3D SDK

LEADTOOLS Medical 3D SDK Technology

LEADTOOLS Medical 3D SDK technology simplifies reconstruction techniques for three dimensional visual representations of two dimensional image slices such as MRI and CT stacks. The LEADTOOLS Medical 3D SDK offers many different alternate views of the original data using various 3D reconstruction techniques such as MPR, VRT, MIP and SSD, and projection techniques supporting clipping planes, slab, scale, zoom, camera control, threshold, transparency and image processing.

Examining volumetric data improves the speed of interpretation, recognition and can greatly decreases exam evaluation time for physicians.

3D reconstruction provides visualization of anatomical details which are difficult to evaluate using 2D axial slices alone. Some example scenarios where the various 3D reconstruction techniques would be useful include:

Using Maximum Intensity Projection (MIP), a developer can create an application which makes
it possible for physicians to more quickly and reliably identify pulmonary nodules.
The Minimum Intensity Projection (MinIP) technique, which tends to enhance air spaces, can
be used to create an application for allowing doctors to assess lung structure.
Multi-planar Reconstruction (MPR) is regularly used for examining images of the spine to view
the intervertebral discs which are difficult to see in axial images. A 3D view makes it easier to see
the position of one vertebra in relation to others.
The 3D Volume Reconstruction Technique (VRT), with support for clipping planes, can be used to remove obstructive anatomy from the 3D view. With VRT, transparency can be added to the view which allows bones to be displayed as semi-transparent to transparent for better views of the otherwise concealed anatomy.

LEADTOOLS Medical 3D SDK Technology Features:

Automatically constructs 3D volumes from 2D slices.
Provides five different volume construction techniques:
- MPR: A volume is constructed with Multi-Planar Reconstruction (MPR) by stacking axial slices. Slices of the volume are then cut in a different plane.
- VRT: A volume is constructed with VRT (Volume Rendering Technique) by assigning an opacity range to CT values to provide a clear definition of object outlines or a translucent visualization of objects.
- MIP: A volume is constructed with MIP (Maximum Intensity Projection) by projecting a volume of interest and rendering only the maximum CT values that intersect the viewing plane. MIP reconstructions are useful for angiographic studies.
- MinIP: A volume is constructed with MinIP (Minimum Intensity Projection) by projecting a volume of interest and rendering only the minimum CT values that intersect the viewing plane. MinIP reconstructions are useful for assessing lung structures.
- SSD: A volume is constructed with Shaded Surface Display (SSD) by applying a surface to a structure of interest within the volume. SSD provides a realistic 3D view of objects of interest.
3D rendering is fully integrated with the LEADTOOLS Medical Viewer control.
Draw up to 3 oblique and 3 orthogonal planes when rendering with MPR.
Includes hardware compatibly check utility.
Volume creation and rendering can be completely automated by 3D control.
Draw tags and rulers on the 3D control.
Automated interactive actions can be applied to the 3D volume:
- Window level
- Pan
- Rotate
- Rotate plane
- Move plane
- Move camera
- Rotate camera
- Scale
- Zoom camera
Supports up to 6 orthogonal or oblique clipping planes.
Customize VRT opacity.
Load and save of 3D volume.
Slab feature to render only a portion of the 3D volume.
Invert the volume colors
Load any of the 150+ file formats supported by LEADTOOLS.
Customize features such as the color of the boundaries, boundary box, intersection line, and background.
Apply image processing such as threshold to the rendering.
Camera supports different projection views.
Dynamic rotation.
Save and load object mesh, status and data.
Specify single and double oblique planes to generate an MIP slab.
Orientation cube can be placed anywhere in the rendering area using the mouse.
Flexibility to render various DICOM modalities such as MRI and CT.

Different 3D Volume Types in LEADTOOLS Medical 3D SDK

Using LEADTOOLS Medical 3D SDK technology, developers can create applications to generate 3D volumes using any stack of 2D cross sectional slices. The cross sectional planes must be parallel to each other in order to generate a meaningful 3D volume, so LEADTOOLS provides functions that use DICOM tags to identify, separate and sort volumetric stacks.

Also, the LEADTOOLS Medical 3D SDK provides an interface to define the 3D pixel volume (voxel) and patient orientation for proper measurement, orientation labeling and scaling of the 3D volume and generated oblique and orthogonal slices.

After adding cross sectional slices to the LEADTOOLS Medical 3D SDK engine, developers can switch between different volume types by simply setting a property to desired volume type. The following 3D volumes types are supported by the LEADTOOLS Medical 3D SDK engine:

MPR (Multi Planer Reformatting): MPR is a two-dimensional reformatted image that is reconstructed secondarily in arbitrary planes from the stack of axial image data. In LEADTOLS, this will be rendered as 3 different orthogonal plane views of the 3D volume by default. Users have the option to add up to three additional oblique planes. Additionally, there is an interaction between the position of the 2D and 3D orthogonal planes; so, scrolling in any of the 2D planes will be reflected in the corresponding 3D MPR plane and vice versa.
VRT (Volume Rendering Technique): VRT generates a 3D volume from images of a 3D volumetric data set without explicitly extracting geometric surfaces from the data. With VRT, the optical model is used to map the data values using opacity and color. The advantage of VRT over the Shaded Surface Display (SSD) technique is that VRT uses the volumetric data as a whole and no information is discarded. The mapping of the data to opacity values acts as a classification of the data of interest which allows visualization of the interior of the volume data. LEADTOOLS also uses different 3D rendering techniques to improve the appearance of the 3D volume.
MIP (Maximum Intensity project): With MIP, each voxel along a view line through the volume of data is evaluated, and the maximum voxel value with maximum intensity (i.e. dense structures) is selected for rendering. This provides a better view of hyper dense structures.
MinIP (Minimum Intensity Projection): MinIP is similar MIP, but only the minimum intensity along the view line of the 3D volume data is selected for rendering. This provides a better visualization of low-density structures with respect to surrounding tissues in a volume. For example, MinIP can be used for visualizing the bronchial tree since bronchi, the least dense structures of the thorax, are normally air-filled.
SSD (Shaded Surface Display): SSD is a technique which displays a surface model of the 3D object specified by the ISO threshold.

