Lack of oxygen and specific changes in the microvascular architecture are often undetected and comprise early indications of the return of a brain tumor following previous surgical intervention. This was the result of a study published by an Austrian and German team headed by Karl Landsteiner University of Health Sciences in Krems. The findings showed that initial signs of a recurrence of glioblastomas could be detected more than six months earlier than otherwise possible using standard clinical methods. Published in Clinical Cancer Research, the study was based on retrospective analysis of special MRI data from 56 patients.