Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


CT angiography may be unnecessary in patients with suspected pulmonary embolism

A new study suggests that computed tomography (CT) angiography might be unnecessary in many patients suspected of having pulmonary embolism (PE), based on the results of risk assessment analysis. PE risk assessment could help reduce radiation exposure and costs associated with CT angiography. The results of the study appear in the online edition and August print issue of the journal Radiology.

"Our study suggests that the frequency of ordering CT angiograms can be markedly reduced with resultant cost-savings and decreased radiation exposure," said lead author Mark D. Mamlouk, M.D., radiology resident at the University of California, Irvine in Orange, Calif.

Pulmonary embolism occurs when a blood clot, usually from the leg, travels through the bloodstream and gets lodged in a pulmonary artery. The condition can be fatal, so prompt diagnosis is critical.

CT angiography's high sensitivity and specificity has made it the preferred modality for diagnosing PE. However, the increasing use of the examination has fueled concerns over procedure costs and radiation exposure to patients, along with risks associated with the use of contrast agents.

For the study, the researchers assessed the possibility of using risk factors associated with thromboembolism, or blood clot formation, to reduce the number of CT angiograms for PE. They reviewed the electronic medical records of 2,003 patients who underwent CT angiography for possible PE between July 2004 and February 2006. Among the risk factors assessed were age, history of immobilization and cancer. Other risk factors included excess estrogen state, a history of venous thromboembolism, gender and disorders that cause blood to clot more easily than normal.

Overall, CT angiograms were negative for PE in 1,806 of 2,003 patients, or 90.2 percent. Among the 197 patients with CT angiograms positive for PE, 192, or 97.5 percent, had one or more risk factors.

All of the risk factors except gender were determined to be statistically significant. Age of 65 years or older and immobilization were the most common risk factors in positive PE patients.

Of the 1,806 patients with CT angiograms negative for PE, 520 (28.8 percent) had no risk factors. Furthermore, excluding age and gender, 1,119 (62 percent) had no risk factors. Risk factor assessment had a sensitivity of 97.5 percent and a negative predictive value of 99 percent in all patients.

Without any thromboembolic risk factors, there was only a 0.95 percent chance of a CT angiogram positive for PE, according to Dr. Mamlouk.

"Thromboembolic risk factor assessment is an effective clinical method to determine when to perform CT angiography for PE," Dr. Mamlouk said. "Risk assessment can be performed when clinicians acquire their patients' history. It takes only a few minutes, and there's no cost."

Dr. Mamlouk and colleagues also concluded that the combination of no risk factors and a negative D-dimer, a blood test that helps in the diagnosis of blood clots, yielded an extraordinarily low risk for a positive CT angiogram for PE.

"Pulmonary Embolism at CT Angiography: Implications for Appropriateness, Cost, and Radiation Exposure in 2,003 Patients." Collaborating with Dr. Mamlouk were Eric vanSonnenberg, M.D., Rishi Gosalia, M.D., David Drachman, Ph.D., Daniel Gridley, M.D., Jesus G. Zamora, M.D., Giovanna Casola, M.D., and Sanford Ornstein, M.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. (

RSNA is an association of more than 44,000 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. (

For patient-friendly information on CT angiography, visit

Linda Brooks | EurekAlert!
Further information:

More articles from Studies and Analyses:

nachricht Diagnoses: When Are Several Opinions Better Than One?
19.07.2016 | Max-Planck-Institut für Bildungsforschung

nachricht High in calories and low in nutrients when adolescents share pictures of food online
07.04.2016 | University of Gothenburg

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

All Focus news of the innovation-report >>>



Event News

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

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Oasis of life in the ice-covered central Arctic

24.10.2016 | Earth Sciences

‘Farming’ bacteria to boost growth in the oceans

24.10.2016 | Life Sciences

Light-driven atomic rotations excite magnetic waves

24.10.2016 | Physics and Astronomy

More VideoLinks >>>