Radiation doses in ventriculoperitoneal shunt catheter imaging - Comparing traditional plain radiography with computed tomography and photon counting computed tomography.

INTRODUCTION

Hydrocephalus is a common condition with enlarged ventricles in the brain. It is often surgically treated with a ventriculoperitoneal shunt system. These patients require regular radiological controls, which exposes them to a cumulative dose of ionizing radiation. The aim with this study was to identify CT protocols that provide diagnostically adequate image quality with equal or lower radiation dose, compared with traditional plain radiography.

METHODS

Four anthropomorphic phantoms representing pediatric patients of ages 1, 5 and 10, and an adult, were imaged with a series of CT protocols on three different scanners (including one photon counting) to determine a protocol that would offer the lowest radiation dose with adequate image quality. The image quality was visually assessed and graded by two radiologists. For comparison, a retrospective study was conducted on patients who had undergone a shunt series with plain radiography from April 2021 to December 2023.

RESULTS

The mean effective dose for all the 137 patients imaged with plain radiography was 2.35 mSv, ranging from 0.14 to 3.73 mSv. The mean effective dose increased with age. For all four phantoms, the study identified at least one CT protocol that provided a lower effective dose than the mean dose from plain radiography in the respective age group, as well as one minimal dose protocol per patient group. As expected, CT examinations had significantly shorter time durations (approximately 10 s vs 14.9 min for adults).

CONCLUSION

This study showed that various low-dose CT protocols, with or without photon counting technology, can be used for imaging ventriculoperitoneal shunt catheters, with comparable or lower effective dose compared with plain radiography.

IMPLICATIONS FOR PRACTICE: A transition from plain radiography to CT offers several benefits, such as decreased discomfort for the patient, shorter examination time, richer imaging data, and decreased radiation dose.