title: Object shape dependency of in-plane resolution for iterative reconstruction of computed tomography.
abstract: The present study aimed to investigate whether the in-plane resolution property of iterative reconstruction (IR) of computed tomography (CT) data is object shape-dependent by testing columnar shapes with diameters of 3, 7, and 10cm (circular edge method) and a cubic shape with 5-cm side lengths (linear edge method). For each shape, objects were constructed of acrylic (contrast in Hounsfield units [ΔHU]=120) as well as a soft tissue equivalent material (ΔHU=50). For each shape, we measured the modulation transfer functions (MTFs) of IR and filtered back projection (FBP) using two multi-slice CT scanners at scan doses of 5 and 10mGy. In addition, we evaluated a thin metal wire using the conventional method at 10mGy. For FBP images, the MTF results of the tested objects and the wire method showed substantial agreement, thus demonstrating the validity of our analysis technique. For IR images, the MTF results of different shapes were nearly identical for each object contrast and dose combination, and we did not observe shape-dependent effects of the resolution properties of either tested IR. We conclude that both the circular edge method and linear edge method are equally useful for evaluating the resolution properties of IRs.
authors.affiliation: Department of Diagnostic Radiology, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8641, Japan; Graduate School of Medical Science, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan. Electronic address: t-takata@med.kanazawa-u.ac.jp.
authors.forename: Tadanori
authors.initials: T
authors.lastname: Takata
authors.affiliation: Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan.
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Ichikawa
authors.affiliation: Department of Diagnostic Radiology, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8641, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Mitsui
authors.affiliation: Department of Diagnostic Radiology, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8641, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hayashi
authors.affiliation: Department of Diagnostic Radiology, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8641, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Minehiro
authors.affiliation: Department of Diagnostic Radiology, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8641, Japan.
authors.forename: Keita
authors.initials: K
authors.lastname: Sakuta
authors.affiliation: Department of Diagnostic Radiology, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8641, Japan.
authors.forename: Haruka
authors.initials: H
authors.lastname: Nunome
authors.affiliation: Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan.
authors.forename: Kousuke
authors.initials: K
authors.lastname: Matsubara
authors.affiliation: Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kawashima
authors.affiliation: Department of Diagnostic Radiology, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8641, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Matsuura
authors.affiliation: Department of Radiology, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8641, Japan.
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Gabata
mesh_terms: D007091:Image Processing, Computer-Assisted / Q000379:methods*; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D014057:Tomography, X-Ray Computed
keywords: Computed tomography; Iterative reconstruction; Modulation transfer function; Spatial resolution