Segmentation by thresholding doesnt correspond to HU units

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1

Hello Everyone,

Im trying to segment the bones from a set of CT scans, actually i’ve done this actions both in Slicer and in Python, i have read the segmentation recipes for extracting skeletons but when i apply a threshold for the common bone HU (>225 or >300) values i seem to be extracting incomplete ribcages/bones along with extra artifacts (blood vessels, kidneys)

could this be an error of how the CT scan was taken, i researched and the parameters used for the HU unit calculation are the rescale Slope and rescale intercept

segbones
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, my scans have all values of 1 and -1024 respectively, is there a workaround for mapping the HU units of my CT scans to properly encompass bone between a certain range and blood,

i attach images of the segmentation when applying a thrreshold of 225 HU

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Hounsfield Unit ranges cannot be used for accurate segmentation of different materials for many reasons - noise, partial volume effect, patient-specific bone density differences, etc.

Check out segmentation tutorials here to learn more about segmentation tools: https://slicer.readthedocs.io/en/latest/user_guide/modules/segmenteditor.html#tutorials

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