CT Perfusion Evaluation of Cerebral Haemodynamics before and after Cranioplasty

Abstract

CT Perfusion imaging is usually applied to assess perfusion abnormalities in acute stroke. This prospective study applied the technique to monitor cerebral haemodynamics before and after cranioplasty. Cranioplasty is the surgical correction of a skull defect using autologous or heterologous material to obtain cosmetic repair, restoration of brain protection and neurological improvement (1). As far as we know the effect of cranioplasty on cerebral haemodynamics flow has been analysed by CT perfusion only in one article (2). We tested the examination as method of monitoring intracranial haemodynamics in a larger number of patients evaluating its reliability and efficacy. We prospectively examined cerebral haemodynamics with Perfusion CT before and after (two weeks, three and six months) cranioplasty in ten patients. The data evaluation of dynamic CT was done by an application software package on a workstation (Leonardo) permitting the use of visual assessment combined with quantitative analysis with ROIs. There was a comparison of CBF, CBV and TTP values between the regions of interest and mirror-image control regions, and in the three different examinations for each patient. After cranioplasty there was clearly an improvement in neurological symptoms and CT perfusion in the majority of cases showed a slight increase in CBF, CBV and decrease of TTP in the cerebral parenchyma close to the cranioplasty, not only on the symptomatic side but also on the opposite side. Even though there was neurological improvement and improved cranial perfusion from the first to the last examinations, our data were not statistically significant. The method is easily reproducible, well tolerated by all patients but has several limitations related to data processing and radiation exposure.