The Distance Measure tool enables you to measure the distance between two points in any image. For example, it can be used to measure the size of a tumor by measuring its length, depth and width. One of the most powerful options available with the distance measure is the capability to perform landmark co-registration.
The Distance Measure Tool can be accessed via the tool pull-down menu on the IVS front panel.
Upon selection of the distance measure tool a Distances window is displayed. The physical distance between two points can be measured by left clicking the cursor on one point on the image and moving the cursor to the second point and left clicking again. A line is displayed between the two points to show what is being measured.
In the Distances window, each line is identified by a unique color tag. For each line, the 3D start and end points of the line are displayed as well as the length of the line (in mm). Multiple distances can be measured on the same image and are easily distinguished by their unique color. The results can be saved into an Excel file by clicking Save. The Profile function enables a graphic plot of the distance to be displayed for both the reference and the input data.
Double-click on any (x,y,z) triplet in the Distances dialog box to present the planes associated with that triplet in the Display. In other words, the plane corresponding to the x/y (transverse), x/z (sagittal), and y/z (coronal) points for the selected (x,y,z) triplet will be shown in the Display.
Since a single left click sets a new point, you have to use a single middle mouse button click to go to the given position in the two respective other slices.
Clicking on an (x,y,z) triplet in the Distances dialog box activates that point in the Display (double-blick to show point in all three slices). A second left-click in any of the three planar windows (coronal, sagittal, or transverse) will re-position that point, shifting the line accordingly.
When a point is activated (see Editing) a right-click inside any of the three planar windows will remove the entire line (i.e. start and end point) from the Distances dialog.
The Profile tool, available in the Distances window, plots the values in each voxel through which the line passes. Values are displayed for both Reference and input data sets and, given proper calibration, the plot values will be in Houndsfield units and MBq for CT and NM data sets, respectively. The File menu provides an option to save the Profile data as a PDF.
One of the most powerful features of the distance-measure tool is the built-in capability of performing landmark-based co-registration. With two data sets loaded, use the distance measure tool to draw at least two lines that connect corresponding locations (i.e., locations which should be registered) between the reference and input data sets.
Under the "Options" menu, select "Co-Register Data"
After performing the registration, the shifted input data set will appear in the Main Window as Input 2.
