Assessment of Regional Cerebral Blood Flow Using the XE-133 Inhalation Method in Patients Undergoing EIAB Surgery

Abstract

Since the advent of extra-intracranial arterial bypass (EIAB) surgery in the treatment of ischaemic cerebrovascular disease, few attempts were undertaken^1–3 to relate rCBF findings to the explanation of underlying pathology as well as to the selection of patients for operation, using the intracarotid injection method. Though noninvasive and repeatable, the Xe-133 inhalation technique was considered unfavourable for such studies. In spite of the indisputable superiority of the intracarotid injection method with respect to the more simple mathematical model, and lack of distortion due to recirculation and extracerebral contamination, the inhalation method has its points. Both hemispheres are readily accessible for comparison, and no problem emerges on how to label all regions of interest, since the isotope is distributed over the entire circulation. The recent innovation of new parameters such as Φ and S⁴ may increase the sensitivity of the method, particularly in cases of impaired perfusion, thus overcoming the disadvantage of less power of spatial resolution inherent in this technique.