ORIGINAL RESEARCH PEDIATRICS Diffusion Tensor Imaging and Fiber Tractography in Children with Craniosynostosis Syndromes

BACKGROUND AND PURPOSE: Patients with craniosynostosis syndromes caused by mutations in FGFR-2, FGFR-3, and TWIST1 genes are characterized by having prematurely fused skull sutures and skull base synchondroses, which result in a skull deformity and are accom-panied by brain anomalies, including altered white matter microarchitecture. In this study, the reliability and reproducibility of DTI fiber tractography was investigated in these patients. The outcomes were compared with those of controls. MATERIALS AND METHODS: DTI datasets were acquired with a 1.5T MR imaging system with 25 diffusion gradient orientations (voxel size 1.8 1.8 3.0 mm3, b-value 1000 s/mm2). White matter tracts studied included the following: corpus callosum, cingulate gyrus, fornix, corticospinal tracts, and medial cerebellar peduncle. Tract pathways were reconstructed with ExploreDTI in 58 surgically treated patients with craniosynostosis syndromes and 7 controls (age range, 6–18 years). RESULTS: Because of the brain deformity and abnormal ventricular shape and size, DTI fiber tractography was challenging to perform in patients with craniosynostosis syndromes. To provide reliable tracts, we adapted standard tracking protocols. Fractional anisotropy was equal to that in controls (0.44 versus 0.45 0.02, P .536), whereasmean, axial, and radial diffusivity parameters of themeanwhitematter were increased in patientswith craniosynostosis syndromes (P .001). No craniosynostosis syndrome–specific difference inDTI properties was seen for any of the fiber tracts studied in this work. CONCLUSIONS: Performing DTI fiber tractography in patients with craniosynostosis syndromes was difficult due to partial volume effects caused by an anisotropic voxel size and deformed brain structures. Although these patients have a normal fiber organization, increased diffusivity parameters suggest abnormal microstructural tissue properties of the investigated white matter tracts