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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'.
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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 
Breast MRI - Distributors - Blood Flow Imaging - Abdominal Imaging - Hospitals - Quality Advice
 
DeviceForum -
related threadsInfoSheet: - Devices -
Intro, 
Types of Magnets, 
Overview, 
etc.
 
Magnetic resonance imaging (MRI) is based on the magnetic resonance phenomenon, and is used for medical diagnostic imaging since ca. 1977 (see also MRI History).
The first developed MRI devices were constructed as long narrow tunnels. In the meantime the magnets became shorter and wider. In addition to this short bore magnet design, open MRI machines were created. MRI machines with open design have commonly either horizontal or vertical opposite installed magnets and obtain more space and air around the patient during the MRI test.
The basic hardware components of all MRI systems are the magnet, producing a stable and very intense magnetic field, the gradient coils, creating a variable field and radio frequency (RF) coils which are used to transmit energy and to encode spatial positioning. A computer controls the MRI scanning operation and processes the information.
The range of used field strengths for medical imaging is from 0.15 to 3 T. The open MRI magnets have usually field strength in the range 0.2 Tesla to 0.35 Tesla. The higher field MRI devices are commonly solenoid with short bore superconducting magnets, which provide homogeneous fields of high stability.
There are this different types of magnets:
Resistive Magnet
Permanent Magnet
Superconducting Magnet
The majority of superconductive magnets are based on niobium-titanium (NbTi) alloys, which are very reliable and require extremely uniform fields and extreme stability over time, but require a liquid helium cryogenic system to keep the conductors at approximately 4.2 Kelvin (-268.8 Celsius). To maintain this temperature the magnet is enclosed and cooled by a cryogen containing liquid helium (sometimes also nitrogen).
The gradient coils are required to produce a linear variation in field along one direction, and to have high efficiency, low inductance and low resistance, in order to minimize the current requirements and heat deposition. A Maxwell coil usually produces linear variation in field along the z-axis; in the other two axes it is best done using a saddle coil, such as the Golay coil.
The radio frequency coils used to excite the nuclei fall into two main categories; surface coils and volume coils. The essential element for spatial encoding, the gradient coil sub-system of the MRI scanner is responsible for the encoding of specialized contrast such as flow information, diffusion information, and modulation of magnetization for spatial tagging.
An analog to digital converter turns the nuclear magnetic resonance signal to a digital signal. The digital signal is then sent to an image processor for Fourier transformation and the image of the MRI scan is displayed on a monitor.

For Ultrasound Imaging (USI) see Ultrasound Machine at US-TIP.com.

See also the related poll results: 'In 2010 your scanner will probably work with a field strength of' and 'Most outages of your scanning system are caused by failure of'
Radiology-tip.comGamma Camera,  Linear Accelerator
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Radiology-tip.comUltrasound Machine,  Real-Time Scanner
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Further Reading:
  Basics:
Linear Collider Final FocusMagnet Construction
   by www.bnl.gov    
  News & More:
Selection Criteria For an MR System
   by dspace.dial.pipex.com    
MRI Resources 
Databases - Societies - Online Books - Most Wanted - MRA - Mobile MRI Rental
 
MRIForum -
related threads
 
Magnetic resonance imaging is a radiological diagnostic procedure without X-rays.

Magnetic resonance imaging, see also: MRI history, medical imaging, nuclear magnetic resonance, spin, precession, T1 time, T2 time, MRI equipment, MRI devices, MRI coils, MRI sequences, MRI contrast agents.

MRI resources, MRI congresses, and MRI news.

 
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• View the DATABASE results for 'MRI' (561).Open this link in a new window


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Further Reading:
  Basics:
A Short History of the Magnetic Resonance Imaging (MRI)
   by www.teslasociety.com    
Magnetic Resonance Imaging, History & Introduction
2000   by www.cis.rit.edu    
  News & More:
The 2003 Nobel Prize in Physiology or Medicine
2003   by www.nobel.se    
Bringing innovative technologies together
Monday, 18 November 2013   by www.european-hospital.com    
Advancing MRI scans for foetal development
Wednesday, 27 November 2013   by cordis.europa.eu    
MRI Use Common, But Not Always Evidence-Based
Sunday, 15 December 2013   by www.clinicaloncology.com    
Searchterm 'MRI History' was also found in the following service: 
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Magnetic Resonance Imaging MRI
 
