volshow

Display a chest CT volume saved as a directory of DICOM files. The volume is part of a data set containing three CT volumes. The size of the entire data set is approximately 81 MB.

Run this code to download the data set from the MathWorks® website and unzip the folder.

zipFile = matlab.internal.examples.downloadSupportFile("medical","MedicalVolumeDICOMData.zip");
filepath = fileparts(zipFile);
unzip(zipFile,filepath)

The dataFolder folder contains the downloaded CT scan used by this example.

dataFolder = fullfile(filepath,"MedicalVolumeDICOMData","LungCT01");

Create a medical image volume object that contains the image data and spatial referencing information for the CT volume.

medVol = medicalVolume(dataFolder);

Specify a custom colormap and transparency map that highlight the ribcage.

alpha = [0 0 0.72 1.0];
color = [0 0 0; 186 65 77; 231 208 141; 255 255 255] ./ 255;
intensity = [-3024 100 400 1499];
queryPoints = linspace(min(intensity),max(intensity),256);
alphamap = interp1(intensity,alpha,queryPoints)';
colormap = interp1(intensity,color,queryPoints);

Display the volume with the custom display settings. Specify the cinematic rendering style, which displays the volume with realistic lighting and shadows. The volshow object function displays the volume in the patient coordinate system defined by the spatial properties of medVol. The axes display indicators label the inferior/superior (S), left/right (L), and anterior/posterior (P) anatomical axes.

volshow(medVol,Colormap=colormap,Alphamap=alphamap,RenderingStyle="CinematicRendering")

Pause to apply all of the cinematic rendering iterations before updating the display in Live Editor.

pause(3.5)
drawnow

Optionally, you can clean up the viewer window by using the 3-D Scissors tool, , to remove the patient bed. For a detailed example, see Remove Objects from Volume Display Using 3-D Scissors. This image shows the final volume display after removing the patient bed and rotating to view the anterior plane.

Display a chest CT volume saved as a directory of DICOM files. The volume is part of a data set containing three CT volumes. The size of the entire data set is approximately 81 MB.

Run this code to download the data set from the MathWorks® website and unzip the folder.

zipFile = matlab.internal.examples.downloadSupportFile("medical","MedicalVolumeDICOMData.zip");
filepath = fileparts(zipFile);
unzip(zipFile,filepath)

The dataFolder folder contains the downloaded CT scan.

dataFolder = fullfile(filepath,"MedicalVolumeDICOMData","LungCT01");

Create a medical volume object that contains the image data and spatial referencing information for the CT volume. The Voxels property contains a numeric array of the voxel intensities. The VoxelSpacing property indicates that the voxels are anisotropic, with a size of 0.7285-by-0.7285-by-2.5 mm in the patient coordinate system.

medVol = medicalVolume(dataFolder)

medVol = 
  medicalVolume with properties:

                 Voxels: [512×512×88 int16]
         VolumeGeometry: [1×1 medicalref3d]
           SpatialUnits: "mm"
            Orientation: "transverse"
           VoxelSpacing: [0.7285 0.7285 2.5000]
           NormalVector: [0 0 1]
       NumCoronalSlices: 512
      NumSagittalSlices: 512
    NumTransverseSlices: 88
           PlaneMapping: ["sagittal"    "coronal"    "transverse"]
               Modality: "CT"
          WindowCenters: [88×1 double]
           WindowWidths: [88×1 double]

Display the volume in the intrinsic coordinate system by using volshow with the numeric array from the Voxels property as input. The intrinsic coordinate system assumes cubic voxels with uniform dimensions. Therefore, this anisotropic volume appears squished. The x-, y- and z-axis display markers align with the first, second, and third dimensions of the image array, respectively, rather than the x-, y-, and z-axes of the patient coordinate system.

vol = volshow(medVol.Voxels,RenderingStyle="MaximumIntensityProjection");