Inclusion Criteria:  Brain metastasis from histologically proven tumor GK treatment within 4 month prior to the inclusion  Lesions suspected of progression/ radionecrosis :  i.e.≥ 25% of the size progression  Lesion size: gadolinium enhanced part of the tumour ≥1 cm  Exclusion Criteria:  Pregnancy Medical history of primitive brain tumour MRI incompatibility/ medical history of contrast agent allergy Claustrophobia Patient unable to consent Epilepsia/recent stroke Patients participating in other studies Patients without health care insurance