More than 50 years ago, Dr. Charles T. Dotter, a Portland, Oregon radiologist, performed the first angioplasty; not on a coronary artery, but on the leg of an 82-year-old woman whose blocked circulation caused gangrene in her toes. Since the founding of interventional radiology, IRs have constantly collaborated with medical teams to expand the frontiers of modern medicine. We have been able to use advanced imaging to treat increasingly complex conditions, even cardiovascular disease and cancer, less invasively and with unprecedented precision.
From fluoroscopy to ultrasound, CT scans and MRIs—and beyond—we have been able to stay at the forefront of medical innovation. Interventional radiologists and our physician partners are constantly looking ahead to find new ways to reduce medical errors, diminish risks and take advantage of the latest technologies to improve the patient experience and outcomes. IR specialists have helped reduce the length of hospital stays, minimize potential complications and save lives.
Just recently, we were honored to be able to present two separate pilot studies to the Society of Interventional Radiology’s 2018 Annual Scientific Meeting in Los Angeles, and share with our colleagues our cutting-edge research that we hope will move the field of IR even further on its future-forward path.
Each of us, along with our colleagues at Stanford University School of Medicine, focused our research on how we could use the newest technologies: interactive virtual reality to improve treatment planning for highly intricate, complex procedures, and 3D-printing to enhance the training of medical students who have never performed these types of difficult procedures.
Interactive virtual reality brings medical images to life, showing physicians a patient’s unique internal anatomy to help them effectively prepare and tailor a meticulous approach to complicated treatments—in the case presented by Dr. Devcic, splenic artery aneurysm repair. SAA repair can be an extremely challenging procedure, with a complex web of inflow and outflow blood vessels associated with the life-threatening condition. Moreover, the process can be further complicated by the anatomic variations from patient to patient.
Typically, as physicians prepare to perform a procedure like SAA repair, they commonly use a visualization software system that displays images on a standard two-dimensional platform. By contrast, VR takes the patient’s pre-procedural CT scan, and converts it into a 3-D image allowing interventional radiologists to view an individual patient’s arterial anatomy as a hologram, as if it is right in front of them. This provides a look into a patient’s organs and tissues that had not been possible outside of the human body, until now. As a result, the operator is armed with a deeper and intuitive understanding of spatial relationships, such as between an aneurysm and the surrounding arteries. Additionally, physicians can more quickly and thoroughly plan for the equipment and tools they’ll need for a successful outcome.
In Dr. Devcic’s study, three radiologists, using both technologies, independently evaluated 17 aneurysms in 14 patients. We measured the interventional radiologists’ accuracy in identifying inflow and outflow arteries associated with the aneurysms, using each method. In addition to assessing accuracy, the study also asked each radiologist to rank improvements in their confidence on a four-point scale when using VR compared to the standard volume-rendering software.
We found accuracy was similar with both methods, but also found that the physicians’ confidence level improved substantially when they used VR. In examining the 17 inflow and 22 outflow arteries associated with the SAAs, the IRs reported that in 93 percent of the readings they experienced a confidence level of 3 or 4, with 4 being the highest rating.
By preparing for the unexpected, pre-operative planning is possibly the most important step toward successful treatment, so the value of VR cannot be understated. We also hope that future studies may demonstrate that this technology will ultimately help reduce the time needed to perform the treatment, and as a result reduce the amount of radiation and contrast exposure to the patient.
The other study, presented by Dr. Sheu at the Los Angeles meeting, also demonstrated the advantage of using three-dimensional models. In this case, a 3-D printed replica of a patient’s blood vessels was used to train medical students in the IR technique for inserting an ultrasound-guided catheter through the femoral artery in the groin in order to reach internal organs or blood vessels.
Currently, commercially available ultrasound-compatible vascular access models are relatively expensive, with many devices costing $2,000 to $3,000. The models also lack the ability to replicate an individual patient’s anatomy. By contrast, the 3-D printer is able to create a less expensive version that is also customizable to individual patients, and therefore provides medical students a more realistic experience that allows them to better prepare for performing procedures on real patients.
3-D printing technology allowed us to use a tissue-mimicking material that was durable enough to withstand punctures, but still felt realistic. By reproducing a patient’s exact vessels based on a CT scan, the printed model allows trainees to practice with variations in anatomy before they encounter them during a procedure, which may help to lower complication rates.
We tested the effectiveness and comfort level of 32 medical students who were randomized to practice on the commercial model or the 3-D printed model. Almost all the students had never performed a femoral artery access. Prior to the simulation exercise, 73 percent of the 3-D group and 76 percent of the commercial-model group indicated that they did not feel confident in performing the procedure.
After the training, most of the 3-D group and the commercial group trainees agreed that their respective models were easy to use and helpful for practice (93.3 percent and 94.1 percent). In addition, confidence in performing the procedure increased a similar amount for both groups.
Now that we know that the 3-D model is just as effective at training medical students, we can make this simulation experience available to more trainees and potentially improve procedural skills for residents, fellows and attendees. We may also develop 3-D models for other parts of the body with arteries accessed in IR. We foresee this making a positive impact on the world of interventional radiology training.
In both studies, we are proud to be continuing the tradition of interventional radiology pioneering new uses of technology to identify creative solutions to complex medical challenges. We are encouraged by the opportunity to enhance the skills and capabilities of IR professionals, but more importantly, it is gratifying to think that we are ultimately helping to ease the pain and even save the lives of our patients.
