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 'T2 Weighted' 
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Result : Searchterm 'T2 Weighted' found in 2 terms [] and 44 definitions []
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Searchterm 'T2 Weighted' was also found in the following services: 
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FerumoxideInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.
 
Short name: AMI-25, generic name: Ferumoxide (SPIO)
Ferumoxides are superparamagnetic (T2*) MRI contrast agents, so the largest signal change is on T2 and T2* weighted images.
The agent distributes relatively rapidly to organs with reticuloendothelial cells primarily the liver, spleen and bone marrow. The liver shows decreased signal intensity, as does the spleen and marrow. The agent is taken up by the normal liver, resulting in increased CNR between tumor and normal liver. Hepatocellular lesions, such as adenoma or focal nodular hyperplasia, contain reticuloendothelial cells, so they will behave similar to the liver, with decreased signal on T2 weighted images. On T1 images, there is typically some circulating contrast agent, and blood vessels show increased signal intensity.
Current MRI protocols involve T1 weighted breath-hold gradient echo images of the liver, and fast spin echo T2 weighted pictures. This requires about 15 minutes. The patient is then removed from the scanner, and the contrast agent administered. After contrast administration, the same pulse sequences are again repeated.

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• Related Searches:
    • Intracellular Contrast Agents
    • Ultrasmall Superparamagnetic Iron Oxide
    • Liver Imaging
    • Superparamagnetic Iron Oxide
    • Very Small Superparamagnetic Iron Oxide Particles
 
Further Reading:
  Basics:
Comparison of Two Superparamagnetic Viral-Sized Iron Oxide Particles Ferumoxides and Ferumoxtran-10 with a Gadolinium Chelate in Imaging Intracranial Tumors
2002   by www.ajnr.org    
Optimized Labelling of Human Monocytes with Iron Oxide MR Contrast Agents
Sunday, 30 November 2003   by rsna2003.rsna.org    
MRI Resources 
Open Directory Project - NMR - Resources - Musculoskeletal and Joint MRI - Mobile MRI - Liver Imaging
 
Lumbar Spine MRI
 
MRI of the lumbar spine, with its multiplanar 3 dimensional imaging capability, is currently the preferred modality for establishing a diagnosis. MRI scans and magnetic resonance myelography have many advantages compared with computed tomography and/or X-ray myelography in evaluating the lumbar spine. MR imaging scans large areas of the spine without ionizing radiation, is noninvasive, not affected by bone artifacts, provides vascular imaging capability, and makes use of safer contrast agents (gadolinium chelate).
Due to the high level of tissue contrast resolution, nerves and discs are clearly visible. MRI is excellent for detecting degenerative disease in the spine. Lumbar spine MRI accurately shows disc disease (prolapsed disc or slipped disc), the level at which disc disease occurs, and if a disc is compressing spinal nerves. Lumbar spine MRI depicts soft tissues, including the cauda equina, spinal cord, ligaments, epidural fat, subarachnoid space, and intervertebral discs. Loss of epidural fat on T1 weighted images, loss of cerebrospinal fluid signal around the dural sac on T2 weighted images and degenerative disc disease are common features of lumbar stenosis.

Common indications for MRI of the lumbar spine:
Neurologic deficits, evidence of radiculopathy, acute spinal cord compression (e.g., sudden bowel/bladder disturbance)
Suspected systemic disorders (primary tumors, drop metastases, osteomyelitis)
Postoperative evaluation of lumbar spine: disk vs. scar
Localized back pain with no radiculopathy (leg pain)
Lumbar spine imaging requires a special spine coil. often used whole spine array coils have the advantage that patients do not need other positioning if also upper parts of the spine should be scanned. Sagittal T1 and T2 weighted FSE sequences are the standard views. With multi angle oblique techniques individually oriented transverse images of each intervertebral disc at different angles can be obtained.

