MAGNETIC RESONANCE IMAGING

2003 Noble Prize Laureates in Physiology or Medicine

Paul C. Lauterbur and Peter Mansfield

Noble Prize

6 October 2003Press Release

The Nobel Assembly at Karolinska Institute has today decided to award

The Nobel Prize in Physiology or Medicine for 2003 jointly to

Paul C. Lauterbur and Peter Mansfieldfor their discoveries concerning“magnetic resonance imaging”

“for their discoveries concerning magnetic resonance imaging”

 

Paul C. Lauterbur Peter Mansfield½ of the prize USA ½ of the prize United KindomUniversity of Illinois University of Notingham Urbana, IL, USA. United Kingdom. b. 1929 b. 1933

Paul C. Lauterbur born May 6, 1929 in Sidney, Ohio, USA. 1951 B.S. in Chemistry, Case Institute of

Technology, Cleveland 1962 Ph.D. in Chemistry, University of

Pittsburgh, Pennsylvania 1969-85 Professor of Chemistry, Radiology,

New York University at Stony Brook 1985-90 Professor, University of Illinois,

College of Medicine at Chicago 1985-Professor and Director, Biomedical

Magnetic Resonance Laboratory, University of Illinois, College of Medicine at Urbana, IL.

Peter Mansfield born October 9, 1933. 1959 B.Sc. Queen Mary College, University of

London 1962 Ph.D. Physics, University of London 1962-64 Research Associate, University of

Illinois. 1964 Lecturer, University of Nottingham. 1968 Senior Lecturer, University of

Nottingham. 1972-73 Senior Visitor, Max Planck Institut

für Medizinische Forschung, Heidelberg 1979- Professor, University of Nottingham.

History of MRI Late 1800’s November 5, 1895. William Roentgen

discovered X-rays. Roentgen discovered that: X-rays travel in straight lines, could not be refracted or reflected did not respond to magnetic or electric

field. February, 1896, X-rays were being used

clinically in the United States.

History of MRI In the 1930’s, a physics phenomenon was

discovered, called nuclear magnetic resonance or NMR.

Felix Bloch, working at Stanford University, and Edward Purcell, from Harvard University, discovered NMR.

In NMR nuclei were placed in a magnetic field, they absorbed energy in the radiofrequency range of the electromagnetic spectrum, and re-emitted this energy when the nuclei transferred to their original state.

History of MRI This phenomenon was termed NMR as follows: "Nuclear" as only the nuclei of certain atoms reacted in that way; "Magnetic" as a magnetic field was

required; "Resonance" because of the direct frequency

dependence of the magnetic and radiofrequency fields.

History of MRI For their discovery of NMR Bloch and Purcell

were awarded the Nobel Prize for Physics in 1952.

Use of NMR to investigate the chemical composition and physical structure of matter.

Relaxation times, T1 and T2. T1: Time taken by nuclei in test samples to

return to their natural alignment T2: Duration of the magnetic signal from the

sample.

History of MRI In 1970s Raymond Damadian, proposed

that each tissue in the body has a different relaxation time, but cancerous tissue has an abnormally long relaxation time.

He believed that the NMR could be used as an “external probe for the internal detection of cancer”

Damadian presented first commercial NMR scanner at the annual meeting of the American Roentgen Ray Society in 1980.

History of MRI Paul C. Lauterbur determined the

origin of the radio waves by analysis of their characteristics.

Discovered the possibility to create a two-dimensional picture by introducing gradients in the magnetic field.

In 1972, obtained the first MRI.

History of MRI Pater Mansfield further developed the

utilization of gradients in the magnetic field.

Signals could be mathematically analyzed. Showed how extremely fast imaging could

be achievable. In 1976, he and his colleagues created the

first MRI of a human body part, a finger.

What is an MRI? Magnetic Resonance Imaging (MRI) :safe and

noninvasive test. Diagnostic technique :uses strong magnetic

field and pulses of radio waves. Produces pictures of structures inside the

body. Images :slices of an organ or part of body. MRI’s computer: 3-D images.

