Annotate Images

The V3 viewer comes with a series of tools that allow you to create annotations, measurements or regions of interest (ROIs). These annotations and measurements can be saved as a DICOM Structured Report and be re-loaded in the viewer for further review and analysis.

Create an annotation, measurement or ROI

1. In the Viewer, select a tool from the Measure Tools menu in the right-side toolbar.

   

2. Depending on which tool you chose, draw an annotation, measurement or ROI on the image. Once you are done drawing, the Measurements panel will automatically open and your annotation, measurement or ROI will be listed there. Note: by default, the name of of that measurement will show as (empty), except when using the Annotation tool, which requires a label to be typed in upon creation.

   

3. Additional annotations, measurements or ROIs can be created on different slices or even on different image series from the same study (series with the same StudyInstanceUID), and will be displayed in the measurement panel. Clicking on a measurement in the measurement panel automatically displays that measurement in the viewport.

Tools

The following tools are available by default in the viewer:

Annotation

• Annotation tool: Adds an arrow to the image with custom text (label) as annotation. Label is required.

Measurements

• Length tool: Measures the length between two points on an image. Length is displayed in mm if images have the Pixel Spacing (0028,0030) tag. It is displayed pixels (px) otherwise.
• Bi-directional tool: Measures the width and length of a structure on an image by drawing two perpendicular lines. Length and Width are displayed in mm if images have the Pixel Spacing (0028,0030) tag. It is displayed in pixels (px) otherwise.
• Angle tool: Measures the angle formed by three points on the image.
• Freehand tool (open contour): Measures the length of a freehand-drawn contour. Length is displayed in mm if images have the Pixel Spacing (0028,0030) tag. It is displayed pixels (px) otherwise.

ROIs

• Circle ROI: Measures the radius, area, and pixel intensity statistics (mean, max, standard deviation) of a circle region of interest.
• Ellipse ROI: Measures the area and pixel intensity statistics (mean, max, standard deviation) of an elliptical region of interest.
• Rectangle ROI: Measures the area and pixel intensity statistics (mean, max, standard deviation) of an rectangular region of interest.
• Freehand tool (closed contour): Measures the area and perimeter of a freehand-drawn region of interest.

Edit the label of an annotation, measurement or ROI

The label of a measurement can be edited by clicking on the Edit Label icon in the measurement panel, or by using the right-click menu while the measurement is active (green contour) in the viewport.

From the measurement panel:

From the context menu on right-click:

Depending on the viewer’s configuration for the project you can type in a label and/or select a label from a pre-defined list. If a pre-defined list of labels exists, you can start typing the name of a label from that list to quickly find it.

Hide an annotation, measurement or ROI

Annotations, measurements and ROIs can be hidden by clicking on the Hide icon in the measurement panel, or by using the right-click menu while the measurement is active (green contour) in the viewport. When a measurement is hidden, it is no longer displayed on the image. The label of a hidden measurement can still be edited.

From the measurement panel:

From the context menu on right-click:

Lock an annotation, measurement or ROI

Annotations, measurements and ROIs can be locked to avoid accidentally editing them. This can be done from the measurement panel or by using the right-click menu while the measurement is active (green contour) in the viewport. When a measurement is locked, it cannot be edited or deleted.

From the measurement panel:

From the context menu on right-click:

Delete an annotation, measurement or ROI

Annotations, measurements and ROIs can be deleted from the image with the delete icon in the measurement panel or by using the right-click menu while the measurement is active (green contour) in the viewport. Deleting a measurement removes it from the image and from the measurement panel. Deleting a measurement cannot be undone.

From the measurement panel:

From the context menu on right-click:

Hide output values for annotations, measurements and ROIs

Output values are displayed on the image by default for each measurement. These can be moved by clicking and dragging. However, if multiple measurements or ROIs need to be created on one image, output values can rapidly get in the way. You have the option to hide the output values for each individual measurement or ROI from the right-click menu while the measurement is active (green contour) in the viewport.

You can also decide to hide output values for all measurements and ROIs from the Settings menu in the measurement panel. Note: this does not apply to annotations.

Save annotations, measurements and ROIs

Annotations, measurements and ROIs can be saved as a DICOM Structured Report (SR) by clicking the Save Measurements button at the bottom of the measurement panel.

When saving measurements for the first time, the only option is to “Save as…”, which lets you type in a name for your DICOM SR.

Upon saving, the DICOM Structured report is added to the first acquisition of the Flywheel session and becomes available in the Study Browser on the left of the viewport.

Each time a report gets saved under the same name, it creates a new version of that report. Older versions can be restored from the Flywheel acquisition page.

Note: Saving annotations, measurements and ROIs as a DICOM SR requires the Create/Upload file permission to the project. If you don’t have this permission, the Save option will be disabled. Please contact your site administrator if you believe that you should have this permission.

Export annotations, measurements and ROIs

You can export a csv file containing information about your annotations, measurements and ROIs by clicking Export (.csv) in the Save Measurements menu at the bottom of the measurement panel.

The exported csv file contains one row per measurement and the following columns:

• PatientID: populated with the PatientID (0010,0020) value of the annotated DICOM series.

• PatientName: populated with the PatientName (0010,0020) value of the annotated DICOM series.

• StudyInstanceUID: populated with the StudyInstanceUID (0020,000D) value of the annotated DICOM series.

• SeriesInstanceUID: populated with the SeriesInstanceUID (0020,000E) value of the annotated DICOM series.

• SOPInstanceUID: populated with the SOPInstanceUID (0008,0018) value of the annotated DICOM series.

• Label: Label assigned to the annotation in the Viewer.

• AnnotationType: The tool that was used for this annotation.

• FrameofReferenceUID: populated with the FrameOfReferenceUID (0020,0052) value of the annotated DICOM series.

• points: points coordinates of the contour’s annotation on the image

• Length: the length value of the annotation (if applicable)

• Unit: the unit of length of the annotation (if applicable)

Close annotations, measurements and ROIs

You can close measurements by clicking on the close icon at the top-right corner of the measurement panel, or by selecting “Close” from the “Save Measurements” menu at the bottom of the panel. This will close the measurement panel.

If you have unsaved measurements, you will see a warning asking you if you are sure that you want to close. Click Yes to continue without saving, or Cancel to go back to the measurement panel and save your measurements.

If you would like to close the measurement panel without closing your measurements, simply click on the measurement icon at the bottom of the toolbar on the right of the viewport to collapse the panel.