Objectives
The aim of this study was to compare cerebral blood flow single-photon emission tomography (CBF SPET) and vascular reserve in patients with premature craniosynostosis before and after surgery using regional CBF on anatomically standardized resting and acetazolamide (ACZ)-challenged CBF SPET images, which were obtained using 3DSRT, fully automated ROI analysis software.
Method
Twenty patients with premature craniosynostosis from 5 months to 5 years of age were treated in Saitama Children's Medical Center, 1 patient with cloverleaf skull associated with hydrocephaly, 3 patients with oxycephaly, 7 patients with brachycephaly, 4 patients with scaphocephaly, 3 patients with trigonochepaly, 1 patient with plagiocephaly and 1 patient with lamboid synostosis. Tc-99 m ECD brain SPET with ACZ challenge were performed before and after surgery on all patients. The SPET images were anatomically standardized using SPM99 followed by quantification of 318 constant ROIs, grouped into 12 segments in each hemisphere to calculate segmental CBF as the area-weighted mean value for each of the respective 12 segments based on the regional CBF in each ROI. The percent change in CBF following the administration of ACZ was computed for each of the 12 segments.
Results
Only 1 patient with cloverleaf skull showed abnormal CBF distribution on resting CBF SPET image before surgery, decreased CBF in bilateral parietal, occipital lobes and cerebellum. After surgery, abnormal CBF distribution was not detected in this patient. There was no abnormal CBF distribution on resting CBF SPET image in 19 patients. Sixteen patients showed poor vasodilatory reactivity to ACZ in whole cerebral cortex, with under 10% of the percent change, before surgery. Four patients with 1 scaphocephaly, 1 trigonocephaly, 1 plagiocephaly and 1 lamboid synostosis were confirmed good reactivity to ACZ, with over 20% of the percent change, before surgery. After surgery, 13 patients in 15 patients with poor vasodilatory reactivity (86.7%) showed improvement of vasodilatory reactivity to ACZ in whole cerebral cortex, in 9 patients with over 20% of the percent change. Three patients with 1 cloverleaf skull, 1 brachysephaly and 1 scaphocephaly were not confirmed improvement of reactivity to ACZ after surgery.
Conclusion
Patients with usual premature craniosynostosis without cloverleaf skull associated with hydrocephaly did not show abnormal CBF distribution or definite decreased CBF in cerebral parenchyma, however 78.9% (15/19) were confirmed poor vasodilatory reactivity to ACZ in cerebral cortex. After surgery, 86.7% (13/15) showed improvement of vasodilatory reactivity. ACZ-activated quantitative SPET images showed diffuse cerebral impairment of vascular reserve before surgery and improvement after surgery in usual premature craniosynostosis. In severe premature craniosynostosis i.e. cloverleaf skull associated with hydrocephaly, hypoperfusion was detected in cerebral and cerebellar cortex before surgery and improvement of resting perfusion was showed with limited vasodilatory potential after surgery.