Kelly BeamMark Bailly

Danielle AllenAthena Turner

Magnetic Resonance Imaging

Greg Pawlowski Ryan YanigaJoseph 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 AnExternal Magnetic Field (Bø)

How does MRI work?

*Based on ρ=111 for 12mM aqueous NiCl2

50 - 10053 - 940.2 - 0.75Adipose

45 - 9020 - 670.95 - 1.82Muscle

5 - 4450 - 1650.5 - 2.2Meninges

85 - 12561 - 1091.09 - 2.15Gray

70-9061-1000.76 - 1.08White

70-230110 - 20000.8 - 20CSF

ρ*T2 (ms)T1 (s)Tissue

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 Gyromagnetic Ratio (MHz / T)1H 42.6

19F 40.123Na 11.313C 10.72H 6.517O 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/physics-

tutorial/electromagnetism-mri.shtml