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Result : Searchterm 'T2 Time' found in 1 term [] and 16 definitions [], (+ 17 Boolean[] results
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T2* Time
 
(T2 Star) The characteristic time constant that describes the decay of transverse magnetization, taking into account the inhomogeneity in static magnetic fields and the spin spin relaxation in the human body. This results in a rapid loss of phase coherence and the MRI signal. The T2* time is always less than the T2 time.
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• Related Searches:
    • Refocusing
    • T2 Relaxation
    • T2 Time
    • T2 Weighted
    • Refocused Gradient Echo Sequence
 
Further Reading:
  News & More:
Iron Measurements with MRI Reveal Stroke's Impact on Brain
Tuesday, 12 March 2019   by www.rsna.or    
Automatic Mapping Extraction from Multiecho T2-Star Weighted Magnetic Resonance Images for Improving Morphological Evaluations in Human Brain
Wednesday, 5 June 2013   by www.hindawi.com    
T2* cardiac MRI allows prediction of severe reperfusion injury after STEMI
Tuesday, 9 November 2010   by www.medwire-news.md    
MRI Resources 
Portals - MR Guided Interventions - - MRI Physics - Software - Examinations
 
Transverse Relaxation Time
 
The T2 time constant, which determines the rate at which excited protons reach equilibrium, or go out of phase with each other. A measure of the time taken for spinning protons to lose phase coherence among the nuclei spinning perpendicular to the main field due to interaction between spins, resulting in a reduction in the transverse magnetization. The transverse magnetization value will drop from maximum to a value of about 37% of its original value in a time of T2.
 
Images, Movies, Sliders:
 Brain MRI Images Axial T2  Open this link in a new window
      

 Breast MRI 2 Transverse T2 001  Open this link in a new window
 
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• View the DATABASE results for 'Transverse Relaxation Time' (4).Open this link in a new window

MRI Resources 
Intraoperative MRI - Jobs - Databases - MR Myelography - Functional MRI - DICOM
 
O-SCANā„¢InfoSheet: - Devices -
Intro, 
Types of Magnets, 
Overview, 
etc.
 
www.fonar.com/standup.htm www.fonar.com/standup.htm O-scan is manufactured and distributed by Esaote SpA
O-scan is a compact, dedicated extremity MRI system designed for easy installation and high throughput. The complete system fits in a 9' x 10' room, doesn't need for RF or magnetic shielding and it plugs in the wall. The 0.31T permanent magnet along with dual phased array RF coils, and advanced imaging protocols provide outstanding image quality and fast 25 minute complete examinations.
Esaote North America is the exclusive distributor of the O-scan system in the USA.
Device Information and Specification
CLINICAL APPLICATION
Dedicated Extremity
CONFIGURATION
Closed
Dual phased array knee, hand, foot//ankle/elbow
PULSE SEQUENCES
SE, HSE, HFE, GE, 2dGE, ME, IR, STIR, Stir T2, GESTIR, TSE, TME, FSE STIR, FSE (T1, T2), X-Bone, Turbo 3DT1, 3D SHARC, 3D SST1, 3D SST2
IMAGING MODES
2D, 3D multi-plane, half echo, half scan, real time
TR
10 - 10,000 msec.
TE
6 - 220 msec.
SINGLE SLICE
0.1 sec.
MULTI SLICE
0.1 sec.
14 cm
2D: 2mm - 10 mm, 3D: 0.6 - 10 mm
MEASURING MATRIX
512 x 512 max.
PIXEL INTENSITY
4,096 grey levels
MAGNET TYPE
Permanent - NdFeB
MAGNET WEIGHT
2,733 lbs
POWER REQUIREMENTS
100/110/200/220/230/240
STRENGTH
20 mT/m
5 GAUSS FRINGE FIELD, radial/axial
67 cm / 75 cm
passive
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Spin Echo SequenceInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.MRI Resource Directory:
 - Sequences -
 
