MRI History

• The SI unit tesla (T) for measuring magnetic flux density or magnetic induction was named in Tesla's honor at the Conférence Générale des Poids et Mesures, Paris in 1960
• Carl Friedrich Gauss, a German mathematician and scientist, had the CGS unit for magnetic induction named gauss in his honor
• Nikola Tesla discovered the Rotating Magnetic Field in Budapest, Hungary


  1882
• The Fourier transform is a mathematical procedure to separate out the frequency components of a signal from its amplitudes as a function of time
• Isidor Isaac Rabi succeeded in detecting and measuring single states of rotation of atoms and molecules, and in determining the mechanical and magnetic moments of the nuclei
• Wolfgang Ernst Pauli, an Austrian Theoretical Physicist, proposed a quantum spin number for electrons in 1924 and the Pauli exclusion principle in 1925, for which he received the Nobel Prize for Physics in 1945
• Magnetic Resonance Imaging


  A noninvasive medical imaging technique that uses the interaction between radio frequency pulses, a strong magnetic field, and body tissue to obtain images of slices/planes from inside the body
• 1 tesla = 10,000 gauss (G)
• The inverse Fourier transformation (IFT) calculates the time domain from the frequency domain
• Jean Baptiste Joseph Fourier, a French mathematician and physicist, is best known for initiating the investigation of Fourier series and their application to problems of heat flow
• Isidor Isaac Rabi was influenced by Cornelius Jacobus Gorter and awarded the Nobel Prize for Physics in 1944
• George Eugene Uhlenbeck, a Dutch-American theoretical physicist, introduced the concept of a spinning electron with resultant angular momentum and a magnetic dipole moment arising from the spinning electrical charge
• Nikola Tesla was an Austrian-American inventor and mechanical and electrical engineer, best known for revolutionary contributions in the field of electricity and magnetism in the late 19th and early 20th centuries
• Fourier Transform


  An operation that transforms one function of a real variable into another
• 200 nanotesla is the US Congress and WHO recommended limit for constant human exposure = 2 mG
• Columbia University Professor Isidor I. Rabi observed the quantum phenomenon dubbed nuclear magnetic resonance (NMR)


  1937
• Cornelius Jacobus Gorter, a Dutch Physicist, reported unsuccessful attempts in September 1937
• Sir Joseph Larmor, an Irish physicist and mathematician, developed the equation that the angular frequency of precession of the nuclear spins being proportional to the strength of the magnetic field (Larmor relationship)
• Cornelius Jacobus Gorter, a Dutch Physicist, reported unsuccessful attempts to observe nuclear magnetic resonance in pure crystalline materials in September 1937
• Felix Bloch and Edward Purcell discovered the magnetic resonance phenomenon, sharing the Nobel Prize for Physics


  1946
• Felix Bloch, a Swiss-American physicist, conducted experiments measuring an electromotive force resulting from the forced precession of nuclear magnetization in the applied RF field
• Peter Mansfield further developed the utilization of gradients in the magnetic field and mathematically analyzed signals for a more useful imaging technique
• Paul C Lauterbur and Peter Mansfield were awarded the 2003 Nobel Prize in Physiology and Medicine
• Raymond Vahan Damadian demonstrated in the early 70s with his NMR device the different T1 relaxation times between normal and abnormal tissues of the same type, as well as between different types of norm
• "A New Method of Measuring Nuclear Magnetic Moment" was published by Jacobus Gorter, reporting the first MR signal from LiCl


  1938
• Cornelius Jacobus Gorter was the first to demonstrate the phenomenon of paramagnetic relaxation
• Felix Bloch (Stanford University) and Edward Purcell (Harvard University) developed instruments to measure magnetic resonance in bulk materials like liquids and solids
• 1952 is often regarded as the birth year of MR, with Herman Carr creating a one-dimensional MR image


  1950s
• Peter Mansfield was the first to demonstrate clinical MR images of a human finger and showed how signals can be mathematically analyzed, leading to the EPI technique in 1977
• John Mallard, Professor of Medical Physics at the University of Aberdeen, known for his work in the development of radionuclide imaging, MRI, and PET
• The "Tesla Unit" was proclaimed in Munich, Germany by the International Electro-technical Commission-Committee of Action for calibrating MRI machines

  1956
• Yevgeny Konstantinovich Zavoisky, a Soviet physicist, discovered electron paramagnetic resonance in 1944
• Jacobus Gorter was awarded the Nobel Prize for Physics in 1944
• Edward Mills Purcell, an American physicist, along with his colleagues Torrey and Pound, prepared a resonant cavity to study the absorption of RF energy in paraffin
• EPI (echo-planar imaging) was the first ultra high-speed imaging technique
• The whole body magnet was first built by Oxford Instruments Ltd. in cooperation with the University of Aberdeen under the direction of John Mallard and led by James Hutchison
• Raymond Damadian demonstrated different T1 relaxation times between normal and abnormal tissues of the same type, as well as between different types of normal tissues


  1971
• The first 'magnetization-transfer' imaging was done by Robert N. Muller


  1982
• Richard Ernst proposed using phase and frequency encoding and Fourier transform for the acquisition of MR images in 1975, which is the basis of current MRI techniques
• Raymond Damadian applies for a patent describing the concept of NMR being used for the above purpose and illustrates major parts of the MRI machine in his patent application


  1972