Optimal tube voltage for abdominal enhanced CT in children: a self-controlled study

Abstract

Background The use of weight-adapted pediatric computed tomography (CT) tube voltage protocols has been suggested, but a consensus standard has not been established and clinical available studies are not sufficient. Purpose To determine the best tube voltage for low dose abdominal CT imaging in children. Material and Methods Eighty-seven cases who needed three CT exams in a 1–3-month interval between scans were enrolled (mean age = 4.69 ± 3.20 years). The three scans were performed with three different tube voltages at 80 kV, 100 kV, and 120 kV, keeping the same radiation dose and same contrast injection protocol. Patients were divided into five groups for analysis based on their body weight. The subjective image quality of the three exams were evaluated using a 4-point scale (4 being the best) for image noise and image quality. The objective evaluation in terms of CT values and standard deviation in aorta, liver, spleen, pancreas, and kidney were measured to calculate the degree of enhancement and contrast-to-noise ratio (CNR) of organs. One-way ANOVA was used to compare the subjective and objective image quality with respect to different tube voltages and different patient weights. Result The 80-kV tube voltage provided the highest overall enhancement and CNR for the entire patient population and the best objective image quality for the 6.1–28.0 kg subgroup. Conclusion Patient weight-dependent tube voltage selection maximizes image quality for abdominal enhanced CT in children. The optimal tube voltage for children with weight <28 kg is 80 kV; higher voltages should be selected for children weighing 28.1–50.0 kg.