New cardiovascular imaging: the who, what, when and why

In part two of this round table, panelists consider issues related to training, collaboration with radiology, and how technology is changing.

Cardiology Today convened this round table in November during the American Heart Association Scientific Sessions 2005 in Dallas. Chief Medical Editor Carl J. Pepine, MD, moderated the discussion. Part two of the round table is presented here. Part one was published in the February issue of Today in Cardiology.

Moderator
Carl J. Pepine, MD Eminent Scholar, Professor and Chief, Division of Cardiovascular Medicine, University of Florida, Gainesville; Chief Medical Editor of Cardiology Today.
Daniel Berman, MD Director, Nuclear Cardiology/Cardiac Imaging at Cedars Sinai Medical Center; Professor at University of California, Los Angeles School of Medicine.	W. Greg Hundley, MD Associate Professor of Radiology and Medicine (Cardiology) at Wake Forest University Health Sciences in Winston Salem; Medical Director, Cardiovascular Magnetic Resonance.
Mario Garcia, MD Director, Cardiovascular Imaging, Department of Cardiovascular Medicine at The Cleveland Clinic.	João A. C. Lima, MD Director of Cardiovascular Imaging in Cardiology; Associate Professor of Medicine and Radiology; Johns Hopkins University.
James A. Hill, MD Professor of Medicine and Pharmacology, Co-Director of CTMR for CV Medicine at the University of Florida, Gainesville.	Norbert Wilke, MD Associate Professor of Radiology and Medicine, University of Florida; Chief of Cardiovascular MR and CT at University of Florida Health Science Center, Jacksonville.

CARL J. PEPINE, MD: CT and MR are labor intensive even before the study. Some MR and CT suites in cardiology are spending about 25 to 30 minutes reviewing the chart for every patient referral, and then a comparable amount of time during the procedure and a similar amount of time after the procedure postprocessing. That is about 1.5 hour of physician labor per study. What do you estimate the times are?

JAMES A. HILL, MD: The postprocessing is a bit of an issue, but the screening of the patient will be much more streamlined when these tests are done on a more regular basis. Look at echo, treadmill exercise testing, nuclear scans. Everything is done with a slick system.

PEPINE: There are many slices to look at and a lot to review in the chart, such as whether a patient is a candidate for a beta-blocker or whether they are better suited for MR or CT, etc.

DANIEL BERMAN, MD: In a clinical practice, the cardiologist will see a patient and say he needs a CT or MR. The person doing the procedure will make sure that the patient can safely take a beta-blocker and make sure there is no suspicion of renal dysfunction so that the patient can tolerate the dye. They may not even see a physician before the test is done.

During the test, it will depend on practice patterns whether you have a physician assistant or whether the physician has to be the one who must give IV beta-blockers should they be needed, and that could take time.

As we go forward, that time won't be needed. The time that is hard to reduce is the interpretation time. You're dealing with a very large 3-D data set; it can't be considered like a standard CT scan of organs that don't require this 3-D manipulation. The interpretation involves the physician's interaction on a workstation with the 3-D data, and that is time consuming.

NORBERT WILKE, MD: There is currently a disparity between the growing numbers of physicians who are very interested in CT and MR imaging and the lack of adequate training sites where people can get experience. We should not be mistaken that anyone who can look at the coronary angiogram by x-ray is also qualified for looking at a CTA. It takes a learning curve and a lot of studies to look at.

The Society of Cardiovascular Computed Tomography and Society for Cardiovascular Magnetic Resonance [SCMR] are spearheading standards through the American College of Cardiology where there is now also a position paper published. The American College of Radiology also published a position paper on how proper training should be conducted.

But there are vast differences depending on the exposure and volume that different sites have to offer. It is not only the training but also setting up an infrastructure for cardiovascular CT and MR in general, which is not trivial. In our institution we have trained cardiology fellows and radiology residents and we offer this 24-7. I am confident that residents can have a minimum competency for looking at these cardiac CTs at night, but it took a considerable amount of time to get them trained to the point where they are comfortable reading those studies. Physicians often underestimate that effort it takes, because they want to enter the field as quick as possible.

HILL: I'd like to make the opposite point: Just because you can read a coronary angiogram doesn't mean you can read a CT scan. There are different learning curves. The opposite is also true: Just because you can read a CT scan doesn't mean you can read a coronary angiogram from a CT standpoint.

When I was a cath lab director, I'd get panicked calls from radiology residents who were about to take the radiology boards asking if I would come teach them how to read a coronary angiogram because they had never done it. The training has to go both ways, not just for cardiologists but for radiologists as well.

PEPINE: I guess you are all confirming that it is labor intensive?

WILKE: Once you are trained you can perform a cardiac CT study in five to 15 minutes with a well-trained team that includes technologists and coordinators. Once the scan is done at my center, we have a reading within 15 minutes for the ER, which we do with a lot of chest pain patients. There is a call within 30 minutes and a report out between two to three hours.

That may not be the standard everywhere, but one can see how far you can go if you put effort into that. it's not necessarily more intensive than with other studies once the training is in place. Cardiovascular MR involves much more training, of course.

BERMAN: It takes more time to interpret a CTA than it does to interpret a nuclear cardiology study.

WILKE: That is correct because you have to look at many different things, and it is a more complex structure.

BERMAN: Compared to when radiologists read a CT of the chest not gated and with no cardiac structures to look at, it is also more time consuming because someone experienced has to look at the extra cardiac finding as you would with a CT of the chest. Also, you don’t just look a the coronaries on CT in a 2-D fashion but you have to manipulate the 3-D data. We need to recognize that the physician’s work is not inconsequential.

