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Lung Emphysema Program

The Lung Emphysema program is designed for quantitative assessment of emphysematous areas in the lungs:

Segmentation of lung tissue from airways and soft tissues
Calculation of the volume of both lungs, the right and left lungs separately
Determination of the mean density of lung parenchyma, standard deviation of parenchyma density, and median
Calculation of the volume and percentage (emphysema index) of emphysema-affected tissue based on a predetermined density threshold for both lungs, and for the right and left lungs separately
Display of a histogram of the distribution of lung tissue by density
A 3D model with color mapping of emphysema in halftones

Launching the "Lung Emphysema" Program

Click in the Tool Panel, in the "Studies" group, on the "Programs" button or press the key on the keyboard
Click on the "Lung Emphysema" button

Selecting a Series for Analysis

In the window that appears, click the down arrow button
Select a series in the "lung" reconstruction mode and click on it
Click the "OK" button

Program Appearance

The screen will split into 5 panels:

Three panels of standard MPR display
A 3D model panel
A control panel with a histogram and a results table

The program will automatically perform lung segmentation and emphysema calculations based on the default threshold values
Automatically detected emphysema zones are colored orange

Quantitative Emphysema Analysis Settings

Program settings control buttons are located in the bottom panel, to the left of the histogram

Setting the Emphysema Threshold

As a result of a meta-analysis conducted by Xie X., de Jong P. A., Oudkerk M. et al. (2012), it was established, and currently most researchers agree, that the most accurate threshold level is -950 HU
However, calculations are highly dependent on the technical conditions of the study and image reconstruction
Therefore, it is necessary to adjust the threshold value in accordance with the visual assessment of emphysema areas
The acceptable range in the program is from -1000 to -850

Options for Changing the Emphysema Threshold:

Click on the numeric value field and enter numbers from the keyboard
Change the threshold by clicking the arrows next to the numeric value field

Applying the New Emphysema Threshold

Click the

button to the right of the slider

Reset to Default Value

Click the

button to the right of the slider

Coloring Control:

Move the transparency slider (bottom left) to the right
Click the "Show/Hide Emphysema Coloring" button / in the control panel

Editing Emphysema Coloring

Click the "Delete Emphysema Area" button to delete an unnecessary area, or the "Add Emphysema Area" button to add a missed area
For both functions (removing and adding):
- Outline the necessary fragment of the lung on any of the MPR projections
- Actions are similar to the program's "Closed Pencil" tool
- Scroll through the images, selecting all areas to be edited
Removing part of the volume identified as emphysema
- The tool captures selected areas in the volume, less precise than the previous ones
- Click the button
- With left mouse clicks on areas incorrectly marked and delete them
Undo the last edit - the last button in the row

Editing Segmentation (selection) of Lungs

If automatic lung segmentation contained errors, use the buttons:

and (add or remove lung area)
For both functions (removing and adding):
- Outline the necessary fragment of the lung on any of the MPR projections
- Actions are similar to the program's "Closed Pencil" tool
- Scroll through the images, selecting all areas to be edited

Emphysema Analysis Results

Presented as a histogram and a table in the center and right part of the bottom panel

Saving Results

Saving in Vidar Dicom Viewer

The Lung Emphysema program is automatically saved upon exit in the Finds list
To display on screen, click on the "Lung Emphysema" item in the Finds list in the Preview Bar

Saving the Results Table

If a region of interest (rows or columns of the table) is not selected, then all table data is saved
Click the "Copy" button to copy the table to the clipboard for pasting into a standard text document
Click the "Save" button to save the analysis results table to a *.csv format file for subsequent use in MS Excel
Click the "Print" button to send the analysis results table to print

Saving the Histogram

Click the "Save Histogram" button under the histogram to save it to a user series (it will be located in the Preview Bar at the end of the study)
Subsequently, it can be dragged onto the screen and printed

Saving the Entire Screen (Images, Histogram, and Table) to a User Series

Click the "Save User Series" button under the table to save the entire screen to a user series (it will be located in the Preview Bar at the end of the study)

Exiting the "Lung Emphysema" Program Mode

Click the "Lung Emphysema" button in the program header on the left
Click on the "Exit Mode" item

Split screen will return to standard mode

Afterword:

Standard measurements in computed tomography for Lung emphysema currently are:

Emphysema index - ES (emphysema score), in particular - ES-950 — the percentage of emphysema for the -950 HU level
Mean lung density (MLD) measured in volume

The Fleischner Society classification considers only the severity of emphysema based on the measured volume
Lynch D. A. et al. (Fleishner society recommendations):

Grade 1 (A) – minimal (less than 0.5% of lung zone)
Grade 2 (B) – moderate (0.5-5% of lung zone)
Grade 3 (C) – moderate degree (more than 5% of any lung zone)
Grade 4 (D) – confluent
Grade 5 (E) – severe destructive emphysema

However, due to the lack of standardization of quantitative emphysema analysis in CT and the dependence of results on equipment, technical parameters of the study and software, spirometry data dominates the diagnosis of chronic obstructive pulmonary disease