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GE's Joe Osani
Steve Refai and Charles Taylor
Steve Refai (left) and Charles Taylor explain the blood pressure gradients from four CAMP simulations of alternate surgical procedures for correcting vascular disease in the legs.
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vascular surgical procedures
Four alternate surgical procedures for correcting vascular disease in the legs are shown. Blood flow for these different procedures can be simulated under different conditions including rest and exercise.

A patient lies on an operating table, awaiting surgery. The problem is vascular disease, the leading cause of death in the western world. Relying on the patients' history and traditional diagnostic-based technology, the doctor has recommended a specific procedure that appears to have the best chance of correcting the problem.

What if the doctor already knew which procedure would provide the best treatment?

Thanks to NASA's High-Performance Computing and Communications (HPCC) Program's Cooperative Research Agreement (CRA), which developed the underlying parallel technology, that concept is reality and health care professionals will soon have the ability before operating to simulate procedures and gauge their benefits to the patientıs long-term health.

HPCC's focus on leading-edge research through the CRA has enabled Centric Engineering Systems and Stanford University's Vascular Surgery Research Laboratory to develop computer simulations that provide noninvasive assistance in the planning of medical procedures, in this case, vascular surgery. The system is referred to as Computer-Aided Medical Planning (CAMP) and is currently also receiving funding through the Advanced Technology Program of the National Institute for Standards and Technology (NIST).

"This is a new concept, a new paradigm in vascular surgery, and that [paradigm] is predictive vascular surgery," stated Dr. Christopher K. Zarins at the 1998 Society for Vascular Surgery (SVS) meeting. At this meeting, four prominent vascular surgeons used software developed by Stanford University and Centric to plan a clinical case in a live demonstration on Silicon Graphics' computers. "When we change the geometry [of blood flow] with a vascular operation, we need to see how it functions not only at rest, but also during exercise," said Dr. Zarins, chief of vascular surgery at Stanford University and president of the Society for Vascular Surgery.

"What Stanford University and Centric are trying to do is get simulation to the point that it can actually be used in a predictive setting in a clinical environment," said Steve Rifai, President of Centric. "And the seeds of that work were done with the CRA. By having high-performance computing available, that vision comes closer to reality."

CAMP
CAMP allows physicians to simultaneously view the results of surgical procedures using different parameters. Among other options, blood flow results and vascular geometry can be viewed with a patient's history and diagnostic data. In this screen, an arterial bypass procedure is shown. 62K size

As an outgrowth of the CRA's concentration on using a highly parallel computing environment for solving critical problems, Rifai notes that now, "we can apply a high-performance computing, multi-physics simulation, which is coupling fluids and structures in analysis of blood flow within the arteries. The idea is that blood flow within the human body is a very complex process. With the fluid mechanics as the first step and fluid structure interaction--what we call multi-physics simulation--you can actually simulate the flow of blood within the arteries of a human being and then, ultimately, the heart."

Predictive medical capabilities (as demonstrated by CAMP) are based upon the creation of computer models that represent the current anatomic and physiological state of a specific patient, then adding mathematical models of the biophysical response of the vascular system to predict possible future states. Using that data, CAMP provides solutions to equations from different procedures based on the physiologic models, thereby producing clinically relevant, three-dimensional qualitative and quantitative data. This enables the doctor to know precisely which procedure will be most effective for any one patient.

"Diagnostic data provides only part of the information needed for surgery planning," noted Dr. Charles Taylor, assistant professor of surgery and director of the Stanford Vascular Surgery Research Laboratory. "The diagnostic imaging data, such as an ultrasound, computed tomography (CAT) scan and magnetic resonance imaging (MRI), provide data about the present state of the patient, but what is really needed for surgical planning is a prediction of the future state of the patient, after surgery. Diagnostic data is a 'what's there' tool. CAMP is a 'what if' tool. It tells you 'what if I do this surgical procedure versus another?' That's why it's very different."

Different may be an understatement. From the initial modeling for vascular applications, the future for CAMP appears unlimited. The methods of predictive modeling can be applied in every field of medicine.

"The methods of predictive modeling will ultimately play a fundamental role in medical practice, just as diagnostic and empirical methods do now," predicted Dr. Taylor. "These tools will be used by physicians around the world, not just at major academic medical centers. High-performance computing software, like that developed by Centric with the support of the CRA, will play a fundamental role in the development of predictive modeling systems used in clinical practice."

CAMP, and the cooperative efforts of Stanford University and Centric that led to its creation, is just one example of the many applications that resulted from the CRA and it may be the one that someday saves your life.

 

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