Notes From a Cardiac AV Superuser: Wm. Guy Weigold, MD

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Guy WeigoldFor a cardiologist, Wm. Guy Weigold, MD, spends an unusual amount of time in front of a monitor. “I happen to be a cardiologist who has expertise in cardiac CT,” he explains. “I spend the majority of my time looking at images.” Weigold is director of the cardiac CT program at the MedStar Washington Hospital Center in Washington, DC, and he directs that institution’s cardiac CT core laboratory (part of a large cardiovascular-imaging laboratory that also offers cardiac MRI, echocardiography, intravascular ultrasound, and basic angiography under the auspices of the MedStar Research Institute).

To keep from slipping over to the dark side, Weigold maintains a regular schedule of clinical service each week, either participating in rounds with colleagues or covering the cardiac ICU, for instance. “I try not to turn completely into a radiologist,” he says, only half in jest. Nonetheless, when it comes to the mysteries of atherosclerotic disease—understanding, for instance, what triggers an acute myocardial infarction—Weigold believes that CT imaging and advanced visualization software will provide at least some of the answers.

Weigold has played an active role in cardiac-imaging research, participating in the SPARC trial,¹ a comparative-effectiveness study that looked at the impact of various diagnostic strategies (including coronary CT angiography) on downstream testing. In his capacity as CT core laboratory director, Weigold helps research organizations conduct the cardiac CT portions of their studies, using the suite of advanced visualization tools in Synapse® 3D (FUJIFILM Medical Systems USA, Inc) to probe and manipulate the image information. Research organizations often turn to a core laboratory for analysis of imaging data for consistency, expertise, and accuracy—but also to avoid confounding and bias by keeping analysis walled off from clinical evaluation of the patient, he explains.

Rigorous Demands

In fact, reading cardiac CT studies for research often demands more specific detail than would a straightforward clinical study. “A core laboratory will often engage in a more rigorous quantification of the imaging data and calculations, and a very thorough going over of the data,” he notes. “The power of the Fujifilm system is that it has a lot of capability and applications built within it.”

On any given day, Weigold might need to do a large-scale analysis of the aorta and peripheral vasculature or a detailed analysis of the heart’s structure and function. The Synapse 3D tools make detailed analysis of the coronary arteries possible, from the detection of coronary calcification and quantification of coronary stenosis to drilling down to the analysis of plaque composition.

“Research organizations are going to come to you with any variety of questions, depending on what their studies are, and they are going to ask for a variety of different types of analysis,” he explains. “One study may looking at aortic diameters, aortic aneurysms, and aortic dissections, and that’s a completely different set of analyses from those needed by someone interested in plaque characteristics of coronary atherosclerotic lesions. Having a panoply of applications is a required feature when you are looking for a robust system for a core laboratory, which is why we like it.”

The Elusive Trophy

As Weigold explains it, atherosclerotic lesions are histologically complex, presenting medicine with an enduring mystery: “The challenge in coronary atherosclerotic disease is to try to do something to address this problem of a disease entity that has a long subclinical course that can undergo an acute destabilization and produce a lethal affliction—which is an acute myocardial infarction. It is well known that people can harbor this disease for years without any symptoms whatsoever until the day of their infarction, yet we still know very little about what triggers that destabilization; frequently, the first manifestation of coronary atherosclerosis is an acute myocardial infarction,” he says.

Ideally, physicians would detect this disease early in its subclinical phase and intervene in the disease process, Weigold says, but that has been stymied by multiple complexities: Many people walk around with this disease process and never have a myocardial infarction; others can walk around with extensive, severe disease that never causes an infarct, but might lead to bypass surgery. Still others have a very small burden of disease—only one small