title: Diagnostic image quality of a comprehensive high-pitch dual-spiral cardiothoracic CT protocol in patients with undifferentiated acute chest pain.
abstract: OBJECTIVE
  To evaluate diagnostic image quality of high-pitch dual source comprehensive cardiothoracic CT protocol in patients presenting with acute undifferentiated chest pain.
  
  
  METHODS
  Consecutive symptomatic subjects (n=51) with undifferentiated acute chest pain underwent ECG-synchronized high-pitch dual-spiral chest CT angiography (Definition Flash, Siemens Medical Solutions, 2 × 100 kVp or 2 × 120 kV if BMI>30, collimation: 128 × 0.6mm, pitch: 3.2). Independent investigators determined the image quality of each cardiac and pulmonary vessel segment, measured contrast-to-noise-ratio (CNR), and determined radiation exposure. In addition, the prevalence of CT findings (pulmonary embolism (PE), aortic dissection (AD) and significant coronary stenosis (≥ 50%)) was determined. Univariate and multivariate analysis were performed to determine the subpopulation with highest diagnostic quality.
  
  
  RESULTS
  Among 51 subjects (66% male, average age: 63 ± 15.8), the prevalence of positive CT findings was moderate (overall: 11.7%). Overall, image quality of the pulmonary, aortic and coronary vasculature was good (1.26 ± 0.43 and CNR: 2.52) with an average radiation dose of 3.82 mSv and 3.2% of segments rated non-evaluable. The image quality was lowest in the coronary arteries (p=0.02), depending on the heart rate (r=0.52, p<0.001). In subjects with a heart rate of ≤ 65 bpm (n=30) subjective image quality and CNR of the coronary arteries were higher (1.6 ± 0.5 vs. 2.1 ± 0.5, p=0.03 and 1.21 ± 0.3 vs. 1.02 ± 0.3, p=0.05) with only 1.5% segments classified as non-evaluable.
  
  
  CONCLUSIONS
  High-pitch dual-spiral comprehensive cardiothoracic CT provides low radiation exposure with excellent image quality at heart rates ≤ 65 bpm. In subjects with higher heart rates, image quality of the aortic and pulmonary vasculature remains excellent, while the assessment of the coronary arteries degrades substantially.
authors.affiliation: Department of Clinical Radiology, Ludwig-Maximilians University, Klinikum Grosshadern, Munich, Germany. fbamberg@med.lmu.de
authors.forename: Fabian
authors.initials: F
authors.lastname: Bamberg
authors.forename: Roy
authors.initials: R
authors.lastname: Marcus
authors.forename: Wieland
authors.initials: W
authors.lastname: Sommer
authors.forename: Florian
authors.initials: F
authors.lastname: Schwarz
authors.forename: Konstantin
authors.initials: K
authors.lastname: Nikolaou
authors.forename: Christoph R
authors.initials: CR
authors.lastname: Becker
authors.forename: Maximilian F
authors.initials: MF
authors.lastname: Reiser
authors.forename: Thorsten R C
authors.initials: TR
authors.lastname: Johnson
mesh_terms: D000208:Acute Disease; D000465:Algorithms; D000792:Angiography / Q000379:methods*; D002637:Chest Pain / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods*; D013902:Radiography, Thoracic / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed / Q000379:methods*