Three-dimensional Quantitative Ultrasound Imaging

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Three-dimensional Quantitative Ultrasound Imaging
Tonydev2_at_aol.com
Devaney_at_ece.neu.edu

• A.J. Devaney
• Department of electrical and computer engineering
• Northeastern university
• Boston, MA 02115

Acoustical Holography, Encyclopedia of Applied
Physics, Americal Institute of Physics 1993.
A.J. Devaney Associates, Inc. 295 Huntington
Ave-suite 208. Boston, MA 02115
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Canonical Imaging Configuration
Quantitative imaging problem Given set of
scattered field measurements
determine object
function
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Data Model

• Nonlinear and nonlocal mapping from object
  function to scattered field
• Mapping from 3D to 2D thus non-unique

Born approximation Rytov approximation
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Born Approximation Imaging
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Analog Two-dimensional Imaging
x,y
x,y
Lens
Object
Image
Lens converts outgoing spherical waves into
incoming spherical waves to produce the image
field.
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Backpropagation Imaging
Backpropagated wavefield
Image
Sensor system aperture
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Backpropagation--the Acoustic Lens
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The backpropagation Algorithm
Scattered wavefield
Object
Sensor system aperture
Backpropagated wavefield
Image
Sensor system aperture
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The backpropagation Point Spread Function
spherical wave
Sensor system aperture
backpropagated spherical wave
Point spread function is the image of a point
(delta function) scatterer
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Point Spread Function
Point spread function
Coherent transfer function
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Improving Image Qualityconfocal Ultrasound
Imaging
Focus-on-transmit and focus-on-receive
Confocal mode rr0
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Plane wave insonification Diffraction tomography
source array
detector array
Partial image
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Image Quality
Point spread function
Transfer function
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Image Processing

• Image processing performed directly on 3D image
  in confocal system
• Image processing performed on raw data in
  diffraction tomography
• (yields filtered backpropagation algorithm)

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Summary and Conclusions

• Single experiment ultrasound imaging of 3D
  objects yields extremely low image quality
• Multiple experiments via confocal scanning or
  diffraction tomography yields high image quality
• Post image processing and algorithm optimization
  can improve image quality
• Born approximation not adequate for strong
  scattering and/or extended objects
• Conventional (optical) measures of image quality
  not appropriate for 3D ultrasound