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Result : Searchterm 't2' found in 8 terms [] and 150 definitions []
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Searchterm 't2' was also found in the following services: 
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News  (28)  Resources  (5)  Forum  (67)  
 
Balanced Fast Field EchoInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.MRI Resource Directory:
 - Sequences -
 
(bFFE) A FFE sequence using a balanced gradient waveform. A balanced sequence starts out with a RF pulse of 90° or less and the spins in the steady state. Before the next TR in the slice phase and frequency encoding, gradients are balanced so their net value is zero. Now the spins are prepared to accept the next RF pulse, and their corresponding signal can become part of the new transverse magnetization. Since the balanced gradients maintain the transverse and longitudinal magnetization, the result is, that both T1 and T2 contrast are represented in the image. This pulse sequence produces images with increased signal from fluid, along with retaining T1 weighted tissue contrast. Because this form of sequence is extremely dependent on field homogeneity, it is essential to run a shimming prior the acquisition. A fully balanced (refocused) sequence would yield higher signal, especially for tissues with long T2 relaxation times.

See Steady State Free Precession and Gradient Echo Sequence.
 
Images, Movies, Sliders:
 Cardiac Infarct Short Axis Cine bFFE 1  Open this link in a new window
    
 
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Further Reading:
  News & More:
T1rho-prepared balanced gradient echo for rapid 3D T1rho MRI
Monday, 1 September 2008   by www.ncbi.nlm.nih.gov    
Utility of the FIESTA Pulse Sequence in Body Oncologic Imaging: Review
June 2009   by www.ajronline.org    
MRI Resources 
Homepages - Safety pool - MRI Accidents - Directories - NMR - Distributors
 
Balanced SequenceForum -
related threadsInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.
 
This family of sequences uses a balanced gradient waveform. This waveform will act on any stationary spin on resonance between 2 consecutive RF pulses and return it to the same phase it had before the gradients were applied. A balanced sequence starts out with a RF pulse of 90° or less and the spins in the steady state. Prior to the next TR in the slice encoding, the phase encoding and the frequency encoding direction, gradients are balanced so their net value is zero. Now the spins are prepared to accept the next RF pulse, and their corresponding signal can become part of the new transverse magnetization. If the balanced gradients maintain the longitudinal and transverse magnetization, the result is that both T1 and T2 contrast are represented in the image.
This pulse sequence produces images with increased signal from fluid (like T2 weighted sequences), along with retaining T1 weighted tissue contrast. Balanced sequences are particularly useful in cardiac MRI. Because this form of sequence is extremely dependent on field homogeneity, it is essential to run a shimming prior the acquisition.
Usually the gray and white matter contrast is poor, making this type of sequence unsuited for brain MRI. Modifications like ramping up and down the flip angles can increase signal to noise ratio and contrast of brain tissues (suggested under the name COSMIC - Coherent Oscillatory State acquisition for the Manipulation of Image Contrast).
These sequences include e.g. Balanced Fast Field Echo (bFFE), Balanced Turbo Field Echo (bTFE), Fast Imaging with Steady Precession (TrueFISP, sometimes short TRUFI), Completely Balanced Steady State (CBASS) and Balanced SARGE (BASG).
 
Images, Movies, Sliders:
 Cardiac Infarct Short Axis Cine Overview  Open this link in a new window
    

Courtesy of  Robert R. Edelman
 Infarct 4 Chamber Cine  Open this link in a new window
    

Courtesy of  Robert R. Edelman
 
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• View the DATABASE results for 'Balanced Sequence' (5).Open this link in a new window

 
Further Reading:
  News & More:
Generic Eddy Current Compensation for Rapid Magnetic Resonance Imaging(.pdf)
   by www.switt.ch    
Magnetic resonance imaging guided musculoskeletal interventions at 0.23T: Chapter 4. Materials and methods
2002
MRI Resources 
Veterinary MRI - Homepages - Calculation - Research Labs - Lung Imaging - Education
 
