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Spine Labeling

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This is a premium feature and may not be available in all installations.


The Workstation allows you to quickly and accurately label the spine in the patient space (in 3 dimensions). To label the spine:

1.Open a CT or MR study where the patient's spine has been imaged. If the study does not have a sagittal series of images, you may need to open the study in MPR.
2.In the viewer toolbar, select the Spine Labeling tool.
3.Make sure a sagittal series is visible in the viewer. See Laying Out Images for details on how to do this.
4.In the sagittal display set, stack to an image that is roughly in the middle of the patient's spine.
5.Using the assigned mouse button (left by default), click repeatedly in the centre of each vertebra you wish to label. Each click puts a marker on a vertebra.

You must label the spine starting from the top, moving down the spine; however you can start on any vertebra you wish.


The spine labeling tool does not perform any automatic segmentation (detection of the shape of the vertebra). You must click on the centre of each vertebra in order to ensure the accurate display of spine labels in the other views.

6.To stop labeling, deposit the last marker by double-clicking on the last vertebra you wish to label.
7.When labeling is complete, a context menu will automatically appear near the mouse pointer, as shown below.

The context menu shows you all the possible ranges of vertebrae for the number of markers deposited. The first possible range for each region of the spine is shown at the top level of the menu for convenience (e.g. C1-C7, T1-T7, etc). The remaining possible ranges are grouped under headings by region (e.g. Cervical, Thoracic).

8.Select the correct range of vertebrae from the context menu. If you choose not to, the spine will simply be labeled numerically (e.g. 1-7). However, you can always change the vertebrae range by right-clicking anywhere on the spine label.
9.You can repeat this process if you wish to label different parts of the spine separately; you can label the spine in the same image(s) as many times as you like, although it won't necessarily make sense to do so.


Once the spine label is drawn:

The markers will appear in all images within the same imaging study, from the same acquisition (or "frame of reference", in DICOM).
Each marker (small ellipse) can be moved independently, and those changes are reflected everywhere that marker is visible.
Markers can be moved in all imaging planes (Sagittal, Coronal, Axial) in order to accurately label the spine in 3 dimensions, if desired.


In images where the patient is not upright (e.g. not Sagittal, Coronal), like axial images for example, only the label closest to the image (in the 3-D patient space) is shown.

If the marker is very close (<2mm) to one marker (e.g. C5), the text callout will only show the text for the one marker.
If the marker is not very close to one marker, and is in between two markers, the text callout will show the text for both markers, as shown above. The first one will always indicate the marker that is closest (e.g. C4/C5 means C4 is closest; C5/C4 means C5 is closest). If you were to manipulate such a marker on an axial view, it is this closest marker that you will see moving in the other images. The reference lines tool can aid you in seeing this for yourself.


Finally, you may notice that some (or all) markers will disappear as you stack through images in a display set (shown below). This is because only markers that are within 2.5cm of the current image (in the patient space) are shown.

On "upright" views (sagittal, coronal), consecutive markers are connected by a dashed line. A broken line means at least one marker is not within the stated tolerance. This can be seen in the above screenshot in the bottom-right image (T7 is missing, and the line is broken).
On non-upright views (e.g. axial), only one marker is ever shown, as stated earlier.


Note also that there are other tools available to you that can help you get the most out of spine labeling, namely:

Reference Lines
Spatial Locator
Synchronized Stacking


ClearCanvas Workstation, Personal - User's Guide
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