(Press-News.org) CHICAGO – In a study being presented today at the annual meeting of the Radiological Society of North America (RSNA), researchers say they may have an explanation as to why African Americans, despite having lower amounts of coronary artery calcification, are at increased risk for heart attacks and other cardiovascular events compared with Caucasians.
The answer, according to researchers at the Medical University of South Carolina (MUSC) in Charleston, S.C., may be increased levels of non-calcified plaque, which consists of buildups of soft deposits deep in the walls of the arteries that are not detected by some cardiac tests. Non-calcified plaque is more vulnerable to rupturing and causing a blood clot, which could lead to a heart attack or other cardiovascular event.
"The African Americans and Caucasians we studied had approximately the same amount of plaque in their arteries, but different kinds of plaque," said John W. Nance Jr., M.D., researcher in the Department of Radiology and Radiological Sciences at MUSC.
Calcium scoring with CT is a common screening tool for patients at risk for cardiovascular disease, because increased calcification in the coronary arteries correlates with a greater risk for a heart attack or other cardiovascular event. However, calcium scoring does not detect non-calcified plaque.
Dr. Nance and a team of researchers compared 301 patients who underwent two types of CT imaging for acute chest pain: calcium scoring, in which the amount of calcified plaque in the coronary arteries is measured, and contrast-enhanced coronary CT angiography (cCTA), which provides a more comprehensive picture of the arteries, including the presence of non-calcified and mixed plaques.
The study group comprised 50 percent each of African American and Caucasian patients, 33 percent of whom were male (mean age 55).
Calcium scoring revealed that calcified plaque was much more prevalent in the coronary arteries of Caucasian patients than in the African Americans (45 percent, versus 26 percent). The cCTA revealed that, compared with Caucasians, African American patients had a significantly higher prevalence of non-calcified plaque (64 percent, versus 41 percent), and more of it. The median volume of non-calcified plaque among the African American patients was 2.2 milliliters (mL), compared with 1.4 mL among Caucasians.
"This study confirms that the coronary artery disease pathways that lead to acute cardiovascular events are different for Caucasians and African Americans," explained coauthor U. Joseph Schoepf, M.D., professor of radiology and medicine and director of cardiovascular imaging at MUSC. "Coronary CT angiography is an effective and noninvasive tool for studying the pathology of atherosclerosis among different ethnicities."
According to Dr. Nance, further research is warranted to determine whether non-calcified plaque detection can improve cardiovascular risk prediction for African Americans. In the meantime, the value of calcium scoring as a screening tool for this patient group should be reinterpreted.
While cCTA does expose patients to ionizing radiation, according to Dr. Schoepf, the effective dose of this procedure has been considerably reduced over the past few years, making it a viable screening option.
"For African American patients, coronary CT angiography may be a more appropriate screening tool for cardiovascular risk," he said.
###
Other coauthors are Fabian Bamberg, M.D., J. Michael Barraza, B.S., Gorka Bastarrika, M.D., and Joseph Abro, M.A.
Note: Copies of RSNA 2010 news releases and electronic images will be available online at RSNA.org/press10 beginning Monday, Nov. 29.
RSNA is an association of more than 46,000 radiologists, radiation oncologists, medical physicists and related scientists committed to excellence in patient care through education and research. The Society is based in Oak Brook, Ill. (RSNA.org)
Editor's note: The data in these releases may differ from those in the published abstract and those actually presented at the meeting, as researchers continue to update their data right up until the meeting. To ensure you are using the most up-to-date information, please call the RSNA Newsroom at 1-312-949-3233.
For patient‑friendly information on CT angiography, visit RadiologyInfo.org.
END
CHICAGO – Researchers in London say they have found an effective two-part treatment for microtears in the hamstring: injections of the patient's own blood and a steroid along with "dry-needling," in which repeated needle punctures cause controlled internal bleeding in the injured area. Results of the study were presented today at the annual meeting of the Radiological Society of North America (RSNA).
"By injecting the patient's own blood where it is needed at the site of a damaged tendon, we help the patient heal themselves," said lead researcher Waseem A. Bashir, M.D., ...
