D I G I TA L
H E A LT H
I n the industrialized nations, the quality of medical care has reached a very high level. Even so, not every patient receives the right treatment. In a 2003 report, for example, the Professional Health Council estimated that there are 40,000 instances of malpractice in Germany every year. But experts believe that’s only the tip of the iceberg. According to a 1999 study by the Bonn University Medical Center, the incidence of medical errors in Ger- many may be as high as 400,000 cases, many of which remain undetected — and things are no better in other countries. Also in 1999, the Institute of Medicine (IOM) in Washington, D.C., published a report titled “To Err is Human,” according to which more people in the U.S. die from medical errors every year than from traffic accidents. These estimates are based on two studies and range from 50,000 to 100,000 fatalities. The IOM report prompted President Clinton to call for massive investments in information technology for the healthcare system, especially in software for improving safety in medications, diagnosis and therapy.
The potential for improvement is im- mense. For example, better communications could substantially reduce the incidence of wrong medications prescribed in hospitals — an area in which Siemens’ Soarian software (Pictures of the Future, Spring 2005, p. 28 and 58), in conjunction with electronic pa- tient files, can help. Software furthermore helps improve the quality of diagnoses, for in- stance in the early detection of cancer (p. 67). On the therapeutic side, intelligent systems
The usefulness of computer technology is not limited to manag- ing patient data or to diagnostic procedures. Software-based systems can also aid physicians performing treatment.
Computers in Therapy
are especially useful in treating cardiovascular diseases, the leading cause of death in indus- trialized nations. In the U.S. for instance, one person dies of cardiovascular disease every 33 seconds. According to the Center for Dis- ease Control in Atlanta, such diseases cost the American healthcare system $351 billion in 2003. Many of these disorders are caused by pathological narrowing of blood vessels near the heart. To treat these, cardiologists use a flexible catheter, which they introduce into a blood vessel and maneuver toward the heart with the aid of a thin guide wire. Then the
physician expands the narrowed section by inflating a balloon and stabilizes the vessel by implanting a stent — a tubular prop. To help the cardiologist see where to guide the catheter, a contrast agent is injected into the patient that makes blood vessels visible in the X-ray image displayed on a monitor by an an- giography system.
In more difficult procedures, the wire must be introduced into very small branches of the coronary arteries, or positioned with millime- ter precision at a particular location. “Manual control of guide wires can be extremely com-
plicated in vessels with intricate branches,” says Arne Westphal, marketing manager for Cardiology at Siemens Medical Solutions (Med). For this tricky task, Siemens has worked with Stereotaxis, Inc., its cooperative partner in the U.S., to develop an angiogra- phy system based on the use of magnetic navigation. In the Axiom Artis dFC MN, for in- stance, two refrigerator-sized rotatable mag- nets create controllable magnetic fields within the patient that navigate a magnetic- tipped guide wire or catheter to its destina- tion. Using a joystick, the cardiologist can control the magnets and thus move the mag- netic field with millimeter precision. This guides the wire, which can also be advanced or withdrawn by means of a small motor. The magnetic control system guides the wire around even the sharpest curves.
Magnetic guidance can steer a catheter around even the sharpest curves.
“This substantially reduces radiation exposure to both the doctor and the patient — for the latter by some 50 to 80 percent — in compar- ison with procedures without magnetic con- trol,” explains Dr. Sabine Ernst, a St. Georg cardiologist. She performs the operation from an adjacent control room and no longer has to stand beside the patient in the cath lab throughout the procedure.
totally blocked site in a vessel. The cardiac surgeon then proceeds to install a bypass around the blockage. “But even in a vessel that seems totally occluded there is still a small open passage,” Westphal explains. Even a highly skilled physician would have diffi- culty in locating this tiny passage, but the
software-controlled searches it out.
Autopilot to the Heart. Automatic naviga- tion is an alternative to the joystick. In this ap- proach, angiography is preceded by tomogra- phy. A three-dimensional image of the heart
In certain patients, cardiologists may wish to avoid using X-rays altogether. For instance such an option would be beneficial to chil- dren with congenital heart defects who have already undergone multiple catheterizations
To position catheters with millimeter-precision, physicians can now simply use a joystick — thanks to the new method of magnetic navigation (left images). An additional device now also makes it possible to obtain 3D images during surgery (right).
Cardiologists at St. Georg General Hospital in Hamburg, Germany, have been testing the magnetic navigation system for two years. Their clinical research is focused on using catheter ablation (vaporization) in treating disturbances in the normal rhythm of the heartbeat. This approach uses a special catheter with a metallic tip that can be heated to about 60 degrees Celsius to obliterate cells in the heart muscle. The motorized naviga- tion system assures positioning with millime- ter precision. During the ablation procedure, additional X-ray control is often unnecessary.
is then generated from the tomograms using syngo Inspace 3D software, developed by Siemens with its partner HipGraphics, of Bal- timore. All the physician now needs to do is mouse-click on the destination location, and the catheter automatically advances to the se- lected spot.
There are also other potential applications. “Some of our customers are even looking at the possibility of using the system to keep pa- tients from having to undergo bypass sur- gery,” explains Westphal.
Normally the guide wire stops at an almost
According to a study by the National Radi- ological Protection Board in the UK, one in every 1,000 children will develop a tumor within five years after a catheterization. Re- searchers are therefore experimenting with magnetic resonance (MR) tomography as an alternative imaging method for cardiac catheterization that doesn’t use radiation.
Magnetic resonance imaging is especially well suited to displaying soft tissues. Unlike X- ray angiography, which creates a projection image, MR creates a series of sectional im- ages. To enable the cardiologist to observe
Pictures of the Future | Fall 2005