Clinical Applications of Advanced Ultrasound Imaging

Ultrasound is a noninvasive imaging modality that provides anatomical and functional information of various human body areas. It is one of the most widely used imaging modalities worldwide, with frequent use in oncology. Novel ultrasound techniques, such as elastography and contrast-enhanced ultrasound, have evolved and have led to new clinical applications beyond conventional anatomical imaging with conventional ultrasound or blood flow assessment using Doppler ultrasound. Contrast-enhanced ultrasound (CEUS) uses microbubbles as a contrast medium, and specific contrast-enhanced ultrasound techniques have been developed, making CEUS an extremely sensitive imaging modality. Classic microbubbles remain strictly intravascular due to their size and can be detected down to the capillary level. Together with the most recent techniques (super-resolution imaging), bubbles even allow for an extremely high spatial resolution ultrasound imaging beyond the wavelength barrier. This chapter within Recent Results in Cancer Research Under Molecular Imaging in Oncology provides an overview of current applications in humans. Since specific microbubbles are not yet available as commercial products and their wide clinical use is still limited, results of first experiences with molecular ultrasound imaging in humans are presented. Furthermore, to give an overview in a broader sense-not only of molecular ultrasound imaging but also of contrast-enhanced ultrasound for molecular or specific diagnosis-also related studies with nonspecific, commercial ultrasound contrast agents are briefly described within the field of molecular diagnosis and monitoring of targeted therapies in oncology. Furthermore, first experiences in humans with super-resolution ultrasound imaging as a potential breakthrough technique are presented.