Measuring and Marking Up Images

Kantrad lets you take measurements, draw regions of interest, and add notes directly on your images. Everything you mark is saved automatically and will be there the next time you open the study.

Taking Length Measurements

  1. Press L on your keyboard to activate the length tool.
  2. Click on the starting point of your measurement.
  3. Click on the ending point.
  4. The distance in millimetres appears next to the line.

For tumour measurements using the RECIST method (longest diameter plus perpendicular), press B for the bidirectional tool. Click to place the first line, then the perpendicular line is drawn automatically.

Measuring Angles

  • Standard angle: Press G, then click three points to define the angle. The measurement in degrees appears on screen.
  • Cobb angle (for spine assessment): Press C, then draw two lines. The angle between them is calculated automatically.

Drawing Regions of Interest

When you need to measure a specific area, you have four options:

  1. Ellipse — Press E, then click and drag to draw an oval shape. Kantrad shows the area, average value, and variation within that region.
  2. Rectangle — Press R, then click and drag to draw a box.
  3. Freehand — Press N, then draw any shape by clicking and dragging freely.
  4. Smooth curve — Press S, then click points to create a smooth curved outline.

All region tools display the same statistics: area, average pixel value, and standard deviation. For CT scans, these values are shown in Hounsfield Units.

Tip: After drawing a region, click the histogram button (the bar chart icon in the toolbar) to see a detailed breakdown of pixel values within that region. This is useful for tissue analysis.

Checking a Single Point Value

Press H to activate the probe tool, then click on any point in the image. Kantrad shows the pixel intensity at that exact spot. For CT scans, this is the Hounsfield Unit value.

Adding Labels and Arrows

  • Arrow with text: Press A, click where you want the arrow to point, then drag to place the tail. Type your label text.
  • Text label: Press T, then click where you want to place a note and type your text.

Managing Your Markings

  • Undo the last marking: Cmd+Z
  • Delete a specific marking: Click on it to select it, then press Backspace or Delete.
  • Remove all markings at once: Cmd+Shift+Backspace
  • Show or hide the text labels: Click the checklist button in the toolbar.

Note: All your measurements and annotations are saved automatically about one second after you make any change. When you come back to this series later, everything will still be there.

Adding Measurements to Your Report

You can insert your measurements directly into your report in several ways:

  1. Insert all at once: Click the ruler button in the report toolbar. All measurements are added as a formatted list at your cursor position.
  2. Insert one at a time: Right-click on the image to see a list of your measurements. Click on the one you want to insert.
  3. From the report editor: Right-click inside the report to see available measurements and pick which ones to insert.
  4. From the measurement panel: Click the ruler button in the viewer toolbar to open a panel listing all measurements, each with its own insert button.

Tip: After inserting a measurement into your report, you can click on it in the report text to jump back to the exact slice and see the marking highlighted on the image. This makes it easy to verify your findings.