title: [Image distortion and artifacts caused by the use of a titanium aneurism clip in 1.5 tesla- and 3 tesla-magnetic resonance imaging: effect on 60cobalt stereotactic radiosurgery treatment planning].
abstract: In gamma knife stereotactic radiosurgery (GKSRS) treatment planning, 1.5 tesla (T)-magnetic resonance imaging (MRI) is normally used to identify the target lesion. Image artifacts and distortion arise in MRI if a titanium clip is surgically implanted in the brain to treat cerebral aneurysm. 3-T MRI scanners, which are increasingly being adopted, provide imaging of anatomic structures with better clinical usefulness than 1.5-T MRI machines. We investigated signal defects and image distortions both close to and more distant from the titanium clip in 1.5-T and 3-T MRI. Two kinds of phantoms were scanned using 1.5-T and 3-T MRI. Acquisitions with and without the clip were performed under the same scan parameters. No difference was observed between 1.5 T and 3 T in local decrease of signal intensity; however, image distortion was observed at 20 mm from the clip in 3 T. Over the whole region, the distortions caused by the clip were less than 0.3 mm and 1.6 mm under 1.5-T and 3-T MRI, respectively. The geometric accuracy of 1.5-T MRI was better than 3-T MRI and thus better for GKSRS treatment planning. 3-T MRI, however, appears less suitable for use in treatment planning.
authors: Department of Radiological Sciences, Nagoya University Graduate School of Medicine.
authors: Hisato
authors: H
authors: Nakazawa
authors: Osamu
authors: O
authors: Yamamuro
authors: Yukio
authors: Y
authors: Uchiyama
authors: Masataka
authors: M
authors: Komori
mesh_terms: D016477:Artifacts; D003035:Cobalt; D006801:Humans; D002532:Intracranial Aneurysm / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D010347:Patient Care Planning; D019047:Phantoms, Imaging; D016634:Radiosurgery; D013525:Surgical Instruments; D014025:Titanium
chemical_list: D003035:Cobalt; D014025:Titanium