112 Chapter 7 METHODS The Institution Research Ethics Board at Erasmus University Medical Center, Rotterdam, the Netherlands approved this study (approval no.: MEC-2014-461), which is a part of ongoing work at the Dutch Craniofacial Center and involves protocolized care, brain imaging, clinical assessment, and data summary and evaluation.6, 20, 21 We reviewed the medical records of CP syndrome patients who were managed at our center between 2008 and 2018. Our usual practice in such patients involves scheduled primary vault expansion in the first year of life. Patients were included in this study if they had cranial magnetic resonance imaging (MRI) data that could be extracted and analyzed from three-dimensional T1-weighted fast spoiled gradient echo sequences. We excluded patients in whom the quality of imaging was not suitable for analysis. Additional clinical and demographic data collected include sex, age at the time of MRI, birth weight, age at the time of vault expansion, initial type of vault expansion, and synostosis pattern. Initial type of vault expansion was classified as frontal or occipital. Suture-specific synostosis was noted in each patient as a binary variable for each of the 6 major sutures. Partial involvement of a suture was considered as positive. Fundoscopy to assess for papilledema was also performed in all cases by a pediatric ophthalmologist before surgery, 3 months postoperatively, biannually until the age of 4, annually until the age of 6 and then upon indication in older patients. When papilledema was detected, it was followed up with confirmatory fundoscopy and imaging 4–6 weeks later. Data from these examinations were collected to analyze the presence of ICH both pre and postoperatively. MRI Acquisition All MRI scans were performed on a 1.5 T scanner (GE Healthcare, MR Signa Excite HD, Little Chalfont, UK) with the imaging protocol, including a three-dimensional fast spoiled gradient echo T1-weighted MR sequence. Imaging parameters for craniosynostosis patients were the following: 2 mm slice thickness, no slice gap; field of view (FOV): 22.4 cm; matrix size: 224 × 224; in plane resolution of 1 mm; echo time : 3.1 ms; and repetition time: 9.9 ms.22 MRI was the imaging modality of choice in this study because of its ability to adequately distinguish between tissue densities (white matter, grey matter, and dura) critical to the calculation of cerebral cortical thickness. Cortical Thickness and Brain Volume MRI dicom files were exported and converted to neu-roimaging informatics technology initiative (NIfTI)-1 file format on a computer cluster with Scientific Linux as the operating system before analysis with FreeSurfer software modules (v6.0, see https://surfer. nmr.mgh.harvard.edu) developed by the Athinoula A. Martinos Center for Biomedical
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