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

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.