The application of different color-coding techniques in transcranial color-coded duplex sonography (TCCD) was assessed for detection and measurement of the size of intracranial aneurysms. Thirty-two consecutively examined patients with 36 angiographically verified cerebral aneurysms underwent TCCD with color Doppler flow imaging (CDFI), power Doppler imaging (PDI), and both methods with contrast enhancement. The diameters of the aneurysms were measured in comparable planes by means of angiography and TCCD-PD with and without 400 mg/ml of the monosaccharide microparticle contrast agent Levovist. TCCD with CFD enabled detection of 27 of 36 aneurysms (75%), and PD depicted 29 aneurysms (80%). After administration of Levovist, an additional two aneurysms were detected with CFD and three with PD color coding. Measurements of aneurysm size obtained by means of PD with contrast enhancement corresponded more highly with angiographic findings than did measurements obtained with PD alone. Use of alternative color-coding techniques with the addition of contrast agents increases the number of intracranial nonthrombosed aneurysms detectable with TCCD.