Researchers at Johns Hopkins developed a new imaging technique that allows them to view the vasculature of experimental animals in great detail. Research into a variety of conditions, from vascular disease to cancer, relies on acquiring images of the vasculature in animals, with a variety of imaging techniques available. These researchers have created a unique blend of polymer contrast agents which can be perfused into the vasculature, permitting imaging using optical microscopy, MRI, and computed tomography (CT). The combined imaging creates highly detailed tissue maps of the vasculature at different spatial scales, revealing insights into cell types and tissue structures that surround blood vessels.
Blood vessels play a role in many disease states, and researchers have spent years developing and fine-tuning imaging techniques that let us view these complex and winding structures. This includes imaging within our human bodies and also within experimental animals to increase our understanding of various diseases. There are numerous techniques available to image blood vessels, such as MRI or CT scans, and they all provide slightly different information and have different strengths and weaknesses.
“Usually, if you want to gather data on blood vessels in a given tissue and combine it with all of its surrounding context like the structure and the types of cells growing there, you have to re-label the tissue several times, acquire multiple images and piece together the complementary information,” said Arvind Pathak, a researcher involved in the study. “This can be an expensive and time-consuming process that risks destroying the tissue’s architecture, precluding our ability to use the combined information in novel ways.”
This new technique allows the same sample to be imaged using optical microscopy, CT imaging and MRI imaging. The approach relies on a combination contrast agent, which the researchers have called VascuViz. It consists of a blend of a fluorescent MRI contrast agent called Galbumin-Rhodamine and a CT contrast agent called BriteVu. The relatively inexpensive polymer blend rapidly sets when perfused into the vasculature, allowing both the micro- and macro-vasculature to be imaged.
The new imaging technique allows the researchers to assemble complex visualizations of the vasculature and surrounding anatomy, providing more information than could be achieved by using just one imaging modality. “Now, rather than using an approximation, we can more precisely estimate features like blood flow in actual blood vessels and combine it with complementary information, such as cell density,” said Akanksha Bhargava, another researcher involved in the study.
See a video about the technique below.
Study in Nature Methods: VascuViz: a multimodality and multiscale imaging and visualization pipeline for vascular systems biology