Brain structure in sagittal craniosynostosis

Abstract

Craniosynostosis, the premature fusion of one or more cranial sutures, leads to grossly abnormal head shapes and pressure elevations within the brain caused by these deformities. To date, accepted treatments for craniosynostosis involve improving surgical skull shape aesthetics. However, the relationship between improved head shape and brain structure after surgery has not been yet established. Typically, clinical standard care involves the collection of diagnostic medical computed tomography (CT) imaging to evaluate the fused sutures and plan the surgical treatment. CT is known to provide very good reconstructions of the hard tissues in the skull but it fails to acquire good soft brain tissue contrast. This study intends to use magnetic resonance imaging to evaluate brain structure in a small dataset of sagittal craniosynostosis patients and thus quantify the effects of surgical intervention in overall brain structure. Very importantly, these effects are to be contrasted with normative shape, volume and brain structure databases. The work presented here wants to address gaps in clinical knowledge in craniosynostosis focusing on understanding the changes in brain volume and shape secondary to surgery, and compare those with normally developing children. This initial pilot study has the potential to add significant quality to the surgical care of a vulnerable patient population in whom we currently have limited understanding of brain developmental outcomes.

Keywords: Brain Tissue segmentation; Computer Assisted Intervention Planning; Full vault reconstructive surgery; Osteoarthritis; Statistical Shape Analysis; sagittal craniosynostosis.

Figure 1

Example of anatomical features displayed in a male sagittal craniosynostosis subject. Areas of enlargement and compressing are indicated with red arrows in a) axial, b) sagittal and c) coronal views.

Figure 2

Scatterplots for different imaging-derived volumetric data: a) ICV volume (non-regressed), b) WM + GM volume, c) CSF volume and d) MR T1-w image of a pre-surgical craniosynostosis (left) and label segmentation (right) displaying WM in red, GM in green and CSF in blue.

Figure 3

Scatterplot for the ICV volumes obtained from the 4D model of normative evolution. Solid line blue line indicates the mean healthy atlas with one and minus standard deviations displayed in dashed blue. Red arrows indicate the pre- and post-surgical ICV measurements obtained from a sagittal craniosynostosis patient for which surgery did not normalize the volume, whereas green arrows indicate the pre- and post-surgical ICV measurements from a patient for which surgery did helped normalizing ICV.

Figure 4

Example of shape analysis for a patient for which ICV did not normalize after surgery (on the left) and another patient for which ICV did normalize after surgery (on the right). a) pre-surgical and c) post-surgical semitransparent overlays between (green) age matched normal brain shape and (red) brain shape for the patient. b) pre-surgical and d) post-surgical shape analysis measurements illustrating the magnitude and the direction (compression – red, expansion – blue) of shape changes.