title: The effect of late-phase contrast enhancement on semi-automatic software measurements of CT attenuation and volume of part-solid nodules in lung adenocarcinomas.
abstract: OBJECTIVE
  To evaluate the differences in semi-automatic measurements of CT attenuation and volume of part-solid nodules (PSNs) between unenhanced and enhanced CT scans.
  
  
  METHODS
  CT scans including unenhanced and enhanced phases (slice thickness 0.625 and 1.25mm, respectively) for 53 adenocarcinomas presenting as PSNs in 50 patients were retrospectively evaluated. For each nodule, semi-automatic segmentation provided the diameter, mean attenuation, mass, and volume of a whole nodule and its solid component. Interscan variability and statistical significance of the differences in those measures according to the adenocarcinoma category were evaluated by one reader.
  
  
  RESULTS
  All parameters except for the mean attenuation of the solid components, were significantly increased on enhanced CT (p<0.05). For the whole nodule, the mean relative differences were as follows: the longest diameter, 1.4% (limits of agreement, -6.2-9.1); volume, 2.4% (-26.7-31.4); mass, 7.0% (-11.3-25.2); mean attenuation, 2.7% (-5.6-11). For the nodule's solid component, those differences were as follow: the longest diameter, 6.9% (-34.4-48.2); volume, 17.9% (-77.8-113.7); mass, 18.8% (-77.8-115.4). The differences of measures between the unenhanced and enhanced CT were not significantly different between two groups of adenocarcinoma in situ/minimally invasive adenocarcinomas and invasive adenocarcinomas (p>0.05).
  
  
  CONCLUSIONS
  As most volumetric and attenuation measurements changed significantly after contrast enhancement, care should be taken in comparing unenhanced and enhanced CT in the evaluation of PSNs.
authors.affiliation: Department of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea; Clinique Universitaire de Radiologie et Imagerie Médicale (CURIM), Université Joseph Fourier, Centre Hospitalier Universitaire de Grenoble, CS 10217, 38043 Grenoble Cedex 9, France.
authors.forename: Julien G
authors.initials: JG
authors.lastname: Cohen
authors.affiliation: Department of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea; Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea. Electronic address: jmgoo@plaza.snu.ac.kr.
authors.forename: Jin Mo
authors.initials: JM
authors.lastname: Goo
authors.affiliation: Department of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.
authors.forename: Roh-Eul
authors.initials: RE
authors.lastname: Yoo
authors.affiliation: Department of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.
authors.forename: Su Bin
authors.initials: SB
authors.lastname: Park
authors.affiliation: Department of Radiology and Nuclear Medicine, Radboud University Nijmegen Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands.
authors.forename: Bram
authors.initials: B
authors.lastname: van Ginneken
authors.affiliation: Clinique Universitaire de Radiologie et Imagerie Médicale (CURIM), Université Joseph Fourier, Centre Hospitalier Universitaire de Grenoble, CS 10217, 38043 Grenoble Cedex 9, France; INSERM U 823, Institut A Bonniot, 38700 La Tronche, France.
authors.forename: Gilbert R
authors.initials: GR
authors.lastname: Ferretti
authors.affiliation: Department of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.
authors.forename: Chang Hyun
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Department of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea; Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Chang Min
authors.initials: CM
authors.lastname: Park
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging*; D000077192:Adenocarcinoma of Lung; D000328:Adult; D000368:Aged; D003287:Contrast Media; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008168:Lung / Q000000981:diagnostic imaging; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods*; D012189:Retrospective Studies; D012984:Software; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media
keywords: Adenocarcinoma; Contrast media; Lung cancer; Lung nodule; Solitary pulmonary nodule; Subsolid nodule