Why Does Weasis Display Three Sets of Measurement Values Compared to Single Values in Other DICOM Viewers?

[Yunus eşme]

Hello,

I performed similar measurements for the same region of a PET/CT image using Osirix, Weasis, and Horos. However, in Weasis, the min, max, mean, median, and StDev values appear three times, as shown in the attached image.

Why does Weasis display these values three times, while other DICOM viewers show a single value? Should we take the average of these three values in Weasis? If yes, why are the values displayed separately instead of as a single number? Is there a way to view only one set of data in Weasis, like in the other viewers?

Additionally, if StDev corresponds to SD, why does it show a greater deviation compared to other viewers?

Lastly, while other applications don’t show units for these values, Weasis displays them as HU. Why is this the case? Does this have any significance for PET/CT evaluations?

I would appreciate your guidance on these questions. Thank you!

[Nicolas Roduit]

The 3 values represent the 3 channels of a color image. I return the question, why display only one value, is it an average or a grayscale conversion (which is not exactly an average)?

However, It would be better to measure directly on the PET image, as this image is a fusion with reduced intensity values (16-bit to 8-bit). See also the other statistics values.

There are several ways to calculate the standard deviation. Weasis uses the OpenCV function.

For units, it's a bug because Weasis displays HU for all CT images. In this case, the modality after fusion is retained in CT. I've opened a bug for this specific case.