Introduction

The most widely used single-arterial injection technique used for analysis of blood–brain barrier function is without doubt the Brain Uptake Index (BUI) method. This is a tissue-sampling, multiple isotope technique that was first described by Oldendorf (1970). Although widely applied to animal studies, the origins of the method may lie in the training that Bill Oldendorf received as a neurology resident at the University of Minnesota. A case of status epilepticus was not responding to even vigorous treatment and the serious consequences of this situation were being discussed. Dr Juhn Wada, a fellow resident, indicated that he could stop the seizures. Bill Oldendorf related that Dr Wada simply proceeded to inject barbiturate directly into the common carotid artery, and the seizures were arrested. Neurologists and neurosurgeons all know Juhn Wada for the test that bears his name, wherein a short-acting barbiturate is injected into the carotid artery of a conscious patient to determine the dominant cerebral hemisphere. In current clinical practice, the intracarotid injection is achieved via a femoral catheter rather than direct needle puncture of the carotid artery.