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| Result: Searchterm 'ffe'
found in 134 messages |
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More Results:  Database (446) News Service (436) Resources (66) |
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Elise Gough
Fri. 4 Mar.11,
13:56
[Reply (2 of 8) to:
'6-1.5T MAGNETS, DIFFERING GRADIENTS'
started by: 'Elise Gough'
on Wed. 23 Feb.11]
 Category:
Applications and Examinations
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| 6-1.5T MAGNETS, DIFFERING GRADIENTS |
Thank you for your response. Our group is strict about FOV, thickness/gap parameters being the same across all magnets. One magnet has slew rate of 77, FRFSE T2, TE 85,TR 3500 Classic Fat supressed images which are pristine, vs magnets of 120 slew rate same parameters look signal starved. So gradient strength makes a speed difference, not an image quality difference?
Elise Gough RT(R)(CT)(MR)
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|  View the whole thread | | |
Steven Ford
Thu. 3 Mar.11,
20:28
[Reply (1 of 8) to:
'6-1.5T MAGNETS, DIFFERING GRADIENTS'
started by: 'Elise Gough'
on Wed. 23 Feb.11]
Category:
Applications and Examinations
|
| 6-1.5T MAGNETS, DIFFERING GRADIENTS |
I assume that you mean a t2 fat suppressed sequence. Differing gradient strengths have only an indirect effect on these images. The fat saturation sequences require additional pulses which take time to execute; stronger gradient systems can execute these pulses faster.
If you see different results, it can be caused by a number of factors; if you can describe the differences, that would be helpful. Generally speaking, the quality of the magnet homogeneity makes a big difference. If the small FOV scans (wrist) look different from magnet to magnet, that's probably not the cause.
You should ask your MRI applications specialist about this, and pay attention to the TE and bandwidth. Are the FOV and number of steps the same?
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mike lozito
Tue. 28 Dec.10,
16:10
[Reply (3 of 4) to:
'please help me for find user manual siemens avento'
started by: 'reza beigi'
on Tue. 6 Jul.10]
Category:
Devices, Scanner, Machines
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| please help me for find user manual siemens avento |
i agree, that you should try to contact siemens directly. if they cannot help you i have an extra copy that i might be able to sent you for a small fee. based on my experience,the manuals really are NOT much help as, performing the required actions needed to complete scans are not fully outlined in the manuals, that usally comes from applications training from the manufacturer. it sounds like you purchased a used system with no applications support. siemens systems are fantastic mri scanners. but you are going to need applications help. i can offer assistance in this area if you would like . i am a chief mri technologist here in ny, and have 23 years mri scanning experience.i have 5 years siemens avanto expertise, performing body, msk, neuro, angio and breast mri and biopsy experience. you can contact me at my email mcl1956m@aol.com
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Don LaVille
Tue. 21 Dec.10,
20:57
[Reply (1 of 3) to:
'Muscle shading in 3T Images'
started by: 'Travis Conley'
on Thu. 21 Oct.10]
Category:
Applications and Examinations
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| Muscle shading in 3T Images |
This artifact is known as the dielectric effect. It is a phenomena to all magnets. At 1.5T the dielectric effect is at 60cm so when we scan at a FOV of 40 or less we don't see it. At 3t the dielectric effect is reduced to 30cm so we now see it when using a FOV of 30 or more. There is no way to get rid of it that I know of and you will see an increase with patients with more magnetic suseptibility (ie. patients with ascities, and pregnant patient). You could try using Surface Coil Intensity Correction (SCIC) and it will help to even out the extreme dark and light in your image. Some vendors will suggest using a Fat Sat pad to help reduce this artifact. I have tried it with little success.
Looking at your image, it looks like you were scanning on a GE 3T HDX. I hope that the vendors will have a fix for this artifact soon. For right now though we are just dealing with it. I hope this helps.
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Steven Ford
Thu. 2 Dec.10,
15:18
[Reply (1 of 2) to:
'T1&T2 WAIGHTED MEANING ?'
started by: 'BINU VAEGHESE'
on Wed. 1 Dec.10]
Category:
Basics and Physics
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| T1&T2 WAIGHTED MEANING ? |
All MRI images have contrast (the bright and the dark) that is based on properties of the tissue that's being imaged. In MRI (unlike, for example, CT) those images are based on a combination of several physical properties. So to some extent ALL MRI images are based partly on property A, property B, etc.
The tissue properties that are referred to include proton density (how many hydrogen nuclei are in a given area), motion, and two other properties that are called T1 and T2. These are properties that can be seen onloy by using the MRI instrument, much as without a microscope one cannot see inside a cell.
A T1 weighted image is one in which the differences between T1 properties of the various tissues are the predominant reason why some parts of the image are bright and others are not as bright.
This is medically useful because, since T1 and T2 are distinct properties, diseased tissue may show up different than normal tissue on either the T1 weighted scan or the T2.
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