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How to distinguish stack DICOM images from overview image?

I have a stack of DICOM coronal images where I have used the Image Position (Patient)(0020,0032) tag to sort the images in correct order.
However, the stack also contains an "overview" image showing how the coronal slices where generated from an axial stack - see attachment.enter image description here

Obviously I want to automatically skip this overview image when sorting the stack - does anyone know how to utilize DICOM tags (which?) to distinguish this one from the rest of the stack?

Solution

  • Sorting on Image Position (Patient)(0020,0032) seems correct.

    Sorting on other tags like:

    • (0008,0012) Instance Creation Date and (0008,0013) Instance Creation Time
    • (0008,0022) Acquisition Date and (0008,0032) Acquisition Time

    may not work. Technician may acquire intermediate images afterward if missing in earlier scan sequence.

    (0020,0012) Acquisition Number and (0020,0013) Instance Number may not work for same reason.

    So, tag you choose for sorting looks correct.

    Now, images you are interested in are "AXIAL" and you want to skip "OVERVIEW" images from stacking.

    Well, I am not sure if "OVERVIEW" is correct term. Do you mean Topogram/Scout/Scanogram/Localizer/Patient Protocol or something? Anyway, we will continue with your term.

    Check the (0008,0008) Image Type attribute. For "AXIAL" images, it should contain value "AXIAL" generally at third position. Something like following:

    ORIGINAL\PRIMARY\AXIAL
OR
DERIVED\SECONDARY\AXIAL

    For "OVERVIEW" images, this either will not present or it will be different ("LOCALIZER" most probably assuming CT Image).

    Please note that only first two values are mandatory. Values beyond that are optional.

    Reference:

    ftp://dicom.nema.org/MEDICAL/dicom/2016a/output/chtml/part03/sect_C.7.6.html#sect_C.7.6.1.1.2

    https://dicom.innolitics.com/ciods/ct-image/ct-image/00080008

    ftp://dicom.nema.org/MEDICAL/dicom/2016a/output/chtml/part03/sect_C.8.16.html#table_C.8-129