Freehand 3D endosonography

Type: Bachelor/Master/Diploma Thesis
Thesis by: N.N.
Advisor: Nassir Navab
Supervision by: Tobias Reichl

Abstract

Gastrointestinal endoscopic 2-D ultrasound is routinely used for diagnosis of the pancreas. However, it is desirable to record 3-D ultrasound volumes from sequences of 2-D images, together with position and orientation information for each frame. Such volumes can be visualised in a more comprehensive and repeatable manner, e.g. viewed from any angle. This work will be done in close collaboration with the gastroenterological department of hospital rechts der Isar. A three-dimensional ultrasound machine and electromagnetic tracking system are available at our research lab at hospital rechts der Isar.

Clinical setting

Gastrointestinal endoscopic ultrasound is routinely used for diagnosis of the pancreas. However, ultrasound as a real-time imaging modality is strongly operator-dependent and interpretation of images is strongly tied to interaction with the endoscopic probe (simply speaking: a surgeon needs to know how he moved the probe, in order to interpret the images). Thus, it is desirable to record three-dimensional ultrasound volumes, which can be visualised in a more comprehensive and repeatable manner, and e.g. be viewed from any angle.

Task

A three-dimensional ultrasound volume is to be reconstructed from a sequence of two-dimensional images together with position and orientation information for each frame. Methods for reconstruction of the three-dimensional volume need to be evaluated. In particular due to tracking errors and local deformation, the spatial location of the ultrasound images might need to be corrected or optimised. Under the assumption that the endoscope does not jump too far between consecutive frames, the spatial coherence of the image sequence might also be able to be exploited.

Methods

Methods have been proposed for three-dimensional ultrasound mosaicking [Wachinger2007], simultaneous registration [Wachinger2009], and volume reconstruction [Karamalis2009]. Endoscopic ultrasound data will be provided by our clinical collaborators, and an electromagnetic tracking system is available at our research lab at hospital rechts der Isar.

Literature

• Karamalis, A.; Wein, W.; Kutter, O. & Navab, N. Fast hybrid freehand ultrasound volume reconstruction Proceedings of SPIE Medical Imaging 2009: Visualization, Image-Guided Procedures, and Modeling, 2009, 7261, 726114 SPIE
• Wachinger, C. & Navab, N. Similarity metrics and efficient optimization for simultaneous registration. Computer Vision and Pattern Recognition, 2009. CVPR 2009. IEEE Conference on, 2009, 667-674
• Wachinger, C. & Navab, N. Alignment of viewing-angle dependent ultrasound images. Proceedings of Int'l Conference on Medical Image Computing and Computer-Assisted Intervention (MICCAI), 2009, 5761, 779-786
• Housden, R. J.; Gee, A. H.; Treece, G. M. & Prager, R. W. Sensorless reconstruction of unconstrained freehand 3D ultrasound data. Ultrasound in Medicine & Biology, 2007, 33, 408-419
• Gee, A.; Prager, R.; Treece, G. & Berman, L. Engineering a freehand 3D ultrasound system Pattern Recognition Letters, 2003, 24, 757 - 777