CHICAGO – For years, it was believed that obese women were at lower risk for developing osteoporosis, and that excess body fat actually protected against bone loss. However, a study presented today at the annual meeting of the Radiological Society of North America (RSNA) found that having too much internal abdominal fat may, in fact, have a damaging effect on bone health.
"We know that obesity is a major public health problem," said the study's lead author, Miriam A. Bredella, M.D., a radiologist at Massachusetts General Hospital and assistant professor of radiology at ...
CHICAGO – Using functional magnetic resonance imaging (fMRI), researchers have captured pictures of the brain while patients experienced a pain stimulus with and without acupuncture to determine acupuncture's effect on how the brain processes pain. Results of the study, which the researchers say suggest the effectiveness of acupuncture, were presented today at the annual meeting of the Radiological Society of North America (RSNA).
"Until now, the role of acupuncture in the perception and processing of pain has been controversial," said lead researcher Nina Theysohn, M.D., ...
A new report in the December Cell Metabolism identifies a protein without which diets high in saturated fat lead to a massive inflammatory response that can prove fatal. The studies in mice suggest that deficiencies in this protective pathway could promote inflammation in those who regularly consume high levels of saturated fat.
"In mice without this protein that ate a lot of saturated fat, the lymph nodes blew up to extreme levels," said Sander Kersten of the Nutrigenomics Consortium and Wageningen University in the Netherlands. "I'd never seen anything like it before."
Kersten ...
Our brains are packed with cholesterol, almost all of which has to be produced within the brain itself, where it is critical for normal brain functions. Now, a new study in the December Cell Metabolism, a Cell Press publication, reveals how that critical cholesterol synthesis in the brain is derailed in mice with diabetes.
The findings offer a new explanation for the neurologic and cerebral complications that come with diabetes, including cognitive dysfunction, depression, and an increased risk of Alzheimer's disease, according to the researchers.
"People with diabetes ...
HOUSTON - (Dec. 1, 2010) – SRC-1 (steroid receptor coactivator) orchestrates glucose production in the liver, regulating the activity of a cascade of enzymes that turns sugar production on and off in the liver, said Baylor College of Medicine (www.bcm.edu) and Duke University Medical Center (www.dukehealth.org) researchers in a report that appears in the current issue of Cell Metabolism (http://www.cell.com/cell-metabolism/).
"As we achieve a better understanding of gluconeogenesis (production of glucose) in the liver, we can look for new ways to treat metabolic diseases ...
Washington, D.C. (November 30, 2010) -- Nuclear magnetic resonance (NMR) is one of the best tools for gaining insight into the structure and dynamics of molecules because nuclei in atoms within molecules will behave differently in a variety of chemical environments. Nuclei can be thought of as tiny compasses that align when placed in the field of a strong magnet. Similar to magnetic resonance imaging (MRI), conventional NMR uses short pulses of radio waves to drive nuclei away from equilibrium and a 'signal' emerges as nuclei slowly realign with the field.
Results reported ...
Washington, D.C. (November 30, 2010) -- One of the holy grails of nanotechnology in medicine is to control individual structures and processes inside a cell. Nanoparticles are well suited for this purpose because of their small size; they can also be engineered for specific intracellular tasks. When nanoparticles are excited by radio-frequency (RF) electromagnetic fields, interesting effects may occur. For example, the cell nucleus could get damaged inducing cell death; DNA might melt; or protein aggregates might get dispersed.
Some of these effects may be due to the ...
Washington, D.C. (November 30, 2010) -- Quantum information processing is arguably one of the most fascinating facets of modern quantum physics.
A quantum computer operates with quantum bits (qubits) as units of information. Obeying the laws of quantum mechanics, such a computer would be capable of addressing several of the most difficult computational tasks unsolvable with present technology. In the past few decades, scientists learned to perform room-sized experiments to optically control and read out a small number of qubits.
Now, researchers in Germany have successfully ...
Washington, D.C. (November 30, 2010) -- A broad review of current research on nuclear power economics has been published in the Journal of Renewable and Sustainable Energy. The report concludes that nuclear power will continue to be a viable power source but that the current fuel cycle is not sustainable. Due to uncertainty about waste management, any projection of future costs must be built on basic assumptions that are not grounded in real data.
"The goal of this study was to determine what assumptions are key to reaching conclusions about the relative costs of technologies," ...