Spin Echo Timing Diagram (SE) The most common pulse sequence used in MR imaging is based of the detection of a spin or Hahn echo. It uses 90Ā° radio frequency pulses to excite the magnetization and one or more 180Ā° pulses to refocus the spins to generate signal echoes named spin echoes (SE).
In the pulse sequence timing diagram, the simplest form of a spin echo sequence is illustrated.
The 90Ā° excitation pulse rotates the longitudinal magnetization (Mz) into the xy-plane and the dephasing of the transverse magnetization (Mxy) starts.
The following application of a 180Ā° refocusing pulse (rotates the magnetization in the x-plane) generates signal echoes. The purpose of the 180ƂĀ° pulse is to rephase the spins, causing them to regain coherence and thereby to recover transverse magnetization, producing a spin echo.
The recovery of the z-magnetization occurs with the T1 relaxation time and typically at a much slower rate than the T2-decay, because in general T1 is greater than T2 for living tissues and is in the range of 100-2000 ms.
The SE pulse sequence was devised in the early days of NMR days by Carr and Purcell and exists now in many forms: the multi echo pulse sequence using single or multislice acquisition, the fast spin echo (FSE/TSE) pulse sequence, echo planar imaging (EPI) pulse sequence and the gradient and spin echo (GRASE) pulse sequence;; all are basically spin echo sequences.
In the simplest form of SE imaging, the pulse sequence has to be repeated as many times as the image has lines.
Contrast values:
PD weighted: Short TE (20 ms) and long TR.
T1 weighted: Short TE (10-20 ms) and short TR (300-600 ms)
T2 weighted: Long TE (greater than 60 ms) and long TR (greater than 1600 ms)
With spin echo imaging no T2* occurs, caused by the 180Ā° refocusing pulse. For this reason, spin echo sequences are more robust against e.g., susceptibility artifacts than gradient echo sequences.

See also Pulse Sequence Timing Diagram to find a description of the components.
 
Images, Movies, Sliders:
 Shoulder Coronal T1 SE  Open this link in a new window
    

Courtesy of  Robert R. Edelman
 Shoulder Axial T1 SE  Open this link in a new window
 MRI Orbita T1  Open this link in a new window
    
 
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• View the DATABASE results for 'Spin Echo Sequence' (24).Open this link in a new window

 
Further Reading:
  Basics:
Fast Spin Echo(.pdf)
Tuesday, 24 January 2006   by www.81bones.net    
Magnetic resonance imaging
   by www.scholarpedia.org    
FUNDAMENTALS OF MRI: Part I
   by www.e-radiography.net    
  News & More:
New MR sequence helps radiologists more accurately evaluate abnormalities of the uterus and ovaries
Thursday, 23 April 2009   by www.eurekalert.org    
MRI techniques improve pulmonary embolism detection
Monday, 19 March 2012   by medicalxpress.com    
MRI Resources 
MRI Reimbursement - Devices - Cochlear Implant - Developers - Universities - Implant and Prosthesis pool
 
Opera (E-SCANā„¢ XQ)InfoSheet: - Devices -
Intro, 
Types of Magnets, 
Overview, 
etc.MRI Resource Directory:
 - Devices -
 
www.esaote.com/products/MRI/eScanXQ/products1.htm Manufactured by Esaote S.p.A.;
a low field open MRI scanner with permanent magnet for orthopedic use. The outstanding feature of this MRI system is a patient friendly design with 24 cm diameter, which allows the imaging of extremities and small body parts like shoulder MRI. The power consumption is around 1.3 kW and the needed minimum floor space is an area of 16 sq m.
At RSNA 2006 Hologic Inc. introduced a new dedicated extremity MRI scanner, the Opera. Manufactured by Esaote is the Opera a redesign of Esaote's 0.2 Tesla E-Scan XQ platform, which now enables complete imaging of all extremities, including hip and shoulder applications. 'Real-time positioning' reportedly speeds patient setup and reduces exam times.
Esaote North America and Hologic Inc are the U.S. distributors of this MRI device.
Device Information and Specification
CLINICAL APPLICATION
Dedicated extremity
CONFIGURATION
Extremity, shoulder (2), flex coil, knee dual phased array, ankle//foot dual phased array, hand//wrist dual phased array coil
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
10 - 5000 msec
TE
6 - 110 msec
SINGLE SLICE
0.6 sec/image
MULTISLICE
0.6 sec/image
17 cm
2D: 2 mm - 10 mm;
3D: 0.6 mm - 10 mm
MEASURING MATRIX
256 x 256 maximum
PIXEL INTENSITY
4096 gray lvls, 256 lvls in 3D
MAGNET TYPE
Permanent
24 cm H, open
MAGNET WEIGHT
2250 kg, 4960 lbs
H*W*D
79 x 65 x 85 cm
POWER REQUIREMENTS
2,0 kW; 110/220 V single phase
STRENGTH
20 mT/m
5-GAUSS FRINGE FIELD, radial/axial
150 cm/130 cm
Passive
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• View the DATABASE results for 'Opera (E-SCAN™ XQ)' (2).Open this link in a new window

 
Further Reading:
  News & More:
E-Scan, 510(k) Summary(.pdf)
Saturday, 15 May 2004   by www.accessdata.fda.gov    
MRI Resources 
Online Books - Intraoperative MRI - Absorption and Emission - Supplies - Libraries - Knee MRI
 
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