title: Prospectively ECG-triggered high-pitch spiral acquisition for cardiac CT angiography in routine clinical practice: initial results.
abstract: OBJECTIVE
  This study was conducted to evaluate the mode of application, image quality (IQ), and radiation exposure resulting from introduction of a prospectively electrocardiogram-triggered high-pitch cardiac computed tomography angiography (CTA) acquisition mode into routine clinical practice.
  
  
  METHODS
  A total of 42 prospectively triggered cardiac CTAs were conducted on 34 patients (11 female, 23 male; mean age 56 ± 15 y) using a high-pitch mode (pitch 3.4) on a dual-source CT. In 8 of these patients with higher heart rates or occasional premature ventricular contractions, 2 immediately subsequent CTAs were performed ("double flash protocol"). Subjective IQ was assessed for coronary arteries using a 4-point scale (1=unevaluable to 4=excellent). Contrast-to-noise ratio (CNR) was measured in 9 locations. CT Dose Index and dose-length product were obtained, and the patients' effective dose was calculated.
  
  
  RESULTS
  Mean effective doses were 2.6 ± 1.4 mSv (range: 1.1 to 6.4) for the entire cardiac examination and 1.4 ± 0.7 mSv (0.4 to 3.1) for individual high-pitch cardiac CTA. z-coverage ranged from 9.9 cm in a native coronary CTA to 31.4 cm in a bypass graft case. The overall subjective IQ was good to excellent (mean score: 3.5), with 1.5% unevaluable coronary segments. The "double flash protocol" resulted in a fully diagnostic CT study in all cases just after taking both scans into consideration. The mean CNR of all locations was 19.7 ± 2.6.
  
  
  CONCLUSIONS
  Prospectively electrocardiograph-triggered high-pitch-mode cardiac CTA is a feasible and promising technique in clinical routine, allowing for evaluation of coronaries at good-to-excellent IQ and providing high CNR and minimal radiation doses. The "double flash protocol" might become a more robust tool in patients with elevated heart rates or premature ventricular contractions.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University of Duesseldorf, Medical Faculty, Düsseldorf, Germany.
authors.forename: Patric
authors.initials: P
authors.lastname: Kröpil
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Rojas
authors.forename: Brian
authors.initials: B
authors.lastname: Ghoshhajra
authors.forename: Rotem S
authors.initials: RS
authors.lastname: Lanzman
authors.forename: Falk R
authors.initials: FR
authors.lastname: Miese
authors.forename: Axel
authors.initials: A
authors.lastname: Scherer
authors.forename: Mannudeep
authors.initials: M
authors.lastname: Kalra
authors.forename: Suhny
authors.initials: S
authors.lastname: Abbara
mesh_terms: D000704:Analysis of Variance; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007479:Iopamidol; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D036542:Tomography, Spiral Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007479:Iopamidol