(MRI) Magnetic resonance imaging is 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. These magnets generate fields from approx. 2000 times up to 30000 times stronger than that of the Earth. The use of nuclear magnetic resonance principles produces extremely detailed pictures of the body tissue without the need for x-ray exposure and gives diagnostic information of various organs.
Measured are mobile hydrogen nuclei (protons are the hydrogen atoms of water, the 'H' in H20), the majority of elements in the body. Only a small part of them contribute to the measured signal, caused by their different alignment in the magnetic field. Protons are capable of absorbing energy if exposed to short radio wave pulses (electromagnetic energy) at their resonance frequency. After the absorption of this energy, the nuclei release this energy so that they return to their initial state of equilibrium.
This transmission of energy by the nuclei as they return to their initial state is what is observed as the MRI signal. The subtle differing characteristic of that signal from different tissues combined with complex mathematical formulas analyzed on modern computers is what enables MRI imaging to distinguish between various organs. Any imaging plane, or slice, can be projected, and then stored or printed.
The measured signal intensity depends jointly on the spin density and the relaxation times (T1 time and T2 time), with their relative importance depending on the particular imaging technique and choice of interpulse times. Any motion such as blood flow, respiration, etc. also affects the image brightness.
Magnetic resonance imaging is particularly sensitive in assessing anatomical structures, organs and soft tissues for the detection and diagnosis of a broad range of pathological conditions. MRI pictures can provide contrast between benign and pathological tissues and may be used to stage cancers as well as to evaluate the response to treatment of malignancies. The need for biopsy or exploratory surgery can be eliminated in some cases, and can result in earlier diagnosis of many diseases.
See also MRI History and Functional Magnetic Resonance Imaging (fMRI).
 
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Courtesy of  Robert R. Edelman

 
Radiology-tip.comConventional Radiography,  Computed Tomography
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Further Reading:
  Basics:
A Short History of the Magnetic Resonance Imaging (MRI)
   by www.teslasociety.com    
MRI's inside story
Thursday, 4 December 2003   by www.economist.com    
On the Horizon - Next Generation MRI
Wednesday, 23 October 2013   by thefutureofthings.com    
  News & More:
The 2003 Nobel Prize in Physiology or Medicine
2003   by www.nobel.se    
New imaging technology promising for several types of cancer
Thursday, 29 August 2013   by medicalxpress.com    
Study Shows MRI Can Be Used for Orthodontic Imaging
Monday, 12 August 2013   by www.sbwire.com    
MRI method for measuring MS progression validated
Thursday, 19 December 2013   by www.eurekalert.org    
MRI technique allows study of wrist in motion
Monday, 6 January 2014   by www.healthimaging.com    
MRI Resources 
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Marconi Medical Systems MRI Resource Directory:
 - Manufacturers -
 
On October 19, 2001, Philips Medical Systems completed an acquisition strategy through its purchase of Marconi Medical Systems.
The History of Marconi Medical Systems
2001 Royal Philips Electronics and Marconi plc announced that Philips has agreed to acquire Marconi Medical Systems for $1.1 billion.
2000 Marconi introduces Infinite Detector Technology for Mx8000 multislice CT scanner, which acquires an unprecedented 16 simultaneous slices with sub-millimeter isotropic accuracy.
1999 At RSNA, Picker International unveils the new Marconi Medical Systems name and corporate vision.
1998 Picker International acquires the Computed Tomography Division of Elscint Ltd, immediately positioning Picker at the forefront of major global CT suppliers.
1986 Picker produces the industry's first 1.0T MR imager.
1981 Picker is sold to General Electric Co. Ltd. of England (GEC). Picker merged with Cambridge Instruments, GEC Medical, and American Optical to form Picker International.
1967 The name changed from Picker X-ray to Picker Corporation. Picker acquired Dunlee.
1946 The Dunlee Corporation started in Chicago by Dunmore Dunk and Zed. J. Atlee to meet demand for quality X-ray tubes and special purpose tubes.
1915 James Picker Company formed in New York City offering sales and service of X-ray equipment, film and accessories.
See also Philips Medical Systems and MRI History.
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