Surface Mesh-Based Ultrasound Simulator For Spinal Interventions
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Authors
Bartha, Laura
Date
2013-07-24
Type
thesis
Language
eng
Keyword
Simulation , Surface Mesh , Training , Ultrasound
Alternative Title
Abstract
Purpose: Ultrasound is prevalent in image-guided therapy as a safe, inexpensive,
and widely available imaging modality. However, extensive training in interpreting
ultrasound images is essential for successful procedures. An open-source ultrasound
image simulator was developed to facilitate the training of ultrasound-guided spinal
intervention procedures, thereby eliminating the need for an ultrasound machine from
the phantom-based training environment. Methods: Anatomical structures and surgical
tools are converted to surface meshes for data compression. Anatomical data
is converted from segmented volumetric images, while the geometry of surgical tools
is available as a surface mesh. The pose of the objects are either constants or live
measurements from a pose tracking device. Intersection points between the surface
models and the ultrasound scan lines are determined with a binary space partitioning
tree. The scan lines are divided into segments and filled with grey values determined
by an intensity calculation accounting for material properties, reflection, and attenuation
parameters defined in a configuration file. The scan lines are then converted to
a regular brightness-mode ultrasound image. Results: The simulator was tested in a
tracked ultrasound imaging system, with a mock transducer tracked by an Ascension
TrakStar electromagnetic tracker, on a spine phantom. A mesh model of the spine
was created from CT. The simulated ultrasound images were generated at a speed
of 50 frames per second, and a resolution of 820 x 616 pixels on a PC with a 3.4
GHz processor. A human subject trial was conducted to compare the learning performance of novice trainees with real and simulated ultrasound in the localization of
the facet joints of a spine phantom. With 22 participants split into two equal groups
and each participant localizing 6 facet joints, there was no statistical difference in the
performance of the two groups, indicating that simulated ultrasound could indeed
replace the real ultrasound in phantom-based ultrasonography training for spinal
interventions. Conclusion: The ultrasound simulator was implemented and integrated
into the open-source Public Library for Ultrasound (www.plustoolkit.org) and
SlicerIGT (www.SlicerIGT.org) toolkits
Description
Thesis (Master, Computing) -- Queen's University, 2013-07-24 12:28:57.201
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