Long-duration and non-invasive photoacoustic imaging of multiple anatomical structures in a live mouse using a single contrast agent

Abstract

Long-duration in vivo simultaneous imaging of multiple anatomical structures is useful for understanding physiological aspects of diseases, informative for molecular optimization in preclinical models, and has potential applications in surgical settings to improve clinical outcomes. Previous studies involving simultaneous imaging of multiple anatomical structures, e.g., blood and lymphatic vessels as well as peripheral nerves and sebaceous glands, have used genetically engineered mice, which require expensive and time-consuming methods. Here, an IgG4 isotype control antibody is labeled with a near-infrared dye and injected into a mouse ear to enable simultaneous visualization of blood and lymphatic vessels, peripheral nerves, and sebaceous glands for up to 3 hours using photoacoustic microscopy. For multiple anatomical structure imaging, peripheral nerves and sebaceous glands are imaged inside the injected dye-labeled antibody mass while the lymphatic vessels are visualized outside the mass. The efficacy of the contrast agent to label and localize deep medial lymphatic vessels and lymph nodes using photoacoustic computed tomography is demonstrated. The capability of a single injectable contrast agent to image multiple structures for several hours will potentially improve preclinical therapeutic optimization, shorten discovery timelines, and enable clinical treatments.

Nanoparticles as Contrast Agents for Preclinical and Clinical Bioimaging

“…Bioimaging is the most widely used application of photoacoustic effect and it has gained success in both preclinical and clinical imaging right from imaging anatomical structures, studying drugs, imaging tumors, imaging cellular structures, imaging neuronal function, and histology. [38][39][40][41][42][43] One of the significant advantages of photoacoustic imaging over fluorescence imaging is that it has a higher resolution to depth ratio thus allowing imaging of deeper biological structures at a greater resolution. 36 Given that different biomolecules have unique chemical compositions and light absorption fingerprints, photoacoustic imaging has been employed to image a wide range of biological structures from DNA to lipids to proteins.…”

Optoacoustic tones generated by nanosecond laser pulses can cover the entire human hearing range

“…Numerous applications of optoacoustics in the medical field use linear absorption for imaging and sensing, such as photoacoustic microscopy and tomography, both in vitro and in vivo [16][17][18][19][20]. Furthermore, sounds were generated by linear absorption of laser in atmospheric water by amplitude-modulation of a constant laser beam using linear absorption [21].…”