Hepatic enhancement analysis in children using Smart Prep monitoring for 2 : 1 pitch helical scanning

Abstract

Purpose. To analyze hepatic enhancement by using Smart Prep protocols appropriate for children of different weight groups and 2:1 pitch helical CT imaging as the investigative tools. Patients and methods. A group of 55 children ranging in weight between 20 and 180 lbs underwent 67 contrast-enhanced abdominal helical CT examinations using Smart Prep (GE Medical Systems, Milwaukee, Wisc.). Of these studies, 21 (31 %) were excluded because of failure to follow the prescribed Smart Prep protocols. Smart Prep protocols were established for nine different weight groups. Scan delay, aorta and liver time to peak, and liver enhancement over baseline were recorded. Results. Optimal abdominal CT studies with adequate contrast enhancement of hepatic and portal veins were obtained in 46 patients. There was no significant difference in the time between peak aortic and the liver enhancement among different weight groups (mean time 12.0 ± 7.1 s for all children). However, the mean hepatic enhancement over baseline in children weighing < 30 lbs was below 50 Hounsfield units (HU) compared to the rest of the children who had mean hepatic enhancement of > 50 HU. Conclusion. Two-thirds of the Smart Prep protocols were successfully implemented, and all of these resulted in good contrast enhancement of hepatic and portal veins. Optimal mean liver enhancement (> 50 HU) was seen in children ≥ 30 lbs. Children < 30 lbs had mean liver enhancement of 33 HU ± 7.2 above the baseline likely caused by contrast dose.