Cerebral blood flow measurement in neurosurgery

Cerebral blood flow (CBF) is the key factor for identifying progressive hypoperfusion that is indicative of numerous pathological conditions. CBF measurement is beneficial for the management of cerebrovascular disease, head injury, and intracranial neoplasms. Of the various imaging modalities developed to assess CBF, the most notable are positron emission tomography, single photon emission computed tomography (CT), xenon CT, magnetic resonance imaging, and perfusion CT. The authors review the advancements in each modality, especially focusing on perfusion CT in neurosurgical applications and the value of acetazolamide challenge during scanning. Software developments have delivered important improvements in processing perfusion data by eliminating the necessity of manually drawing a region of interest (ROI) on each image. Rather, the software enables a digitized ROI template to be applied to each scan for better reproducibility and consistent results. Finally, in assessing CT perfusion for measuring cerebral blood flow in neurosurgical patients, we compare its benefits and limitations with other commonly used imaging methods.