Fantastic voyage
UCI computer scientists take us inside the biological byways of humans and animals.

By GARRY ROBBINS
The Orange County Register

MULTIMEDIA

A virtual tour through a pig's blood vessels

IRVINE — Remember the old sci-fi movie “Fantastic Voyage”?

Hollywood miniaturized a medical team and put them in a miniaturized submarine, which was then injected into a scientist’s bloodstream so they could try to destroy a blood clot in the brain.

	Mathematical simulation of the vascular system of a heart. Animation: Thomas Wischgoll, Biomedical Engineering Department, uci

Joerg Meyer conjures up similar visuals, though not for cheap entertainment. The UC Irvine computer scientist creates virtual tours of the blood stream and other bio-pathways, giving physicians and medical researchers a sense of perspective they otherwise wouldn’t have.

Meyer’s latest creation: a virtual tour of a pig’s blood vessel. The animation will be on display Friday when UCI opens it’s newest research center, the California Institute for Telecommunications and Information Technology, or CAL(IT)2.

We discussed the animation with Meyer while he was preparing to do more work in the center’s Graphics, Visualization and Imaging Technology (GRAVITY) lab.

Question: So why did you create a computer animation of a blood vessel in a pig’s heart?

Answer: Our hope is that this kind of animation will give us a better understanding of the underlying causes of coronary heart disease.

	MEYER

A pig’s heart is as close as we can get anatomically to the heart of humans, and we can cast pig hearts more easily than we can do it with people. We also can create particles that move through the virtual blood stream like red blood cells and platelets. We’ve put them in our animations.

We use wireless game controllers to navigate through the blood vessels, past the cells and platelets. It’s a way of flying through the model, like the submarine in “Fantastic Voyage”.

Q: What do you learn from such virtual trips?

A: In our fly-throughs, we are trying to identify topological structures that are more prone to accumulate plaques, such as sharp angles or narrow pathways that can become a bottleneck. There is a common belief that heart attacks usually arise from arteries being clogged up by atherosclerotic plaque.

Q: How do “cast” a heart?

A: A cast of a pig’s heart is made by extracting the heart from the body and replacing the blood with a contrast agent. The agent makes the blood vessels clearly visible in a CT scan. A scanner produces a sequence of cross-sectional images. It looks as if we cut the heart in thin slices, but we are not actually cutting it. We just scan it electronically with X-rays. Then we stack all the image slices (sometimes more than 100) to obtain a complete model of the heart. Once we have it in the computer, we can electronically remove the muscle tissue so that we can clearly see the vessels.

Q: Will this approach allow scientists to delve ever deeper into the body?

A: At Cal(IT)2, we are going to have a new BioMEMS lab where we can develop nanoscale medical devices that we can implant and later possibly inject into the blood stream and deliver drugs directly to the organ where they are needed. As humans, we might not physically be able to go there, but we can build small robots and little biocompatible machines we can control from the outside, and that can perform certain functions inside the body.

Q: What are some of the obstacles you face in advancing this technology?

A: The resolution of the images is still a problem. Our medical scanners are not good enough to show us the small capillary vessels. Therefore, we need to develop mathematical models to simulate them. Also, the enormous amount of data that we get from a single scan of a heart is still a challenge. Even with supercomputing facilities, such as the San Diego Supercomputer Center and our partner Cal-(IT)2 division at UC San Diego, we are not able to process all the data as fast as we would like. So we are developing smarter software strategies, such as hierarchical data storage and real-time data compression, to overcome these hurdles.

The intelligence is not in the hardware, it is in the software.

Q: Many college students are obsessed with computer games, like “Grand Theft Auto: San Andreas”. Can you learn anything from these games and apply it to your work?

A: Absolutely. The UCI research group has realized that the gaming industry is really one of the driving forces of the visualization community.

Affordable, commodity PC graphics cards have enabled us to do things now on a PC that we could only dream of two years ago, and that were not even possible on the latest supercomputers. For this reason, Cal(IT)2, has established a new Game Culture Lab. I am personally involved and very interested in the game culture, because we want to disseminate the results of our research not only to other researchers, but of course we want the public to benefit from our work.

Imagine you turn the Fantastic Voyage into a game where high-school students can interactively navigate through a heart on their PCs in the classroom, and, without knowing it, learn about the different types of blood cells that they encounter. One student could play the role of a white blood cell and form a strategy with others to attack an enemy, say a virus. That is what we are currently working on. All we need to do is change the user interface and develop strategies to deliver our huge data sets in a reduced form over the Internet to a PC in the classroom.

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