Successful Dose Reduction Using Reduced Tube Voltage With Hybrid Iterative Reconstruction in Pediatric Abdominal CT.

OBJECTIVE: The purpose of this article is to assess radiation dose reduction, image quality, and diagnostic confidence using low tube voltage in combination with hybrid iterative reconstruction in contrast-enhanced pediatric abdominal CT. MATERIALS AND METHODS: CT examinations of 133 patients (median age, 10 years) were performed at sequentially reduced doses. The first group (group 1) was scanned using dimension-based protocols at 120 kV for all patient sizes. The optimized group (group 5) was scanned at 80 kV for less than 18 cm in the lateral dimension and 100 kV in the 19-30 cm lateral dimension. CT examinations reconstructed with filtered back projection (FBP) and four levels of hybrid iterative reconstruction were reviewed by four blinded readers for subjective image quality and diagnostic confidence. Objective noise, volume CT dose index (CTDIvol), and size-specific dose estimate (SSDE) were recorded. Data were analyzed using t tests, one and two-way ANOVA, and the intraclass correlation coefficient. RESULTS: Compared with group 1, the radiation dose was reduced for group 5 by 63% measured by SSDE (4.69 vs 10.00 mGy; p < 0.001). Subjective image noise was increased for FBP images (p < 0.001) but not was statistically significantly different for all levels of hybrid iterative reconstruction; artifacts were reduced and visibility of small structures was improved (both p < 0.001). Diagnostic confidence was improved for solid organ injury and metastatic disease (both p < 0.001) and was not statistically significantly different for appendicitis (p = 0.306). CONCLUSION: Use of hybrid iterative reconstruction with low-tube-voltage protocols enables substantial radiation dose reduction for pediatric abdominal CT with equivalent to improved subjective image quality and diagnostic confidence.

Prophylactic Use of Nebulized Hypertonic Saline in Mechanically Ventilated Children: A Randomized Blinded Pilot Study.

BACKGROUND: Mucolytic agents, such as nebulized hypertonic saline, may improve airway clearance and shorten the duration of mechanical ventilation, but prospective blinded studies in children undergoing mechanical ventilation are lacking. METHODS: Children <18 y old who had been intubated for <12 h and had an expected duration of mechanical ventilation of >48 additional h were prophylactically given 3 mL of either nebulized hypertonic saline or placebo (0.9% saline) 4 times/d. The primary outcome was duration of mechanical ventilation. Ventilator parameters and the presence of wheezing were recorded before and after study drug administration. RESULTS: The duration of mechanical ventilation was significantly longer in children treated with hypertonic saline (208.1 [interquartile range 136.3-319.8] h) versus those treated with placebo (129.5 [interquartile range 74.4-146.1] h) (P = .03 by Wilcoxon rank-sum test). After adjusting for baseline levels of PEEP, the duration of mechanical ventilation did not differ between groups. Mechanical ventilation parameters, including dead space and dynamic compliance, did not differ between measurements taken before study drug administration versus measurements taken after. New onset wheezing following study drug administration was rare (1.0% with hypertonic saline vs 3.0% with placebo, P = .36 by chi-square test). CONCLUSIONS: Administering prophylactic nebulized hypertonic saline to mechanically ventilated children did not improve clinically relevant outcomes, including duration of mechanical ventilation. Wheezing after hypertonic saline treatment was rare.