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 'Rapid Acquisition with Relaxation Enhancement' 
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MRI History
 
Sir Joseph Larmor (1857-1942) developed the equation that the angular frequency of precession of the nuclear spins being proportional to the strength of the magnetic field. [Larmor relationship]
In the 1930's, Isidor Isaac Rabi (Columbia University) succeeded in detecting and measuring single states of rotation of atoms and molecules, and in determining the mechanical and magnetic moments of the nuclei.
Felix Bloch (Stanford University) and Edward Purcell (Harvard University) developed instruments, which could measure the magnetic resonance in bulk material such as liquids and solids. (Both honored with the Nobel Prize for Physics in 1952.) [The birth of the NMR spectroscopy]
In the early 70's, Raymond Damadian (State University of New York) demonstrated with his NMR device, that there are different T1 relaxation times between normal and abnormal tissues of the same type, as well as between different types of normal tissues.
In 1973, Paul Lauterbur (State University of New York) described a new imaging technique that he termed Zeugmatography. By utilizing gradients in the magnetic field, this technique was able to produce a two-dimensional image (back-projection). (Through analysis of the characteristics of the emitted radio waves, their origin could be determined.) Peter Mansfield further developed the utilization of gradients in the magnetic field and the mathematically analysis of these signals for a more useful imaging technique. (Paul C Lauterbur and Peter Mansfield were awarded with the 2003 Nobel Prize in Medicine.)
In 1975, Richard Ernst introduced 2D NMR using phase and frequency encoding, and the Fourier Transform. Instead of Paul Lauterbur's back-projection, he timely switched magnetic field gradients ('NMR Fourier Zeugmatography'). [This basic reconstruction method is the basis of current MRI techniques.]
1977/78: First images could be presented. A cross section through a finger by Peter Mansfield and Andrew A. Maudsley. Peter Mansfield also could present the first image through the abdomen.
In 1977, Raymond Damadian completed (after 7 years) the first MR scanner (Indomitable). In 1978, he founded the FONAR Corporation, which manufactured the first commercial MRI scanner in 1980. Fonar went public in 1981.
1981: Schering submitted a patent application for Gd-DTPA dimeglumine.
1982: The first 'magnetization-transfer' imaging by Robert N. Muller.
In 1983, Toshiba obtained approval from the Ministry of Health and Welfare in Japan for the first commercial MRI system.
In 1984, FONAR Corporation receives FDA approval for its first MRI scanner.
1986: Jürgen Hennig, A. Nauerth, and Hartmut Friedburg (University of Freiburg) introduced RARE (rapid acquisition with relaxation enhancement) imaging. Axel Haase, Jens Frahm, Dieter Matthaei, Wolfgang Haenicke, and Dietmar K. Merboldt (Max-Planck-Institute, Göttingen) developed the FLASH (fast low angle shot) sequence.
1988: Schering's MAGNEVIST gets its first approval by the FDA.
In 1991, fMRI was developed independently by the University of Minnesota's Center for Magnetic Resonance Research (CMRR) and Massachusetts General Hospital's (MGH) MR Center.
From 1992 to 1997 Fonar was paid for the infringement of it's patents from 'nearly every one of its competitors in the MRI industry including giant multi-nationals as Toshiba, Siemens, Shimadzu, Philips and GE'.
 
Images, Movies, Sliders:
 Cardiac Infarct Short Axis Cine Overview  Open this link in a new window
    

Courtesy of  Robert R. Edelman
 
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Further Reading:
  Basics:
Magnetic Resonance Imaging, History & Introduction
2000   by www.cis.rit.edu    
A Short History of the Magnetic Resonance Imaging (MRI)
   by www.teslasociety.com    
Fonar Our History
   by www.fonar.com    
  News & More:
Scientists win Nobels for work on MRI
Tuesday, 10 June 2003   by usatoday30.usatoday.com    
2001 Lemelson-MIT Lifetime Achievement Award Winner
   by web.mit.edu    
MRI's inside story
Thursday, 4 December 2003   by www.economist.com    
MRI Resources 
Sequences - MRI Accidents - Blood Flow Imaging - Contrast Agents - Health - Journals
 
Motion Probing Gradient
 
Many MR imaging techniques using Motion Probing Gradients (MPG's) such as Spin Echo (SE), Stimulated Echo (STE), Rapid Acquisition with Relaxation Enhancement (RARE), Turbo-SE, and SE-EPI (Echo Planar Imaging for Spin echo acquisition), Spiral imaging, and Projection reconstruction including PROPELLER are applicable to DWI. In diffusion weighted imaging, 2 MPG's are required. The MPG's are put symmetrically into both sides of a 180° or 90° RF pulse to change the direction of the magnetized spin in the X-Y plane for spin echo or stimulated echo acquisition.
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• View the DATABASE results for 'Motion Probing Gradient' (2).Open this link in a new window

 
Further Reading:
  Basics:
Diffusion Imaging: From Basic Physics to Practical Imaging
1999   by ej.rsna.org    
  News & More:
Motion Compensation in MR Imaging
   by ccn.ucla.edu    
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Turbo Field EchoInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.MRI Resource Directory:
 - Sequences -
 
(TFE) Turbo field echo is a gradient echo pulse sequence with data acquisition after an initial 180° (similar to IR) preparation pulse for contrast enhancement. The difference between a FFE and TFE other than the speed of the sequence is that the image is acquired while approaching steady state (the echoes are collected during the time in which the tissues are experiencing T1 relaxation).
The contrast is prepared one time, which means the contrast is changing while the echoes are collected and can be manipulated by selecting the type and timing of the prepulse. A delay time is given before the actual image acquisition. To achieve T1 contrast the 180° prepulse is followed by an operator selected delay time, that results in no signal from the targeted tissue. So when the echoes are acquired, no signal is present, additional RF spoiling is performed to optimize for T1 contrast. The delay chosen corresponds to when T1 relaxation reaches and suppresses T1 signal or optimizes the difference between tissues. Contrast for these sequences are enhanced when K-space is filled using a centric or low-high ordering. A TFE can be acquired with a 2D or 3D technique and with or without T1, T2 weighting.
See Ultrafast Gradient Echo Sequence, TurboFLASH and Magnetization Prepared Rapid Gradient Echo (MPRAGE).
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• View the DATABASE results for 'Turbo Field Echo' (6).Open this link in a new window

 
Further Reading:
  Basics:
Sequence for Philips(.pdf)
   by www.droid.cuhk.edu.hk    
Pediatric and Adult Cochlear Implantation1
2003   by radiographics.rsnajnls.org    
MRI Resources 
MR Guided Interventions - DICOM - Musculoskeletal and Joint MRI - Quality Advice - MR Myelography - Online Books
 
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