Contents
 
Inobitec DICOM Viewer

2.15. Measurements

PIC To avoid errors caused by the discrepancy between the image size and the real size, Calibration tool should be used when working with projection images (e.g. X-ray images) (see Section 2.29).
PIC The measurement accuracy is up to one screen pixel. As a screen pixel is smaller than a source image pixel, the true linear measurement accuracy is up to one source image pixel. Errors may also occur in density measurements. The most accurate measurements are performed with bilinear interpolation (see Section 2.4).

The following tools are used to measure various parameters: Ruler, Polygonal Ruler, Corner meter, Kobb angle, Point value, ROI rectangle tool, ROI ellipse tool, ROI polygon tool. To select one of these tools, click on the arrow on the right side of the tool selection button. The button will look different depending on the selected tool:

PIC Ruler (selected by default)
PIC Polygonal Ruler
PIC Corner meter
PIC Cobb angle measurement
PIC Intensity value at point
PIC ROI rectangle tool
PIC ROI ellipse tool
PIC ROI polygon tool

To activate or deactivate the tool that is currently selected, just click on the left side of the tool selection button. If some tool is activated, the button is highlighted. The drawn objects will be displayed in the window while it is open, and you can pan, zoom or rotate them together with the image.

If the series is open in multiple windows or tabs, the measurements made in any window, appear in all the other windows.

2.15.1 Ruler

To measure distance in an image:

  1. Activate the Ruler PIC tool on the toolbar by clicking the left/right/middle mouse button. To continue work with this tool, use the button with which the tool was activated. To learn more about tool control, see Section 1.14.
  2. Click the mouse button on the image to mark the first point.
  3. Move the cursor over the screen. The distance from the first point to the current point will be displayed next to the line.
  4. Click the mouse button to fix the current point.
  5. To cancel an incomplete measurement, press Esc.

This tool is also available from the image context menu and from the Image main menu item. Activation is only possible with the left mouse button.

2.15.2 Polygonal Ruler

To perform plygonal linear measurements:

  1. Activate the Polygonal ruler PIC tool by clicking the left/right/middle mouse button. To continue work with this tool, use the button with which the tool was activated. To learn more about tool control, see Section 1.14.
  2. Mark the first point on the toolbar by clicking the mouse button.
  3. Drag the cursor over the screen. The distance from the first point to the current point will be displayed beside the line.
  4. To fix the current point, click the mouse button.
  5. Repeat Steps 3 and 4 until the last but one point is fixed.
  6. Fix the last point by double-clicking the mouse.
  7. To cancel an incomplete measurement, press Esc.

To move the linear measurement point:

  1. Locate the cursor on the point to be moved.
  2. Drag the point, holding any mouse button.
  3. Release the mouse button.

To delete a point:

  1. Locate the cursor on the point to be deleted.
  2. Right-click the mouse and select the Remove point command.

To insert a point:

  1. Locate the cursor on the ruler where you want to insert a point.
  2. Right-click the mouse and select the Insert point command.

This tool is also available from the image context menu and from the Image main menu item. Activation is only possible with the left mouse button.

2.15.3 Corner meter

To measure an angle:

  1. Activate the Corner meter PIC tool from the toolbar by clicking the left/right/middle mouse button. To continue work with this tool, use the button with which the tool was activated. To learn more about tool control, see Section 1.14.
  2. Put two points on the image, clicking the mouse button. The second point is the angle apex.
  3. Move the cursor over the screen to set the other side of the angle.
  4. Click the mouse button to fix the second side of the angle.
  5. To cancel an incomplete measurement, press Esc.

The DICOM Viewer allows you to build as many angles as you need. To deactivate the tool, click on the left side of the tool selection button.

This tool is also available from the image context menu and from the Image main menu item. Activation is only possible with the left mouse button.

2.15.4 Cobb angle meter

To measure a Cobb angle:

  1. Activate the Cobb angle PIC tool from the toolbar by clicking the left/right/middle mouse button. To continue work with this tool, use the button with which the tool was activated. To learn more about tool control, see Section 1.14.
  2. Draw a line that runs along the border of one of the vertebrae. To do this, click the mouse button to set two points through which the line must pass.
  3. Likewise, construct a line for the second vertebra.
  4. To cancel an incomplete measurement, press Esc.

