Image lighter contrast in Kpacs

  • Hello,
    I'm using K-pacs I have many modalities sending studies to k-pacs server.
    But images coming from one of them are shown lighter on server then the modality it self
    and we have to adjust the contrast manually.
    I tried the portable viewer of that modality and many other viewer from the internet and the images are displayed correctly.
    Only k-pacs (server and lite) does not display the contrat's images pretty.
    If you may help
    Thanks

  • K-PACS will read out the information in the DICOM image to present it in the viewer. For windowing, this are usually the DICOM attributes 0028,1050 (WindowCenter) and 0028,1051 (WindowWidth). Alternatively, there may be used special look-up tables. If K-Pacs does not find values for these DICOM attributes or the type of look-up table encoded in the images is not supported, K-PACS will calculate its own automatic contrast for the image. The result may not look the same as on your original modality, because the calculation method might be different.


    My recommendation: Check if the center/window values are stored in the DICOM information of the images. If not, adapt your modality to save the values used at the modality so that they can also be used at other stations, such as K-PACS.


    Of course, also different display types and/or differences in the calibration of the displays connected to the modality and the workstations can lead to differences in the visualization of the images.

  • Thanks for your kind reply,


    The window center and window width are correct in k-pacs and they are the same as in any other dicom viewer
    but the screen shows wrong display in k-pacs and it's different from any other dicom viewer.


    what other attribute can affect the screen display in k-pacs?


    N.B. I notice that the adjustment of contrast is working in reverse order for that study.


    for other study when window center grows up the image become more dark
    but for this study when window center grows up the image becomes more white.


    Thanks for your help

  • There is a number of attributes and values that affect how the image is presented on the screen or how the image is handled by an application. The fact that you say that the windowing works differently on the study makes it an interesting case. I've never heard of such a behavior. Note, however, that we do not grant technical support for the freeware K-PACS. I can only suggest that you try out our professional radiology reading station iQ-VIEW and check how the study is handled in this software. If the behavior is the same as in K-PACS, you may contact our support team, e.g. by using our web form. Attach the study or at least one representative image for further evaluation. Without such a sample it will be difficult to give an answer or maybe even a solution.