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Using ROI to measure attenuation value in Osirix

  • Dear Howard:

    Thank you for your help previously. I have another quick question: I want to use the ROI to measure the attenuation value in Hounsfield Units (HU) in Osirix. However, I am having difficulty with some of the reformats as the ROIs I draw don't seem to be measuring attenuation values in HU. For example, if I place ROI over air within the bowel lumen, it displays 0 instead of the expected attenuation value of -1000HU.

    I was wondering if you have previously ran into this problem before and if you have any solutions.


  • administrators



    Is it a conventional DICOM image ?

    If you examine the metadata, what do you see for the following fields ?:

    • BitsAllocated
    • BitsStored


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