1. Purpose
This IFU explains how to configure the Comparison Exam Display Rule, a Hanging Protocols setting that lets a user override the system's default, recency-based selection of the comparison exam shown in the comparison panel of the viewer.
2. Intended Use
This setting is intended for radiologists and other authorized viewer users who want the comparison panel to automatically surface the prior exam that is most clinically relevant to their reading workflow, rather than always the most recent relevant prior. Configuring this setting reduces manual navigation when opening a study and supports faster, more consistent reads.
Note: This setting only changes which relevant prior is auto-displayed and whether the viewer opens in compare mode. It does not change how prior relevancy itself is determined — that continues to be governed by the System Default (or Facility Level, if enabled) Comparison Rules. |
3. Before You Begin
Confirm the following before configuring this setting:
You have access to the Hanging Protocols window.
You understand your facility's existing System Default (or Facility Level) Comparison Rules, since this setting is applied on top of that pool of relevant priors.
4. Accessing the Comparison Exam Display Rule Setting
Open the Hanging Protocols (HP) window.
Navigate to User Level Settings.
Select the Comparison Exam Display Rule category.
Choose the modality group you want to configure: MR, CT, PT, NM — US — XR, XA, RF — MG — BMD.
Note: An “ALL” tab is available for the multi-modality groups (MR, CT, PT, NM and XR, XA, RF) to configure all modalities in that group at once. Individual modalities (US, MG, BMD) do not have an ALL tab and are configured on their own tab only. |
5. Configuring the “ALL” Tab (Multi-Modality Groups Only)
When the ALL tab is selected for MR/CT/PT/NM or XR/XA/RF, three settings are available:
Setting 1 — Display relevant comparison exams with (choose one):
Same exam type
Same region
Same modality
Same modality and region
Setting 2 — Other preferences (choose one or both):
Skip most recent relevant exam — displays the 2nd most recent relevant match.
Show oldest relevant exam — displays the oldest relevant match.
Setting 3 — Open exam in compare mode (choose one or both):
Any time there is a relevant comparison exam
Any time there is more than one relevant comparison exam
You may select options from all three settings, from only two, from only one, or leave all unset.
Changing a saved configuration
To unselect a Setting 1 option, click the selected radio button again, or choose a different option.
To unselect a Setting 2 option, click the selected checkbox again.
⚠ IMPORTANT: Configuring criteria in the ALL tab applies it to every modality in that group. If a specific modality already has its own criteria and you then change the ALL tab, the ALL criteria will overwrite that modality's existing settings. If you configure ALL first and later configure an individual modality, the individual modality keeps its own settings while all remaining, unconfigured modalities continue to follow ALL. |
6. Configuring an Individual Modality Tab
Within each modality tab (MR, CT, PT, NM, US, XR, XA, RF, MG, BMD), choose an “Apply to” option:
All exam types with this modality — selected by default if no preference has been configured for that modality.
Exam types selected below
Note: Compare mode (Setting 3) is not available for the MG modality, because compare mode is not currently supported for MG. |
6.1 Apply To: Exam Types Selected Below
Select “Exam types selected below.” An exam types table appears, listing exam codes for the modality filtered to the entries you have visibility to (global, group, or both).
Create one or more named tabs, each containing its own selected exam types and its own Setting 1/2/3 configuration.
Select at least one exam type before saving a tab — a tab with no exam types selected cannot be saved.
Note: The same exam type cannot be assigned to more than one tab. |
6.2 Example Configurations
Tab 1 applied to MR exam types “14203” and “14202”, with Same exam type / Skip most recent relevant exam / Open in compare mode when a relevant exam exists: opening an MR exam of type 14203 or 14202 displays the second most recent relevant prior of the same exam type, and the viewer opens in compare mode if a match exists.
Tab 2 applied to MR exam types “14198” and “14197”, with Same region / Show oldest relevant / Open in compare mode when more than one relevant exam exists: opening an MR exam of type 14198 or 14197 displays the oldest relevant prior of the same region, and the viewer opens in compare mode only if more than one match exists.
7. How the Display Rule Is Applied
Prior relevancy is still determined first by the System Default (or Facility Level, if enabled) Comparison Rules. Your Comparison Exam Display Rule is then applied on top of that pool of relevant priors.
“Display relevant comparison exam with” behavior:
Same exam type — shows the relevant prior with the same exam type as the current exam.
Same region — shows the relevant prior with the same region as the current exam.
Same modality — shows the relevant prior with the same modality as the current exam.
Same modality and region — shows the relevant prior matching both modality and region.
Note: If no relevant exam matches, the comparison panel shows nothing by default and you may select a comparison exam manually. |
“Other preferences” behavior:
Skip most recent relevant exam — shows the 2nd most recent relevant match. If only one relevant exam exists, that single exam is shown.
Show oldest relevant exam — shows the oldest relevant match. If only one relevant exam exists, that single exam is shown.
“Open exam in compare mode” behavior:
Any time there is a relevant comparison exam — the viewer opens in compare mode when at least one relevant exam matches your Setting 1/2 criteria (or, if no criteria are set, when at least one relevant exam exists for the modality/exam type).
Any time there is more than one relevant comparison exam — the viewer opens in compare mode only when more than one relevant exam matches your criteria (or exists, if no criteria are set).
Both compare-mode options may be selected together. If neither is selected, the viewer does not open in compare mode and instead falls back to displaying a single comparison exam as usual.
8. Fallback Behavior (No Rule Configured)
Modality groups (MR, CT, PT, NM — XR, XA, RF):
If no rule is set for a specific modality, the group's ALL tab criteria apply.
If rules exist only for certain exam types within a modality, unconfigured exam types in that modality use the ALL tab criteria.
If the ALL tab has no rule configured either, the system falls back to default behavior: the most recent relevant comparison exam is displayed.
Individual modalities (US, MG, BMD):
If no rule is set for the modality, the system falls back to default behavior: the most recent relevant comparison exam is displayed.
If rules exist only for certain exam types, unconfigured exam types in that modality also fall back to default behavior.
9. Effect on the Reporting Screen
The Comparison Report tab on the Reporting Screen reflects whichever comparison exam your Hanging Protocols rule causes the viewer to display. If that comparison exam has no associated report, the Comparison Report tab will be empty.