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Result : Searchterm 'MRI' found in 26 terms [] and 446 definitions []
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Searchterm 'MRI' was also found in the following services: 
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News  (1300)  Resources  (333)  Forum  (379)  
 
Blood Oxygenation Level Dependent ContrastInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.MRI Resource Directory:
 - Functional MRI -
 
(BOLD) In MRI the changes in blood oxygenation level are visible. Oxyhaemoglobin (the principal haemoglobin in arterial blood) has no substantial magnetic properties, but deoxyhaemoglobin (present in the draining veins after the oxygen has been unloaded in the tissues) is strongly paramagnetic. It can thus serve as an intrinsic paramagnetic contrast agent in appropriately performed brain MRI. The concentration and relaxation properties of deoxyhaemoglobin make it a susceptibility , e.g. T2 relaxation effective contrast agent with little effect on T1 relaxation.
During activation of the brain, the oxygen consumption of the local tissue increase by approximately 5% with that the oxygen tension will decrease. As a consequence, after a short period of time vasodilatation occurs, resulting in a local increase of blood volume and flow by 20 - 40%. The incommensurate change in local blood flow and oxygen extraction increases the local oxygen level.
By using T2 weighted gradient echo EPI sequences, which are highly susceptibility sensitive and fast enough to capture the three-dimensional nature of activated brain areas will show an increase in signal intensity as oxyhaemoglobin is diamagnetic and deoxyhaemoglobin is paramagnetic. Other MR pulse sequences, such as spoiled gradient echo pulse sequences are also used.
As the effects are subtle and of the order of 2% in 1.5 T MR imaging, sophisticated methodology, paradigms and data analysis techniques have to be used to consistently demonstrate the effect.
As the BOLD effect is due to the deoxygenated blood in the draining veins, the spatial localization of the region where there is increased blood flow resulting in decreased oxygen extraction is not as precisely defined as the morphological features in MRI. Rather there is a physiological blurring, and is estimated that the linear dimensions of the physiological spatial resolution of the BOLD phenomenon are around 3 mm at best.
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• Related Searches:
    • Functional Magnetic Resonance Imaging
    • Oxygen Mapping
    • Haemoglobin
    • Blood Flow Imaging
    • T2 Relaxation
 
Further Reading:
  Basics:
IMAGE CONTRAST IN MRI(.pdf)
   by www.assaftal.com    
Vascular Filters of Functional MRI: Spatial Localization Using BOLD and CBV Contrast
  News & More:
A mechanistic computational framework to investigate the hemodynamic fingerprint of the blood oxygenation level-dependent signal
Tuesday, 29 August 2023   by analyticalsciencejournals.onlinelibrary.wiley.com    
The utility of texture analysis of kidney MRI for evaluating renal dysfunction with multiclass classification model
Tuesday, 30 August 2022   by www.nature.com    
MRI Technique Used to Identify Future Risk of Binge Drinking
Monday, 6 January 2020   by www.diagnosticimaging.com    
Gold Acupuncture Needle MRI Pain Discovery
Friday, 3 January 2014   by www.healthcmi.com    
MRI method for measuring MS progression validated
Thursday, 19 December 2013   by www.eurekalert.org    
Searchterm 'MRI' was also found in the following services: 
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Radiology  (20) Open this link in a new windowUltrasound  (24) Open this link in a new window
Blood Pool AgentsInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.MRI Resource Directory:
 - Contrast Agents -
 
Blood pool agents (intravascular contrast agents) remain in the blood for a prolonged time compared with conventional contrast agents, which diffuse quickly into the interstitial space. Magnetic resonance angiography (MRA), cardiovascular imaging, or contrast enhanced MRIs are possible over an hour or more. This advantage over conventional MRI contrast media allows also higher resolution MRA of several territories using respiratory or cardiac gating techniques with a single contrast bolus.
Different types of blood pool contrast agents:
Blood pool MRI contrast agents with their longer intravascular circulation can be designed to be targeted to necrotic myocardium, to assess myocardial viability, or tumor directed to provide better diagnostic information for various tumors. A disadvantage of the use of blood pool agents for MRA is that the separation of arteries and veins is more difficult because they are present in both and the overlapping of those vessels is disturbing. This can be solved by e.g. different MIP segmentation algorithms.