This tool is also available from the image context menu and from the Image main menu item. Activation is only possible with the left mouse button.

2.15.5 Measure Intensity at a Point

PIC If non-bilinear interpolation filters are used, significant errors may occur when intensity is measured in a certain point. In this case, the intensity value will be marked by an asterisk in the top right-hand corner. For accurate measurements, use the bilinear interpolation filter (see Section 2.4).

To measure intensity at some point:

  1. Activate the Intensity value at point PIC tool from the toolbar by clicking the left/right/middle mouse button. To continue work with this tool, use the button with which the tool was activated. To learn more about tool control, see Section 1.14.
  2. Click the mouse button on the target point.

The point will be highlighted at the image, and the intensity value will be displayed next to it.

This tool is also available from the image context menu and from the Image main menu item. Activation is only possible with the left mouse button.

2.15.6 Measure the Intensity Average and Standard Deviation in an Area

To measure the average intensity value and standard deviation in a particular area:

  1. Activate one of the ROI ... tools (rectangle PIC , ellipse PIC , or polygon PIC ) from the toolbar by clicking the left/right/middle mouse button. To continue work with this tool, use the button with which the tool was activated. To learn more about tool control, see Section 1.14.
  2. To draw a rectangle, click the mouse button in its top left-hand and bottom right-hand corners.
  3. To draw an ellipse, just draw the rectangle the ellipse is inscribed in.
  4. To draw a polygon, click the mouse button to mark each apex and then double-click the mouse to finish.
  5. To cancel an incomplete measurement, press Esc.

These tools are also available from the image context menu and from the Image main menu item. Activation is only possible with the left mouse button.

The following parameters will be displayed next to the highlighted area:

  • minimum intensity value;
  • maximum intensity value;
  • average intensity value;
  • standard deviation;
  • area perimeter;
  • area space.

2.15.7 Drawing Parameters

To set the default drawing parameters for measurement tools:

  1. Click on the arrow on the right side of the measurement tool selection button.
  2. Select the item Set default ROI render params....
  3. In the dialog box that appears, set the color by clicking on the color box.
  4. Set the line thickness and the font size.
  5. Set length and area units (millimetres or centimetres).
  6. To connect the footnote and the measurement of the dotted line, check the box Footline.
  7. To apply the settings, click OK. To cancel the settings, click Cancel.

Drawing parameters are available as well from the image context menu and from the Image main menu item.

The settings will be applied only to the measurements conducted in the flat image view window. For multiplanar reconstruction, similar settings should be saved separately.

To edit the drawing parameters of an existing measurement:

  1. Locate the cursor on the measurement to highlight a line or a point.
  2. Right-click the mouse.
  3. Select the Set render params item from the context menu.
  4. In the dialog box that appears, set the parameters in the same way as the default drawing parameters.
  5. To use these parameters by default, check the box Set as default. Set the measurement name if necessary.

2.15.8 Move Measurements

To move a measurement:

  1. Locate the cursor on the measurement to highlight the line or point or to magnify the cross, marking the angular point. Do not locate the cursor on angle points.
  2. Move the measurement, holding any mouse button.

2.15.9 Move Measurement Results

To move a measurement result:

  1. Locate the cursor on the measurement so that it is highlighted by a dotted frame.
  2. Move the measurement result, holding any mouse button.

If the cursor is located on the measurement, the corresponding measurement result will be highlighted, and vice versa.

2.15.10 Delete all Annotations and Measurements

To delete annotations and measurements:

  1. Locate the cursor on the measurement to highlight a line or a point.
  2. Right-click the mouse.
  3. Select the Remove object item from the context menu.

To delete all annotaions and measurements, click the Delete all Annotations and Measurements PIC button on the toolbar or select the corresponding item from the image context menu. In the dialog box that appears, Click Yes to delete or No to cancel. If you want the DICOM Viewer to always delete annotations and measurements without this confirmation, check the box Don‘t show this dialog again and click Yes. If you want the DICOM Viewer to show the confirmation dialog, check the box Ask before deleting all annotations and measurements (see Section 14.5.1). Please note that all other graphic objects created manually will be deleted as well.

This tool is also available from the image context menu and from the Image main menu item.

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