How it works? Body :strong magnetic field. Machine uses :strong magnetic field and

pulses of radio waves. Machine creates an image :how

hydrogen atoms react. Usually images are created as single

slices of organs or structures. MRI computer combine them to give a 3

D image.

Using Our Body’s Magnets Because of predictions from

physics and math we know there are very weak magnets in all living tissues

These magnets are atoms with unpaired numbers of protons and electrons like hydrogen 1H

There are billions and billions of hydrogens in your body

Using Our Body’s Magnets

1H do not have a matched pair of neutrons and protons

When atomic nuclei do have perfectly matched neutrons and protons, these always arrange in pairs and rotate in opposite directions to one another

With 1H, there is no match and there is a nuclear spin and slight + charge

Using Our Body’s Magnets

One way is to stick these very weakly magnetic tissues in a gigantic, strong MAGNET and see what happens!!!!!!

This is the principle of Magnetic Resonance Imaging, (MRI) used in research and diagnostic radiology today!!!!!!!!!

A moving electric charge produces a magnetic field

Protons have a positive charge

Protons spin

Protons produce a small magnetic field

No external field…Randomly aligned

External field…Aligned with field

Some protons align with the field…

Some protons align against the field…

Protons continually oscillate – always a slight excess aligning with field

Aligning with field – slightly lower energy state

Protons Wobble

Spinning protons wobble about the axis of the external field

Frequency of precession = Resonance Frequency

Depends on strength of magnetic field

RF Pulse

Apply RF pulse at resonance frequency

Protons absorb energy

Protons ‘jump’ to a higher state

What goes up…

…must come down

Energy is re-transmitted as RF signal

Summary

MRI Signal

MRI HardwareControl Room

Scanner

Console

MRI HardwareScanner

Liquid Helium Cooled1.5 Tesla Solenoid Magnet

Patient Platform

RadiofrequencyTransmitter/Recieiver

Coil

MRI of the Brain - Sagittal

T1 ContrastTE = 14 msTR = 400 ms

T2 ContrastTE = 100 msTR = 1500 ms

Proton DensityTE = 14 msTR = 1500 ms

MRI of the Brain - Axial

T1 ContrastTE = 14 msTR = 400 ms

T2 ContrastTE = 100 msTR = 1500 ms

Proton DensityTE = 14 msTR = 1500 ms

T1 and T2 Weighting

Brain - Axial Multislice T1

Contrast in MRI

T1 T2 Gadolinium

The Whole Brain Atlas: http://www.med.harvard.edu/AANLIB/

Brain Tumor

Laser Polarized Gas Lung ImagingChronic Obsructive Pulmonary Disease Healthy Volunteer

Advantages of MRI Diagnosing multiple sclerosis (MS) Diagnosing tumors of the pituitary

gland and brain. Diagnosing infections in the brain,

spine or joints Visualizing torn ligaments in the

wrist, knee and ankle

Advantages of MRI Visualizing shoulder injuries Diagnosing tendonitis Evaluating masses in the soft tissues of

the body Evaluating bone tumors, cysts and

bulging or herniated discs in the spine

Diagnosing strokes in their earliest stages.

Disadvantages of MRI Not for everybody. machine makes a tremendous amount

of noise. require patients to hold very still for

extended periods of time. Orthopedic hardware (screws, plates,

artificial joints) in the area of a scan can cause severe artifacts (distortions) on the images.

very expensive.

Future of MRI Very small scanners. Functional brain mapping. Ventilation dynamics of the lungs

through the use of hyperpolarized helium-3 gas.

Image strokes in their earliest stages. Limitless future

Laser Polarized Xenon MRIFunctional Brain Imaging

Map of Blood Flow in the Rat Brain

Functional Brain Imaging Blood Oxygenation Affects Contrast Metabolism uses oxygen Contrast Reveals regions of oxygen

consumption

University of Minnesotahttp://www.cmrr.drad.umn.edu/highlight/index.html

Laser Polarized Gas Images

University of Virginia

Sources used:

http://www.nobel.se/medicine/laureates/2003/

http://inventors.about.com/ http://www.bae.ncsu.edu/ http://www.isbe.man.ac.uk/ www.cmrr.drad.umn.edu/ Slides provided by Dr. Vankley.