See also Necrosis Avid Contrast Agent, Tumor Specific Agents, Feruglose, Gadofosveset Trisodium (Vasovist), Ultrasmall Superparamagnetic Iron Oxide and Contrast Medium.
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• View the DATABASE results for 'Blood Pool Agents' (16).Open this link in a new window


• View the NEWS results for 'Blood Pool Agents' (1).Open this link in a new window.
 
Further Reading:
  Basics:
Ablavar Prescribing Information
   by www.ablavar.com    
Lantheus Medical Imaging, Inc. Launches ABLAVAR™ (Gadofosveset Trisodium), a New Diagnostic Magnetic Resonance Angiography Agent
Wednesday, 20 January 2010   by www.radiopharm.com    
Blood-Pool Imaging Using Technetium-99m-Labeled Liposomes(.pdf)
   by jnm.snmjournals.org    
  News & More:
Multimodal Nanoparticles for Quantitative Imaging(.pdf)
Tuesday, 13 December 2011   by alexandria.tue.nl    
MAGNETIC RESONANCE IMAGING OF FOCAL LIVER LESIONS(.pdf)
2002
MRI Resources 
Cardiovascular Imaging - Liver Imaging - PACS - Pregnancy - Safety Products - Devices
 
C-SCAN™InfoSheet: - Devices -
Intro, 
Types of Magnets, 
Overview, 
etc.MRI Resource Directory:
 - Devices -
 
www.gehealthcare.com/usen/mr/cscan/index.html Manufactured by Esaote S.p.A.; compact in-office MRI system, fits in a 90 ft2 (8.4 m2) space and requires no shielding or special power. This low field MRI magnet is optimized for orthopedic use and imaging of the extremities.
The C-SCAN™ is developed from the ARTOSCAN™ - M with a new computer platform, and is also known as Artoscan C.
Esaote North America and Hologic Inc. are the U.S. distributors of this MRI device.
Device Information and Specification
CLINICAL APPLICATION
Dedicated extremity
CONFIGURATION
Closed
Linear and dual phased array, knee, ankle, wrist (6 total) coils
PULSE SEQUENCES
SE, GE, IR, STIR, FSE, 3D CE, GE-STIR, 3D GE, ME, TME, HSE
IMAGING MODES
Single, multislice, volume study, fast scan, multi slab
TR
12 - 5,000 msec
TE
5 - 220 msec
SINGLE SLICE
0.8 sec/image
MULTISLICE
0.8 sec/image
FOV
10 - 20 cm
2D: 2 mm - 10 mm;
3D: 0.6 mm - 10 mm
512 x 512
MEASURING MATRIX
256 x 256 maximum
PIXEL INTENSITY
4,096 gray lvls, 256 lvls in 3D
MAGNET TYPE
Permanent
BORE DIAMETER
or W x H
33.6 x 16 cm
MAGNET WEIGHT
960 kg
H*W*D
124 x 76 x 60 cm
POWER REQUIREMENTS
100/110/200/220/230/240
STRENGTH
10 mT/m
5-GAUSS FRINGE FIELD, radial/axial
28 cm/60 cm
Passive
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• View the DATABASE results for 'C-SCAN™' (4).Open this link in a new window

Searchterm 'MRI' was also found in the following services: 
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News  (1300)  Resources  (333)  Forum  (379)  
 
CoilForum -
related threadsInfoSheet: - Coils - 
Intro, 
Overview, 
etc.MRI Resource Directory:
 - Coils -
 
