Tsichian Chao

1
3D Ultrasound Imaging

• Tsi-chian Chao
• Chang-gung University
• 3/21/2003

2
Historic Review for US

• Developed from 1960
• Handy
• Real-time
• Harmless
• Low cost
• The most used imaging equipment
• Noisy
• Positioning

3
The Trends of Medical Imaging

• From 2D to 3D.
• From structural to functional.
• From post-processing to real time processing.
• From harmful to safe.
• From high cost to low cost.
• From analog to digital.

3D/4D ultrasound may be a solution.
4
The processes
Image Acquisition
Registration
User Interface
3D Visualization
Image Processing
5
Image Acquisition
6
Positioning
Step Driver
3D Probe
Free Hand
7
Scan Modes
Parallel Scan Fan Scan Rotate Scan
8
Different Signal Systems
9
Registration
Shift
Rotate
Scale
10
Multi-Window Views
11
Image Processing

• 3D Gaussian Smooth
• Eraser
• 3D Cut
• Undo
• Threshold
• Active Contour

• Rotation
• Lighting
• Brightness
• Contrast
• Movie

12
3D Visualization

• Volume rendering, which takes a set of vexels as
  inputs to generate 3D rendition.
• Surface rendering , which takes a set of surfaces
  as inputs to generate 3D rendition.

13
Pros and Cons for Volume Rendering

• Pros
• can represent tiny and complicated structures.
• has better tolerance on noise.
• provides more information for deeper layers.
• .

• Cons
• does not promise good depth perception.
• are more time-consuming.

14
Ray Casting
15
Volume Rendering- History of Intensity
Intensity
Maximum
Distance to first voxel higher than x
Average
Distance
16
Surface Rendering-Roughness of Surface
Rough Surface Smooth Surface
17
MIP
18
X-ray
19

• Distance

• Composition

20
Composition Surface I Surface II
21
Blood Vessel around Kidney-using Doppler US
22
4D Ultrasound

• To see the movement or behavior of internal
  structures in 3D in real-time.
• Started in conventional real-time 2D
• Good positioning is required for non-stop 3D
  rendering by rapidly moving the acoustic array
  within the transducer housing.

23
Summaries

• From 2D to 3D.
• From structural to functional.
• From post-processing to real time processing.
• From harmful to safe.
• From high cost to low cost.
• From analog to digital.

24
Conclusion

• 3D ultrasound is a handy and low-cost way to help
  diagnosing
• 4D ultrasound is opening a new window for
  motional imaging
• Such real-time imaging systems demand huge amount
  of computing resources
• - can be improved with the improvements of new
  computers