MRI Could Be Used For Routine Surveillance Of Great Vessel Stents

Researchers have found that magnetic resonance imaging (MRI) may be sufficient for the routine surveillance of some great vessel (primary blood vessels [e.g., aorta and vena cavae]) stents that are commonly used to treat congenital heart defects (a defect in the structure of the heart and great vessels that is present at birth) in children and young adults, according to a study in the October issue of the American Journal of Roentgenology (http://www.ajronline.org). MRI is a noninvasive medical test that helps physicians diagnose and treat medical conditions.

"Computed tomography (CT) is regarded as the best method for follow-up of endovascular stents. However, there are concerns regarding the long-term health effects of ionizing radiation exposure," said Andrew M. Taylor, MD, lead author of the study. "Conventional angiography can be used to image stents; however, it is not suitable for routine surveillance because of the invasive nature of the procedure," said Taylor.

The study, performed at the Great Ormond Street Hospital for Children in London, included three contemporary great vessel stent materials (nitinol, platinum-iridium and stainless steel) that were implanted into an aorta model and imaged with conventional angiography, ten different MRI sequences and CT. "Study results showed that the diagnostic accuracy of conventional angiography and CT was high for all stents and MRI visualization of the stent depended on the type of stent and the sequence used," said Taylor.

source: ARRS


FDA Drug Safety Communication: New warnings for using gadolinium-based contrast agents in patients with kidney dysfunction

[09-09-2010] The U.S. Food and Drug Administration (FDA) is requiring changes in the drug label for gadolinium-based contrast agents (GBCAs) to minimize the risk of nephrogenic systemic fibrosis (NSF), a rare, but serious, condition associated with the use of GBCAs in certain patients with kidney dysfunction. GBCAs are intravenous drugs used in diagnostic imaging procedures to enhance the quality of magnetic resonance imaging (MRI) or magnetic resonance angiography (MRA). (See Approved Gadolinium-Based Contrast Agents below).

These label changes are intended to help ensure these drugs are used appropriately, and that patients at risk for NSF who receive GBCAs are actively monitored for the development of NSF. Symptoms of NSF include scaling, hardening and tightening of the skin; red or dark patches on the skin; and stiffness. NSF can also cause fibrosis of internal organs which may lead to death. There is no effective treatment for NSF.

NSF has not been reported in patients with normal kidney function. Patients at greatest risk for developing NSF after receiving GBCAs are those with impaired elimination of the drug, including patients with acute kidney injury (AKI) or chronic, severe kidney disease (with a glomerular filtration rate or GFR < 30 mL/min/1.73m2). Higher than recommended doses or repeat doses of GBCAs also appear to increase the risk for NSF.

source: FDA