Contrast enhanced pulsed Doppler and colour-coded duplex studies of the cranial vasculature

The aim of this study was to assess the effect of Albunex, a vascular contrast agent based on albumin-coated air microbubbles, on pulsed Doppler and colour-coded duplex sonography of the cranial vasculature.

Twenty healthy male volunteers received intravenous injections of contrast in single doses ranging from 0.08 to 0.30 ml/kg. Pulsed wave Doppler sonography examination and colour-coded duplex sonography were carried out in the right internal carotid artery (ICA) and middle cerebral artery (MCA) before and after i.v. contrast. The relative intensity increase of the Doppler signal was measured in decibels.

Transpulmonary passage of contrast occurred in sufficient amounts to enhance the intensity of the Doppler signal significantly, but the duration of this effect was short. Contrast enhancement also improved visualization of both the ICA and MCA in all subjects. For the transcranial examinations, this resulted in visualization of a greater length of the middle cerebral arteries and additional vessels in the Circle of Willis.

These results confirm that contrast enhancement can significantly improve the quality of Doppler examination and colour-coded duplex sonography of both the intracranial and extracranial vessels. However, the use of Albunex in neurosonology will be of limited value due to its relatively short duration.