title: Systolic acquisition of coronary dual-source computed tomography angiography: feasibility in an unselected patient population.
abstract: OBJECTIVE
  To determine the practicability and potential dose saving of an imaging algorithm incorporating a pulsing scheme applying systolic data acquisition at heart rates >75 beats per minute (bpm).
  
  
  METHODS
  Patients clinically referred for coronary computed tomography angiography (CTA) underwent cardiac CTA using either a diastolic pulsing window (30-70%) or a narrow systolic pulsing window (150 ms at 300 ms). Independent investigators retrospectively determined image quality (1, excellent, to 5, unreadable) and derived effective radiation exposure.
  
  
  RESULTS
  Among all 101 subjects (62 +/- 2 years, 59% male) the predicted decrease in the best reconstruction interval for diastolic phases was 12 ms per 1 bpm [95% confidence interval (CI): -13.5 to -11.2] and -1.9 ms for systolic phases (95% CI: -3.2 to -0.62, p = 0.004), independent of age, gender and body mass index (BMI). The systolic pulsing strategy in 47 subjects (23 subjects >75 bpm) resulted in significantly lower radiation exposure (4.97 +/- 2.3 vs 9.38 +/- 5.5 mSv, p < 0.001 for systolic versus diastolic, respectively), whereas there was no difference with respect to image quality or heart rate (p = 0.65 and p = 0.74, respectively).
  
  
  CONCLUSIONS
  Our results suggest that a systolic window for tube current modulation in subjects with higher heart rates represents a reliable tool to ensure high image quality at significantly lower dose in patients undergoing routine cardiac CTA.
authors.affiliation: Department of Clinical Radiology, Ludwig-Maximilians University, Klinikum Grosshadern, Munich, Germany.
authors.forename: Fabian
authors.initials: F
authors.lastname: Bamberg
authors.forename: Wieland H
authors.initials: WH
authors.lastname: Sommer
authors.forename: Jan C
authors.initials: JC
authors.lastname: Schenzle
authors.forename: Christoph R
authors.initials: CR
authors.lastname: Becker
authors.forename: Konstantin
authors.initials: K
authors.lastname: Nikolaou
authors.forename: Maximilian F
authors.initials: MF
authors.lastname: Reiser
authors.forename: Thorsten R C
authors.initials: TR
authors.lastname: Johnson
mesh_terms: D000465:Algorithms; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013599:Systole; D014057:Tomography, X-Ray Computed / Q000379:methods*