title: Effect of the high-pitch mode in dual-source computed tomography on the accuracy of three-dimensional volumetry of solid pulmonary nodules: a phantom study.
abstract: OBJECTIVE
  To evaluate the influence of high-pitch mode (HPM) in dual-source computed tomography (DSCT) on the accuracy of three-dimensional (3D) volumetry for solid pulmonary nodules.
  
  
  METHODS
  A lung phantom implanted with 45 solid pulmonary nodules (n = 15 for each of 4-mm, 6-mm, and 8-mm in diameter) was scanned twice, first in conventional pitch mode (CPM) and then in HPM using DSCT. The relative percentage volume errors (RPEs) of 3D volumetry were compared between the HPM and CPM. In addition, the intermode volume variability (IVV) of 3D volumetry was calculated.
  
  
  RESULTS
  In the measurement of the 6-mm and 8-mm nodules, there was no significant difference in RPE (p > 0.05, respectively) between the CPM and HPM (IVVs of 1.2 ± 0.9%, and 1.7 ± 1.5%, respectively). In the measurement of the 4-mm nodules, the mean RPE in the HPM (35.1 ± 7.4%) was significantly greater (p < 0.01) than that in the CPM (18.4 ± 5.3%), with an IVV of 13.1 ± 6.6%. However, the IVVs were in an acceptable range (< 25%), regardless of nodule size.
  
  
  CONCLUSIONS
  The accuracy of 3D volumetry with HPM for solid pulmonary nodule is comparable to that with CPM. However, the use of HPM may adversely affect the accuracy of 3D volumetry for smaller (< 5 mm in diameter) nodule.
authors.affiliation: Department of Radiology, Korea University Anam Hospital, Seoul 136-705, Korea.
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Hwang
authors.affiliation: Department of Radiology, Korea University Anam Hospital, Seoul 136-705, Korea.
authors.forename: Yu-Whan
authors.initials: YW
authors.lastname: Oh
authors.affiliation: Department of Radiology, Korea University Anam Hospital, Seoul 136-705, Korea.
authors.forename: Soo-Youn
authors.initials: SY
authors.lastname: Ham
authors.affiliation: Department of Radiology, Korea University Guro Hospital, Seoul 152-703, Korea.
authors.forename: Eun-Young
authors.initials: EY
authors.lastname: Kang
authors.affiliation: Department of Radiology, Korea University Ansan Hospital, Ansan 425-707, Korea.
authors.forename: Ki Yeol
authors.initials: KY
authors.lastname: Lee
mesh_terms: D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation / Q000379:methods*; D008168:Lung / Q000000981:diagnostic imaging; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D055613:Multiple Pulmonary Nodules / Q000000981:diagnostic imaging*; D019047:Phantoms, Imaging; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*
keywords: Computed tomography; Imaging phantom; Pulmonary nodule; Volumetric imaging, computer generated 3D