Nav: Home

New study describes imaging findings in H7N9 influenza

July 02, 2013

OAK BROOK, Ill. - H7N9 pneumonia is characterized by imaging findings that differentiate it from other types of pneumonia, including rapidly progressive changes in the lungs and pulmonary connective tissues, according to the first study to describe radiologic findings in the disease. The results are published online in the journal Radiology.

"The severity of these findings is associated with the severity of the clinical condition of the patients," said study co-author Zhiyong Zhang, M.D., Ph.D., from the Department of Radiology at Shanghai Public Health Clinical Center and Shanghai Medical College of Fudan University in China.

H7N9 is a recently discovered subtype of avian influenza virus or "bird flu," Cases of bird flu infection in humans typically result from direct or close contact with infected poultry, such as domesticated chickens, pigeons or ducks, or with surfaces contaminated with secretions and excretions from infected birds. The first human outbreak of H7N9 was reported in China in March 2013. This new strain in humans has caused severe and rapidly progressing respiratory illness. H7N9 can cause acute respiratory distress syndrome, organ failure and death.

For the study, Dr. Zhang and colleagues evaluated the clinical data and radiologic files of 12 patients with avian-origin influenza A H7N9 virus who were admitted to Shanghai Public Health Clinical Center between April 3, 2013, and April 20, 2013. The 12 patients included nine men and three women, 47 to 81 years old (mean age, 66 years).

None of the patients raised pigeons or lived in or near a pigeon-infested area. One patient kept chickens at home, and four patients had gone to various farmers' markets before the symptom onset. All other patients had no clear history of exposure to poultry. All patients exhibited fever with temperature of 38℃ to 40℃ (100.4℉ to 104℉), cough, shortness of breath, and white phlegm and loss of strength at the onset of the disease or within one week. They rapidly progressed to severe pneumonia and acute respiratory distress syndrome.

The intervals between the onset of symptoms and the initial imaging examinations ranged from one to six days for chest X-rays and two to nine days for computed tomography (CT).

Chest X-rays were taken every one or two days thereafter to monitor disease progression and treatment response. To evaluate disease progression and possible complications, 10 of the patients underwent follow-up CT two to eight days after initial examination.

The imaging findings included ground-glass opacity (a hazy area in the lungs with the appearance of ground glass) in all 12 patients, consolidations (regions of lung tissue filled with liquid) in 11 patients, air bronchograms (air-filled bronchi made visible by swelling in adjacent tissues) in 11 patients, and interlobular septal thickening (thickening of pulmonary connective tissue) in 11 patients. Lung lesions involved three or more lobes in all cases, but were mostly detected in right lower lobe. Follow-up computed tomography (CT) in 10 patients showed interval improvement of the lesions in three patients and worsening of the lesions in seven patients. Imaging findings closely mirrored the overall clinical severity of the disease.

"The distribution and very rapid progression of consolidations, ground-glass opacity, and air bronchograms, with interstitial changes, in H7N9 pneumonia help differentiate it from other causes of pneumonia," Dr. Zhang said.

While these imaging characteristics are similar to those found in other respiratory diseases, such as H1N1, H5N1 and severe acute respiratory syndrome (SARS), there are differences.

"Both H1N1 pneumonia and SARS distribute more peripherally, with more changes in the spaces between tissues, and progress less rapidly than H7N9," Dr. Zhang said. "In our study, the right lower lung was most likely to be involved, while there's no lobar predilection in findings of H5N1 influenza."

-end-

"Emerging H7N9 Influenza A (Novel Reassortant Avian-Origin) Pneumonia." Collaborating with Dr. Zhang were Qingle Wang, M.D., Yuxin Shi, M.D., Ph.D., and Yebin Jiang, M.D., 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..

RSNA is an association of more than 51,000 radiologists, radiation oncologists, medical physicists and related scientists promoting excellence in patient care and health care delivery through education, research and technologic innovation. The Society is based in Oak Brook, Ill. (RSNA.org)

For patient-friendly information on chest X-ray and CT, visit RadiologyInfo.org.

Radiological Society of North America
Birds become immune to influenza
An influenza infection in birds gives a good protection against other subtypes of the virus, like a natural vaccination, according to a new study.
Researchers shed new light on influenza detection
Notre Dame Researchers have discovered a way to make influenza visible to the naked eye, by engineering dye molecules to target a specific enzyme of the virus.
Maternal vaccination again influenza associated with protection for infants
How long does the protection from a mother's immunization against influenza during pregnancy last for infants after they are born?
Influenza in the tropics shows variable seasonality
Whilst countries in the tropics and subtropics exhibit diverse patterns of seasonal flu activity, they can be grouped into eight geographical zones to optimise vaccine formulation and delivery timing, according to a study published April 27, 2016 in the open-access journal PLOS ONE.
Influenza viruses can hide from the immune system
Influenza is able to mask itself, so that the virus is not initially detected by our immune system.
Using 'big data' to combat influenza
Team of scientists from the Icahn School of Medicine at Mount Sinai and Sanford Burnham Prebys Medical Discovery Institute among those who combined large genomic and proteomic datasets to identify novel host targets to treat flu.
Rapidly assessing the next influenza pandemic
Influenza pandemics are potentially the most serious natural catastrophes that affect the human population.
Early detection of highly pathogenic influenza viruses
Lack of appropriate drugs and vaccines during the influenza A virus pandemic in 2009, the recent Ebola epidemic in West Africa, as well as the ongoing Middle Eastern Respiratory Syndrome-Coronavirus outbreak demonstrates that the world is only insufficiently prepared for global attacks of emerging infectious diseases and that the handling of such threats remains a great challenge.
Study maps travel of H7 influenza genes
In a new bioinformatics analysis of the H7N9 influenza virus that has recently infected humans in China, researchers trace the separate phylogenetic histories of the virus's genes, giving a frightening new picture of viruses where the genes are traveling independently in the environment, across large geographic distances and between species, to form 'a new constellation of genes -- a new disease, based not only on H7, but other strains of influenza.'
Influenza A potentiates pneumococcal co-infection: New details emerge
Influenza infection can enhance the ability of the bacterium Streptococcus pneumoniae to cause ear and throat infections, according to research published ahead of print in the journal Infection and Immunity.

Best Science Podcasts 2017

We have hand picked the best science podcasts for 2017. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.

Now Playing: Radiolab

Truth Trolls
Today, a third story of folks relentlessly searching for the truth. But this time, the truth seekers are an unlikely bunch... internet trolls.


Now Playing: TED Radio Hour

Rethinking School
For most of modern history, humans have placed smaller humans in institutions called schools. But what parts of this model still work? And what must change? This hour, TED speakers rethink education.TED speakers include teacher Tyler DeWitt, social entrepreneur Sal Khan, international education expert Andreas Schleicher, and educator Linda Cliatt-Wayman.