basis of MR images / Houndsfield units?

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basis of MR images / Houndsfield units?

Christoph
Hello people,

can someone explain me the basis for MR imaging in Slicer 3D?
I know the basis for imaging of CT is the Hounsfield unit.

What is the basis for MR imaging?

Thx very much,
Chris
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Re: basis of MR images / Houndsfield units?

Kikinis, Ron,M.D.
Hi Chris,

While all CT is calibrated to Hounsfield units and Nuclear Medicine is
in the process to converge to SUV's, there is no such movement in MRI. I
believe that part of this is due to higher complexity of MR
measurements, which make it difficult to introduce a global and
relatively simple calibration approach. There are some exceptions: FA,
for instance is calibrated from 0 to 1.

Slicer in general displays the signal intensities of an image, as they
come from the file.

HTH

Ron

On 10/29/12 3:29 AM, Chris wrote:

> Hello people,
>
> can someone explain me the basis for MR imaging in Slicer 3D?
> I know the basis for imaging of CT is the Hounsfield unit.
>
> What is the basis for MR imaging?
>
> Thx very much,
> Chris
> _______________________________________________
> slicer-users mailing list
> [hidden email]
> http://massmail.spl.harvard.edu/mailman/listinfo/slicer-users
> To unsubscribe: send email to [hidden email] with unsubscribe as the subject
>

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Re: basis of MR images / Houndsfield units?

Joe Grudzinski
In reply to this post by Christoph

It depends on the pulse sequence. Ie T1 weighted

On Oct 29, 2012 2:34 AM, "Chris" <[hidden email]> wrote:
Hello people,

can someone explain me the basis for MR imaging in Slicer 3D?
I know the basis for imaging of CT is the Hounsfield unit.

What is the basis for MR imaging?

Thx very much,
Chris
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Re: basis of MR images / Houndsfield units?

Christoph

Hello Joe,

thx for the answer. But what are the values in the Volumes Module? Are they the T1 weighted pulse sequence of the MR?
In CT they represent the Hounsfield units, but which values are represent with MR?

Thx,
Chris

It depends on the pulse sequence. Ie T1 weighted

On Oct 29, 2012 2:34 AM, "Chris" <[hidden email]> wrote:
Hello people,

can someone explain me the basis for MR imaging in Slicer 3D?
I know the basis for imaging of CT is the Hounsfield unit.

What is the basis for MR imaging?

Thx very much,
Chris
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[hidden email]
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Re: basis of MR images / Houndsfield units?

Christoph
Thx, that makes sense, but does this proton density of the Volumes Module has any unit? 





The values are related to proton density.

On Tue, Oct 30, 2012 at 1:06 AM, Chris <[hidden email]> wrote:

Hello Joe,

thx for the answer. But what are the values in the Volumes Module? Are they the T1 weighted pulse sequence of the MR?
In CT they represent the Hounsfield units, but which values are represent with MR?

Thx,
Chris

It depends on the pulse sequence. Ie T1 weighted

On Oct 29, 2012 2:34 AM, "Chris" <[hidden email]> wrote:
Hello people,

can someone explain me the basis for MR imaging in Slicer 3D?
I know the basis for imaging of CT is the Hounsfield unit.

What is the basis for MR imaging?

Thx very much,
Chris
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Re: basis of MR images / Houndsfield units?

Joe Grudzinski

You'd have to calibrate the scanner to make it quantitative. Until then it's pretty much just signal intensity.

On Oct 30, 2012 5:46 PM, "Chris" <[hidden email]> wrote:
Thx, that makes sense, but does this proton density of the Volumes Module has any unit? 





The values are related to proton density.

On Tue, Oct 30, 2012 at 1:06 AM, Chris <[hidden email]> wrote:

Hello Joe,

thx for the answer. But what are the values in the Volumes Module? Are they the T1 weighted pulse sequence of the MR?
In CT they represent the Hounsfield units, but which values are represent with MR?

Thx,
Chris

It depends on the pulse sequence. Ie T1 weighted

On Oct 29, 2012 2:34 AM, "Chris" <[hidden email]> wrote:
Hello people,

can someone explain me the basis for MR imaging in Slicer 3D?
I know the basis for imaging of CT is the Hounsfield unit.

What is the basis for MR imaging?

Thx very much,
Chris
_______________________________________________
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[hidden email]
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Re: basis of MR images / Houndsfield units?

madanrao
Hello,

MRI is an application of NuclearMagnetic Resonance (NMR) used in identification of
specific elements in a sample.This method is similar to spectrophotometry and
x-ray diffraction. In NMR, spectrophotometry or colorimetry the structure of molecule is
identified by the frequency of light emitted by crystals. In CT scans x-rays pass through tissues
that have particular radiodensity which is measured in HU . In contrast, MRI uses NMR and there is only resonance of atoms involved (ie., nothing passes through tissues).
Many quantitative techniques (like ELISA, SDS-Gel Electrphoresis) are based on signal intensity and use densitometry
and MRI works on this principle.

I hope this helps.

Regards

AM Mohan Rao

On Wed, Oct 31, 2012 at 4:56 AM, Joe Grudzinski <[hidden email]> wrote:

You'd have to calibrate the scanner to make it quantitative. Until then it's pretty much just signal intensity.

On Oct 30, 2012 5:46 PM, "Chris" <[hidden email]> wrote:
Thx, that makes sense, but does this proton density of the Volumes Module has any unit? 





The values are related to proton density.

On Tue, Oct 30, 2012 at 1:06 AM, Chris <[hidden email]> wrote:

Hello Joe,

thx for the answer. But what are the values in the Volumes Module? Are they the T1 weighted pulse sequence of the MR?
In CT they represent the Hounsfield units, but which values are represent with MR?

Thx,
Chris

It depends on the pulse sequence. Ie T1 weighted

On Oct 29, 2012 2:34 AM, "Chris" <[hidden email]> wrote:
Hello people,

can someone explain me the basis for MR imaging in Slicer 3D?
I know the basis for imaging of CT is the Hounsfield unit.

What is the basis for MR imaging?

Thx very much,
Chris
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To unsubscribe: send email to [hidden email] with unsubscribe as the subject


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