NMR imaging allow specific study of contrast variations due to intravascular agents. It is possible to measure regional cerebral blood volume (rCBV). In brain tumor, this parameter allow to characterize tumoral vascularisation and blood brain barrier lesions. We use today 1st pass bolus technic. Easy to perform in clinical practice, it is useful for differential diagnosis, prebiopsic planning and follow up of lesions. That should be particularly interesting to evaluate the anti-angiogenic treatment efficiency.