Abstract Objectives To analyse changes in the use of paediatric (≤16 years) CT over the past decade and to evaluate the appropriateness of CT examinations at a tertiary teaching hospital. Methods Data of 290 paediatric CTs were prospectively collected in 2022 and compared with data from 2017 (358 cases) and 2012 (538 cases). The justification of CTs was evaluated with regard to medical imaging referral guidelines and appropriateness rates were calculated. Results Paediatric CTs decreased 39.4% over the ten years, contrasting with a 27.6% increase in overall CTs. Paediatric CTs as the share of overall CTs dropped from 2.5% in 2012 to 1.1% in 2022 (p < 0.0001), with a concurrent rise in paediatric MRIs (p < 0.0001). Notable reductions in CT use occurred for head trauma (p = 0.0003), chronic headache (p < 0.0001), epilepsy (p = 0.037), hydrocephalus (p = 0.0078), chest tumour (p = 0.0005) and whole body tumour (p = 0.0041). The overall appropriateness of CTs improved from 73.1% in 2017 to 79.0% in 2022 (p = 0.0049). In 15.4% of the cases, no radiological examination was deemed necessary and in 8.7% of the cases another modality was more appropriate. Appropriateness rates were the highest for the head and neck angiography (100%) and the chest (96%); and the lowest for the neck (66%) and the head (67%). Conclusions Justification of CT scans can be improved by regular educational interventions, increasing MRI accessibility, and evaluating the appropriateness of the requested CT before the examination. Interventions for a more effective implementation of referral guidelines are needed. Advances in knowledge Focus for improvement should be CTs for head and cervical spine trauma, accounting for the majority of inappropriate requests in the paediatric population.