Magnetic Resonance - Technology Information Portal Welcome to MRI Technology
Info
  Sheets


Out-
      side
 



 
 'T1' 
SEARCH FOR    
 
  2 3 5 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
 T1            spin lattice relaxation Time 
Searchterm 'T1' was found in the Abbreviation Register. 
Result : Searchterm 'T1' found in 10 terms [] and 160 definitions []
1 - 5 (of 170)     next
Result Pages : [1 2]  [3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 ... ]
Searchterm 'T1' was also found in the following services: 
spacer
News  (10)  Resources  (5)  Forum  (50)  
 
T1 TimeForum -
related threads
 
The T1 relaxation time (also called spin lattice or longitudinal relaxation time), is a biological parameter that is used in MRIs to distinguish between tissue types. This tissue-specific time constant for protons, is a measure of the time taken to realign with the external magnetic field. The T1 constant will indicate how quickly the spinning nuclei will emit their absorbed RF into the surrounding tissue.
As the high-energy nuclei relax and realign, they emit energy which is recorded to provide information about their environment. The realignment with the magnetic field is termed longitudinal relaxation and the time in milliseconds required for a certain percentage of the tissue nuclei to realign is termed 'Time 1' or T1. Starting from zero magnetization in the z direction, the z magnetization will grow after excitation from zero to a value of about 63% of its final value in a time of T1. This is the basic of T1 weighted images.
The T1 time is a contrast determining tissue parameter. Due to the slow molecular motion of fat nuclei, longitudinal relaxation occurs rather rapidly and longitudinal magnetization is regained quickly. The net magnetic vector realigns with B0 leading to a short T1 time for fat.
Water is not as efficient as fat in T1 recovery due to the high mobility of the water molecules. Water nuclei do not give up their energy to the lattice (surrounding tissue) as quickly as fat, and therefore take longer to regain longitudinal magnetization, resulting in a long T1 time.
See also T1 Weighted Image, T1 Relaxation, T2 Weighted Image, and Magnetic Resonance Imaging MRI.
 
Images, Movies, Sliders:
 Anatomic MRI of the Knee 2  Open this link in a new window
    
SlidersSliders Overview

 Breast MRI Images T2 And T1  Open this link in a new window
 Brain MRI Images T1  Open this link in a new window
      

 
spacer
 
• Share the entry 'T1 Time':  Facebook  Twitter  LinkedIn  
 
• Related Searches:
    • Magnetic Resonance Imaging MRI
    • Repetition Time
    • Short T1-Relaxation Gastrointestinal Agents
    • T1 Weighted Image
    • Paramagnetic Substance
 
Further Reading:
  Basics:
IMAGE CONTRAST IN MRI(.pdf)
   by www.assaftal.com    
Magnetic resonance imaging - From Wikipedia, the free encyclopedia.
   by en.wikipedia.org    
  News & More:
New technique could allow for safer, more accurate heart scans
Thursday, 10 December 2015   by www.gizmag.com    
Rockland Technimed: Tissue Viability Imaging
Saturday, 15 December 2007   by www.onemedplace.com    
MRI Resources 
IR - Raman Spectroscopy - Intraoperative MRI - Sequences - Shoulder MRI - Contrast Enhanced MRI
 
T1 WeightedInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.
 
Every tissue in the human body has its own T1 and T2 value. This term is used to indicate an image where most of the contrast between tissues is due to differences in the T1 value.
This term may be misleading in that the potentially important effects of tissue density differences and the range of tissue T1 values are ignored.
If the machine parameters are chosen, so that TR less than T1 (typically £ 500 ms) and TE less than T2 (typically £ 30 ms), a power series expansion of the exponential functions and then neglecting second and higher order terms yields
Mxy = Mxy0 TR/T1
thus the expression becomes independent of T2 and yields the condition for T1 weighting. Therefore a T1 contrast is approached by imaging with a short TR, compared to the longest tissue T1 of interest and short TE, compared to tissue T2 (to reduce T2 contributions to image contrast). Due to the wide range of T1 and T2 and tissue density values that can be found in the body, an image that is T1 weighted for some tissues may not be so for others.
Lesions with short T1 are (bright in T1 weighted sequences):
fat (lipoma, dermoid)
sub-acute haemorrhage (metHb)
paramagnetic agent (Gd, pituitary)
protein-containing fluid (colloid cyst)
metastatic melanoma (melanotic).
 
Images, Movies, Sliders:
 MRI Orbita T1  Open this link in a new window
    
 MRI Liver In Phase  Open this link in a new window
    
 Sagittal Knee MRI Images T1 Weighted  Open this link in a new window
 MRI - Anatomic Imaging of the Ankle 2  Open this link in a new window
    
SlidersSliders Overview

 
spacer

• View the DATABASE results for 'T1 Weighted' (56).Open this link in a new window

 
Further Reading:
  Basics:
Accurate T1 Quantification Using a Breath-hold Inversion Recovery TrueFISP Sequence
2003   by rsna2003.rsna.org    
  News & More:
T1rho-prepared balanced gradient echo for rapid 3D T1rho MRI
Monday, 1 September 2008   by www.ncbi.nlm.nih.gov    
Possible New MRI Marker for Multiple Sclerosis Progression
Wednesday, 29 August 2007   by www.medpagetoday.com    
T1-weighted Phase Sensitive Inversion Recovery for Imaging Multiple Sclerosis Lesions in the Cervical Spinal Cord(.pdf)
   by www.healthcare.siemens.com    
MRI Resources 
Intraoperative MRI - Colonography - Services and Supplies - MRI Accidents - Liver Imaging - Research Labs
 
T1 Relaxation
 
The return to equilibrium (high energy protons returns to the low energy state) within the lattice is named the T1, spin lattice or longitudinal relaxation. During the time T1, the spinning protons realign with the external magnetic field with an exchange of their energy, resulting in heat. The value of the T1 time depends of the tissues ability for energy exchange. See also Longitudinal Relaxation Time.
spacer

• View the DATABASE results for 'T1 Relaxation' (18).Open this link in a new window

 
Further Reading:
  Basics:
Musculoskeletal MRI at 3.0 T: Relaxation Times and Image Contrast
Sunday, 1 August 2004   by www.ajronline.org    
  News & More:
MRI's inside story
Thursday, 4 December 2003   by www.economist.com    
Searchterm 'T1' was also found in the following services: 
spacer
News  (10)  Resources  (5)  Forum  (50)  
 
T1 Weighted ImageInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.
 
