title: Feasibility and radiation dose of high-pitch acquisition protocols in patients undergoing dual-source cardiac CT.
abstract: OBJECTIVE
  The objective of this study was to compare image quality and radiation dose between high-pitch and established retrospectively and prospectively gated cardiac CT protocols using an Alderson-Rando phantom and a set of patients.
  
  
  METHODS
  An anthropomorphic Alderson-Rando phantom equipped with thermoluminiscent detectors and a set of clinical patients underwent the following cardiac CT protocols: high-pitch acquisition (pitch 3.4), prospectively triggered acquisition, and retrospectively gated acquisition (pitch 0.2). For patients with sinus rhythm below 65 beats per minute (bpm), high-pitch protocol was used, whereas for patients in sinus rhythm between 65 and 100 bpm, prospective triggering was used. Patients with irregular heart rates or heart rates of ≥ 100 bpm, were examined using retrospectively gated acquisition. Evaluability of coronary artery segments was determined, and effective radiation dose was derived from the phantom study.
  
  
  RESULTS
  In the phantom study, the effective radiation dose as determined with thermoluminescent detector (TLD) measurements was lowest in the high-pitch acquisition (1.21, 3.12, and 11.81 mSv, for the high-pitch, the prospectively triggered, and the retrospectively gated acquisition, respectively). There was a significant difference with respect to the percentage of motion-free coronary artery segments (99%, 87%, and 92% for high-pitch, prospectively triggered, and retrospectively gated, respectively (p < 0.001), whereas image noise was lowest for the high-pitch protocol (p < 0.05).
  
  
  CONCLUSIONS
  High-pitch scans have the potential to reduce radiation dose up to 61.2% and 89.8% compared with prospectively triggered and retrospectively gated scans. High-pitch protocols lead to excellent image quality when used in patients with stable heart rates below 65 bpm.
authors.affiliation: Department of Clinical Radiology, University of Munich, Grosshadern Campus, Marchioninstr. 15, 81377, Munich, Germany. Wieland.sommer@med.uni-muenchen.de
authors.forename: Wieland H
authors.initials: WH
authors.lastname: Sommer
authors.forename: Edda
authors.initials: E
authors.lastname: Albrecht
authors.forename: Fabian
authors.initials: F
authors.lastname: Bamberg
authors.forename: Jan C
authors.initials: JC
authors.lastname: Schenzle
authors.forename: Thorsten R
authors.initials: TR
authors.lastname: Johnson
authors.forename: Klement
authors.initials: K
authors.lastname: Neumaier
authors.forename: Maximilian F
authors.initials: MF
authors.lastname: Reiser
authors.forename: Konstatin
authors.initials: K
authors.lastname: Nikolaou
mesh_terms: D000704:Analysis of Variance; D005240:Feasibility Studies; D005260:Female; D006331:Heart Diseases / Q000000981:diagnostic imaging*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D018709:Statistics, Nonparametric; D013819:Thermoluminescent Dosimetry; D014057:Tomography, X-Ray Computed / Q000379:methods*