MATERIALS AND METHODS: The diagnostic accuracies of Doppler ultrasound (DUS), contrast-enhanced magnetic resonance angiography (CEMRA) and computed tomography angiography (CTA) were compared with digital subtraction angiography (DSA) in a multicenter study (CARMEDAS; 206 patients assessable) and in a meta-analysis (for CEMRA and CTA). The direct costs of each imaging method were calculated in 2 university medical centers. Eight hypothetical models were studied with DUS considered as the first-line imaging method and either CEMRA or CTA or DSA as the second or third line method. The effectiveness criterion was the number of potential avoided strokes for each strategy and for 1000 patients.