PEPINE: Dr. Wilke, as a trained radiologist, what do you do with those other noncardiac slices and the other organs? Do you have your radiologist read them routinely or do you feel comfortable that your group can screen?

WILKE: As you acquire basic coronary arteries by CT, you automatically have pictures of the lung and surrounding soft tissues. That becomes important in patients with chest pain in which there can be many causes – cancer, infections and other events – and certainly it is absolutely crucial that radiologists are looking those studies over. There may be a complementary role between cardiologists and radiologists to over-read those studies. There are different strategies at different institutions on how to handle this.

For the sake of patient care, those other surrounding structures have to be looked at as much as the coronaries. There are data that the relevant extra cardiac findings in people with chest pain undergoing coronary CTA can be as high as 15%. That would become a legal issue in the future if you were to ignore that.

PEPINE: It’s no problem for you, but for a cardiology-based CT center, what do you all recommend? Do you have a radiologist outsourced to read this?

BERMAN: In our institution, we’re able to do that because we are cardiologists within a radiology group so we can have two pair of eyes looking at every image. We’re also involved in outside sites that are cardiology-read for coronary arteries and over-read by radiologists in our group for the extra cardiac findings.

It may be that with adequate training it could get to a point that a nonradiologist could be evaluating these things; it’s within the realm of possibility. But also, cardiac CT may provide an ideal opportunity for some collaboration based around this new technology that looks so well at the cardiac and the noncardiac structures. it’s a perfect opportunity to repair some bridges.

W. GREG HUNDLEY, MD: It’s a little bit less of an issue for an MR because the spatial resolution is lower so we’re not going to be able to look at the artifacts in the lungs. For the CT it has to be accounted for and there needs to be a strategy, whether that strategy is to have a person trained to read at that level.

JOÃO A. C. LIMA, MD: We have a radiologist read scans at our institution.

HILL: This has to be addressed in the training standards or else everybody sets themselves up for all kinds of legal problems.

PEPINE: Let’s get your reactions to one other topic in this area. As you probably know, the radiology camp has taken a position that only certain imagers should read these studies. The cardiology camp has taken the viewpoint that an appropriately trained individual – whether it’s a radiologist, a cardiologist or someone who reads 10 different imaging modalities vs. just CT or MR – should be able to do this. What’s your reaction to this issue?

LIMA: The imaging test must be connected with knowledge of the clinical situation. When imaging tests were applied outside that sphere of knowledge or that context, they don’t survive. I think that’s what happened with coronary calcification. You can’t have a center where people go and have a scan. It has to be put in the clinical context. It would be a mistake from a society standpoint to limit the utilization of imaging to only imagers. We have to make sure that people involved in care of patients have access to imaging.

At the same time, it’s a great opportunity to create collaboration because what fosters the field of imaging is the interaction between people who take care of patients. I believe it should be open and it should be inclusive of people with different avenues of training to have the best impact.

WILKE: Traditionally there have been two different approaches to CV imaging. Radiologists in CT and MR are very familiar with the technical aspects of cardiac CT as it pertains to CT instrumentation and the same for MR. They are very familiar with looking at the signals, the densities, and they can look at surrounding structures very effectively.

On the other hand, cardiologists know their patients, they know what to do, and they have a strategy to know what to do with the results. So one could argue that both of them have to learn from each other in an ideal situation.

We can also take the stand that it’s not so important whether it’s the radiologist or cardiologist who is reading it. I think it’s important that both of them need to have sufficient time and emphasis in specializing in this new arena. Proficiency is needed and that’s where they can all come together to learn from each other. It should not be one or the other, but rather who has time to specialize in it and who has the institutional commitment to do so.

PEPINE: I have a belief that the experts here today are at institutions where there is good collaboration and it’s not necessarily the prevailing issue. Where do you think this field is headed?

HUNDLEY: Standards of reporting and standards of collecting information must be addressed. The American Heart Association and other specialty societies involved in imaging and in patient care need to get together and develop these standards so that we can effectively collect the information and generate the outcomes measures to evaluate their utility in clinical practice.

BERMAN: We need to recognize that this is a modality in its infancy and that 64-slice images are great but they’re going to get greater. There is no question that we’re going to have marked technical improvement.

At the same time, we have to recognize that it is currently an anatomic technique that we have to recognize for its strengths and also recognize for its limitations. In that regard we have to be careful not to rush straight from the anatomic information to stents on everybody with an abnormality.

WILKE: MDCT and MR have shown great potential and, I would even go so far to say, superiority over all other noninvasive testing. However, we have to finalize more research studies and improve training and, of course, implement standards to make this a widely used practice. Probably replacing some of what we do currently is needed in terms of achieving valid reimbursements.

LIMA: We need to solidify the comparison with invasive angiography, and we need to get prognostic information from MDCT. We need to press very hard for technologic improvement, particularly those that will lead to safer utilization of this modality.

HILL: We need to solidify training and understand how best to use this and to incorporate new knowledge into the imaging field. Our cardiology fellows are much more interested in this than our radiology fellows because they think this is their future as opposed to what the radiologists think.

MARIO GARCIA, MD: I think the technology will evolve to reduce radiation and reduce the number of artifacts that are currently present. Utilization will depend on the outcome of upcoming studies. Ultimately, I am convinced that CT will dramatically reduce the guessing part of what we do in practice in a patient with chest pain.

Read part one of this round table in the February issue of Cardiology Today.