title: Feasibility of Respiratory-gated High-pitch Spiral CT:: Free-breathing Inspiratory Image Quality.
abstract: OBJECTIVE
  This study aimed to develop and implement a respiratory-gated setup for dual-source computed tomography (CT) at high pitch to examine patients in a reproducible inspiratory phase.
  
  
  METHODS
  Twenty-one patients underwent free-breathing respiratory-gated chest CT using a high-pitch scan mode no more than 6 months after inspiratory breath-held nongated CT, which serves as reference. Scan parameters were as follows: pitch = 3.4, 128 × 0.6 mm collimation, 0.28 s gantry rotation time, and 150 ref.mAs per tube at 120 kV. The examinations were triggered using the tidal wave provided by a respiratory-gating system as input signal. Image quality was assessed focusing on artifacts and delineation of the anatomical and pathological structures. Lung volumes were measured on both free-breathing and reference examinations.
  
  
  RESULTS
  All examinations were performed without complications. Image quality was high with both protocols. Significantly less motion artifacts were recorded with the high-pitch mode compared to the reference (P = 0.02). Most of the artifacts were located in the peripheral parts of the lower lobes for the study group and in the central part of the left lower lobe for the reference. Average total lung volume was 4.5 ± 1.5 L in respiratory-gated examinations and 5.8 ± 0.9 L in examinations with breath-hold in inspiration.
  
  
  CONCLUSIONS
  High-pitch chest CT scanning during free breathing minimizes motion artifacts, improving image quality in patients with limited breath-holding abilities. To assure scanning in an inspiratory phase, data acquisition should be triggered with a respiratory-gating system.
authors: Department of Radiology, University of Erlangen, Maximiliansplatz 1, Erlangen, Germany; Imaging Sciences Institute (ISI), Ulmenweg 18, Erlangen, Germany.
authors: Michael M
authors: MM
authors: Lell
authors: Department of Radiology, University of Erlangen, Maximiliansplatz 1, Erlangen, Germany.
authors: Michael
authors: M
authors: Scharf
authors: Department of Radiology, University of Erlangen, Maximiliansplatz 1, Erlangen, Germany.
authors: Achim
authors: A
authors: Eller
authors: Department of Radiology, University of Erlangen, Maximiliansplatz 1, Erlangen, Germany.
authors: Wolfgang
authors: W
authors: Wuest
authors: Siemens Healthcare, GmbH, CT Division, Siemensstraße 1, Forchheim, Germany.
authors: Thomas
authors: T
authors: Allmendinger
authors: Department of Medicine, Pneumology, University of Erlangen, Ulmenweg 18, Erlangen.
authors: Florian
authors: F
authors: Fuchs
authors: Department of Cardiology, University Hospital Erlangen, Ulmenweg 18, Germany.
authors: Stephan
authors: S
authors: Achenbach
authors: Department of Radiology, University of Erlangen, Maximiliansplatz 1, Erlangen, Germany; Imaging Sciences Institute (ISI), Ulmenweg 18, Erlangen, Germany.
authors: Michael
authors: M
authors: Uder
authors: Department of Radiology, University of Erlangen, Maximiliansplatz 1, Erlangen, Germany; Imaging Sciences Institute (ISI), Ulmenweg 18, Erlangen, Germany. Electronic address: matthias.may@uk-erlangen.de.
authors: Matthias S
authors: MS
authors: May
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D062485:Breath Holding; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008168:Lung / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012119:Respiration; D036542:Tomography, Spiral Computed / Q000009:adverse effects / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods
keywords: CT; adults; artifacts; lung; thorax