Pediatric chest CT: Wide-volume and helical scan modes in 320-MDCT

OBJECTIVE. The purpose of this study was to compare wide-volume and helical pediatric 320-MDCT of the chest with respect to radiation dose and image quality. MATERIALS AND METHODS. From November 2012 to September 2013, 59 widevolume and 47 helical pediatric chest 320-MDCT images were obtained. The same tube potential and effective tube current-time product were applied in the two groups according to patient weight (group A, < 10 kg, n = 18; group B, 10-19.9 kg, n = 60; group C, 20-39.9 kg, n = 28). To compensate for overranging, adjusted CT dose index (CTDI) was calculated by dividing doselength product (DLP) by the scan ranges imaged. Adjusted CTDI, DLP, overall image quality, motion artifact, noise, and scan ranges were compared by Mann-Whitney U test or t test. RESULTS. The adjusted CTDI was significantly lower in the group who underwent widevolume CT than in the group who underwent helical CT (weight group A, p < 0.001; group B, p < 0.001; group C, p = 0.003). The DLP was lower in the wide-volume group than in the helical CT group in weight groups A (p < 0.001) and B (p < 0.001) but not in group C (p = 0.162). All CT scans were of diagnostic quality, and there was no significant difference between the wide-volume and helical CT groups (p = 0.318). The motion artifact score was significantly higher in the wide-volume group than in the helical CT group in groups B (p < 0.001) and C (p = 0.010) but not in group A (p = 0.931). The noise was significantly lower in the wide-volume group than in the helical CT group (p < 0.001). CONCLUSION. In pediatric chest CT, use of wide-volume CT can decrease radiation exposure while preserving image quality. It is associated with less noise than helical CT but may be subject to more motion artifact.