Intravascular Photoacoustic and Ultrasound Imaging: From Tissue Characterization to Molecular Imaging to Image-Guided Therapy

Successful diagnosis and treatment of atherosclerosis demands imaging modalities that can characterize the composition of atherosclerotic plaques, stage the disease, and guide interventional therapy. In this chapter, combined intravascular photoacoustic (IVPA) and intravascular ultrasound (IVUS) imaging is used to address these issues. Based on the difference in optical absorption spectra, lipid-rich tissues can be differentiated using spectroscopic IVPA imaging. Using gold nanoparticles as contrast agent, events happening at the molecular and cellular levels may be visualized in IVPA images. IVPA imaging can also monitor stent deployment during interventional therapy procedures. Design of integrated IVUS/IVPA catheters is discussed. Based on the structural information provided by IVUS images, IVPA images may add further clinically relevant information, helping the management of atherosclerosis.