title: Geometric accuracy of 3D coordinates of the Leksell stereotactic skull frame in 1.5 Tesla- and 3.0 Tesla-magnetic resonance imaging: a comparison of three different fixation screw materials.
abstract: We assessed the geometric distortion of 1.5-Tesla (T) and 3.0-T magnetic resonance (MR) images with the Leksell skull frame system using three types of cranial quick fixation screws (QFSs) of different materials-aluminum, aluminum with tungsten tip, and titanium-for skull frame fixation. Two kinds of acrylic phantoms were placed on a Leksell skull frame using the three types of screws, and were scanned with computed tomography (CT), 1.5-T MR imaging and 3.0-T MR imaging. The 3D coordinates for both strengths of MR imaging were compared with those for CT. The deviations of the measured coordinates at selected points (x = 50, 100 and 150; y = 50, 100 and 150) were indicated on different axial planes (z = 50, 75, 100, 125 and 150). The errors of coordinates with QFSs of aluminum, tungsten-tipped aluminum, and titanium were <1.0, 1.0 and 2.0 mm in the entire treatable area, respectively, with 1.5 T. In the 3.0-T field, the errors with aluminum QFSs were <1.0 mm only around the center, while the errors with tungsten-tipped aluminum and titanium were >2.0 mm in most positions. The geometric accuracy of the Leksell skull frame system with 1.5-T MR imaging was high and valid for clinical use. However, the geometric errors with 3.0-T MR imaging were larger than those of 1.5-T MR imaging and were acceptable only with aluminum QFSs, and then only around the central region.
authors.affiliation: Department of Radiological Sciences, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan Nagoya Radiosurgery Center, Nagoya Kyoritsu Hospital, Nagoya, Aichi, Japan hnakazawa@kaikou.or.jp.
authors.forename: Hisato
authors.initials: H
authors.lastname: Nakazawa
authors.affiliation: Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan.
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Mori
authors.affiliation: East Nagoya Imaging Diagnosis Center, Nagoya, Aichi, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Yamamuro
authors.affiliation: Department of Radiological Sciences, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
authors.forename: Masataka
authors.initials: M
authors.lastname: Komori
authors.affiliation: Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Shibamoto
authors.affiliation: Nagoya Radiosurgery Center, Nagoya Kyoritsu Hospital, Nagoya, Aichi, Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Uchiyama
authors.affiliation: Nagoya Radiosurgery Center, Nagoya Kyoritsu Hospital, Nagoya, Aichi, Japan.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Tsugawa
authors.affiliation: Nagoya Radiosurgery Center, Nagoya Kyoritsu Hospital, Nagoya, Aichi, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hagiwara
mesh_terms: D001863:Bone Screws; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D019047:Phantoms, Imaging; D016634:Radiosurgery / Q000295:instrumentation* / Q000706:statistics & numerical data; D011880:Radiotherapy Planning, Computer-Assisted; D012886:Skull / Q000601:surgery*; D013238:Stereotaxic Techniques; D014057:Tomography, X-Ray Computed
keywords: computed tomography; stereotactic localization; image distortion; magnetic resonance imaging; stereotactic radio-surgery