title: Individualized reduction of radiation dose with a chest circumference-adapted technique and iterative reconstructions in 256-slice retrospective and prospective ECG-triggered computed tomography coronary angiography.
abstract: OBJECTIVE
  To assess the impact of chest circumference (CC)-adjusted tube current and iterative reconstructions (iDose) on individualized radiation dose reduction and image quality (IQ) in ECG-triggered computed tomography coronary angiography (CTCA).
  
  
  METHODS
  A total of 102 patients underwent retrospectively ECG-triggered CTCA utilizing CC-adapted tube current [mAs=1000×(0.051×CC-23.765)/900] and filtered back projection (FBP) reconstruction (group A). On the basis of the CC-adjusted tube current technique, 54 patients (group B) underwent retrospective ECG-triggered CTCA with a 20% mAs reduction compared with group A and 90 patients (group C) underwent prospective ECG-triggered CTCA with an 80% mAs reduction compared with group A; both groups B and C were reconstructed with FBP and iDose. Subjective IQ was assessed, and image noise, signal-to-noise, and contrast-to-noise ratios (SNR and CNR) were quantified.
  
  
  RESULTS
  Patients in group A had the highest radiation dose, followed by group B and group C. iDose provided decreased image noise and increased SNR and CNR, as did subjective IQ. The image noise was higher and SNR and CNR in group B were obviously lower than those in group A with FBP, but in group B, iDose4 increased the mean objective IQ. There was no difference between group B with iDose and group A with FBP, as was the case with subjective IQ.
  
  
  CONCLUSIONS
  The combination of a CC-adapted technique, prospective triggering, and partial iterative reconstruction techniques reduces the radiation dose significantly, without significant degradation of IQ.
authors.affiliation: aDepartment of Radiology, Guangdong General Hospital Guangdong Academy of Medical Sciences, Guangzhou, People's Republic of China bCT Clinical Science, Philips Healthcare, Highland Heights, Ohio, USA.
authors.forename: Jing-Lei
authors.initials: JL
authors.lastname: Li
authors.forename: Mei-Ping
authors.initials: MP
authors.lastname: Huang
authors.forename: Xi-Ming
authors.initials: XM
authors.lastname: Cao
authors.forename: Yan-Hai
authors.initials: YH
authors.lastname: Cui
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Ivanc
authors.forename: Chang-Hong
authors.initials: CH
authors.lastname: Liang
mesh_terms: D000368:Aged; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000379:methods; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*