Purpose: To evaluate the indications, number, and imaging results of brain computed tomography (CT) and diffusion weighted imaging (DWI) in children with ventriculoperitoneal shunt, to estimate the radiation dose, and to evaluate the effectiveness of DWI.
Methods: This retrospectively study included 54 consecutive patients (boys/girls = 30/24, mean age, 3 ± 4.1 years) with shunt that were placed due to congenital abnormalities-hypoxic ischemic encephalopathy between January 2015 and March 2018. The presence of shunt-related complications (SRC) was assessed using clinical and neuroimaging findings, and the standard reference was accepted as the shunt revision. Size comparisons of ventricles were performed using Evans index and the frontal and occipital horn ratio, and each measurement made by the observers were compared using Bland-Altman analysis. A kappa coefficient and the intraclass correlation coefficient were calculated to assess the agreement between observers.
Results: The mean number of hospital admission, number of CT scans, and DWI were 5.8, 4.8, and 1.1, respectively per patient. A significant linear correlation was observed between hospital admission and CT scans (r = 0.288, p = 0.035). The number of CT scans and the cumulative effective dose per patient were higher in patients with SRC than in those without (p < 0.001). The mortality rate due to radiation-induced neoplasia has increased by 0.33% in the study period. The inter-observer agreement was perfect or substantial for the catheter visualization, assessment of the ventricular system on DWI, and for the image quality of DWI between observers (κ = 0.704-1, p ≤ 0.001). No significant difference was found between CT and DWI in the measurements of Evans index and the frontal and occipital horn ratio (p > 0.05). Inter-observer agreements between observers were almost perfect for the Evans index and the frontal and occipital horn ratio (ICC = 0.94-0.99, p < 0.001).
Conclusions: An awareness of the use of CT in children is still inadequate and difficulties in the diagnosis of SRC probably cause the overuse of CT. DWI should be preferred in the diagnosis of SRC and the follow-up of patients. Otherwise, the increase in the prevalence of several diseases, particularly neoplasia, may be inevitable because of the over use of CT.
Keywords: Diffusion weighted imaging; Radiation dose; Ventriculoperitoneal shunt.