Kelly Beam Mark Bailly Danielle Allen Athena Turner Magnetic - PowerPoint PPT Presentation

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 • They Align With An Act Like Little External Magnetic Magnets Field (Bø)

How does MRI work? ρ * T 1 (s) T 2 (ms) Tissue 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 NiCl 2

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 = γ B – Ω = Frequency of Angular Momentum • Larmor Frequency – γ = Represents the Gyromagnetic Ratio –B = Magnetic Field Gyromagnetic Ratio (MHz / Nucleus T) 1 H 42.6 19 F 40.1 23 Na 11.3 13 C 10.7 2 H 6.5 17 O 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