Documentation/Nightly/Extensions/OpenCAD

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Introduction and Acknowledgements

This work is supported by NA-MIC, NCIGT, and the Slicer Community. Author: Vivek Narayan, Jayender Jagadeesan Contact: Jayender Jagadeesan <email> jayender@bwh.harvard.edu</email>

NA-MIC   NCIGT   SPL   This project is supported by...

Module Description

The OpenCAD is designed to segment tumors from DCE-MRI datasets which include 1 pre-contrast image and 2-4 post-contrast images at different time points. OpenCAD uses blackbox methods to calculate the wash-in and wash-out slopes of the contrast dye based on voxel intensity values. The segmentation output is a Label Map with red, yellow, and blue colors respectively identifying washout, plateau, and persistent voxels.

Methods

Only Voxels with a percent increase from pre-contrast to the first post-contrast time point greater than the Minimum Threshold of Increase (default=75.00%) are considered for segmentation and classification. Slope of delayed curve for each voxel is calculated as (Intensity at 4th time point - Intensity at 1st time point) / (Intensity at 1st time point). Segmented voxels are individually classified by color according to slope of delayed curve: Blue for Persistent curve Slope of delayed curve > 0.2 (default) | Type I| Yellow for Plateau curve -0.2 < Slope of delayed curve < 0.2 | Type II Red for Washout curve Slope of delayed curve < -0.2 (default) | Type III

Classification based on Delayed Curve

Features

• Interactive Charting - Calculates and displays the percent increase from baseline(pre-contrast intensity) of the voxel under the current mouse pointer location, at each time point. On the X-axis, 0.0 is Pre-contrast, 1.0 is First Post-contrast, ..., 4.0 is Final Post-contrast time points. The Y-axis represents percentage change from baseline/pre-contrast intensity.
• Volume Rendering - A 3D Volume Rendering of the output Label Map is displayed in the 3D viewer after segmentation.
• Label Statistics - Tabular display of statistics of all First Post-contrast time point voxels highlighted in the output Label Map and grouped according to curve type (Type I, II, and III). These statistics include: Voxel Count, Volume mm^3, Volume cc, Minimum Intensity, Maximum Intensity, Mean Intensity, Standard Deviation. Logic is derived from the Label Statistics Module.

Tutorials

OpenCAD Tutorial (pptx)‎

Data sets

Breast DCE-MRI Data Set 1 (zip file containing the nrrd volumes for the OpenCAD tutorial)‎

Breast DCE-MRI Data Set 2 (zip file containing additional test set of nrrd volumes)‎

Liver DCE-MRI Data Set 1 (zip file containing additional test set of nrrd volumes)‎

Panels and their use

The GUI of the OpenCAD module contains 5 sections: Select DCE-MRI Volumes for Segmentation Pre-contrast Volume: Select the Pre-contrast Image First Post-contrast Volume: Select the Post-contrast Image at the First time point Second Post-contrast Volume: (optional) Select the Post-contrast Image at the Second time point. This will only be used for the Interactive Charting feature. Third Post-contrast Volume: (optional) Select the Post-contrast Image at the Third time point. This will only be used for the Interactive Charting feature. Fourth Post-contrast Volume: Select the Post-contrast Image at the Fourth or Final time point. Use Label Map as ROI: Enable this to select a custom label map input to restrict the segmentation analysis to a specific ROI. Select or Create Output OpenCAD Label Map Output OpenCAD Label Map: Create or select a label map volume node to represent the output of the segmentation. Legend | |: A reference for what type of curves are represented by the colors of the label map. Display Volume Rendering: Enable this to display a 3D Volume Rendering of the Label Map output in the 3D viewer after segmentation. Calculate OpenCAD Label statistics: Enable this to calculate and display statistics of all the First Post-contrast time point voxels highlighted in the output Label Map. Set Advanced Segmentation Parameters Minimum Threshold of Increase: The minimum percentage increase from pre-contrast to the first post-contrast time point for a voxel to be included in the segmentation output and classified. Type I (Persistent) Curve Minimum Slope: The minimum slope of the delayed curve for a voxel to be classified as having a Type I Persistent Curve. Type 3 (Washout) Curve Maximum Slope: The maximum slope of the delayed curve for a voxel to be classified as having a Type III Washout Curve. OpenCAD Label Statistics Statistics Table: Table displaying statistics of all First Post-contrast time point voxels highlighted by the Label Map and grouped according to curve type (Type I, II, and III). Logic is derived from the Label Statistics Module. Chart Statistics: Generates bar graph comparing all labels in the label map based on the statistical criterion specified in the menu. Menu Items: Volume, Curve Type, Voxel Count, Volume mm^3, Volume cc, Minimum Intensity, Maximum Intensity, Mean Intensity, Standard Deviation Ignore Zero label: Ignore the unsegmented region of the First Post-contrast image when displaying bar graph. Interactive Charting Settings Enable/Disable Interactive Charting: Toggle the calculation and display of the percent increase from baseline(pre-contrast intensity) of the voxel under the current mouse pointer location, at each time point. On the X-axis, 0.0 is Pre-contrast, 1.0 is First Post-contrast, ..., 4.0 is Final Post-contrast. Y-axis represents percentage change from baseline intensity.

OpenCAD GUI

Similar Modules

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References

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Information for Developers

Source code: https://github.com/vnarayan13/Slicer-OpenCAD