3D volume rendering shows a full volumetric dataset as a rotatable 3D object. MIP (maximum intensity projection) and MinIP (minimum intensity projection) are simplified variants useful for vascular and airway imaging. AVG (average intensity) smooths the dataset for soft tissue review.
Step 1: Open 3D
Click 3D or MPR > 3D in the toolbar. The volume loads in a dedicated viewport. Use Rotate, Pan, Zoom and Window Level as on any other image.
Step 2: Apply a transfer function preset
Click the transfer-function selector. Presets are grouped by anatomy: Bone, Angio, Soft Tissue, Lung, CTA. Each preset maps HU ranges to colour and opacity. Adjust opacity thresholds with the sliders if the preset does not reveal what you need.
Step 3: Switch to MIP, MinIP or AVG
From the projection selector, choose MIP for bright structures (contrast-enhanced vessels, bone), MinIP for dark structures (airways, vessels on CTP), or AVG for averaged soft-tissue view. Slab thickness is adjustable; a 20mm MIP slab is typical for pulmonary MIP.
Step 4: Compare 3D alongside MPR
Open an MPR/MIP/3D comparison layout to see the volumetric view alongside axial, coronal and sagittal slices. Crosshair is shared; clicking in any pane moves the others.
Step 5: Copy to clipboard
For reports or teaching, right-click the 3D viewport and choose Copy with info labels. Paste into Word, PowerPoint, or the report editor.
Tips
- MIP slabs over 50mm can hide pathology behind strong vascular enhancement. Keep slab thin (under 30mm) for lung nodule hunts.
- 3D rendering is GPU-accelerated. If rendering stutters, switch to a more powerful workstation or reduce the dataset (crop before render).
Related articles
- Multi-planar reconstruction (MPR)
- Curved Planar Reconstruction (CPR)
- Fusion imaging (PET/CT and multimodal)