Dear Kathy and Guillaume, thanks for your advice. Command line conversion and the batch editor DICOM convert both work fine, so I will use those. I tried Matlab R2009b (64bit, Linux) and it behaves just like R2009a for me. It might be a problem with the 64bit version, with the linux version or with my installation... for the time being I will work with the two workarounds suggested. -- Benjamin Bender Abteilung Diagnostische und Interventionelle Neuroradiologie Universitätsklinikum Tübingen Hoppe-Seyler- Str. 3 72076 Tübingen Tel. (07071) 29-85397