Dedicated sub 0.1 mSv 3DCT using MBIR in children with suspected craniosynostosis: quality assessment.

OBJECTIVE: To retrospectively compare image quality of a lowered dose CT protocol to a standard CT protocol in children with suspicion of craniosynostosis.

METHODS: Forty-eight patients (age 0- 35 months), who presented with a cranial deformity underwent cranial 3D CT to assess sutural patency: between 2009 - 2010, 24 patients were imaged with a standard protocol (CTDIvol 32.18 mGy), from 2011-2012, 24 underwent a low dose protocol (0.94 mGy) combined with iterative reconstruction. Image quality was evaluated by both expert reading and objective analysis. Differences were assessed by independent t-test and Mann-Whitney U test, interreader agreement by Cohen's Kappa test.

RESULTS: Effective dose of the low dose protocol was 0.08 mSv, corresponding to a reduction of 97 %. Image quality was similar in both groups in terms of overall diagnostic acceptability, objective noise measurements, subjective cranial bone edge sharpness and presence of artefacts. For objective sharpness of cranial bone-brain interface and subjective perception of noise, the images of the low dose protocol were superior. For all evaluated structures, interreader agreement was moderate to almost perfect.

CONCLUSION: In the diagnosis of craniosynostosis in children with cranial deformities, a dedicated sub 0.1 mSv cranial 3DCT protocol can be used without loss in image quality.

KEY POINTS: 3DCT is used for the diagnosis of craniosynostosis. Imaging protocols should be optimized to minimize radiation exposure to children. Combining 80 kVp with iterative reconstruction can help to reduce dose. A sub 0.1 mSv cranial 3DCT protocol can be used without loss of diagnostic quality.