The early detection of osteoporosis is crucial in order to prevent its progress. This breakthrough simulation could greatly enhance a clinician's ability to better treat fractures and analyse and detect osteoporotic fragility, in order to take preventative measures before osteoporosis advances in patients.
Osteoporosis is the most widespread bone disease worldwide, affecting 75 million people in the United States, 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. (Prevention and Management of Osteoporosis , WHO Technical Report Series, No. 921) Unfortunately, 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 - a highly empirical process. 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 centre. 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 breakthrough 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", explained Dr. Costas Bekas 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.
Ten years ago, the world's most sophisticated supercomputer, called Deep Blue, would not have been able to handle the sheer size of the calculations. Even with sufficient system memory, it would have taken roughly a week of computing time - too long for meaningful impact on diagnosis and treatment.
"It is this combination of increased speed and size that will allow solving clinically relevant cases in acceptable time and unprecedented detail", stated Professor Ralph Müller, the director of the Institute for Biomechanics at ETH Zürich. "Ten years from now, the performance of today's supercomputers will become available in desktop systems, making such simulations of bone strength a routine practice in computer tomography", predicted Dr. Alessandro Curioni, manager of the Computational Sciences group at IBM's Zurich Research Laboratory.
Professor Peter Arbenz of the Institute of Computational Science, who initiated the collaboration among the involved groups, explained that state of the art numerical algorithms were also necessary to solve these extremely large problems in this surprisingly short time. This work is the first fundamental step towards a clinical use of large scale bone simulations. "We are at the beginning of an exciting journey and we need to further continue this line of research in order to achieve this goal", he stated.
In future work, IBM and ETH scientists plan to aim to advance their simulation techniques to go beyond the calculation of static bone strength and to be able to simulate the actual formation of the fractures for individual patients, thereby taking another step towards achieving a fast, reliable and early detection of people with high fracture risk.
The work "Extreme Scalability Challenges in Analyses of Human Bone Structures" by ETH scientists Peter Arbenz, Cyril Flaig, Harry van Lenthe, Ralph Mueller, Andreas Wirth and IBM Zurich Research Lab scientists Costas Bekas and Alessandro Curioni was presented at the IACM/ECCOMAS 2008 Conference in Venice, Italy, on July 2.
The Swiss Federal Institute of Technology Zurich has a student body of 14.000 students from 80 nations. Nearly 360 professors teach mainly in engineering sciences and architecture, system-oriented sciences, mathematics and natural sciences, as well as carry out research that is highly valued worldwide. On a yearly basis, ETH Zurich applies for 80-100 patents and directly supports the founding of up to 20 spin-off companies. Distinguished by the successes of 21 Nobel laureates, ETH Zurich is committed to providing its students unparalleled education and outstanding leadership skills. The Platform of Micro and Nano Sciences is a competence centre at ETH Zurich, connecting the expertise of 43 research groups from nine departments.
The IBM Zurich Research Laboratory is the European branch of IBM Research. This worldwide network of more than 3500 employees in eight laboratories around the globe is the largest industrial IT research organisation in the world. ZRL, which was established in 1956, currently employs some 330 persons, representing more than 30 nationalities. ZRL's spectrum of research activities includes nanoscience, future chip technology, supercomputing, advanced storage and server technologies, security and privacy, risk and compliance, as well as business optimization and transformation. World-class research and outstanding scientific achievements - most notably two Nobel Prizes¬??are associated with the Zurich Lab.
More company news is available in the VMW July 2008 article IBM data sharing technology speeds international collaboration to identify and respond to infectious diseases.