Live Fetoscopic Visualization of 4D Ultrasound Data

149 Pages·2012·23.32 MB·English

Live Fetoscopic Visualization of
4D Ultrasound Data
DISSERTATION
zur Erlangung des akademischen Grades
Doktor der technischen Wissenschaften
eingereicht von
Andrej Varchola
Matrikelnummer 0728357
an der
Fakultät für Informatik der Technischen Universität Wien
Betreuung: Ao.Univ.-Prof. Dipl.-Ing. Dr.techn. Eduard Gröller
Diese Dissertation haben begutachtet:
(Ao.Univ.-Prof. Dipl.-Ing. (Univ.-Doz. Dipl.-Ing. Dr.techn.
Dr.techn. Eduard Gröller) Miloš Šrámek)
Wien, 27.09.2012
(Andrej Varchola)
Technische Universität Wien
A-1040 Wien � Karlsplatz 13 � Tel. [phone] � www.tuwien.ac.at
Live Fetoscopic Visualization of
4D Ultrasound Data
DISSERTATION
submitted in partial fulfillment of the requirements for the degree of
Doktor der technischen Wissenschaften
by
Andrej Varchola
Registration Number 0728357
to the Faculty of Informatics
at the Vienna University of Technology
Advisor: Ao.Univ.-Prof. Dipl.-Ing. Dr.techn. Eduard Gröller
The dissertation has been reviewed by:
(Ao.Univ.-Prof. Dipl.-Ing. (Univ.-Doz. Dipl.-Ing. Dr.techn.
Dr.techn. Eduard Gröller) Miloš Šrámek)
Wien, 27.09.2012
(Andrej Varchola)
Technische Universität Wien
A-1040 Wien � Karlsplatz 13 � Tel. [phone] � www.tuwien.ac.at
Erklärung zur Verfassung der Arbeit
Andrej Varchola
Franzensbrückenstr. 13/22, 1020 Wien
Hiermit erkläre ich, dass ich diese Arbeit selbständig verfasst habe, dass ich die verwende-
ten Quellen und Hilfsmittel vollständig angegeben habe und dass ich die Stellen der Arbeit -
einschließlich Tabellen, Karten und Abbildungen -, die anderen Werken oder dem Internet im
Wortlaut oder dem Sinn nach entnommen sind, auf jeden Fall unter Angabe der Quelle als Ent-
lehnung kenntlich gemacht habe.
(Ort, Datum) (Unterschrift Verfasser)
i
Acknowledgements
This thesis was shaped and influenced by many people. I thank everyone for their support and
help. I am especially grateful to my supervisor Meister Eduard Gröller for his guidance dur-
ing last three years of my doctoral studies. I would also like to express my gratitude to Stefan
Bruckner, for all discussions that were essential for making decisions during the development
of the methods which are discussed in this thesis. This work is a result of a collaboration with
GE Healthcare (Kretztechnik, Zipf, Austria). It could not have been completed without sup-
port of domain experts that were actively involved in the development of all presented ideas and
achievements. I especially thank to Gerald Schröcker and Daniel Buckton. I also like thank
all clinical experts from GE Healthcare, especially Marcello Tassinari who helped me with the
evaluation of results presented in this work. Many appreciation goes to all of my colleagues at
the Institute of Computer Graphics and Algorithms at the Vienna University of Technology for
a productive environment. I am also thankful to students that I was supervising, in particular
Johannes Novotny, Michael Seydl, Daniel Fischl. Furthermore, I thank my former colleagues
from the Comission for Scientific Visualization of the Austrian Academy of Sciences. Special
thanks to Miloš Šrámek, who introduced me to the exciting field of medical visualization. Spe-
cial thanks also to Leonid Dimitrov, who engaged me in many scientific discussions and helped
me also with the careful proofreading of this thesis. My gratitude goes also to many friends and
family members who supported me during the past years of my studies.
iii
Abstract
Ultrasound (US) imaging is due to its real-time character, low cost, non-invasive nature, high
availability, and many other factors, considered a standard diagnostic procedure during preg-
nancy. The quality of diagnostics depends on many factors, including scanning protocol, data
characteristics and visualization algorithms. In this work, several problems of ultrasound data
visualization for obstetric ultrasound imaging are discussed and addressed.
The capability of ultrasound scanners is growing and modern ultrasound devices produce
large amounts of data that have to be processed in real-time. An ultrasound imaging system is in
a broad sense a pipeline of several operations and visualization algorithms. Individual algorithms
are usually organized in modules that separately process the data. In order to achieve the required
level of detail and high quality images with the visualization pipeline, we had to address the flow
of large amounts of data on modern computer hardware with limited capacity. We developed a
novel architecture of visualization pipeline for ultrasound imaging. This visualization pipeline
combines several algorithms, which are described in this work, into the integrated system. In the
context of this pipeline, we advocate slice-based streaming as a possible approach for the large
data flow problem.
Live examination of the moving fetus from ultrasound data is a challenging task which re-
quires extensive knowledge of the fetal anatomy and a proficient operation of the ultrasound
machine. The fetus is typically occluded by structures which hamper the view in 3D rendered
images. We developed a novel method of visualizing the human fetus for prenatal sonography
from 3D/4D ultrasound data. It is a fully automatic method that can recognize and render the
fetus without occlusion, where the highest priority is to achieve an unobstructed view of the fetal
face. Our smart visibility method for prenatal ultrasound is based on a ray-analysis performed
within image-based direct volume rendering (DVR). It automatically calculates a clipping sur-
face that removes the uninteresting structures and uncovers the interesting structures of the fetal
anatomy behind. The method is able to work with the data streamed on-the-fly from the ultra-
sound transducer and to visualize a temporal sequence of reconstructed ultrasound data in real
time. It has the potential to minimize the interaction of the operator and to improve the comfort
of patients by decreasing the investigation time. This can lead to an increased confidence in the
prenatal diagnosis with 3D ultrasound and eventually decrease the costs of the investigation.
Ultrasound scanning is very popular among parents who are interested in the health condition
of their fetus during pregnancy. Parents usually want to keep the ultrasound images as a memory
for the future. Furthermore, convincing images are important for the confident communication
of findings between clinicians and parents. Current ultrasound devices offer advanced imaging
capabilities, but common visualization methods for volumetric data only provide limited visual
v
fidelity. The standard methods render only images with a plastic-like appearance which do not
correspond to naturally looking fetuses. This is partly due to the dynamic and noisy nature of the
data which limits the applicability of standard volume visualization techniques. In this thesis,
we present a fetoscopic rendering method which aims to reproduce the quality of fetoscopic
examinations (i.e., physical endoscopy of the uterus) from 4D sonography data. Based on the
requirements of domain experts and the constraints of live ultrasound imaging, we developed a
method for high-quality rendering of prenatal examinations. We employ a realistic illumination
model which supports shadows, movable light sources, and realistic rendering of the human
skin to provide an immersive experience for physicians and parents alike. Beyond aesthetic
aspects, the resulting visualizations have also promising diagnostic applications. The presented
fetoscopic rendering method has been successfully integrated in the state-of-the-art ultrasound
imaging systems of GE Healthcare as HDlive imaging tool. It is daily used in many prenatal
imaging centers around the world.