|
Magnetic
Resonance -
Technology
Information
Portal |
Welcome to MRI Technology • |
|
|
 | Info
Sheets |
| | | | | | | | | | | | | | | | | | | | | | | | |
 | Out-
side |
| | | | |
|
| | | | | |
| Result: Searchterm 'B1'
found in 8 messages |
| Result Pages: [1] 2 |
More Results:  Database (1346) News Service (1) Resources (1) |
|
|
Brenna Bray
Tue. 10 Mar.20,
15:59
[Start of:
'Proton excitation from B0 to B1'
0 Reply]
 Category:
General
|
| Proton excitation from B0 to B1 |
I'm new to MRI imaging and currently taking an introductory course online. I understand that the introduction of a small magnetic field/RF pulses on top of the static magnetic field (B0) excites protons into a high energy state (B1). Does this mean that the protons are excited from a spin that is parallel to the longitudinal B0 plane to one that is antiparallel to the longitudinal B0 plane, or that the proton spin is excited from one that is aligned/polarized with B0 to one that is either parallel or antiparallel to B0 in the B1/xy plane?
|
| |  Reply to this thread
(login or register first) | |
Schwarz Arni
Sun. 18 Aug.13,
17:11
[Start of:
'Size of B1'
0 Reply]
Category:
Basics and Physics
|
| Size of B1 |
Hello!
How many Tesla does B1 (the HF pulse) have more or less? What range is applicable? I cannot find information about that anywhere.
Thanks!
Arni
|
| | Reply to this thread
(login or register first) | | |
|
Desiree Dupuy
Sat. 3 Dec.16,
22:14
[Reply (2 of 3) to:
'Muscle shading in 3T Images'
started by: 'Travis Conley'
on Thu. 21 Oct.10]
Category:
Applications and Examinations
|
| Muscle shading in 3T Images |
Try running a B1 Map followed by Calibration. Set RF Drive mode to Optimized. This is supposed to optimize for your Patient. Supposed to reduce dielectric effect/shading for Lumbar and Abdomen.
You can find under GE Additional Abdomen Sequences.
Or you can run Ideal with Dixon technique. Turn on IN phase will give you T1 FS & IN Phase is you plane T1. I believe this takes care of the artifact.
|
| | View the whole thread | | |
Iosif Sogolov
Sun. 3 Jan.10,
20:49
[Reply (7 of 12) to:
'90 excitation pulse vs 180 inversion pulse'
started by: 'Bjorn Redfors'
on Sat. 27 Jun.09]
Category:
Basics and Physics
|
| 90 excitation pulse vs 180 inversion pulse |
prior 90: spins precess around B0 uncoherently, there for the sum of their projections on TRANSVERSE plane is ZERO, they are "unfocused" in this plane. 90 and right after: all above mentioned spins are forced to rotate around B1, it should be stressed - in only one for ALL of them chosen direction of rotation (depends of B1 direction) to the TRANSVERSE plane, they all will come compact to this plane and now they do give here NET MAGNETIZATION, become "focused".
|
| | View the whole thread | | |
Reader Mail
Wed. 12 Dec.07,
10:07
[Reply (1 of 2) to:
'double ir physic'
started by: 'soontorn siriserussa'
on Sun. 2 Dec.07]
Category:
Sequences and Imaging Parameters
|
| double ir physic |
Different types of double inversion recovery (DIR, 2IR) sequences are used to improve the suppression of blood signal (black blood technique) or to null the signals from two different tissue types (e.g. white matter and cerebrospinal fluid).
The black blood technique (used in cardiovascular MRI) works with two inversion pulses, where the first pulse is nonselective and the second pulse is slice-selective. TI is set to a value at which the signal of the recovering inverted blood is zero (http://www.mr-tip.com/serv1.php?type=db1&dbs=Double%20Inversion).
The second technique (also named gray matter only) is used in brain imaging to improve the detection of lesions, for example in the diagnostic of multiple sclerosis. Two 180° pulses with different TI are used to suppress two different types of tissue simultaneously.
Hope this helps
|
| | View the whole thread | | |
| |
| | Result Pages : [1] 2 | |
|
| |
 | Look
Ups |
| |
|
MR-TIP.com uses cookies! By browsing MR-TIP.com, you agree to our use of cookies. | | | [last update: 2024-02-26 03:41:00] |
|
|
bottom
top
