News | July 01, 2008

Supercomputing Simulations Help Doctors Analyze Fragile Bones

July 2, 2008 — Using a Blue Gene supercomputer, scientists of the Swiss Federal Institute of Technology Zurich (ETH) and the IBM Zurich Research Laboratory demonstrated reportedly the most extensive simulation yet of real human bone structure.

This development could lead to better clinical tools to improve the diagnosis and treatment of osteoporosis.

The early detection of osteoporosis is crucial in order to prevent its progress. This breakthrough simulation could enhance a clinician’s ability to better treat fractures and analyze and detect osteoporotic fragility, in order to take preventative measures before osteoporosis advances in patients, said the researchers.

Osteoporosis is the most widespread bone disease worldwide, affecting 75 million people in the U.S., Europe and Japan alone, and causing health costs second only to those associated with cardiovascular diseases. Literally “porous bone,” this disease is characterized by loss of bone density, resulting in a high risk of fractures, and is a major cause of pain, disability and death in older persons.

In many cases, osteoporosis is not diagnosed until a fracture has occurred, but by then the disease is already in an advanced stage, requiring implants or surgical plates to treat or prevent further fractures.

Today, osteoporosis is diagnosed by measuring bone mass and density using specialized X-ray or computer tomography techniques. Studies have shown, however, that bone mass measurements are only a moderately accurate way to determine the strength of the bone because bones are not solid structures. Inside the compact outer shell, bones have a sponge-like center. This complex microstructure accounts for the bone’s capability to bear loads and therefore represents a better indicator of a bone’s true strength.

Aiming for an accurate, powerful and fast method to automate the analysis of bone strength, scientists of the Departments of Mechanical and Process Engineering and Computer Science at ETH Zurich teamed up with supercomputing experts of IBM’s Zurich Research Laboratory. The method they developed combines density measurements with a large-scale mechanical analysis of the inner-bone microstructure.

Using large-scale, massively parallel simulations, the researchers were able to obtain a dynamic “heat map”
of strain, which changes with the load applied to the bone. This map shows the clinician exactly where and under what load a bone is likely to fracture.

“Knowing when and where a bone is likely to fracture, a clinician can also detect osteoporotic damage more precisely and, by adjusting a surgical plate appropriately, can determine its optimal location,” said Costas Bekas, M.D., of IBM’s Computational Sciences team in Zurich. “This work is an excellent example of the dramatic potential that supercomputers can have for our everyday lives.”

Utilizing the massively large-scale capabilities of the 8-rack Blue Gene /L supercomputer, the research team was able to conduct the first simulations on a 5 by 5 mm specimen of real bone. In just 20 minutes of computing time, the supercomputer simulation generated 90 Gigabytes of output data.

“It is this combination of increased speed and size that will allow solving clinically relevant cases in acceptable time and unprecedented detail,” said professor Ralph Müller, the director of the Institute for Biomechanics at ETH Zürich.

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