When it comes to the interpretation of coronary CT angiography (CCTA) studies, the bywords are speed and efficiency. There are, however, multiple routes to those ends, as witnessed by the different approaches of three veteran CCTA practitioners. All three radiologists interviewed by Radiology Business Journal use, to a greater or lesser extent, advanced visualization tools to interrogate the images, and all report that radiology plays a key role in the acquisition and interpretation of the studies at their respective institutions.
Old-school Approach The department of radiology at the Medical University of South Carolina, Charleston, acquires the CCTA study using two dual-source CT scanners, one in the emergency department and one in the newly opened Heart and Vascular Center. The university takes a collaborative approach to the interpretation of the images, so radiology partners with cardiologists on collaborative readings, but radiology generates the reports.
Schoepf has been reading CCTA for 10 years, starting with an EBCT scanner and less-than-ideal studies generated by a four-slice scanner and rudimentary software tools. “I have gone through a very long process of interpreting these and, for the longest time, we didn’t have any fancy tools available,” he says. “I learned it the hard way, reading from my transverse sections—which, in the initial years, was all that we had—and I am still doing that. I stick with my transverse sections for as long as I can, and only if I notice that I am getting myself in trouble do I turn to the more sophisticated tools.”
Schoepf’s advice to those who want to begin interpreting CCTA is to develop a system for approaching these cases in the most time-efficient way before starting to explore the advanced visualization tools. “I hear terrible numbers out there,” he reports. “Some people take an hour for the interpretation of a CCTA study; like that, you can never be effective.”
Schoepf uses a three-step approach to CCTA, depending on the complexity of the case, but he always begins with the transverse sections for a sense of the overall quality of the dataset. He says, “I become familiar with potential artifacts that may pose diagnostic pitfalls; I can detect incidental pathology in the lung fields or in the mediastinum, which would be almost impossible to diagnose with more advanced visualization software; and I tune my eye in to those areas with atherosclerotic plaque. If I am dealing with a case that has no (or almost no) atherosclerotic plaque, I stick with my transverse sections.” With more complex cases, in terms of the atherosclerotic disease burden, Schoepf uses the multiplanar reformat and the coronal and sagittal reformatted images created, per default, by technologists for every patient (for a better appreciation of stenosis severity than the transverse sections alone allow).
The presence, in a study, of coronary stents or heavy calcifications with extensive blooming artifacts sends Schoepf to more advanced visualization tools. “The most important ones, and the ones that are my first choice in my clinical practice, are automatically generated curved planar reformats,” Schoepf notes. “That is my three-step approach, depending on the complexity of the case and interpretation, and I use that because I want to be time efficient,” he explains. “I don’t want to waste the time it takes to get a case loaded and processed on a workstation if I have a simple case that can be solved based on the transverse sections. Time efficiency is the major goal of that approach.”
Viewing the transverse sections and the curved multiplanar reformats is fairly straightforward, Schoepf says, but he adds a word of caution about viewing maximum-intensity projections (MIPs). “The use of MIPs is still recommended by some; however, I think they have the inherent danger that you will miss pathology if you choose inappropriate visualization settings, such as the thickness of your maximum-intensity sliding thin slabs, for instance,” Schoepf warns. “I would discourage the use of MIPs and stick to transverse sections, multiplanar reformats, and automatically generated curved multiplanar reformats.”
Preprocessing Proponent The CCTA program at Jewish Hospital in Louisville is currently radiology driven, from the administration of beta-blockers to the interpretation and monitoring of the studies. Half of the referrals come from cardiology and the rest come from primary care.