Technical Advances: Radiation-sparing Techniques and Automated AV Tools
Ask cardiac imagers from both sides of the care team—cardiology and radiology—what they see as the most critical advance in imaging technology, and their answers all have one thing in common: dose reduction. “Prospective gating (or step and shoot) is one; iterative reconstruction is another,” according to Charles White, MD, chief of thoracic radiology at the University of Maryland Medical Center in Baltimore. Guy Weigold, MD, director of cardiac CT at Washington Hospital Center, Washington, DC, from the cardiology side, concurs. “CT is a very nice example of how we can use a noninvasive method to get a ton of information on the status of someone’s heart function and disease, and tremendous strides have been made in getting that information with lower and lower radiation exposures,” he says. He, too, cites prospective-triggering techniques and iterative reconstruction as game changers, saying, ”When you look at cardiac CT now, it’s actually one of the most innocuous tests that uses ionizing radiation, and it gives us a wealth of information, compared with, say, a stress test.” Ricardo Cury, MD, director of cardiac imaging at Baptist Hospital of Miami in Florida and of Baptist Cardiac and Vascular Institute, adds, “In 70% of our cases, we are using prospective triggering, which significantly minimizes the radiation dose to levels of 2 or 3 mSv—which is very low, compared with most diagnostic tests. That has been a major achievement.” James Earls, MD, a radiologist with Fairfax Radiological Consultants in Virginia, notes that in the software arena, automated reconstruction of complex datasets has been a boon to imagers’ efficiency and confidence. “The automated software we now have for both MRI and CT has made our jobs much easier in terms of processing and reading these studies—and made us better and more accurate, too. I’ve gone from spending an hour on a cardiac CT case to a few minutes or less,” he says. Weigold agrees, saying, “Automating the process, to make it as consistent as possible from one reader to the next, is key.” All four imagers note that each of the major CT vendors seems to be taking a different path to higher image quality at a lower dose, and Earls speaks for the group when he says, “We’re trying to figure out which is the best way, which is fun.” Cury adds, “Each vendor definitely has its own pathway; they are all facilitating how we acquire these studies in a shorter period of time, with better diagnostic image quality and better spatial resolution, leading to further improvement in the accuracy of CT angiography.” As the technology continues to improve, Weigold takes heart that imaging will facilitate earlier and earlier diagnosis of coronary-artery disease and other cardiac conditions. “Once cardiac disease has progressed, there’s not much you can do about it except bypass,” he says. “A lot of people are still walking around with undiagnosed coronary-artery disease. CT will be the way of the future to pick it up earlier.”