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 'T2 Weighted' 
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T2 WeightedForum -
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Often used to indicate an image where most of the contrast between tissues or tissue states is due to differences in tissue T2 created typically by using longer TE and TR times.
This term may be misleading in that the potentially important effects of tissue density differences and the range of tissue T2 values are often ignored.
Choosing the machine parameters such that TR greater than T1 (typically 2 000 ms) and TE less than T2 (typically 100 ms) and noting that (1-exp(-TR/T1) = 1 for TR/T1 much greater than 1, will reduce Eq. 1 to the expression
Mxy = Mxy0exp(-TE/T2)
which is dependent on T2 only, hence the term T2 weighting. Therefore T2 weighted image contrast state is approached by imaging with a TR long compared to tissue T1 (to reduce T1 contribution to image contrast) and a TE between the longest and shortest tissue T2s of interest. A TR greater than 3 times the longest T1 is required for the T1 effect to be less than 5%. Due to the wide range of T1 and T2 and tissue density values that can be found in the body, an image that is T2 weighted for some tissues may not be so for others.
See also T2 Time.
Lesions with short T2 are (dark in T2 weighted sequences):
acute haemorrhage (deoxyHb)
haemosiderin
physiologic iron (basal ganglia, etc.)
mucinous lesions.
 
Images, Movies, Sliders:
 MRI Pancreas T2  Open this link in a new window
    
 Anatomic MRI of the Neck  Open this link in a new window
    
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 MRI Liver T2  Open this link in a new window
    
 
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    • T1 Weighted
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    • Contrast Agents
    • Brain MRI
 
Further Reading:
  Basics:
Fast T2 weighted imaging by PSIF at 0.2T for interventional MRI.(.pdf)
   by cds.ismrm.org    
Clinical evaluation of a speed optimized T2 weighted fast spin echo sequence at 3.0 T using variable flip angle refocusing, half-Fourier acquisition and parallel imaging
Wednesday, 25 October 2006
MRI Resources 
Contrast Agents - MR Myelography - Stent - Non-English - Spectroscopy - Service and Support
 
T2 Weighted ImageInfoSheet: - Sequences - 
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T2 weighted imaging relies upon local dephasing of spins following the application of the transverse energy pulse. The contrast of a T2 weighted image is predominantly dependent on T2 and the T2 dependence will be increased by using a long echo time.
Fat has a shorter T2 time than water and relaxes or decays more readily than water. Since the amount of transverse magnetization in fat is small, fat generates very little signal on a strong T2 weighted contrast image and appears intermediate to dark. The T2 weighting is stronger with a longer TE. Water has a very high T2 constant, therefore has very high T2 signal and thus appears bright on a T2 contrast image. Cerebral white matter (fat containing) is less intense than grey matter. Flowing blood (flow effects) and haematomas (haemoglobin, haemosiderin) have a variable signal intensity on MR images.
Images created with TR's and TE's to enhance T2 contrast are referred to as T2 weighted images. Both T1 and T2 weighted images are acquired for most medical MRI examinations.
 
Images, Movies, Sliders:
 Lumbar Spine T2 FSE Sagittal  Open this link in a new window
    

Courtesy of  Robert R. Edelman
 Shoulder Axial T2 FatSat FRFSE  Open this link in a new window
    

Courtesy of  Robert R. Edelman
 Lumbar Spine T2 FSE Axial  Open this link in a new window
 
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• View the DATABASE results for 'T2 Weighted Image' (5).Open this link in a new window

 
Further Reading:
  Basics:
MYELIN-SELECTIVE MRI: PULSE SEQUENCE DESIGN AND OPTIMIZATION
   by www.imaging.robarts.ca    
T2* cardiac MRI allows prediction of severe reperfusion injury after STEMI
Tuesday, 9 November 2010   by www.medwire-news.md    
  News & More:
Ultrashort echo time (UTE) MRI of the spine in thalassaemia
February 2004   by bjr.birjournals.org    
New MR sequence helps radiologists more accurately evaluate abnormalities of the uterus and ovaries
Thursday, 23 April 2009   by www.eurekalert.org    
MRI Resources 
Journals - Online Books - Shielding - MRA - Breast Implant -
 
Fast Spin EchoForum -
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Fast Spin Echo Diagram

