We retrospectively reviewed 70 children with craniosynostosis (2019).
55 children underwent CT using a 64-layer multi-detector scanner (LightSpeed VCT 64, GE), without contrast medium. For 15 children, a 128-layer Siemens Definition Flash CT was used.
Most of the infants underwent CT during spontaneous sleep and only a minority performed the sedation exam.
The average age of the children examined is just under 1 year.
The retrospective study showed a huge variation in the acquisition parameters with CTDIvol varying from 3 mGy to 120 mGy, with an average value of about 33 mGy. This variation is certainly due to the technological difference of the two CT systems but basically it depends on the high number of radiographers and radiologists who perform the tests, with different training.
The in-depth retrospective analysis of the acquisition parameters (Kv, mAs, noise index, CTDI, DLP, pitch etc…) allowed to present a low dose protocol.
The low-dose protocol was tested on a phantom and measurements were made of the following values: Noise (sd HU), Resolution (MTF Cy/cm), Contrast (%), Dose (mGy), Linearity, Uniformity (sd HU).
Data acquisition was carried out on a CATPHAN T600 phantom.
18 series were performed by varying the following parameters: Kv, mA range and the percentage of ASIR, as shown in table 1. Measurements were made on the 64-layer multi-detector scanner (LightSpeed VCT 64, GE). The fixed parameters used are the following: mode helical full, rotation time 1 sec., detector cover 40mm, thickness 0,625mm, SFOV head, DFOV 24cm, noise index 10, automA, smartmA on, pitch 1.