ECHO CONTRAST-ENHANCED 3-DIMENSIONAL POWER DOPPLER OF INTRACRANIAL-ARTERIES

The purpose of this study was to evaluate the potential of contrast-en hanced three-dimensional (3-D) power Doppler (CE3DPD) in the assessmen t of intracranial vascular structures, and to compare the results with unenhanced 3-D power Doppler (3DPD) and magnetic resonance angiograph y (MRA) findings. We insonated 25 patients without cerebrovascular dis eases through the temporal bone window using 3DPD and CE3DPD; for comp arison, 13 patients underwent MRA. Identification rates of vascular se gments and of small branches of intracranial vessels were evaluated by two independent investigators blinded to MRA results. In 21 patients with adequate insonation conditions, CE3DPD significantly improved ide ntification rates compared to 3DPD for the complete visualization of t he pi segment (80.9 vs. 19.0%, p < 0.005, P2 segment (80.9 vs. 42.8%, p < 0.05 and Al segment (85.7 vs. 38.1%, p < 0.005). Furthermore, CE3D PD depicted, in significantly more examinations, branches of the middl e (MCA) and posterior cerebral artery (PCA). Interobserver agreement w as higher than 95% for the main intracranial segments and branches of the MCA, but relatively low (80.1-85.7%) for branches of the PCA. In c omparison to CE3DPD, MRA identified only parieto-occipital branches of the PCA, temporal branches of the MCA, frontal branches of the anteri or cerebral artery and the MCA bifurcation more frequently and accurat ely. In 4 patients with inadequate acoustic temporal bone windows, the application of a galactose-based microbubble suspension allowed clear 3-D visualization of almost all major intracranial vascular segments and some branches of the large arteries. In conclusion, CE3DPD is a mo re sensitive ultrasonic tool compared to unenhanced 3-D reconstruction s. It makes 3-D ultrasound imaging of the basal cerebral circulation e asier to perform and interpret, by providing an improved spatially ori ented display of image position. As such, this method may increase ope rator diagnostic confidence level under pathologic conditions. (C) 199 8 World Federation for Ultrasound in Medicine & Biology.