MR Fingerprinting (MRF) will be performed in patients who will be treated with Gamma Knife radio surgery for a vestibular schwannoma before the intervention. Fifty patients will be included with a vestibular schwannoma of minimum 1cm in size. During follow-up, response of the tumor to radiosurgery will be evaluated for each patient with MRI. The aim of the study is to find patterns of vestibular schwannomas in MRF data which correlate with the type of response to radio surgery, i.e. tumor control after radiosurgery, further tumor growth despite radiosurgery, cystic transformation after radiosurgery.