Low-Dose High-Resolution CT of the Chest in Children and Young Adults

Abstract

OBJECTIVE. The radiation dose, artifact incidence, and image quality of high-resolution chest CT examinations performed with standard and low doses and patient cooperation were investigated in children and young adults. SUBJECTS AND METHODS. Three successive controlled studies were conducted in different groups of children and young adults, totaling 203 patients. Dosimetry of high-resolution CT was performed at 180, 50, and 34 mAs in three groups of 25 patients. Streak artifact incidence using alternating 50- and 34-mAs slices was assessed and correlated with patient compliance with breath-holding commands in 44 children. Image quality was evaluated in scans obtained with 34 versus 180 mAs in cooperative patients (n = 42) and in scans obtained with 50 versus 180 mAs in noncooperative patients (n = 42). Artifacts and image quality were assessed by controlled repeated interpretations. RESULTS. Radiation dose was 5.4 ± 1.6 mSv for 180 mAs, 1.5 ± 0.5 mSv for 50 mAs, and 1.1 ± 0.3 mSv for 34 mAs. Cooperation was obtained in 66% of the patients. Artifacts were more frequently seen in scans of noncooperative patients (30%) and in 34-mAs scans (47%); the highest incidence was found using 34 mAs in noncooperative patients (60%, p = 0.02). No differences in image quality scores were seen in scans obtained with 50 mAs versus those obtained with 180 mAs in noncooperative patients (p < 0.05), and small differences were found in scans obtained with 34 mAs versus those obtained with 180 mAs in cooperative patients for fissures (p = 0.005) and peripheral structures (p = 0.02). CONCLUSION. Low-dose high-resolution CT provided a significant reduction in radiation dose (72% for 50 mAs and 80% for 34 mAs) and good-quality images of the lung when performed with 50 mAs in noncooperative and 34 mAs in cooperative pediatric and young adult patients.