title: Low dose chest CT protocol (50 mAs) as a routine protocol for comprehensive assessment of intrathoracic abnormality.
abstract: OBJECTIVE
  To determine the diagnostic capability of low-dose CT (50 mAs) in comparison to standard-dose CT (150 mAs).
  
  
  METHODS
  Fifty-nine consecutive patients underwent two non-contrast chest CT scans with different current-time products (50 and 150 mAs at 120 kVp) on a 64-detector row CT scanner. Three board certified chest radiologists independently reviewed 118 series of 2 mm-thick images (2 series for each of 59 patients) in a random order. The readers assessed abnormal findings including emphysema, ground-glass opacity, reticular opacity, micronodules, bronchiectasis, honeycomb, nodules (>5 mm), aortic aneurysm, coronary artery calcification, pericardial and pleural effusion, pleural thickening, mediastinal tumor and lymph node enlargement. Five-point scale from 1 (definitely absent) to 5 (definitely present) was used to record the results. The rates of score agreement between two images were calculated. Deviation of one observer's score from other two observers was compared between low dose CT and standard dose CT.
  
  
  RESULTS
  Mean agreement rate of the lung parenchymal findings between low dose CT and standard dose CT images was 0.836 (range, 0.746-0.926). Mean agreement rates for mediastinal and pleural findings were 0.920 (range, 0.735-1.000). There was no statistically significant difference in the deviation of the observers' scores between low-dose CT and standard-dose CT.
  
  
  CONCLUSIONS
  Low dose CT protocol at 50 mAs can produce the screening results consistent with standard dose CT protocol (150 mAs), supporting routine use of low dose chest CT protocol.
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kubo
authors.affiliation: Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ohno
authors.affiliation: Department of Radiology, Dana Farber Cancer Institute, 44 Binney Street, Boston, MA 02115, United States.
authors.forename: Mizuki
authors.initials: M
authors.lastname: Nishino
authors.affiliation: Department of Radiology, Virginia Commonwealth University Medical Center, 1101 East Marshall Street, Room 4-052, Richmond, VA 23298 United States.
authors.forename: Pei-Jan
authors.initials: PJ
authors.lastname: Lin
authors.affiliation: Departments of Radiology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, United States.
authors.forename: Shiva
authors.initials: S
authors.lastname: Gautam
authors.affiliation: Diagnostic and Interventional Radiology, University Clinic Heidelberg, Im Neuenheimer Feld 110, D-69120 Heidelberg, Germany.
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Kauczor
authors.affiliation: Department of Radiology, Brigham and Women's Hospital, 75 Francis Street Boston, MA 02115, United States.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Hatabu
keywords: Chest CT; Diagnostic accuracy; Radiation dose reduction