With the dual echo DSC-based technique Vessel Architectural Imaging (VAI), measurement of oxygenation level (∆SO2) can be obtained. However, how the ∆SO2-parameter is influenced by diffusion have previously not been investigated. Based on simulations, we show that the measured ∆SO2 obtained from VAI have a diffusion dependency proportional to 1/ √D. ADC-maps from 10 glioblastoma patients were used to display the range correction factors in white matter and tumor regions. In conclusion, the diffusion dependency should be corrected for to obtain more accurate measurements of ∆SO2, and may be especially relevant for brain diseases with aberrant diffusion characteristics.