Picker Polaris MR - DICOM

This is a discussion on Picker Polaris MR - DICOM ; Hi Group, I recently came across some strange MR images from a Picker Polaris machine. Some of the images have a very inhomogeneous intensity, something like a horizontal gradient in brightness and contrast. I was told that there are viewers ...

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Thread: Picker Polaris MR

  1. Picker Polaris MR

    Hi Group,

    I recently came across some strange MR images from a Picker Polaris
    machine.
    Some of the images have a very inhomogeneous intensity, something like
    a horizontal gradient in brightness and contrast. I was told that there
    are viewers that actually can display these images correctly but all
    viewers I tested (DicomWorks, E-Film, UniPacs, DicomScope, AccuLite)
    showed the same window gradient as my viewer does.

    Here are some example images:
    www.k-pacs.net/Image1.dcm
    www.k-pacs.net/Image2.dcm

    Does anyone now how to deal with images like this?

    regards,
    Andreas


  2. Re: Picker Polaris MR

    Picker used to sell their IQ line of workstations alongside their CT
    and MRs, much the same way GE sells the AW workstations along with
    their scanners (Ok, to be fair, they sell the workstations as an
    independant product too; but usually at least one gets thrown into the
    deal whenever a scanner is sold).

    But I digress ... i don't know an IQ workstation would make sense of
    those images but suggest you might solict someone who has one of these
    workstations (maybe they have one at the scanner where these images
    originated?).

    Although, looking through the image header, I would anticipate seeing
    some private attributes that the Picker software would use to apply a
    correction factor to that vertical brightness gradien. There don't
    appear to be any private attributes in those images at all. From that I
    conclude they've either been removed, possibly through a
    de-identification process; or those images look exactly the way they're
    supposed to look due to way the images were reconstructed from MR data
    or imaging mode used to create them.

    I doubt you're going to find any software which is going to display
    those particular images in any other way than how they're displaying
    now. If you in fact dif de-identified them with some software before
    posting them on the web, go back and look at the dicom attributes of
    the original images - look for attributes where the first 4 digits of
    the attribute tag ends in an odd number. If there aren't any, I don't
    think you'll find any software that is going to display them any
    differently than what you're seeing now.


  3. Re: Picker Polaris MR

    Bonjour Andreas,

    This does look like a decompression bug. My guess is that they where
    originally in a compressed format and at some point where uncompressed
    and the program that did this decompression created the problem.

    How did you get the images?

    Where they like this straight out of the system console? Does the
    system have the option of exporting the images in another format
    (native maybe?)

    Yves



    On 23 Feb 2006 09:25:42 -0800, "Andreas Knopke"
    wrote:

    >Hi Group,
    >
    >I recently came across some strange MR images from a Picker Polaris
    >machine.
    >Some of the images have a very inhomogeneous intensity, something like
    >a horizontal gradient in brightness and contrast. I was told that there
    >are viewers that actually can display these images correctly but all
    >viewers I tested (DicomWorks, E-Film, UniPacs, DicomScope, AccuLite)
    >showed the same window gradient as my viewer does.
    >
    >Here are some example images:
    >www.k-pacs.net/Image1.dcm
    >www.k-pacs.net/Image2.dcm
    >
    >Does anyone now how to deal with images like this?
    >
    >regards,
    >Andreas
    >




  4. Re: Picker Polaris MR

    Hello Eric and Yves,

    thank's for your replies. I got these images from a user who told me
    that he can view the images with his workstation at the modality but
    not with K-PACS. I don't know if they where compressed and decompressed
    but I will investigate further. The strange thing is, that some images
    of the series I received seem to be ok. My initial thought was that
    this might be an MR artifact.

    regards,
    Andreas


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