Correlation of the Interval Between Single Phase Computed Tomography and Direct Abdominal Radiography with the Success of Collecting System Imaging in Trauma Patients

Abstract

Objective: A triple-phase computed tomography (CT) is required to visualize post-traumatic ureteral injury in children. An abdominal X-ray following single-phase contrast enhanced CT is performed both to evaluate urinary tract and to reduce the radiation exposure in our center. The aim of this study was to designate an optimal interval between CT and X-ray in imaging the urinary collecting system. Method: Records of pediatric trauma patients who underwent a CT scan were analyzed. CT and X-ray images were evaluated and the time interval between two imaging modalities was calculated. The success of X-ray in demonstrating bilateral renal pelvises, ureters and bladder was evaluated. Results: The study population consisted of 190 patients with a male predominance (72.6%) and a median age of 9 years (2 months-17.9 years). The median time interval between the CT and X-ray was 59.5 minutes. Time interval between both imaging modalities was significantly longer if the images were not satifactorily demonstrative (72.5 vs. 39.5 minutes) (p<0.001). Age (p=0.722), gender (p=0.203) and type of trauma (p=0.796) had no effect on this time interval. When the patients were grouped according to the time elapsed between these two imaging modalities as 10-30 minutes (Group 1) and longer (Group 2), the proportion of patients with optimally demonstrative X-rays was significantly higher in Group 1 (p=0.001). Conclusion: Ureter injuries are rare and cannot be mostly diagnosed with single-phase CT-scans, but a triple-phase scan increases the radiation burden especially for children. Our plan is to validate our technique using an X-ray following CT-scan for evaluating the urinary tract in trauma, and this preliminary retrospective study confirmed that time interval of 10-30 minutes between these two imaging modalities should be considered in future studies.

Keywords

• trauma
• injuries
• tomography
• x-ray
• children
• ureter