fluid is bright
    T2
  23. shows anatomy
    T1
  24. fat is bright
    T1
  25. longer at higher field strengths
    T1
  26. unrelated to field strength
    T2
  27. FID
    • - Free Induction Decay
    • - Eddy Current
    • - occur before T1 and T2 (leakage current)
    • - caused by MF inhomogeneous
    • - decays along transverse plan
    • - when reach X-Y plan, becomes - T2*
    • - best for nerve roots
    • Image Upload 7
    • Image Upload 8
  28. T2*
    • product of FID
    • when FID reach X-Y plan, becomes - T2*
    • FID - Free Induction Decay
    • Eddy Current
    • occur before T1 and T2 (leakage current)
    • caused by MF inhomogeneous
    • dephasing the P spin
    • best for nerve roots
    • decays along transverse plan X-Image Upload 9
    • Image Upload 10
  29. Spin Echo PS
    • SE Pulse Sequence:
    •    - has 2 RF - starts w 90, ends w 180
    •    - FID - Free Induction Decay
    •    - TR - Time to repeat
    •    - TE - Time to echo
    •    - T1, T2, PD - SE
    • Image Upload 11
  30. PD Conventional MRI scan
    • PD - Proton Density
    • Brightest signal in MRI
    • Intermediate Pulse Sequence
    • TR↥ - TE↧
    • grayer in appearance
    • b/c 15% tissue differentiation
    • Pathology and anatomy
    • Image Upload 12
  31. TR primarily controls the contrast in...
    T1 (TR­­↧ - TE↧)
  32. TE primarily controls the contrast in...
    T2 (TR↥ - TE↥)
  33. Brightest signal in MRI
    PD - Proton Density
  34. Intermediate Pulse Sequence
    PD - Proton Density
  35. TR­­↧ - TE↧
    T1
  36. TR↥ - TE↥
    T2
  37. TR↥ - TE↧
    PD - Proton Density
  38. What Pulse Sequence is grayer in appearance
    PD - Proton Density
  39. What Pulse Sequence is good for pathology and anatomy
    PD - Proton Density
  40. FSE Sequence
    • Fast Spin Echo
    • start w 90 followed by a train of 180
    • quicker scanning times
    • causes blurring as MRI is a trade-off b/w parameteres
    • blurriness is solved by keeping ETL as low as possible
    • ETL - Echo Train Length - # of 180 pulses after the 90 pulse
    • Image Upload 13
  41. ETL
    • - Echo Train Length in Fast Spin Echo
    • - # of 180 pulses after the 90 pulse
    • Image Upload 14
  42. IR Sequence
    • Inversion Recovery
    • start w 180 followed by 90
    • 180° RF inversion wave
    • 90° RF excitation wave
    • TI - Time to invert (delay between 180° and 90°)
    • TI controls contrast
    • Bone black - if white - pathology
    • Image Upload 15

    Image Upload 16
  43. STIR sequences
    • Short TAU Inversion Recovery
    • TAU - The interpulse times
    •        - time between the 90° and 180° pulse, and between the 180° pulse and the echo
    • Good for:
    •      - osteomyelitis
    •      - all bone work
    • Image Upload 17
    • Image Upload 18
  44. FLAIR sequences
    • Fluid Attenuated Inversion Recovery
    • Good for:
    •     - multiple sclerosis
    •     - whenever CSF flow
    • Image Upload 19
  45. Gradient GRE echo
    • Grade and Echo
    • the flip angle usually below 90°
    • the absence of a 180° RF rephasing pulse (GRE instead)
    • Image Upload 20
  46. T1 GRE
    • T1 Grade and Echo
    • TR­­↧ - TE↧
    • Flip Ang ↥ <90
    • the absence of a 180° RF rephasing pulse (GRE instead)
    • MRA - Angiography
    • Blood is bright
    • Image Upload 21
  47. T2 GRE
    • T2 Grade and Echo
    • TR↥ - TE↥
    • Flip Ang ↧ <90
    • the absence of a 180° RF rephasing pulse (GRE instead)
    • Blood imaging
    • Image Upload 22
  48. Spin start w 90 followed by a train of 180
    Fast Spin Echo
  49. Spin with quicker scanning times
    Fast Spin Echo
  50. Why Fast Spin causes blurring?
    causes blurring as MRI is a trade-off b/w parameters
  51. How to solve blurriness in Fast Spin Echo?
    • - by keeping ETL as low as possible
    • - ETL - Echo Train Length - # of 180 pulses after the 90 pulse
  52. Spin start w 180 followed by 90
    Inversion Recovery
  53. What kind of wave are 180 and 90 in Inversion Recovery?
    • - 180° RF inversion wave
    • - 90° RF excitation wave
  54. In what sequence TI controls contrast?
    Inversion Recovery
  55. What is TI?
    • - Time to Invert
    • - delay between 180° and 90° in Inversion Recovery
    • Image Upload 23
  56. In what spin if bone black - pathology?
    • Inversion Recovery
    • Bone black - if white - pathology
  57. In what spin the flip angle usually below 90° with the absence of a 180° RF rephasing pulse (GRE instead)
    Gradient GRE echo
  58. What is ETL?
    • - Echo Train Length in Fast Spin Echo
    • - # of 180 pulses after the 90 pulse
  59. Good for all bone work
    STIR sequences
  60. Good for osteomyelitis
    STIR sequences
  61. Good for CSF flow
    FLAIR sequences
  62. Good for multiple sclerosis
    FLAIR sequences
  63. What Grade and Echo
    TR­­↧ - TE↧
    T1 GRE
  64. What Grade and Echo
    Flip Ang ↥ <90
    T1 GRE
  65. What Grade and Echo
    TR↥ - TE↥
    T2 GRE
  66. What Grade and Echo
    Flip Ang ↧ <90
    T2 GRE
Author
flashsmilenet
ID
348344
Card Set
FSP MRI Spins
Description
FSP MRI Spins
Updated