A coil consists of one or more loops of conductive wire, looped around the core of the coil. Coils are part of the hardware of MRI machines and are used to create a magnetic field or to detect a changing magnetic field by voltage induced in the wire. A coil is usually a physically small antenna.
The perfect coil produces a uniform magnetic field without significant radiation.
Different types of MRI coils are used in MR systems:
Gradient coils are used to produce controlled variations in the main magnetic field (B0) to provide spatial localization of the signals and to apply reversal pulses in some imaging techniques.
MR imaging radio frequency coils to receive and/or transmit the RF signal.
Shim coils provide auxiliary magnetic fields in order to compensate for inhomogeneities in the main magnetic field of the MRI machine.

See also Gradient Coil, Radio Frequency Coil, Hardware and Coil Loading.

See also the related POLL result: '3rd party coils are better than the original manufacturer coils'
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• View the DATABASE results for 'Coil' (193).Open this link in a new window


• View the NEWS results for 'Coil' (11).Open this link in a new window.
 
Further Reading:
  News & More:
3T MRI-Compatible Small Body Array Gets FDA Nod
Monday, 15 January 2024   by www.diagnosticimaging.com    
High-field MRI Coils – that work, superbly, even at 750 MHz
   by www.dotynmr.com    
New superconducting coil improves MRI performance
Wednesday, 20 July 2016   by www.eurekalert.org    
First European fully superconductive coil reaching a magnetic field of 25 Tesla produced
Wednesday, 8 June 2016   by www.news-medical.net    
ScanMed Introduces a Groundbreaking New Orbit and Mandible Array to the MRI Market
Wednesday, 26 March 2014   by www.digitaljournal.com    
MRI coil optimized for imaging of infants gets FDA clearance
Tuesday, 17 April 2012   by www.medcitynews.com    
Low-profile MRI coil company inching toward commercialization
Wednesday, 21 December 2011   by www.medcitynews.com    
High-Resolution Uniform MR Imaging of Finger Joints Using a Dedicated RF Coil at 3 Tesla
Sunday, 31 January 2010   by www.ncbi.nlm.nih.gov    
DOTmed Industry Sector Report: MRI Coil Sales & Service Companies
Thursday, 13 December 2007   by www.dotmed.com    
Searchterm 'MRI' was also found in the following services: 
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Radiology  (20) Open this link in a new windowUltrasound  (24) Open this link in a new window
Computer Aided Detection
 
(CAD) 'Computer aided detection' or 'computer assisted diagnosis' systems are tools to improve the efficiency and workflow in medical imaging procedures. The aim of CAD is to increase the diagnostic accuracy of screening procedures by using a computer system to locate abnormalities, improve image management, correct patient movement and assist the radiologists in the interpretation and analysis of data-intensive studies. Typical applications include the tumor detection in mammography, breast MRI, colonography, and lung imaging. Newer applications like prostate MRI are under investigation.

See also MR Guided Interventions, Breast MRI and Hybrid Imaging.
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• View the DATABASE results for 'Computer Aided Detection' (3).Open this link in a new window


• View the NEWS results for 'Computer Aided Detection' (7).Open this link in a new window.
 
Further Reading:
  News & More:
Evaluating brain MRI scans with the help of artificial intelligence
Thursday, 2 June 2022   by www.technologyreview.com    
New AI Tool for Prostate MRI Analysis to Support PI-RADS Scoring
Monday, 11 April 2022   by www.itnonline.com    
Superhuman 20 second AI heart tool begins NHS roll-out
Friday, 11 March 2022   by www.bhf.org.uk    
Computer-aided detection and diagnosis for prostate cancer based on mono and multi-parametric MRI: A review - Abstract
Tuesday, 28 April 2015   by urotoday.com    
MRI method for measuring MS progression validated
Thursday, 19 December 2013   by www.eurekalert.org    
MRI Resources 
Abdominal Imaging - MRI Technician and Technologist Jobs - MRI Accidents - Education - Safety Training - Spine MRI
 
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