A Glimpse of the Heart

UT-Houston Physicians are Making Advances in
Imaging to Detect Heart and Vascular Defects at
Their Earliest Stages

By Meredith Raine

A picture may be worth a thousand words, but physicians who study cardiac images at The University of Texas Medical School at Houston are often searching for just two of those tell-tale terms: heart disease.

Physicians and researchers are working on advances in diagnostic imaging in an attempt to detect coronary artery disease and other heart and vascular defects at their earliest stages.

“Currently, cardiologists don’t have a tool like colonoscopy that detects or rules out disease,” says Andrew Hamilton, M.D., director of cardiac imaging and associate professor of medicine in the Division of Cardiology. “We need a direct, noninvasive way to detect disease early and accurately so that we can offer the best therapies to treat and reverse the disease process.”

Dr. Hamilton, director of cardiovascular imaging at Memorial Hermann Heart & Vascular Institute – Texas Medical Center, may have found one such tool. Called transthoracic echocardiography, the ultrasound provides rapid-fire, high resolution and high frequency images of the heart, capturing pictures of thickened arterial walls.

This thickening, Dr. Hamilton says, is believed to be the first sign of heart disease. “We can see micro vessels – little vessels that start to proliferate and grow into the artery,” he says. “This occurs before any calcium buildup or blockages.”

Current CT (Computed tomography) and MRI (Magnetic Resonance Imaging) reveal calcification and blockages, but by the time these problems are detectable, the disease has usually advanced to Stage 3 or Stage 4. “It’s a little late,” Dr. Hamilton says. “You could cure coronary artery disease if you could detect it in the first stage. It’s an opportunity to stop or regress the disease.”

CT scans can detect the absence or presence of stenosis, the narrowing of vessels, but cannot differentiate between early and advanced stages of heart disease. “It can’t tell the difference between a 23 percent stenosis and a 77 percent stenosis, but it can tell you if you have disease,” Dr. Hamilton says.

Dr. Hamilton says he hopes the high-speed ultrasound will provide a more complete picture. “We’re creating an imaging modality that has the potential to detect disease at its earliest stage, and then we can use the same imaging modality to follow the regression,” he says.

Preliminary research shows that statins, cholesterol-lowering drugs, can reverse and eliminate micro vessels in animal models. With the use of ultrasound, Dr. Hamilton hopes to validate this response in humans.

As part of Dr. Hamilton’s research,
he is offering the high-speed
ultrasound as part of a vascular
screening at UT Cardiology and Non-Invasive Cardiology Lab. The test is non-invasive, painless, and takes less than 10 minutes.

A Clear Image and a Clear Pre-Operative Plan

Ultrasound is just one of the diagnostic tools UT physicians are using to detect heart and vascular defects.

“Imaging is one of the most exciting areas in medicine right now,” says Sheila Coogan, M.D., assistant professor in the Department of Cardiothoracic and Vascular Surgery.

CT scans now offer better resolution and can be done in a matter of seconds, giving the surgeon a clear picture and, if surgery is required, a pre-operative plan. One of the biggest advancements, Dr. Coogan says, is 3-D CT reconstruction, an excellent tool for mapping out surgical strategies for correcting aneurysms and vascular trauma.

“The image capability is amazing,” says Dr. Coogan, showing a lifelike animation of a leg on her computer monitor, revealing the cast and every layer underneath – from the skin, to the muscle to the vessels that had been disrupted when the patient injured his leg in a car accident. With the click of the mouse, Dr. Coogan can subtract layers and spin the image to get a detailed look at the vascular injury from every angle.

“An angiogram can take 20 to 30 minutes, and in trauma, we may not have that kind of time,” Dr. Coogan says. “This gives us vital information in quick fashion and helps determine our treatment option.”