The LEADTOOLS Medical 3D SDK engine also contains properties and methods for checking the target system's 3D capabilities. Additionally, image load options are provided for efficient resource and memory usage.

3D Projection and Camera Manipulation

The LEADTOOLS Medical 3D SDK camera is functionally equivalent to the human eye and creates a view of a 3D volume. With the LEADTOOLS Medical 3D SDK, the view of the generated 3D volume can be manipulated. Developers can control the LEADTOOLS Medical 3D SDK camera to zoom, pan and rotate in a 3D space, and can set the projection mode to Orthogonal or Perspective. Unwanted or obstructive anatomy can be removed from the view without removing data from the volume by setting the far and near clipping planes.

3D Object Manipulation

The LEADTOOLS Medical 3D SDK provides complete control over 3D object scale, rotation, pan, ISO threshold, voxel opacity and crop.

The LEADTOOLS Medical 3D SDK Container’s Window Level interface provides easy 3D volume data classification by specifying an intensity range of interest using window center and window width. The change in window width (data range) changes the slope to affect the contrast. Changes to the window center alter the data inclusion from hypo dense to hyper dense structures. For better visual representation of an anatomy of interest, the LEADTOOLS Medical 3D SDK also provides functions to set the transfer table values using linear, exponential, logarithmic and sigmoid mapping.

Load and Save 3D Volume and Mesh

For faster 3D volume generation, the LEADTOOLS Medical 3D SDK includes functions to save and reload 3D volumes and 3D meshes to disk. The capability to load and save a 3D volume state including rotation, offset, threshold value, window level and slab parameters is a time saving benefit for physicians that get interrupted while interpreting a study.

LEADTOOLS Medical 3D Control

The LEADTOOLS Medical 3D SDK includes an easy to use Medical 3D Control with built in action tools. The LEADTOOLS Medical 3D Control is designed for rapid development and ease of use. With a few lines of code, the LEADTOOLS Medical 3D Control is easily integrated into the LEADTOOLS Medical Image Viewer Control, providing an advanced medical viewer with features comparable to high-end radiology workstations.

The LEADTOOLS Medical 3D Control provides the following interactive mouse action tools:

Window Level – Control the brightness, contrast and transparency of the 3D object.
Scale 3D Object – Scale the 3D object.
Translate 3D Object –Pan the 3D object.
Alpha – Adjust the alpha factor of LUT curve.
Rotate 3D Object – Rotate the 3D object.
Rotate 3D Camera – Rotate the view of the 3D object.
Translate 3D Camera – Pan the view of the 3D object.
Zoom 3D Camera – Zoom the view of the 3D object.
Translate Plane – Translates the plane in the container.
Rotate Plane - Rotate the planes.

The LEADTOOLS Medical 3D Control is also capable of generating oblique and orthogonal 2D MPR slices. Typically, an MPR view involves displaying three orthogonal plane views of a desired structure at the same time along with a method of navigating the volume. The LEADTOOLS Medical 3D Control allows each generated 2D orthogonal plane (i.e. Axial, Sagittal and Coronal) to be associated with separate LEADTOOLS Image Medical Viewer Control cells. In this configuration, the LEADTOOLS Medical Image Viewer and LEADTOOLS Medical 3D Control work together to provide interactive 3D cursor synchronization and staking from any orthogonal plane.

In addition, several comprehensive applications such as a DICOM Viewer with advanced 3D visualization are provided with project source code for rapid development of web and workstation based medical viewers.

3D Volume Slab

3D volume slabs are special implementations of clipping planes and can be used from any of the six boundary box planes to “cut away” superficial structures to visualize anatomic structures and pathologic conditions within the volume. Crop Box and Crop Slab can be implemented using this feature.

The LEADTOOLS Medical 3D SDK provides interactive slab manipulation from 2D orthogonal MPR planes. When the 3D volume slab feature is enabled, the LEADTOOLS Image Medical Viewer Controlcan display slab boundaries as rectangles with dotted green lines on each 2D MPR (axial, sagittal, and coronal) plane. Using the mouse, users can adjust the clipping planes by dragging the dotted line. Also, white grab handles are provided for the user to adjust the slab rectangle.

The 3D volume slab feature can be used to interactively “cut away” objects, such as removing the abdominal wall, that are obstructing the view.

Single and Double Cut Plane and MIP Slab

The cut-plane feature of the LEADTOOLS Medical 3D SDK allows the user to generate a slice that results from virtually cutting through a stack of images. A double cut-plane consists of two cut-lines (Cross Section Cut Line) that perpendicular to each other. This allows users to evaluate an anatomy of interest by looking at the perpendicular slice of an object from all directions.

Developers can programmatically set the cut line, center of rotation of the cut line, and slice thickness on any arbitrary position in the volume stack. In addition, the LEADTOOLS Image Medical Viewer Controlimplements interactive single and double cut lines. With the LEADTOOLS Medical Image Viewer control, users can interactively move and rotate cut lines using the built-in handles, and can select the slice thickness to view a thick MIP slab.

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