CT cannot be regarded as a ‘benign’ intervention, on the basis of the rarity of immediate complications, Dr. Yakov Sivan at Tel Aviv Souraski Medical Center and co-authors note.
They reported that a chest radiograph emits a dose of about 0.01 to 0.02 mSv, whereas radiation doses from chest CT are approximately 1.7 to 8 mSv. The dosage depends on the number of scans, the scanning time, and size of the area being scanned.
The investigators reported that the risk is greater in children than adults from a given radiation dose, due to longer life span during which radiation-induced cancer may develop, and the fact that children have more dividing cells at a sensitive neoplastic transformation phase.
Dr. Sivan’s team assessed the initial evaluation of lung disease in children, looking at yield. A positive yield was determined when CT provided at least one of the following: a diagnosis, a clinically important new finding, alteration of the plan of treatment or for further evaluation, or exclusion of lung disease.
The chort study involved 120 patients with median age of 4.7 years at the time of the CT, (range, 2 weeks to 16 years). The positive yield was 61%, after excluding 15 children because of suspected bronchiectasis.
For nonbronchiectatic diffuse lung disease, the positive yield was 23%, whereas the yield was 46% for nonbronchiectatic focal lung disease. The positive yield for patients with congenital lung disease was 98%. For mediastinal disease, the positive yield was 100%, while for the pleural group it was 50%.
In the majority of cases of undiagnosed diffuse lung disease, however, the contribution of CT to the diagnosis was disappointing, the authors note. In many such cases, the final diagnosis depends on histologic definitions that do not necessarily have a specific or pathognomonic radiologic pattern.
They urge, The yield of CT should be taken into consideration whenever this modality is used.
Along with more judicious use of chest CT in children, Dr. Sivan and associates hope that this study will stimulate carefully designed investigations to define the yield of CT in the various presentations of pediatric lung disease.
