One-phase Split-bolus CT Urography – a Novel Approach To Reduce Radiation Dose in Diagnostics of Congenital Anomalies of Kidneys and Urinary Tract in Children

BACKGROUND: Low-dose CT Urography (LD-CTU) has become a standard procedure in urinary tract abnormalities in children, especially when MR Urography is not available. Standard one-phase CTU is performed in excretory phase. There is also a split-bolus technique, which combines two or even three phases during one scan and provides more clinical information without higher radiation exposure. It can be implemented for congenital anomalies of kidneys and urinary tract (CAKUT) in children, however, this application is not deeply discussed in scientific literature. Aim of this publication is to present the protocol and determine the role of LD-CTU in diagnostic imaging of CAKUT in children. MATERIAL AND METHODS: Close to 300 CTUs in children were performed as a standard of care during the last 6 years in our Department. Diagnostic accuracy in suspected CAKUT was analyzed, depending on applied protocol − standard excretory CTU, multiphase CTU and two different one-phase split-bolus CTU protocols. RESULTS: Visualization of the urinary tract was adequate in all study protocols. However, more clinically significant information was received in vascular-excretory protocol, including vascular and renal anatomy. Radiation exposure was similar or even lower than in other study protocols. CONCLUSIONS: One-phase split-bolus CTU protocol is a novel approach in low-dose diagnostic imaging of CAKUT in children. Combination of vascular and excretory phases has been shown as very effective technique, especially in comprehensive anatomical assessment of the abnormality and qualification to surgical intervention.