title: Comparison of conventional ultrasonography and ultrasonography-computed tomography fusion imaging for target identification using digital/real hybrid phantoms: a preliminary study.
abstract: OBJECTIVE
  This preliminary study compared ultrasonography-computed tomography (US-CT) fusion imaging and conventional ultrasonography (US) for accuracy and time required for target identification using a combination of real phantoms and sets of digitally modified computed tomography (CT) images (digital/real hybrid phantoms).
  
  
  METHODS
  In this randomized prospective study, 27 spheres visible on B-mode US were placed at depths of 3.5, 8.5, and 13.5 cm (nine spheres each). All 27 spheres were digitally erased from the CT images, and a radiopaque sphere was digitally placed at each of the 27 locations to create 27 different sets of CT images. Twenty clinicians were instructed to identify the sphere target using US alone and fusion imaging. The accuracy of target identification of the two methods was compared using McNemar's test. The mean time required for target identification and error distances were compared using paired t tests.
  
  
  RESULTS
  At all three depths, target identification was more accurate and the mean time required for target identification was significantly less with US-CT fusion imaging than with US alone, and the mean error distances were also shorter with US-CT fusion imaging.
  
  
  CONCLUSIONS
  US-CT fusion imaging was superior to US alone in terms of accurate and rapid identification of target lesions.
authors.affiliation: Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, N-14, W-5, Kita-ku, Sapporo, Hokkaido, 060-0848, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Soyama
authors.affiliation: Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, N-14, W-5, Kita-ku, Sapporo, Hokkaido, 060-0848, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Sakuhara
authors.affiliation: Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, N-14, W-5, Kita-ku, Sapporo, Hokkaido, 060-0848, Japan. kkudo@huhp.hokudai.ac.jp.
authors.forename: Kohsuke
authors.initials: K
authors.lastname: Kudo
authors.affiliation: Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, N-14, W-5, Kita-ku, Sapporo, Hokkaido, 060-0848, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Abo
authors.affiliation: Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Jeff
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Biostatistics, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Yoichi M
authors.initials: YM
authors.lastname: Ito
authors.affiliation: Department of Radiology, Sapporo-Kosei General Hospital, Sapporo, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Hasegawa
authors.affiliation: Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shirato
mesh_terms: D003198:Computer Simulation; D006801:Humans; D064847:Multimodal Imaging / Q000295:instrumentation / Q000379:methods*; D019047:Phantoms, Imaging; D010820:Physicians; D011214:Practice, Psychological; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*; D014463:Ultrasonography / Q000295:instrumentation / Q000379:methods*
keywords: Computed tomography; Digital phantom; Hybrid phantom; US-CT fusion imaging; Ultrasonography