Cerebral Perfusion CT: Technique and Clinical Applications

Abstract

Perfusion computed tomography (CT) is a relatively new technique that allows rapid qualitative and quantitative evaluation of cerebral perfusion by generating maps of cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT). The technique is based on the central volume principle (CBF = CBV/MTT) and requires the use of commercially available software employing complex deconvolution algorithms to produce the perfusion maps. Some controversies exist regarding this technique, including which artery to use as input vessel, the accuracy of quantitative results, and the reproducibility of results. Despite these controversies, perfusion CT has been found to be useful for noninvasive diagnosis of cerebral ischemia and infarction and for evaluation of vasospasm after subarachnoid hemorrhage. Perfusion CT has also been used for assessment of cerebrovascular reserve by using acetazolamide challenge in patients with intracranial vascular stenoses who are potential candidates for bypass surgery or neuroendovascular treatment, for the evaluation of patients undergoing temporary balloon occlusion to assess collateral flow and cerebrovascular reserve, and for the assessment of microvascular permeability in patients with intracranial neoplasms. This article is a review of the technique, clinical applications, and controversies surrounding perfusion CT.

Early Cerebral Circulatory Disturbance in Patients Suffering Subarachnoid Hemorrhage Prior to the Delayed Cerebral Vasospasm Stage: Xenon Computed Tomography and Perfusion Computed Tomography Study

“…In particular, recent studies have reported the utility of perfusion CT for SAH. 8,9,16,28) MTT values obtained from this modality are believed to be much more sensitive than other parameters for evaluating cerebral vasospasm. 28) However, CBF values obtained from perfusion CT are not quantitative, although they are correlated with those obtained from Xe-CT. 22) Based on these reports, we performed Xe-CT and perfusion CT simultaneously to examine whether CBF, CBV, and MTT and maps of these parameters created by image processing are useful for evaluating cerebral circulatory disturbance following SAH and whether they can be used to predict outcomes.…”

Classification of Hypervascular Liver Lesions Based on Hepatic Artery and Portal Vein Blood Supply Coefficients Calculated from Triphasic CT Scans

“…Portal vein occlusion results in increased HAC and PVC in the affected portion of the liver. We can speculate that this is analogous to the compensatory increased cerebral blood volume caused by vasodilation in an acute ischemic stroke [22].…”

Validation of frontal near-infrared spectroscopy as noninvasive bedside monitoring for regional cerebral blood flow in brain-injured patients

“…The transient increase in radiation attenuation is proportional to the amount of contrast in a given region and the speed at which the agent passes from arterial to venous circuits through the tissue bed. 9 The CT perfusion technique is based on the central volume principle, which relates CBF, CBV, and MTT in the following equation: CBF = CBV/ MTT. Contrast agent time-concentration curves are generated in arterial and venous regions of interest and in each pixel.…”

“…The central volume equation can then be solved for CBF. 9 The CT perfusion images were analyzed on a Siemens Leonardo postprocessing workstation. The CT perfusion regions of interest were obtained 2.5 cm below the NIRS frontal scalp probes with an average region of interest volume of 2-4 ml.…”