Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

MRI techniques improve pulmonary embolism detection

19.03.2012
New research shows that the addition of two magnetic resonance imaging (MRI) sequences to a common MR angiography technique significantly improves detection of pulmonary embolism, a potentially life-threatening condition traditionally diagnosed through computed tomography (CT). Results of the study are published online in the journal Radiology.

Pulmonary embolism occurs when a blood clot—usually from the leg—travels to the lung and blocks the pulmonary artery or one of its main branches. CT angiography is the gold standard for diagnosis, but it exposes patients to ionizing radiation and iodinated contrast agent, which carries a risk of allergic reactions and kidney damage in some patients.

"MRI is developing much faster than CT," said Diego R. Martin, M.D., Ph.D., head of the Department of Radiology at the University of Arizona College of Medicine in Tucson. "The images we're getting are already significantly better than they were a year ago. There is no doubt that in the future we will be able to offer a non-radiation-based alternative to CT for the diagnosis of pulmonary embolism."

MRI has been used for pulmonary embolism detection in pregnant women and patients whose kidneys may be harmed by CT angiography contrast agents. However, the Prospective Investigation of Pulmonary Embolism Diagnosis III (PIOPED III) study, a major multicenter trial, found that centers had difficulty obtaining adequate quality MR pulmonary angiography (MRPA) for suspected pulmonary embolism. The PIOPED researchers determined that MRPA should be considered only at centers that routinely perform it and perform it well, and for patients who have contraindications to standard tests.

In the new study, the research team assessed the impact of two additional MRI sequences on MRPA's accuracy. The two techniques—contrast-enhanced volumetric interpolated breath-hold examination (VIBE) and non-contrast true fast imaging with steady-state precession (true FISP)—complement MRPA, according to Dr. Martin.

The addition of VIBE provides a gray scale that enables readers to distinguish between the clot, or thrombus, and the lung, which both appear dark on MRPA.

"Also, VIBE is not time sensitive," Dr. Martin said. "If the patient coughs, you can do it again. You don't have that option with MRPA."

The true FISP test does not require contrast agent or a breath hold, an important consideration for embolism patients who often cannot hold their breath long enough for image acquisition on MRPA.

When Dr. Martin and colleagues studied the three techniques on 22 patients with CTA diagnosis of pulmonary embolism, they found a sensitivity of 55 percent, 67 percent and 73 percent for MRPA, true FISP and VIBE, respectively. Combining all three MRI sequences improved the overall detection rate to 84 percent. Specificity was 100 percent for all detection methods except for MRPA, which demonstrated one false positive.

Dr. Martin hopes his findings stimulate discussion of a new, redesigned PIOPED study.

"PIOPED III did not answer the question of whether or not MRI is a useful alternative to CT, because it didn't use all the tools available," he said.

The MRI sequences used in the study are offered on all the major vendor systems, according to Dr. Martin, with the entire three-sequence protocol taking only 15 minutes to set up and perform.

"MR Imaging of Pulmonary Embolism: Diagnostic Accuracy of Contrast-enhanced 3D MR PulmonaryAngiography, Contrast-enhanced Low–Flip Angle 3D GRE, and Nonenhanced Free-induction FISP Sequences." Collaborating with Dr. Martin were Bobby Kalb, M.D., Puneet Sharma, Ph.D., Stefan Tigges, M.D., M.S.C.R., Gaye L. Ray, N.P., Hiroumi D. Kitajima, Ph.D., James R. Costello, M.D., Ph.D., and Zhengjia Chen, Ph.D.

Radiology is edited by Herbert Y. Kressel, M.D., Harvard Medical School, Boston, Mass., and owned and published by the Radiological Society of North America, Inc. (http://radiology.rsna.org/)

RSNA is an association of more than 48,000 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)

For patient-friendly information on MR angiography, visit RadiologyInfo.org.

Linda Brooks | EurekAlert!
Further information:
http://www.rsna.org

More articles from Medical Engineering:

nachricht UTSA study describes new minimally invasive device to treat cancer and other illnesses
02.12.2016 | University of Texas at San Antonio

nachricht Earlier Alzheimer's diagnosis may be possible with new imaging compound
02.11.2016 | Washington University School of Medicine

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>