Synchronization
VOI, pan/zoom, and slice sync across viewports; when to enable each; clinical comparison patterns.
Prism can lock display and navigation so multiple viewports stay aligned. Use sync when you compare the same region in two or more series or when MPR panes should move together. Disable sync when you intentionally want independent navigation (for example different zoom levels in each eye).
Sync kinds
| Kind | What it links | Typical use |
|---|---|---|
| VOI (window/level) | Contrast and brightness settings | Match appearance of two series (e.g. soft tissue in CT abdomen). |
| Pan / zoom | Spatial position and zoom factor | Side-by-side follow-up: same organ coverage and magnification. |
| Slice | Index along the stack or coupled navigation | Scroll together in paired series, or MPR triplet with linked stepping. |
You toggle each kind from the toolbar synchronization controls. The exact iconography is theme-dependent, but the three toggles line up with the table above.
When to turn VOI sync on
- Comparing reconstructions with different default window (for example, soft vs lung): turn off for discovery, then on to harmonize for apples-to-apples comparison after you have chosen a window.
- Chest CT nodule vs mediastinal windows: turn off if you need two different VOI on purpose in adjacent panes (many readers turn sync off in that case).
Use case: two CTs with default windows chosen differently by the technologist; enable VOI sync, then nudge W/L on one until both match, so subtle density differences are not an artifact of display.
When to use pan/zoom sync
- Prior vs current of the same body part, same orientation.
- Two phases in one exam where slice thickness matches closely.
Caution: if pixel spacing or FOV differ greatly (different kernels or reformats), linked pan/zoom can feel wrong—disable for one pane, align manually, then re-enable if needed.
Use case: follow-up HCC; sync pan/zoom so the liver segment fills both panes identically for visual comparison of enhancing foci.
When to use slice sync
- Two stacks of similar slice spacing along the same axis; scroll one, the other follows.
- MPR layouts: moving through thickness should stay in step across planes in many workflows.
When to disable: you need a offset (for example, compare a lesion at two different vertebral levels intentionally).
Use case: long-segment V/Q comparison—sync slice to ensure you are the same anatomic level when slices were acquired on different days.
Layout interactions
- Entering an MPR preset may auto-enable certain sync kinds (the viewer tries to be helpful when planes share the same study volume). You can still override.
- In fullscreen, sync still applies to other non-fullscreen viewports; exit fullscreen to see cross-pane effects.
Related
- Viewports and layouts — choose a grid that supports the comparison you need.
- Window, level, and LUT — adjust VOI before or during sync.