A New 3-D Experience
If hearing “3-D” conjures up images of summer movie blockbusters, strange glasses, and Godzilla leaping from the screen, think again. Three-dimensional technology is revolutionizing medical science, with pictures just as dramatic and the stakes much higher.
Until recently, medical imaging could only represent the standard two dimensions, with MRIs and CT scans capturing a projected image of their target, whether an organ, a muscle, or a limb. However, new technology involves not only recording the three spatial dimensions, but also changes that occur as the target moves. The resulting image actually yields a fourth dimension: time.
Multidimensional imaging is not limited to diagnostics. Employed in the operating room, it radically improves surgical precision and safety. The technology can be equally useful in prevention, providing patients with such clear images of their condition that they might be more likely to take the necessary steps to regain or maintain their health.
In addition, the new world of 3-D printing is leading scientists down avenues unimaginable even to their relatively recent forefathers.
At Cedars-Sinai, researchers are making groundbreaking strides using three- and now four-dimensional imaging as well as 3-D printing to obtain better diagnoses and highly effective, targeted treatments for optimal outcomes.
Congenital heart defects affect eight out of every 1,000 newborns. Although many do not require immediate treatment, most cases will require a surgical or catheterbased intervention during their lifetime. Young patients suffering from pulmonary valve stenosis or leaking pulmonary valve have few treatment options. The only available transcatheter valve repair — the Melody valve — is suitable for only 15 percent of cases. For the remaining 85 percent, open-heart surgery has typically been the only option.
Now, Evan Zahn, MD, and Alistair Phillips, MD — codirectors of the Guerin Family Congenital Heart Program — are harnessing 3-D-printing technology to make the less invasive transcatheter valve technology available to more patients.
Two-dimensional images from MRIs or CT scans are sent to a 3-D printer housed in the Women’s Guild Simulation Center for Advanced Clinical Skills. After about three hours’ processing, the printer turns out a model of the patient’s heart. The printer works a bit like an inkjet, but instead of ink, it emits layer upon layer of a thin, clear plastic material. Using the precise specifications of the data, it yields a perfectly reconstructed model of the patient’s heart, with all of its unique features and irregularities. It also provides Zahn, Phillips, and their team with critical spatial information.
“We can work with the model at our desks to figure out exactly how to place a transcatheter valve in patients previously thought to not be candidates for this minimally invasive treatment option,” says Dr. Zahn. “We can literally work out where gaps need be filled and where we might need to use stents and other devices to create an ideal ‘landing zone’ for the valve in these complex patients. “We are so used to making decisions with our eyes, on a screen or on paper,” he adds. “There’s a change that’s hard to describe when you can take something like the heart and hold it in your hands and feel it. You can conceptualize the entire procedure. And doing so in a simulated way allows us to figure out the most intricate details before we actually perform the procedure.” Results are more predictable, allowing new minimally invasive technologies such as transcatheter valve therapy to be extended to a greater number of patients than ever before, says Dr. Zahn.
The Fourth Dimension
The next big thing in imaging will capture the fourth dimension: time.
“We’re currently working on ways to improve our view of the heart, an organ that moves constantly,” says Debiao Li, PhD, director of the Biomedical Imaging Research Institute at Cedars-Sinai.
“Angiograms are currently used for clinical diagnosis of coronary artery disease, but are limited because you can’t gauge exactly how much blood flow has been reduced to the heart, how much of the heart muscle appears to be dead, and how much cardiac function has been affected,” he adds. “To evaluate both heart/ coronary artery anatomy and function, we need to capture the entire heart over the entire heart-beating cycle. MRI is also noninvasive, unlike angiograms. With MRI we don’t need to insert a catheter.”
Dr. Li and his colleagues are among the world leaders in developing this advanced 4-D imaging technology and conducting clinical trials in this field. The functional information the technology yields is thanks to improvements in the fields of hardware, computer science, electrical engineering, and superconducting.
“We are exploring many different advances in technology that can make imaging a central piece of modern medicine for diagnosis and treatment decisions, and to evaluate the effectiveness of a therapy.”