title: Lung nodule detection performance in five observers on computed tomography (CT) with adaptive iterative dose reduction using three-dimensional processing (AIDR 3D) in a Japanese multicenter study: Comparison between ultra-low-dose CT and low-dose CT by receiver-operating characteristic analysis.
abstract: OBJECTIVE
  To compare lung nodule detection performance (LNDP) in computed tomography (CT) with adaptive iterative dose reduction using three dimensional processing (AIDR3D) between ultra-low dose CT (ULDCT) and low dose CT (LDCT).
  
  
  METHODS
  This was part of the Area-detector Computed Tomography for the Investigation of Thoracic Diseases (ACTIve) Study, a multicenter research project being conducted in Japan. Institutional Review Board approved this study and informed consent was obtained. Eighty-three subjects (body mass index, 23.3 ± 3.2) underwent chest CT at 6 institutions using identical scanners and protocols. In a single visit, each subject was scanned using different tube currents: 240, 120 and 20 mA (3.52, 1.74 and 0.29 mSv, respectively). Axial CT images with 2-mm thickness/increment were reconstructed using AIDR3D. Standard of reference (SOR) was determined based on CT images at 240 mA by consensus reading of 2 board-certificated radiologists as to the presence of lung nodules with the longest diameter (LD) of more than 3mm. Another 5 radiologists independently assessed and recorded presence/absence of lung nodules and their locations by continuously-distributed rating in CT images at 20 mA (ULDCT) and 120 mA (LDCT). Receiver-operating characteristic (ROC) analysis was used to evaluate LNDP of both methods in total and also in subgroups classified by LD (>4, 6 and 8 mm) and nodular characteristics (solid and ground glass nodules).
  
  
  RESULTS
  For SOR, 161 solid and 60 ground glass nodules were identified. No significant difference in LNDP for entire solid nodules was demonstrated between both methods, as area under ROC curve (AUC) was 0.844 ± 0.017 in ULDCT and 0.876 ± 0.026 in LDCT (p=0.057). For ground glass nodules with LD 8mm or more, LNDP was similar between both methods, as AUC 0.899 ± 0.038 in ULDCT and 0.941 ± 0.030 in LDCT. (p=0.144).
  
  
  CONCLUSIONS
  ULDCT using AIDR3D with an equivalent radiation dose to chest x-ray could have comparable LNDP to LDCT with AIDR3D except for smaller ground glass nodules in cases with normal range body habitus.
authors.affiliation: Department of Radiology, Shiga University of Medical Science, Otsu 520-2192, Shiga, Japan. Electronic address: yatsushi@belle.shiga-med.ac.jp.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Nagatani
authors.affiliation: Department of Radiology, Shiga University of Medical Science, Otsu 520-2192, Shiga, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: Department of Radiology, Shiga University of Medical Science, Otsu 520-2192, Shiga, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Murata
authors.affiliation: Department of Radiological and Medical Laboratory Science, Nagoya University Graduate School of Medicine, Nagoya 461-8673, Aichi, Japan.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Ikeda
authors.affiliation: Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara 903-0215, Okinawa, Japan.
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Yamashiro
authors.affiliation: Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara 903-0215, Okinawa, Japan; Department of Radiology, Okinawa Prefectural Yaeyama Hospital, Ishigaki 907-0022, Okinawa, Japan.
authors.forename: Tetsuhiro
authors.initials: T
authors.lastname: Miyara
authors.affiliation: Department of Radiology, Kobe University Graduate School of Medicine, Kobe 650-0017, Hyogo, Japan.
authors.forename: Hisanobu
authors.initials: H
authors.lastname: Koyama
authors.affiliation: Department of Radiology, Osaka Medical College, Takatsuki 569-8686, Osaka, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Koyama
authors.affiliation: Department of Radiology, Osaka University Graduate School of Medicine, Suita 565-0871, Osaka, Japan; Department of Radiology, Osaka Medical Center of Cancer and Cardiovascular Diseases, Osaka 537-8511, Osaka, Japan.
authors.forename: Yukihisa
authors.initials: Y
authors.lastname: Sato
authors.affiliation: Department of Radiology, Ohara General Hospital, Fukushima 960-8611, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Moriya
authors.affiliation: Department of Radiology, Tenri Hospital, Tenri 632-8552, Nara, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Noma
authors.affiliation: Department of Radiology, Osaka University Graduate School of Medicine, Suita 565-0871, Osaka, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Tomiyama
authors.affiliation: Department of Radiology, Kobe University Graduate School of Medicine, Kobe 650-0017, Hyogo, Japan.
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ohno
authors.affiliation: Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara 903-0215, Okinawa, Japan.
authors.forename: Sadayuki
authors.initials: S
authors.lastname: Murayama
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D002983:Clinical Competence / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007564:Japan; D008168:Lung / Q000000981:diagnostic imaging; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012372:ROC Curve; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D013902:Radiography, Thoracic / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Adaptive iterative dose reduction; Chest; Computed tomography; Image quality; Ultra-low dose scanning