Cord Finder Tool - Areas and Volumes

Cord Areas and Volume

Now that you have outlined the cord between your two landmarks, you can calculate the cross-sectional areas along the cord, and the total cord volume.

First, select the whether you want to:

. This produces an image that aids visualisation of the cord and its pathology, but is not needed for quantification. The cord centre-line is straightened, and a new image is created with scan planes that are now perpendicular to the cord centre-line. An example unfolded image is shown below for the cervical cord, seen in orthogonal views.

Straightened cervical cord image in coronal (left) and sagittal (right) views.

The straightened cord image will take its name from the input image, but with a suffix "Cord" added.

Note: normally, in the straightened cord image, the pixel size (pixel width and pixel height) and field of view in the left-right and anterior-posterior directions will be half that of the input image. If you use a heavily cropped input image (cropped close to the cord in the left-right or anterior-posterior directions), the straightened cord image may not contain the whole of the spinal cord. In which case, you can create an image with the orginal field-of-view and pixel sizes by selecting the check-box.
. With this selected, a surface model of the cord will be created, which can then be loaded into the 3-D Display as a virtual reality modelling language (VRML) file. The VRML file created will have a name taken from the input image name, with an extension .wrl. An example is shown below, with the VRML cord surface shown as a mesh against a background of the cord image in orthogonal views.

Surface mesh of cervical cord.

Now click on the calculate_button button. When the calculation is finished, a dialog will pop up, showing the cord volume between the landmarks.

cord_result_dialog

You can create a more detailed report by clicking on the text_report_button

button (to a get a report in text format) or the pdf_report_button

button to get a report in PDF format. Click the dismiss_button

button if you do not want a detailed report.

A report will detail the cord length, total volume and cross-sectional areas at regular intervals (in steps equal to the original slice thickness) down the cord. The cross-sectional areas are measured in a plane that is perpendicular to the local cord centre-line.

You will also see a pop-up graph dialog showing the cross-sectional area long the cord.

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