CT scans show patients with severe cases of H1N1 are at risk for developing acute pulmonary emboli

Researchers utilizing computed tomography (CT) scans have found that patients with severe cases of the H1N1 virus are at risk for developing severe complications, including pulmonary emboli (PE), according to a study to be published online Oct. 14, 2009, in the American Journal of Roentgenology. The study will be published in the December issue of the AJR.

A pulmonary embolism occurs when one or more arteries in the lungs become blocked. The condition can be life-threatening. However, if treated aggressively, anti-coagulants (blood thinners) can reduce the risk of death.

The study, performed at the University of Michigan Health Service, included 66 patients diagnosed with the H1N1 flu. Two study groups were formed. Group one consisted of 14 patients who were severely ill and required Intensive Care Unit (ICU) admission. Group two consisted of 52 patients who were not severely ill and did not require ICU admission.

All 66 patients underwent chest X-rays for the detection of H1N1 abnormalities. Ten patients from the ICU group and five patients from the largely outpatient group, underwent CT scans. "Pulmonary Emboli were seen on CT in five of 14 ICU patients," said Prachi P. Agarwal, M.D., lead author of the study.

"Our study suggests that patients who are severely ill with H1N1 are also at risk for developing PE, which should be carefully sought for on contrast-enhanced CT scans," she said.

"With the upcoming annual influenza season in the United States, knowledge of the radiologic features of H1N1 is important, as well as the virus's potential complications. The majority of patients undergoing chest X-rays with H1N1 have normal radiographs. CT scans proved valuable in identifying those patients at risk of developing more serious complications as a possible result of the H1N1 virus, and for identifying a greater extent of disease than is appreciated on chest radiographs," said Dr. Agarwal.

This study will be posted online at www.ajronline.org, Wednesday, Oct. 14, 2009, and will appear in the December issue of the American Journal of Roentgenology. For a copy of the full study, please contact Heather Curry via email at hcry@acr-arrs.org or at 703-390-9822.

ur The American Roentgen Ray Society (ARRS) was founded in 1900 and is the oldest radiology society in the United States. Its monthly journal, the American Journal of Roentgenology, began publication in 1906. Radiologists from all over the world attend the ARRS annual meeting to participate in instructional courses, scientific paper presentations and scientific and commercial exhibits related to the field of radiology. The Society is named after the first Nobel Laureate in Physics, Wilhelm Röentgen, who discovered the X-ray in 1895.