A report is given on our experience gained in the introduction of the method of detachable microballoon catheters in the sense of the intervention neuroradiological operative technique. Twenty patients with arteriovenous angiomas, bag-like aneurysms, a carotid Sinus vernosus fistula and intracranial tumours rich in blood vessels were treated according to this method. Adjoining procedures such as embolisation are discussed.