Computed tomography (CT) scans are better than standard radiography (X-rays) in showing the extent of disease in patients with the H1N1 virus, according to a study to be published online Oct. 21, 2009, in the American Journal of Roentgenology. The study will be published in the December issue of the AJR.

The study group consisted of seven patients with the H1N1 virus. All seven patients received chest X-rays and three patients had CT scans. "All patients with CT abnormalities showed abnormal findings on the corresponding chest X-rays," said Amr M. Ajlan, M.D., lead author of the study. "However, the extent of involvement was more diffuse and the distribution of disease was better characterized on CT," said Dr. Ajlan.

"The strength of our study is that all CT scans performed showed a similar distribution of abnormalities, which might help physicians prospectively diagnose H1N1 using medical imaging," he said.

"Most cases of H1N1 are mild and self-limited; however, high-risk patients are more likely to have severe complications. Our study suggests that CT is superior to standard chest X-rays and should be the imaging modality of choice in high-risk patients," said Dr. Ajlan.