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Result : Searchterm 'Fourier Transformation' found in 8 terms [] and 31 definitions []
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Searchterm 'Fourier Transformation' was also found in the following services: 
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DC Offset ArtifactInfoSheet: - Artifacts - 
Case Studies, 
Reduction Index, 
etc.MRI Resource Directory:
 - Artifacts -
 
This artifact looks like a pixel at the exact center, which is brighter or darker than the surroundings by the Fourier transformation of a constant raw data offset.

See Central Point Artifact.
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Further Reading:
  Basics:
Image Artefacts
   by www.fmrib.ox.ac.uk    
Searchterm 'Fourier Transformation' was also found in the following services: 
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Radiology  (3) Open this link in a new windowUltrasound  (5) Open this link in a new window
Dephasing Gradient
 
Magnetic field gradient pulse used to create spatial variation of phase of transverse magnetization. For example, it may be applied prior to signal detection in the presence of a magnetic field gradient with opposite polarity (or of the same polarity if separated by a refocusing RF pulse) so that the resulting gradient echo signal will represent a more complete sampling of the Fourier transformation of the desired image.

See also Spoiler Gradient Pulse.
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Further Reading:
  Basics:
RARE
Monday, 3 December 2012   by www2.warwick.ac.uk    
MRI Resources 
Quality Advice - - Safety Products - Mobile MRI - General - Liver Imaging
 
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:
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 Medical-Ultrasound-Imaging.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.comradGamma Camera,  Linear Accelerator
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Medical-Ultrasound-Imaging.comUltrasound Machine,  Real-Time Scanner
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• View the DATABASE results for 'Device' (141).Open this link in a new window


• View the NEWS results for 'Device' (29).Open this link in a new window.
 
Further Reading:
  News & More:
small-steps-can-yield-big-energy-savings-and-cut-emissions-mris
Thursday, 27 April 2023   by www.itnonline.com    
Portable MRI can detect brain abnormalities at bedside
Tuesday, 8 September 2020   by news.yale.edu    
Point-of-Care MRI Secures FDA 510(k) Clearance
Thursday, 30 April 2020   by www.diagnosticimaging.com    
World's First Portable MRI Cleared by FDA
Monday, 17 February 2020   by www.medgadget.com    
Low Power MRI Helps Image Lungs, Brings Costs Down
Thursday, 10 October 2019   by www.medgadget.com    
Cheap, portable scanners could transform brain imaging. But how will scientists deliver the data?
Tuesday, 16 April 2019   by www.sciencemag.org    
The world's strongest MRI machines are pushing human imaging to new limits
Wednesday, 31 October 2018   by www.nature.com    
Kyoto University and Canon reduce cost of MRI scanner to one tenth
Monday, 11 January 2016   by www.electronicsweekly.com    
A transportable MRI machine to speed up the diagnosis and treatment of stroke patients
Wednesday, 22 April 2015   by medicalxpress.com    
Portable 'battlefield MRI' comes out of the lab
Thursday, 30 April 2015   by physicsworld.com    
Chemists develop MRI technique for peeking inside battery-like devices
Friday, 1 August 2014   by www.eurekalert.org    
New devices doubles down to detect and map brain signals
Monday, 23 July 2012   by scienceblog.com    
Searchterm 'Fourier Transformation' was also found in the following services: 
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Driven EquilibriumInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.
 
In fast imaging sequences driven equilibrium sensitizes the sequence to variations in T2. This MRI technique turns transverse magnetization Mxy to the longitudinal axis using a pulse rather than waiting for T1 relaxation.
The first two pulses form a spin echo and, at the peak of the echo, a second 90° pulse returns the magnetization to the z-axis in preparation for a fresh sequence. In the absence of T2 relaxation, then all the magnetization can be returned to the z-axis. Otherwise, T2 signal loss during the sequence will reduce the final z-magnetization.
The advantage of this sequence type is, that both longitudinal and also transverse magnetization are back to equilibrium in a shorter amount of time. Therefore, contrast and signal can be increased while using a shorter TR. This pulse type can be applied to other sequences like FSE, GE or IR.

Sequences with driven equilibrium:
Driven Equilibrium Fast Gradient Recalled acquisition in the steady state - DE FGR,
Driven Equilibrium Fourier Transformation - DEFT,
Driven Equilibrium magnetization preparation - DE prep,
Driven Equilibrium Fast Spin Echo - DE FSE.
 
Images, Movies, Sliders:
 MRI of the Skull Base  Open this link in a new window
    
SlidersSliders Overview

 
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Further Reading:
  Basics:
3D Turbo Spin-Echo Sequence with Motion-Sensitized Driven-Equilibrium Preparation for Detection of Brain Metastases on 3T MR Imaging
Saturday, 3 December 2011   by www.ajnr.org    
  News & More:
Advances in high-field MR imaging of the spine
Wednesday, 5 August 2009   by www.appliedradiology.com    
Comparison of New Methods for Magnetic Resonance Imaging of Articular Cartilage(.pdf)
2002
Searchterm 'Fourier Transformation' was also found in the following services: 
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Radiology  (3) Open this link in a new windowUltrasound  (5) Open this link in a new window
Frequency Encoding
 
Encoding the distribution of sources of MR signals along a direction in space with different frequencies. In general, it is necessary to acquire a set of signals with a suitable set of different frequencies in order to reconstruct the distribution of the sources along the encoded direction. In the absence of other position encoding, the Fourier transformation of the resulting signal is a one-dimensional projection profile of the object.
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• View the DATABASE results for 'Frequency Encoding' (31).Open this link in a new window

 
Further Reading:
  Basics:
Measuring T1 and T2 Relaxation - Introductory NMR & MRI from Magritek
   by www.azom.com    
Aliasing or wrap around artifacts
Thursday, 31 March 2011   by de.slideshare.net    
MRI Resources 
Spine MRI - Used and Refurbished MRI Equipment - Education pool - Breast Implant - Directories - Abdominal Imaging
 
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