| DICOM PS3.17 2021e - Explanatory Information |
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This CT example describes a set of measurements (volume. long axis and mean attenuation coefficient) made from a single volumetric ROI encoded as a single segment that spans two source CT images, and includes a description of the measurement methods and the finding site, as well as an image library to describe characteristics of the images used, and categorical observations at the measurement group and entire subject level.
For a different modality than CT, the choice of measurement for the mean intensity would not be (122713, DCM, "Attenuation Coefficient").
For MR one might use (110852, DCM, "MR signal intensity"), or (110804, DCM, "T1 Weighted MR Signal Intensity"), etc. See also CID 7180 “Abstract Multi-dimensional Image Model Component Semantics” for various appropriate signal intensity types for MR and other modalities.
For PET one might use (110821, DCM, "Nuclear Medicine Tomographic Activity"), in which case the specific type of signal would be apparent from the units, e.g., ({SUVbw}g/ml, UCUM, "Standardized Uptake Value body weight") or for activity-concentration, (Bq/ml, UCUM, "Becquerels/milliliter"). See also CID 84 “PET Units”.
Care should be taken when selecting modifiers such as (370129005, SCT, "Measurement Method") versus (121401, DCM, "Derivation").
The finding site and laterality within the measurement template (TID 1419 “ROI Measurements”) are factored out and shared by both measurements.
The pattern used for the image library uses TID 4020 “CAD Image Library Entry”, though commonality may be refactored.
The length of the long axis of the volumetric ROI is encoded, but the end points of the line segment used to make that measurement are not recorded, since only the volumetric spatial description of TID 1411 is used. For an alternative encoding, see Section RRR.5.
| DICOM PS3.17 2021e - Explanatory Information |
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