Steffen Oeltze has defended his Phd thesis “Visual Exploration and Analysis of Perfusion Data”. Steffen dealt with the visual exploration and visual analysis of perfusion data and their applications in the diagnosis of the coronary heart disease, in breast tumor and cerebral stroke diagnosis. To tackle clinically relevant problems in a uniform way, he developed a pipeline including preprocessing, data analysis and visual exploration. Steffen has cooperated with the VRVis in Vienna and the visualization group in Bergen as well as with colleagues from Fraunhofer MEVIS . Also several clinical partners were involved in this endeavor. Specific results have been published already in IEEE TVCG and IEEE TMI as well as EuroVis. The thesis was graded with the highest possible “Summa Cum Laude”. External reviewers have been Prof. Helwig Hauser (Bergen, Norway) and Prof. Frits Post (Delft, The Netherlands) .