New standard proposed for coronary artery calcium screening

December 01, 2003

CHICAGO - Computed tomography (CT) scanning of the coronary arteries for calcium is widely used as a noninvasive method for assessing early heart disease. However, because imaging equipment settings and individual physician interpretation can affect a patient's diagnosis, an international consortium of scientists, physicians and CT manufacturers has developed a new standard for measuring the amount of calcium found in a person's coronary arteries. The recommendations were presented today at the 89th Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA).

"The original way of scoring calcium was good, but it had weaknesses," said Cynthia McCollough, Ph.D., lead author of the research. "We've addressed many of those weaknesses, added an important calibration step so the reported values can be compared from one test to another, even on different brands of equipment, and adjusted the radiation dose according to a patient's size."

Most radiologists and cardiologists agree that the presence of coronary artery calcium (CAC) is a statistically valid predictor - independent of traditional risk factors - of increased risk for future coronary events, according to Dr. McCollough, associate professor of radiologic physics at the Mayo Clinic College of Medicine in Rochester, Minn.

"The problem has been in the variability of the scoring in CAC screening," Dr. McCollough said. "Every day, there are a variety of CT scanners using different scoring systems producing CAC screening results. In order for these numbers to be meaningful and comparable, we need to be measuring and scoring in the same way."

Using specially developed testing software and simulated human chests and hearts with fixed amounts of calcium, the researchers were able to generate a more accurate, calibrated result, independent of the scanner being used or the patient's size. The new standards also include recommendations that allow for reduced radiation doses for small and medium-size patients. The consortium's research lays the groundwork for a database that will reference a patient's calcium score against the scores of others who are the same age and gender.

"The clinical success of CT scanners for detecting and quantifying coronary artery calcium requires some method of assessing patient risk based on calcium burden, patient age and gender," Dr. McCollough said.

Recent studies have shown that the presence of calcium in the coronary arteries is direct evidence of atherosclerosis - a narrowing and hardening of the arteries due to a build-up of plaque. The plaque consists of fat, cholesterol and calcium. Using a CT scanner, radiologists are able to determine the number and density of calcified plaques in the arteries.

The consortium, which included participation from four major CT manufacturers - GE Medical Systems, Philips Medical Systems, Siemens Medical Solutions and Toshiba Medical Systems - was formed to reach a consensus on a comprehensive measurement system for coronary artery calcium. The group, started in late 1999 by Dr. Richard White, a cardiovascular radiologist at the Cleveland Clinic, developed the new standard using multi-detector-row CT (MDCT) systems, but the standard is also applicable to the electron-beam CT (EBCT) scanners often used for CAC screening.

Co-authors of the Mayo study were Willi A. Kalender, Ph.D., and Stefan Ulzheimer, Ph.D., from the Institute for Medical Physics in Erlangen, Germany; and Sandra S. Halliburton, Ph.D., Richard D. White, M.D., from the Cleveland Clinic. The study represents the work of the consortium, whose members come from leading healthcare centers and universities in the United States, Europe and Israel. (W.K. is a consultant for QRM and Siemens Medical Solutions.)

RSNA is an association of more than 35,000 radiologists, radiation oncologists and related scientists committed to promoting excellence in radiology through education and by fostering research, with the ultimate goal of improving patient care. The Society is based in Oak Brook, Ill.
-end-
Note: Copies of 2003 RSNA news releases and electronic images will be available online at www.rsna.org/press03 beginning Monday, Dec. 1.

Editor's note: The data in these releases may differ from those in the printed 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 312-949-3233.

Radiological Society of North America

Related Calcium Articles from Brightsurf:

A new strategy for the greener use of calcium carbide
Computational chemists from St Petersburg University and the Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences have developed a new strategy for using calcium acetylide in the synthesis of organic compounds.

New link between calcium and cardiolipin in heart defects
To function properly, the heart needs energy from cells' powerhouses, the mitochondria.

'Give me the calcium!' Tulane virus takes over cellular calcium signaling to replicate
Researchers uncover the first piece of functional evidence suggesting that Tulane virus and human norovirus use viroporins to control cellular calcium signaling.

Carbon dots make calcium easier to track
Prof. DONG Wenfei's research group from the Suzhou Institute of Biomedical Engineering and Technology (SIBET) has developed a new type of fluorescent carbon dot that can effectively detect calcium levels in cells.

Calcium batteries: New electrolytes, enhanced properties
Calcium-based batteries promise to reach a high energy density at low manufacturing costs.

Chelated calcium benefits poinsettias
Cutting quality has an impact on postharvest durability during shipping and propagation of poinsettias.

New study uncovers the interaction of calcium channels
Korean researchers have identified the interactions of the combinants among calcium channel proteins that exist in nerve and heart cells.

Calcium-catalyzed reactions of element-H bonds
Calcium-catalyzed reactions of element-H bonds provide precise and efficient tools for hydrofunctionalization.

A bioengineered tattoo monitors blood calcium levels
Scientists have created a biomedical tattoo that becomes visible on the skin of mice in response to elevated levels of calcium in the blood.

The dinosaur menu, as revealed by calcium
By studying calcium in fossil remains in deposits in Morocco and Niger, researchers have been able to reconstruct the food chains of the past, thus explaining how so many predators could coexist in the dinosaurs' time.

Read More: Calcium News and Calcium Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.