Continuous administration of contrast medium for transcranial colour-codedsonography

Since the introduction of contrast media, transcranial colour-coded sonogra phy (TCCS) has become increasingly important for examination of the intracr anial vessels. However, the widely practised bolus injection of these agent s leads to initial blooming artefacts and thereafter the level of contrast enhancement decreases rapidly, reducing the effective time of enhancement. It was our aim to investigate the effect of continuous administration of co ntrast medium at a defined infusion rate. We performed 28 TCCS examinations of the intracranial vessels in 26 patients using a 2.25 MHz phased-array t ransducer during administration of 4 g Levovist (Schering, Berlin, Germany) 300 mg/ml with a constant infusion rate of 60 ml/h into an antecubital vei n. The degree of enhancement was graded over time in a subjective analysis by two independent observers. During continuous administration, a constant level of contrast enhancement was reached after 60.1 +/- 26.2 s and this la sted 663.4 +/- 55.8 s as assessed by the first observer (66.6 +/- 26.2 s an d 664.3 +/- 55.9 s according to the second observer). The limits of interob server agreement ranged from -10.1 % to 9.9 %. No major blooming effect was seen in the initial phase of the examination.