(FSE) In the pulse sequence timing diagram, a fast spin echo sequence with an echo train length of 3 is illustrated. This sequence is characterized by a series of rapidly applied 180░ rephasing pulses and multiple echoes, changing the phase encoding gradient for each echo.
The echo time TE may vary from echo to echo in the echo train. The echoes in the center of the K-space (in the case of linear k-space acquisition) mainly produce the type of image contrast, whereas the periphery of K-space determines the spatial resolution. For example, in the middle of K-space the late echoes of T2 weighted images are encoded. T1 or PD contrast is produced from the early echoes.
The benefit of this technique is that the scan duration with, e.g. a turbo spin echo turbo factor / echo train length of 9, is one ninth of the time. In T1 weighted and proton density weighted sequences, there is a limit to how large the ETL can be (e.g. a usual ETL for T1 weighted images is between 3 and 7). The use of large echo train lengths with short TE results in blurring and loss of contrast. For this reason, T2 weighted imaging profits most from this technique.
In T2 weighted FSE images, both water and fat are hyperintense. This is because the succession of 180░ RF pulses reduces the spin spin interactions in fat and increases its T2 decay time. Fast spin echo (FSE) sequences have replaced conventional T2 weighted spin echo sequences for most clinical applications. Fast spin echo allows reduced acquisition times and enables T2 weighted breath hold imaging, e.g. for applications in the upper abdomen.
In case of the acquisition of 2 echoes this type of a sequence is named double fast spin echo / dual echo sequence, the first echo is usually density and the second echo is T2 weighted image. Fast spin echo images are more T2 weighted, which makes it difficult to obtain true proton density weighted images. For dual echo imaging with density weighting, the TR should be kept between 2000 - 2400 msec with a short ETL (e.g., 4).
Other terms for this technique are:
Turbo Spin Echo
Rapid Imaging Spin Echo,
Rapid Spin Echo,
Rapid Acquisition Spin Echo,
Rapid Acquisition with Refocused Echoes

 
Images, Movies, Sliders:
 Lumbar Spine T2 FSE Sagittal  Open this link in a new window
    

Courtesy of  Robert R. Edelman
 MRI - Anatomic Imaging of the Foot  Open this link in a new window
    
SlidersSliders Overview

 Lumbar Spine T2 FSE Axial  Open this link in a new window
    

Courtesy of  Robert R. Edelman
 
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• View the DATABASE results for 'Fast Spin Echo' (31).Open this link in a new window

 
Further Reading:
  Basics:
MYELIN-SELECTIVE MRI: PULSE SEQUENCE DESIGN AND OPTIMIZATION
   by www.imaging.robarts.ca    
Advances in Magnetic Resonance Neuroimaging
Friday, 27 February 2009   by www.ncbi.nlm.nih.gov    
  News & More:
New MR sequence helps radiologists more accurately evaluate abnormalities of the uterus and ovaries
Thursday, 23 April 2009   by www.eurekalert.org    
Spin echoes, CPMG and T2 relaxation - Introductory NMR & MRI from Magritek
2013   by www.azom.com    
Scanning the Abdomen
   by www.mrprotocols.com    
Searchterm 'T2 Weighted' was also found in the following services: 
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Abdominal ImagingMRI Resource Directory:
 - Abdominal Imaging -
 
General MRI of the abdomen can consist of T1 or T2 weighted spin echo, fast spin echo (FSE, TSE) or gradient echo sequences with fat suppression and contrast enhanced MRI techniques. The examined organs include liver, pancreas, spleen, kidneys, adrenals as well as parts of the stomach and intestine (see also gastrointestinal imaging). Respiratory compensation and breath hold imaging is mandatory for a good image quality.
T1 weighted sequences are more sensitive for lesion detection than T2 weighted sequences at 0.5 T, while higher field strengths (greater than 1.0 T), T2 weighted and spoiled gradient echo sequences are used for focal lesion detection. Gradient echo in phase T1 breath hold can be performed as a dynamic series with the ability to visualize the blood distribution. Phases of contrast enhancement include the capillary or arterial dominant phase for demonstrating hypervascular lesions, in liver imaging the portal venous phase demonstrates the maximum difference between the liver and hypovascular lesions, while the equilibrium phase demonstrates interstitial disbursement for edematous and malignant tissues.
Out of phase gradient echo imaging for the abdomen is a lipid-type tissue sensitive sequence and is useful for the visualization of focal hepatic lesions, fatty liver (see also Dixon), hemochromatosis, adrenal lesions and renal masses. The standards for abdominal MRI vary according to clinical sites based on sequence availability and MRI equipment. Specific abdominal imaging coils and liver-specific contrast agents targeted to the healthy liver tissue improve the detection and localization of lesions.
See also Hepatobiliary Contrast Agents, Reticuloendothelial Contrast Agents, and Oral Contrast Agents.

For Ultrasound Imaging (USI) see Abdominal Ultrasound at US-TIP.com.
 
