Features | Partner Sites | Information | LinkXpress
Sign In
Schiller
VIEWORKS
TeraRecon

Benefits Weighed of Targeted Clot Removal Based on Brain Status

By Medimaging International staff writers
Posted on 19 Feb 2013
The use of cutting-edge imaging technology just after the onset of acute stroke failed to identify a subgroup of patients who could benefit from a clot-removal procedure.

The randomized, controlled trial known as Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy (MR RESCUE) was funded by the US National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health (Bethesda, MD, USA), and the findings were published online February 12, 2013, in the New England Journal of Medicine (NEJM).

In patients with ischemic stroke (caused by a blockage in an artery), brain cells deprived of blood die within minutes to hours. Quickly opening the artery can stop brain cell death. Intravenous tissue plasminogen activator (t-PA), an agent that dissolves clots has been shown to improve outcomes in these stroke patients. However, intravenous t-PA is not effective in many patients with large clots blocking the major brain arteries that cause the most damaging strokes. MR RESCUE scientists evaluated an invasive clot removal approach devised to remove clots from these large arteries. Patients in the study were enrolled at 22 centers in the United States within approximately 5.5 hours of their stroke onset. Their ability to function independently was assessed at 90 days.

All MR-RESCUE patients underwent emergency computed tomography (CT) or magnetic resonance (MRI) perfusion imaging to find the brain areas with decreased blood flow, as well as regions that could not be salvaged.

The investigators theorized that patients in whom the MRI scan suggested that less than 70% of the brain with decreased blood flow had already died would benefit from the clot-removal procedures. Based on the imaging findings, the 118 study patients were randomly assigned to receive a clot-removal procedure within eight hours of symptom onset (64 patients) or conventional therapy (54 patients) according to medical protocols. The procedure involves threading a customized catheter through an artery in the groin up to the site of a clot in a brain artery, then removing the blockage.

“Despite a lack of evidence showing that these clot-removal devices improve outcomes, they are already widely used in patients who are not able to get to the hospital in time to receive t-PA,” said Walter J. Koroshetz, MD, deputy director of NINDS. “Though some patients have had dramatic improvements with clot removal, it has not been shown effective in this or another larger study, the Interventional Management of Stroke [IMS III], which was halted early because it did not find the procedure to be of significant benefit.”

“The majority of patients were not eligible to receive intravenous t-PA, the only drug approved by the Food and Drug Administration for the treatment of stroke, because they arrived at the hospital too late for t-PA to be effective,” said one of the lead investigators, Chelsea Kidwell, MD, from Georgetown University Medical Center (Washington DC, USA).

The patients with the presumed optimistic imaging findings had the same level of disability at 90 days whether or not they had undergone the clot-removal procedure or had received standard therapy. The researchers hypothesized that the lack of a treatment effect may reflect the fact that these patients had enough blood flow to the brain from secondary sources to support the brain tissue until spontaneous reperfusion occurred. Patients without the favorable imaging findings did not benefit from the clot-removal procedure.

However, the MR RESCUE results were not consistent with the conclusions of a separate NINDS-funded observational study called DEFUSE-2 that suggested that a slightly different brain imaging approach could predict patients who benefited from the clot-removal procedure.

In addition to other imaging modalities, “it’s possible that newer intra-arterial devices that were not available when the study started could improve functional outcomes,” said Scott Janis, PhD, program director, NINDS. “But an important message from MR RESCUE is that those newer devices still need to go head to head with standard therapy.”

“Advances in neuroimaging are promising and may someday help to identify who will benefit from a device-based approach. But the MR RESCUE results show that more work needs to be done,” Dr. Koroshetz concluded.

Related Links:
US National Institute of Neurological Disorders and Stroke
Georgetown University Medical Center



Channels

Radiography

view channel

Coronary CT Used to Measure a Recreational Athlete's Risk of a Cardiovascular Event

Researchers presented the results of the Measuring Athlete's Risk of Cardiovascular events (MARC) study at the 2015 European Congress of Radiology (ECR) in Vienna (Austria).  Researchers at the University Medical Center Utrecht (UMC; Utrecht, Netherlands) investigated the added value of low-dose ECG-triggered Coronary... Read more

Ultrasound

view channel

Breakthrough Ultrasound Treatment for Alzheimer's Developed

A new, revolutionary technique that can be used to treat Alzheimer's disease and restore memory has been discovered by researchers at the University of Queensland (Queensland, Australia). The treatment uses noninvasive ultrasound to break apart neurotoxic amyloid plaques that cause cognitive decline and memory loss,... Read more

Nuclear medicine

view channel

Collaboration Agreement to Share Best Practices for Improved Cancer Treatment

The World Molecular Imaging Society (WMIS; Culver City, CA, USA) and the US National Cancer Institute (NCI; Rockville, MD, USA) have announced that they will begin collaborating to promote best practices for the treatment of cancer and other diseases. The clinical goals of the collaboration are to establish effective mouse/human... Read more

General/Advanced Imaging

view channel
Image: Measuring the Magnetic Activity in the Brain of a Child, Using a MEG machine. (Photo courtesy of Children\'s Hospital of Philadelphia).

Study Suggests Language Delay Linked to Chromosome Deletion in Children with Neurological Disorders

A study found that children with neuro-developmental problems born with DNA duplications or deletions on part of chromosome 16, show measurable delays in their ability to process sound and language.... Read more

Imaging IT

view channel

New Release of Image Management and Advanced Visualization Solution Unveiled at ECR 2015

A new version of an enterprise medical image management and advanced visualization solution has been launched at the 2015 European Congress of Radiology (ECR) in Vienna (Austria). The visualization solution provider also released new processing capabilities for cardiac Magnetic Resonance (MR), optimized low-dose workflow... Read more

Industry News

view channel

Analysis of Worldwide CT Scanner Sector Released

A report by Kalorama Information (New York, NY, USA) analyzing the global Computed Tomography (CT) market has been published. The report surveyed the CT market outlook until 2018, and the drivers behind the changes. The report investigated CT market sizing, market forecast to 2018, analysis of trends, how the market... Read more
 
Copyright © 2000-2015 Globetech Media. All rights reserved.