See also the related poll result: 'MRI will have replaced 50% of x-ray exams by'
 
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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Further Reading:
  Basics:
Lumbar Spine Stenosis: A Common Cause of Back and Leg Pain
   by www.aafp.org    
MRI Findings Linked to Effect of Lumbar Spine Surgery
Wednesday, 26 June 2013   by www.doctorslounge.com    
Spine imaging after lumbar disc replacement: pitfalls and current recommendations
Tuesday, 21 July 2009   by 7thspace.com    
  News & More:
Inappropriate Ordering of Lumbar Spine Magnetic Resonance Imaging: Are Providers Choosing Wisely? -
Tuesday, 2 February 2016   by www.ajmc.com    
Lumbar spine MRI limited in diagnosing ankylosing spondylitis
Friday, 7 March 2014   by www.healio.com    
How Weight-Bearing MRIs Can Improve Care & Lower Costs While Meeting Milliman Criteria
Friday, 4 October 2013   by www.beckersspine.com    
Lumbar Diskal Cyst Containing Intervertebral Disk Materials
Tuesday, 1 November 2011   by www.orthosupersite.com    
A Study of the Morphology of Lumbar Discs in Sitting and Standing Positions Using a 0.5T Open- Configuration MRI(.pdf)
2001   by cds.ismrm.org    
MRI Resources 
MR Myelography - Research Labs - Calculation - Services and Supplies - MRI Technician and Technologist Schools - Jobs pool
 
Signal Intensity
 
Signal intensity interpretation in MR imaging has a major problem.
Often there is no intuitive approach to signal behavior as signal intensity is a very complicated function of the contrast-determining tissue parameter, proton density, T1 and T2, and the machine parameters TR and TE. For this reason, the terms T1 weighted image, T2 weighted image and proton density weighted image were introduced into clinical MR imaging.
Air and bone produce low-intensity, weaker signals with darker images. Fat and marrow produce high-intensity signals with brighter images.
The signal intensity measured is related to the square of the xy-magnetization, which in a SE pulse sequence is given by
Mxy = Mxy0(1-exp(-TR/T1)) exp(-TE/T2) (1)
where Mxy0 = Mz0 is proportional to the proton or spin density, and corresponds to the z-magnetization present at zero time of the experiment when it is tilted into the xy-plane.
See also T2 Weighted Image and Ernst Angle.
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• View the DATABASE results for 'Signal Intensity' (56).Open this link in a new window


• View the NEWS results for 'Signal Intensity' (1).Open this link in a new window.
 
Further Reading:
  Basics:
Contrast mechanisms in magnetic resonance imaging
2004   by www.iop.org    
Image Characteristics and Quality
   by www.sprawls.org    
  News & More:
Kidney stone imaging with 3D ultra-short echo time (UTE) magnetic resonance imaging. A phantom study - Abstract
Wednesday, 11 March 2015   by www.urotoday.com    
High-Field MRI Superior for Delineation of Alar Ligaments
Friday, 13 April 2012   by www.jaapa.com    
Searchterm 'T2 Weighted' was also found in the following services: 
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T2 TimeForum -
related threads
 
The T2 relaxation time (spin spin relaxation time or transverse relaxation time), is a biological parameter that is used in MRIs to distinguish between tissue types and is termed 'Time 2' or T2. It is a tissue-specific time constant for protons and is dependent on the exchanging of energy with near by nuclei. T2 weighted images rely upon local dephasing of spins following the application of the transverse energy pulse. T2 is the decay of magnetization perpendicular to the main magnetic field (in an ideal homogeneous field).
Due to interaction between the spins, they lose their phase coherence, which results in a loss of transverse magnetization and MRI signal. After time T2 transverse magnetization has lost 63% of its original value. This tissue parameter determines the contrast.
The T2 relaxation is temperature dependent. At a lower temperature molecular motion is reduced and the decay times are reduced.
Fat has a very efficient energy exchange and therefore it has a relatively short T2.
Water is less efficient than fat in the exchange of energy, and therefore it has a long T2 time.
See also T2 Weighted Image and Magnetic Resonance Imaging MRI.
 
Images, Movies, Sliders:
 Breast MRI Images T2 And T1  Open this link in a new window
      
 MRI of the Skull Base  Open this link in a new window
    
SlidersSliders Overview

 Knee MRI Transverse 002  Open this link in a new window
    
 
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• View the DATABASE results for 'T2 Time' (16).Open this link in a new window

 
Further Reading:
  News & More:
MYELIN-SELECTIVE MRI: PULSE SEQUENCE DESIGN AND OPTIMIZATION
   by www.imaging.robarts.ca    
MRI Resources 
Bioinformatics - PACS - Musculoskeletal and Joint MRI - Developers - IR - Breast Implant
 
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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• View the DATABASE results for 'Apparent Diffusion Coefficient' (4).Open this link in a new window

 
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    
MRI Resources 
MRI Accidents - Colonography - General - DICOM - Education - MRI Centers
 
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