The basis of T1 weighted imaging is the longitudinal relaxation. A T1 weighted magnetic resonance image is created typically by using short TE and TR times.
The final image is a reflection of more than one of these pulse sequence parameters, weighted according to the type of sequence and its timing. T1 signals determine predominantly the contrast and brightness in this type of images but proton density will always contribute to the image intensity. The T1 dependence is mainly determined by the repetition time or any pre-pulses (such as in an inversion recovery pulse sequence).
Due to the larger longitudinal and transverse magnetization, fat has a higher signal and will appear bright on a T1 contrast MR image. Conversely, water has less longitudinal magnetization prior to a RF pulse, therefore less transverse magnetization after a RF pulse yielding low signal appearing dark on a T1 contrast image. Often, a paramagnetic contrast agent, a gadolinium compound, is administered, and both pre-contrast T1 weighted images and post-contrast T1 weighted images are obtained.
 
Images, Movies, Sliders:
 Lumbar Spine T1 SE Sagittal  Open this link in a new window
    

Courtesy of  Robert R. Edelman
 Shoulder Axial T1 SE  Open this link in a new window
 Shoulder Coronal T1 SE  Open this link in a new window
    

Courtesy of  Robert R. Edelman
 
spacer

• View the DATABASE results for 'T1 Weighted Image' (5).Open this link in a new window

 
Further Reading:
  Basics:
Magnetic resonance imaging - From Wikipedia, the free encyclopedia.
   by en.wikipedia.org    
  News & More:
Possible New MRI Marker for Multiple Sclerosis Progression
Wednesday, 29 August 2007   by www.medpagetoday.com    
MRI Resources 
Artifacts - Bioinformatics - RIS - Mobile MRI Rental - Process Analysis - Developers
 
Short T1 Inversion RecoveryInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.MRI Resource Directory:
 - Sequences -
 
(STIR) Also called Short Tau (t) (inversion time) Inversion Recovery. STIR is a fat suppression technique with an inversion time TI = T1 ln2 where the signal of fat is zero (T1 is the spin lattice relaxation time of the component that should be suppressed). To distinguish two tissue components with this technique, the T1 values must be different. Fluid Attenuation Inversion Recovery (FLAIR) is a similar technique to suppress water.
Inversion recovery doubles the distance spins will recover, allowing more time for T1 differences. A 180° preparation pulse inverts the net magnetization to the negative longitudinal magnetization prior to the 90° excitation pulse. This specialized application of the inversion recovery sequence set the inversion time (TI) of the sequence at 0.69 times the T1 of fat. The T1 of fat at 1.5 Tesla is approximately 250 with a null point of 170 ms while at 0.5 Tesla its 215 with a 148 ms null point. At the moment of excitation, about 120 to 170 ms after the 180° inversion pulse (depending of the magnetic field) the magnetization of the fat signal has just risen to zero from its original, negative, value and no fat signal is available to be flipped into the transverse plane.
When deciding on the optimal T1 time, factors to be considered include not only the main field strength, but also the tissue to be suppressed and the anatomy. In comparison to a conventional spin echo where tissues with a short T1 are bright due to faster recovery, fat signal is reversed or darkened. Because body fluids have both a long T1 and a long T2, it is evident that STIR offers the possibility of extremely sensitive detection of body fluid. This is of course, only true for stationary fluid such as edema, as the MRI signal of flowing fluids is governed by other factors.
See also Fat Suppression and Inversion Recovery Sequence.
 
Images, Movies, Sliders:
 Sagittal Knee MRI Images STIR  Open this link in a new window
      

 
spacer

• View the DATABASE results for 'Short T1 Inversion Recovery' (3).Open this link in a new window

 
Further Reading:
  Basics:
Techniques of Fat Suppression(.pdf)
   by cds.ismrm.org    
MRI GLOSSARY
   by fonar.com    
  News & More:
Contrast mechanisms in magnetic resonance imaging
2004   by www.iop.org    
MRI Resources 
Image Quality - Resources - Pacemaker - Anatomy - Stimulator pool - Shielding
 
     1 - 5 (of 170)     next
Result Pages : [1 2]  [3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 ... ]
 Random Page
 
Share This Page
FacebookTwitterLinkedIn

MR-TIP    
Community   
User
Pass
Forgot your UserID/Password ?  



In 2075 (after about 100 years of ...) the MRI scan will be :
obsolete 
done with handheld probe 
done at home (app, ...) 
a 3 second walk through 
daily done 
replaced by something much ... 

Look
      Ups





Magnetic Resonance - Technology Information Portal
Member of SoftWays' Medical Imaging Group - MR-TIP • Radiology-TIP • US-TIP • The-Medical-Market
Copyright © 2003 - 2016 SoftWays. All rights reserved. [ 19 January 2017]
Terms of Use | Privacy Policy | Advertising
 [last update: 2017-01-13 03:47:00]