Ventriculoperitoneal shunt survey in pediatric patients in an emergency setting: a comparison between ultra-low-dose CT using a tin filter and plain radiography.

OBJECTIVE: The aim of this study was to investigate the diagnostic performance, effective radiation dose, and examination time of ventriculoperitoneal shunt evaluation using full-body ultra-low-dose CT (ULD CT) with a tin filter compared with digital plain radiography in a pediatric population. METHODS: A retrospective cross-sectional study was conducted in an emergency setting. Data from 143 children were collected. Sixty were examined with ULD CT with a tin filter and 83 with digital plain radiography methods. Effective doses and times were compared between the two methods. Two observers in pediatric radiology evaluated the patient images. Clinical findings and results from shunt revision, if it was performed, were used to evaluate the diagnostic performance between modalities. An examination-room simulation was performed of the two methods to estimate representative examination times. RESULTS: The mean effective radiation dose for ULD CT with the tin filter was estimated to be 0.29 ± 0.16 mSv compared with 0.16 ± 0.19 mSv for digital plain radiography, with both examinations associated with a very low lifetime attributable risk (< 0.01%). The shunt tip could be more reliably located with ULD CT. ULD CT also allowed assessment of additional findings to explain patient symptoms, such as a cyst at the tip of the shunt catheter and the presence of an obstructing rubber nipple in the duodenum that could not have been observed on a plain radiograph. The examination time with ULD CT of the shunt was estimated to be 20 minutes. The examination time of the shunt with digital plain radiography, including the examination itself time and transfer of the patient between rooms, was estimated to be 60 minutes. CONCLUSIONS: ULD CT using a tin filter allows good visualization of the position or disruption of the shunt catheter that is comparable or superior to plain radiography, at a higher dose, while providing additional findings and reduced patient discomfort.

Diagnosis of foreign body aspiration with ultralow-dose CT using a tin filter: a comparison study.

PURPOSE: Suspected airway foreign body aspiration (FBA) is a common event in paediatric emergency units, especially in children under 3 years of age. It can be a life-threatening event if not diagnosed promptly and accurately. The purpose of this study is to compare the diagnostic performance of an ultralow-dose CT (DLP of around 1 mGycm) with that of conventional radiographic methods (fluoroscopy and chest radiography of the airways) in the diagnosis of FBA children's airways. METHODS: Retrospective cross-sectional study. Data from 136 children were collected: 75 were examined with conventional radiographic methods and 61 with ultralow-dose CT. Effective doses were compared using independent t tests. The results of bronchoscopy, if performed, were used in creating contingency 2 × 2 tables to assess the diagnostic performance between modalities. An extra triple reading of all images was applied for this purpose. RESULTS: The effective doses used in the ultralow-dose CT examinations were lower compared with those in conventional methods (p < 0.001). The median dose for CT was 0.04 mSv compared with 0.1 mSv for conventional methods. Sensitivity and specificity were higher for ultralow-dose CT than those for conventional methods (100% and 98% versus 33% and 96%) as were the positive and negative predicted values (90% and 100% versus 60% and 91%). CONCLUSION: Ultralow-dose CT can be used as the imaging of choice in the diagnosis of airway FBA in emergency settings, thereby avoiding concerns about radiation doses and negative bronchoscopy outcomes.