Segment Statistics module computes area and volume of each segment. Area is computed in 3D, which means both sides of a flat single-slice segments are included. You can divide the reported surface value by 2 to get the cross-sectional area, i.e., the area that you see on a single image.
There are also several modules for computing area. I generated this summary using ChatGPT, but I confirm that it is accurate (I reviewed it and fixed minor inaccuracies):
1. Segment Cross‑Section Area (in Sandbox extension)
- This module computes cross‑sectional area of a segmentation along an image axis (e.g., axial, sagittal, coronal or any IJK axis you choose).
- You can install it by opening the Extensions Manager in Slicer and installing the Sandbox extension.
Best when you want area per slice along standard image axes.
2. SegmentGeometry (in SlicerBiomech extension)
- This extension can compute cross‑sectional area (plus other shape metrics) along an arbitrary direction or line, not just the image axes.
- It’s useful if you want cross‑sections in non‑orthogonal directions or aligned with a specific anatomical axis.
- It outputs area and additional geometric properties like perimeter, Feret diameter, moments of inertia, etc.
Best when you need cross‑section metrics oriented in a custom way.
3. VMTK modules (in SlicerVMTK extension)
- The Vascular Modeling Toolkit (VMTK) extension includes modules like Cross‑section analysis or Stenosis measurement.
- These can compute cross‑sections along a centerline or curved path, often used for vessels or tubular structures.
Best for vascular work or when the structure follows a path rather than straight sections.
3. Markups module
- If you need the area of a structure in a single 2D slice, you can draw a closed curve markup and enable area measurement in the Markups module’s Measurements section.
Best for measuring area of a simple shape in a single 2D slice.