Thin-Section CT 12 Months After the Diagnosis of Severe Acute Respiratory Syndrome in Pediatric Patients

Abstract

OBJECTIVE. The objective of our study was to report the thin-section CT findings 12 months after the diagnosis of severe acute respiratory syndrome (SARS) in pediatric patients who had recovered clinically but had persistent abnormal CT findings 6 months after the diagnosis. The clinical data for these patients were correlated to identify risk factors that might increase the likelihood of the development of CT abnormalities. SUBJECTS AND METHODS. The study involved an extended 12-month thin-section CT follow-up of 16 of 47 pediatrics patients with SARS coronavirus-associated pneumonia proven serologically (21 girls and 26 boys; age range, 1.5-17 years; median age, 13.6 years). Patients' clinical information, the extent of radiographic opacification during the acute phase of illness, and conventional pulmonary function test results on follow-up were obtained for correlation. The clinical parameters were compared with other pediatric SARS patients who had normal CT findings at the 6-month follow-up. RESULTS. Fifteen patients still had abnormal CT findings 12 months after diagnosis, all of whom were older than 10 years (age range, 10-17 years). In seven patients with previous residual ground-glass opacification at the 6-month follow-up, two showed persistent changes and three had a reticular pattern in the area of the previously detected abnormality, whereas two showed complete resolution. The extent of air trapping remained similar to that at the 6-month follow-up in nine of 11 patients while two showed a slight increase in the same segments. Parenchymal scars remained unchanged from the 6- to 12-month follow-up in all six patients with that finding. None of our patients showed any evidence of bronchiectasis or bronchial wall thickening. Lymphopenia (p = 0.03), extent of radiographic opacification at acute illness (p = 0.047), and duration of use of ribavirin (p = 0.03) were significant risk factors in predicting whether abnormal CT features persisted 12 months after diagnosis. CONCLUSION. We found that 32% of the children (15/47) affected with SARS showed thin-section CT abnormalities up to 12 months after diagnosis despite clinical remission and unremarkable pulmonary function assessment. Persistent CT abnormalities are more likely to develop in patients who are older and who present with more severe disease. The CT changes in children with SARS are, however, minor.