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Apparent Diffusion CoefficientInfoSheet: - Artifacts -
Case Studies, 
Reduction Index, 
etc.MRI Resource Directory:
 - Diffusion Weighted Imaging -
 
(ADC) A diffusion coefficient to differentiate T2 shine through effects or artifacts from real ischemic lesions. In the human brain, water diffusion is a three-dimensional process that is not truly random because the diffusional motion of water is impeded by natural barriers. These barriers are cell membranes, myelin sheaths, white matter fiber tracts, and protein molecules.
The apparent water diffusion coefficients can be calculated by acquiring two or more images with a different gradient duration and amplitude (b-values). The contrast in the ADC map depends on the spatially distributed diffusion coefficient of the acquired tissues and does not contain T1 and T2* values.
The increased sensitivity of diffusion-weighted MRI in detecting acute ischemia is thought to be the result of the water shift intracellularly restricting motion of water protons (cytotoxic edema), whereas the conventional T2 weighted images show signal alteration mostly as a result of vasogenic edema.
The reduced ADC value also could be the result of decreased temperature in the nonperfused tissues, loss of brain pulsations leading to a decrease in apparent proton motion, increased tissue osmolality associated with ischemia, or a combination of these factors. The lower ADC measurements seen with early ischemia, have not been fully established, however, a lower apparent ADC is a sensitive indicator of early ischemic brain at a stage when ischemic tissue remains potentially salvageable.
See also Diffusion Weighted Imaging and Diffusion Tensor Tractography.
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Further Reading:
  Basics:
Implementation of Dual-Source RF Excitation in 3 T MR-Scanners Allows for Nearly Identical ADC Values Compared to 1.5 T MR Scanners in the Abdomen
Wednesday, 29 February 2012   by www.plosone.org    
EVALUATION OF HUMAN STROKE BY MR IMAGING
2000
Diffusion Imaging: From Basic Physics to Practical Imaging
1999   by ej.rsna.org    
  News & More:
EORTC study aims to qualify ADC as predictive imaging biomarker in preoperative regimens
Monday, 4 January 2016   by www.eurekalert.org    
Novel MRI Technique Could Reduce Breast Biopsies, University of Washington Study
Tuesday, 2 October 2012   by www.eurekalert.org    
Combination of diffusion tensor and functional magnetic resonance imaging during recovery from the vegetative state.
Tuesday, 31 August 2010   by 7thspace.com    
Hopkins researchers use diffusion MRI technique to monitor ultrasound uterine fibroid treatment
Monday, 8 August 2005   by www.eurekalert.org    
ArcForum -
there are related threadsInfoSheet: - Artifacts -
Case Studies, 
Reduction Index, 
etc.
 
Static discharge.
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• View the DATABASE results for 'Arc' (62).Open this link in a new window

MRI Resources 
Shielding - Services and Supplies - MRI Technician and Technologist Schools - MRCP - Societies - Nerve Stimulator
 
Archiving
 
The storage of image and patient data for future retrieval.
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• View the DATABASE results for 'Archiving' (6).Open this link in a new window

Array CoilInfoSheet: - Coils -
Intro, 
Overview, 
etc.MRI Resource Directory:
 - Coils -
 
An array coil combines the advantages of smaller coils (high SNR) with those of larger coils (large measurement field). This type of RF coil is composed of separate multiple smaller coils, which can be used individually (switchable coil) or combined.
When used simultaneously, the elements can either be:
coupled array coils - electrically coupled to each other through common transmission lines or mutual inductance
isolated array coils - electrically isolated from each other with separate transmission lines and receivers and minimum effective mutual inductance, and with the signals from each transmission line processed independently or at different frequencies
phased array coils - multiple small coils arranged to efficiently cover a specific anatomic region and obtain high-resolution, high-SNR images of a larger volume. The data from the individual coils is integrated by special software to produce the high-resolution images.

See also the related poll result: '3rd party coils are better than the original manufacturer coils'
 
Images, Movies, Sliders:
 Anatomic Imaging of the Lumbar Spine  Open this link in a new window
      

Courtesy of  Robert R. Edelman

 
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• View the NEWS results for 'Array Coil' (1).Open this link in a new window.

• View the DATABASE results for 'Array Coil' (22).Open this link in a new window

 
Further Reading:
  Basics:
RF Coils in MRI
Sunday, 1 January 2006   by ric.uthscsa.edu    
  News & More:
Endorectal Coil Improves Prostate Cancer Detection
Friday, 25 November 2005   by www.sciencedaily.com    
Array Processor
 
Optional component of the computer system used to perform Fourier transformations to accelerate the processing of the received numerical data relative to the MR imaging process, to speed them up.
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MRI Resources 
MRI Centers - Devices - Supplies - Brain MRI - Claustrophobia - Implant and Prosthesis
 
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