Blood Flow ImagingMRI Resource Directory:
 - Blood Flow Imaging -
 
MR imaging techniques capable to provide maps of cerebral activity. All these techniques are based on indirect assessment of local cerebral haemodynamics that have been demonstrated to be closely related to cerebral activity.
Two kinds of techniques have been developed:
based on the assessment of the decrease in the content of deoxyhaemoglobin in local activated tissue that can be revealed as an increase of signal on T2* and T2 weighted sequences in which deoxyhaemoglobin has low signal (see Blood Oxygenation Level Dependent Contrast)
based on the time of flight or flow-related enhancement that is revealed either directly with T1 weighted images or through the use of modified angiographic bolus tracking techniques.
 
Images, Movies, Sliders:
 Circle of Willis, Time of Flight, MIP  Open this link in a new window
    
SlidersSliders Overview

 
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• View the NEWS results for 'Blood Flow Imaging' (1).Open this link in a new window.
 
Further Reading:
  News & More:
Turbo-FLASH Based Arterial Spin Labeled Perfusion MRI at 7 T
Thursday, 20 June 2013   by www.plosone.org    
Non-invasive MRI technique distinguishes between Alzheimer's and frontotemporal dementia
Saturday, 18 June 2005   by www.eurekalert.org    
Searchterm 't2' was also found in the following services: 
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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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• View the DATABASE results for 'Blood Oxygenation Level Dependent Contrast' (6).Open this link in a new window

 
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    
MRI Resources 
Contrast Agents - Intraoperative MRI - Mobile MRI - Guidance - Used and Refurbished MRI Equipment - Diffusion Weighted Imaging
 
Cervical Spine MRI
 
Cervical spine MRI is a suitable tool in the assessment of all cervical spine (vertebrae C1 - C7) segments (computed tomography (CT) images may be unsatisfactory close to the thoracic spine due to shoulder artifacts). The cervical spine is particularly susceptible to degenerative problems caused by the complex anatomy and its large range of motion.
Advantages of magnetic resonance imaging MRI are the high soft tissue contrast (particularly important in diagnostics of the spinal cord), the ability to display the entire spine in sagittal views and the capacity of 3D visualization. Magnetic resonance myelography is a useful supplement to conventional MRI examinations in the investigation of cervical stenosis. Myelographic sequences result in MR images with high contrast that are similar in appearance to conventional myelograms. Additionally, open MRI studies provide the possibility of weight-bearing MRI scan to evaluate structural positional and kinetic changes of the cervical spine.
Indications of cervical spine MRI scans include the assessment of soft disc herniations, suspicion of disc hernia recurrence after operation, cervical spondylosis, osteophytes, joint arthrosis, spinal canal lesions (tumors, multiple sclerosis, etc.), bone diseases (infection, inflammation, tumoral infiltration) and paravertebral spaces.
State-of-the-art phased array spine coils and high performance MRI machines provide high image quality and short scan time. Imaging protocols for the cervical spine includes sagittal T1 weighted and T2 weighted sequences with 3-4 mm slice thickness and axial slices; usually contiguous from C2 through T1. Additionally, T2 fat suppressed and T1 post contrast images are often useful in spine imaging.

See also Lumbar Spine MRI.
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• View the DATABASE results for 'Cervical Spine MRI' (2).Open this link in a new window


• View the NEWS results for 'Cervical Spine MRI' (1).Open this link in a new window.
 
Further Reading:
  News & More:
Ultrafast MRI protocol reduces scan time by 10 minutes for cervical imaging
Monday, 26 September 2022   by healthimaging.com    
In Vivo 3-D Cervical Spine Kinematics Demonstrated
Thursday, 19 May 2011   by www.doctorslounge.com    
MRI Images at a 45-Degree Angle Through The Cervic al Neural Forami na:A Technique For Improved Visualization(.pdf)
2006   by www.painphysicianjournal.com    
MRI Resources 
Breast MRI - Implant and Prosthesis pool - Non-English - Contrast Enhanced MRI - Musculoskeletal and Joint MRI - Developers
 
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