Determination of Regional Brain Perfusion by Functional CT

Abstract

Due to the increasing recognition that noninvasive measurements of cerebral blood flow (CBF) parameters may play a major role in the clinical management of patients with neurological disorders, a variety of functional imaging techniques have been developed in the past. Single photon emission computed tomography (SPECT) and xenon computed tomography (CT) have gained significant clinical acceptance, because these methods may be used as routine procedures for the investigation of chronic occlusive vascular disease. However, although accurate assessment of perfusion impairment has to be performed if modern therapeutic strategies are intended for acute stroke patients, only limited data are available concerning the application of these functional modalities within the first few hours of brain ischemia [1,2]. Cerebral SPECT imaging using blood flow tracers provides useful information regarding the full three-dimensional extent of CBF impairment; however, it takes about 15–20 min for a complete examination to be performed. This causes substantial motion artifacts in many cases due to the limited compliance of the patients. Moreover, at present only a few community hospitals offer SPECT for 24 h a day as a routine measure. Xenon CT has not been widely applied in stroke patients within the acute phase due to the limited practicability of a measure that requires a face mask and inhalation of a narcotic gas to be accepted by the patient.