Kelly Beam Mark Bailly Danielle Allen Athena Turner

Kelly Beam Mark Bailly Danielle Allen Athena Turner

Magnetic Resonance Imaging

Greg Pawlowski Ryan Yaniga Joseph Sisson

MRI History • First Images were taken in the 1970s • NMRI or MRI?

How does MRI work? • Spinning Protons Act Like Little Magnets

• They Align With An External Magnetic Field (Bø)

How does MRI work? Tissue

T1 (s)

T2 (ms)

ρ*

CSF

0.8 - 20

110 - 2000

70-230

White

0.76 - 1.08

61-100

70-90

Gray

1.09 - 2.15

61 - 109

85 - 125

Meninges

0.5 - 2.2

50 - 165

5 - 44

Muscle

0.95 - 1.82

20 - 67

45 - 90

Adipose

0.2 - 0.75

53 - 94

50 - 100

*Based on ρ=111 for 12mM aqueous NiCl2

Questions ?

The End

History • 1946 – Felix Bloch and Edward Purcell

• 1973 – Paul Lauterbur

• 1975 – Richard Ernst

• 1977 – Peter Mansfield and Andrew Maudsley

• 1977 – Raymond Damadian

• 1980 – FONAR Corporation

How it Works • Magnetic Resonance Imaging (MRI) • Intense Magnetic Field

• Second Electromagnetic Field • Oscillated, Specific Radio Frequencies • Perpendicular Alignment of Atoms

• After Second Field is Turned Off • Atoms in the Body

The Larmor Equation • ω=γB – Ω = Frequency of Angular Momentum • Larmor Frequency

– γ = Represents the Gyromagnetic Ratio – B = Magnetic Field Nucleus 1H 19F 23Na 13C 2H 17O

Gyromagnetic Ratio (MHz / T)

42.6 40.1 11.3 10.7 6.5 5.8

The Larmor Equation

Relation to Class • Magnetic fields – Static – Time-varying – Maxwell’s equations

• Gradients – In relation to magnetic fields

References • Magnetic Resonance Imaging – Stwart C. Bushong

• MRI for Technologist – Peggy Woodward / Roger Freimarck

• http://en.wikipedia.org/wiki/Magnetic_reson ance_imaging • http://www.physics247.com/physicstutorial/electromagnetism-mri.shtml