Images, Movies, Sliders:
 MR Colonography Gadolinium per Rectum  Open this link in a new window
      

Courtesy of  Robert R. Edelman
 Anatomic Imaging of the Liver  Open this link in a new window
      

 CE MRA of the Aorta  Open this link in a new window
    
SlidersSliders Overview

 
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• View the DATABASE results for 'Abdominal Imaging' (11).Open this link in a new window


• View the NEWS results for 'Abdominal Imaging' (3).Open this link in a new window.
 
Further Reading:
  Basics:
Abdominal MRI at 3.0 T: The Basics Revisited
Wednesday, 20 July 2005   by www.ajronline.org    
Usefulness of MR Imaging for Diseases of the Small Intestine: Comparison with CT
2000   by www.ncbi.nlm.nih.gov    
MAGNETIC RESONANCE IMAGING OF FOCAL LIVER LESIONS(.pdf)
2002
  News & More:
Nottingham scientists exploit MRI technology to assist in the treatment of IBS
Thursday, 9 January 2014   by www.news-medical.net    
MRI identifies 'hidden' fat that puts adolescents at risk for disease
Tuesday, 27 February 2007   by www.eurekalert.org    
New MR sequence helps radiologists more accurately evaluate abnormalities of the uterus and ovaries
Thursday, 23 April 2009   by www.eurekalert.org    
MRI Resources 
Chemistry - Musculoskeletal and Joint MRI - Colonography - Libraries - Process Analysis - Diffusion Weighted Imaging
 
ContrastForum -
related threads
 
Contrast is the relative difference of signal intensities in two adjacent regions of an image.
Due to the T1 and T2 relaxation properties in magnetic resonance imaging, differentiation between various tissues in the body is possible. Tissue contrast is affected by not only the T1 and T2 values of specific tissues, but also the differences in the magnetic field strength, temperature changes, and many other factors. Good tissue contrast relies on optimal selection of appropriate pulse sequences (spin echo, inversion recovery, gradient echo, turbo sequences and slice profile).
Important pulse sequence parameters are TR (repetition time), TE (time to echo or echo time), TI (time for inversion or inversion time) and flip angle. They are associated with such parameters as proton density and T1 or T2 relaxation times. The values of these parameters are influenced differently by different tissues and by healthy and diseased sections of the same tissue.
For the T1 weighting it is important to select a correct TR or TI. T2 weighted images depend on a correct choice of the TE. Tissues vary in their T1 and T2 times, which are manipulated in MRI by selection of TR, TI, and TE, respectively. Flip angles mainly affect the strength of the signal measured, but also affect the TR/TI/TE parameters.
Conditions necessary to produce different weighted images:
T1 Weighted Image: TR value equal or less than the tissue specific T1 time - TE value less than the tissue specific T2 time.
T2 Weighted Image: TR value much greater than the tissue specific T1 time - TE value greater or equal than the tissue specific T2 time.
Proton Density Weighted Image: TR value much greater than the tissue specific T1 time - TE value less than the tissue specific T2 time.
See also Image Contrast Characteristics, Contrast Reversal, Contrast Resolution, and Contrast to Noise Ratio.

 
Images, Movies, Sliders:
 Fetus (Brain) and Dermoid in Mother  Open this link in a new window
      

Courtesy of  Robert R. Edelman

 Circle of Willis, Time of Flight, MIP  Open this link in a new window
    
SlidersSliders Overview

 Anatomic MRI of the Knee 1  Open this link in a new window
    
SlidersSliders Overview

 Anatomic Imaging of the Liver  Open this link in a new window
      

 Brain MRI Inversion Recovery  Open this link in a new window
    
 
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• View the DATABASE results for 'Contrast' (373).Open this link in a new window


• View the NEWS results for 'Contrast' (77).Open this link in a new window.
 
Further Reading:
  Basics:
Magnetic resonance imaging
   by www.scholarpedia.org    
MRI's inside story
Thursday, 4 December 2003   by www.economist.com    
Image Characteristics and Quality
   by www.sprawls.org    
  News & More:
Sharpening MRI Images
Sunday, 1 December 2013   by www.onlinetmd.com    
A natural boost for MRI scans
Monday, 21 October 2013   by www.eurekalert.org    
A groundbreaking new graphene-based MRI contrast agent
Friday, 8 June 2012   by www.nanowerk.com    
New MRI Chemical Offers Amazing Contrast
Friday, 22 January 2010   by news.softpedia.com    
MRI Resources 
Education - Nerve Stimulator - Movies - Contrast Agents - Abdominal Imaging - Veterinary MRI
 
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