Ultrasound

Demonstration of ultrasound data being manipulated dynamically in an interactive interface.

Author(s): Ed Allard

Quick Start:

The initial view displays raw data from an UltraSound scanner, being warped into the correct view for medical diagnosis. Move and manipulate the data using:

Left Mouse Button: Click and drag to translate the warped ultrasound data.

Middle Mouse : Click and drag to scale.

Start/Stop Scan: Click to toggle playback of ultrasound data frames.

Frame Wheel: Click and drag the wheel to view individual frames and scrub between them. Only enabled when the playback mode is stopped.

Color Doppler: Overlay Color Doppler data indicating blood flow.

M-Mode: Map a radial line over time. (Use slider to select radial lines)

More Details:

This demo shows the O2 system's ability to use texture mapping to perform image warping and manipulation in a medical environment. Due to the shape of many ultrasound scanners, the data obtained from such devices is not in a form that can be directly visualized. Typically, manufacturers of ultrasound machines use expensive "black box" hardware to perform the warping that is needed to correctly visualize the data.

In this demo, raw ultrasound data is used as a texture map on a set of geometry which maps the data correctly for visualization. Since the O2 system is a workstation, and not specialized hardware, we can perform a number of useful manipulations on the data which allow for more refined examinations. Following are descriptions of key features for this demo program.

General Manipulation:

Left Mouse Button: Click and drag to translate the warped ultrasound data.
Middle Mouse: Click and drag to scale.

Start/Stop Scan: Click to toggle playback of ultrasound data frames. When playback is enabled, we are simulating a live data stream coming into the O2 system. Frames are read from disk sequentially and mapped to the geometry. When playback is disabled, individual frames of data can be examined by scrubbing through them using the "Frame" wheel.

Frame Wheel: Click and drag the wheel to view individual frames and scrub between them. Only enabled when the playback mode is stopped.

Color Doppler: When enabled, this will overlay Color Doppler data on top of the normal (echo) data. This color indicates blood flow, with red indicating blood coming toward you, and blue going away from you. This slows down, because we are reading twice the amount of data, and doing real-time alpha blending of 2 texture sources on top of each other.

M-Mode: Enable M-Mode to map one radial line from the Echo data over time. This displays in a rectangle to the left-hand side of the display window. Move the M-Mode slider to change which radial line of the Echo data you are displaying.

Show the benefit of the M-Mode output but moving the M-Mode slider to 83. The valve never quite closes correctly due to a tear, shown by the continuous horizontal black in the middle of the reading over time.

Inter-frame averaging: This displays the average of two sequential frames using alpha blending. Frame averaging is a common way to remove noise from noisy data sets like ultrasound data.

Outline Geometry: overlays a wire-frame representation of the geometry which we are using to perform the image warping

Unwarp Geometry: Shows the unwarped data as it would appear from an ultrasound scanner. This is what the data looks like as we read it in.

Image Processing Features: The image processing features of UltraSound were designed to run on an IMPACT system only . They are not optimized to use O2 system's accelerated image processing. In most cases they run very slowly on O2 system, in some cases they do not work at all. Use these features only on Impact systems.

Other Information:

The full demo scenario: The ultrasound data in this demo shows four valves in a human heart. In this particular case, visualization of the data reveals a tear between the two valves on the right side of the screen. Here's a recommended set of steps to get through all the features in a sensible order:

Start up the demo. As soon as the demo starts, click on the Start/Stop scan button to get the data moving. If you are reading the data off of CD or over the network, the first 12 frames will load fairly slowly, but things will speed up once it's cached. Click and drag (left button) to center the data set.
Explain what's going on. Show what the data actually looks like by clicking on the "Unwarp Geometry" button. Explain that we're using the texture mapping capabilities of the O2 warp it to the proper shape. Unselect "Unwarp Geometry", and then click on "Outline Geometry" to show the geometry we're using to make this happen. Turn this off after a couple of seconds.
Turn on color Doppler data. Explain the significance of this, and also explain that we're using alpha blending to overlay the color data on top of the normal gray-scale data.
Show how useful zooming and panning can be. Since we're using texture mapping, we get smooth, bilinear interpolation when we zoom the data. Zoom way in on the image and note how smooth it is. Zoom back out.
Since we're using a workstation, we can add more interactive diagnostic tools. Turn on M-Mode, and explain how it maps radial data over time. Show the benefit of the M-Mode output by moving the M-Mode slider to 83. The valve never quite closes correctly due to a tear, shown by the continuous horizontal black in the middle of the reading over time. Turn off M-Mode
Turn on the Inter-frame Filter. Explain how this is a simple image processing operation to filter out noise, which is accelerated by the O2 system's hardware.
This doesn't have to be a live data feed. Click on Start/Stop to stop the sequential data playback. It this mode, we could be diagnosing data that was captured and stored to disk. This gives us random access to the data by clicking and dragging the frame wheel - another advantage workstations have over black boxes.

Features:	Industries:	Hardware Options:
IMAGE PROCESSING OPEN GL TEXTURE MAPPING	MEDICAL SCIENTIFIC VISUALIZATION	HARDWARE TEXTURING