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 (G-C036, SRT, "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.
Table RRR.2-1. Volumetric ROI on CT Example
|
Node |
Code Meaning of Concept Name |
Code Meaning or Example Value |
TID |
|---|---|---|---|
|
1 |
Oncology Measurement Report | ||
|
1.1 |
Language of Content Item and Descendants |
English |
|
|
1.2 |
Observation Context |
||
|
1.2.1 |
Person Observer Name |
Doe^Jane |
|
|
1.3 |
Procedure Reported |
Chest+Abd CT W+WO contr IV |
|
|
1.4 |
Image Library |
||
|
1.4.1 |
IMAGE - CT image #1 |
||
|
1.4.1.1 |
Study Date |
20030417 |
|
|
1.4.1.2 |
Study Time |
104607 |
|
|
1.4.1.3 |
Horizontal Pixel Spacing |
0.810547 mm |
|
|
1.4.1.j |
... |
... |
|
|
1.4.1.n |
Pixel Data Columns |
512 pixels |
|
|
1.4.2 |
IMAGE - CT image #2 |
||
|
1.4.2.j |
... |
... |
|
|
1.5 |
Measurements |
||
|
1.5.1 |
Measurement Group |
||
|
1.5.1.1 |
Tracking Identifier |
Object1 |
|
|
1.5.1.2 |
Tracking Unique Identifier |
1.2.276.0.7230010... |
|
|
1.5.1.3 |
Referenced Segment |
IMAGE - Segmentation, Segment #1 |
|
|
1.5.1.4 |
Source image for segmentation |
IMAGE - CT image #1 |
|
|
1.5.1.5 |
Source image for segmentation |
IMAGE - CT image #2 |
|
|
1.5.1.6 |
Finding Site |
Adrenal Gland |
|
|
1.5.1.6.1 |
Laterality |
Right |
|
|
1.5.1.7 |
Volume |
3267.46 mm3 |
|
|
1.5.1.7.1 |
Measurement Method |
Sum of segmented voxel volumes |
|
|
1.5.1.8 |
Long Axis |
9.21 mm |
|
|
1.5.1.8.1 |
Measurement Method |
RECIST 1.1 |
|
|
1.5.1.9 |
Attenuation Coefficient |
70.978 Hounsfield unit |
|
|
1.5.1.9.1 |
Derivation |
Mean |
|
|
1.5.1.10 |
Necrosis |
Present |
|
|
1.5.1.11 |
Hemorrhage |
Absent |
|
|
1.6 |
Qualitative Evaluations |
||
|
1.6.1 |
Renal Vein Involvement |
Absent |