Multimodal Integration of Medical Ultrasound

Ultrasound is a popular, cost-effective and§non-invasive medical imaging modality. If an§ultrasound probe is equipped with a 3D position§sensor, the acquired images can be obtained in their§spatial context, a technique commonly denoted 3D§freehand ultrasound.§Combining ultrasound and a pre-operative Computed§Tomography (CT) scan of the same patient can be§beneficial for a number of clinical applications. The§core of this thesis is the development of novel§methods for fully automatic alignment (i.e.§registration) of 3D freehand ultrasound and CT data,§based on the image content and the physical§properties of both modalities.§Furthermore, we introduce new techniques for 3D§freehand ultrasound calibration and reconstruction,§as well as visualization of fused CT and ultrasound data.§Two clinical applications are investigated in detail.§We use a designated version of an automatic§registration algorithm to integrate diagnostic§ultrasound into radiation treatment planning for head§and neck cancer.§Different methods are applied, in the context of§treating liver and kidney metastases, for fusing CT§with both diagnostic and interventional ultrasound of§the abdomen. While diagnostic fusion helps doctors to§assess indeterminate lesions in those organs,§interventional fusion using our techniques allows for§advanced image-guided navigation, in particular, for§needle biopsies and radio-frequency ablations.