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
|Contact: Linda Brooks|
Radiological Society of North America