For radiological examinations, propofol is administered, depending on the indications, at following doses: - for anxiolysis : i.v. bolus of 10-20 mg, repeated as required; - for sedation with maintenance of spontaneous ventilation: i.v. bolus of 0.5 mg . kg-1 or continuous infusion of 3 mg . kg . h-1. - for general anaesthesia : i.v. bolus of 2 mg . kg-1 and maintenance with a continuous infusion of 6-10 mg . kg-1 . h-1. These doses are modified according to the patient's reactions and painful episodes. In neuroradiology, indications for anaesthesia include vascular explorations, MRI, computerized axial tomography, as well as biopsies of organs and tumors, with the exception of explorations in patients with tight stenoses of the carotid artery. The use of propofol for cardiological explorations is questioned in adults and mainly in children with a congenital cardiopathy. For some authors this agent is contra-indicated, as during induction it decreases, sometimes excessively, the mean arterial pressure.