Comparison of perfusion computed tomography and computed tomography angiography source images with perfusion-weighted imaging and diffusion-weighted imaging in patients with acute stroke of less than 6 hours duration - Schramm, P; Schellinger, PD; Klotz, E; Kallenberg, K; Fiebach, JB; Kulkens, S; Heiland, S; Knauth, M; Sartor, K (Stroke, 2004)