title: Combined use of automatic tube potential selection with tube current modulation and iterative reconstruction technique in coronary CT angiography.
abstract: OBJECTIVE
  To analyze the effect of automatic tube potential selection with tube current modulation (APSCM) and iterative reconstruction on image quality, diagnostic accuracy, and radiation dose at computed tomographic (CT) angiography and compare it with APSCM-only and body mass index (BMI)-based examination protocols.
  
  
  METHODS
  This study was approved by the institutional review board, and informed consent was obtained from all patients. Images from 185 patients who underwent a BMI-based protocol and 197 patients who underwent an APSCM protocol with filtered back projection (FBP) and an APSCM protocol with sinogram-affirmed iterative reconstruction (SAFIRE) were retrospectively evaluated. Diagnostic performance was compared with that of conventional coronary angiography in a subgroup of 51 patients. Statistical analysis was performed by using the independent or paired t test, Mann-Whitney U test, Wilcoxon signed rank test, χ(2) statistics, linear weighted κ statistics, and generalized estimating equation.
  
  
  RESULTS
  The APSCM group with SAFIRE had a significant reduction in image noise and a significant increase in CT number, contrast enhancement, signal-to-noise ratio, and contrast-to-noise ratio compared with the APSCM group with FBP (P < .0001) and the BMI-based group (P < .001, except P = .002 for image noise). Image quality and diagnostic accuracy showed no significant difference between the three groups. The use of APSCM resulted in a significant reduction in radiation dose compared with the BMI-based protocol.
  
  
  CONCLUSIONS
  The combination of SAFIRE and APSCM at coronary CT angiography significantly improves objective image quality while maintaining diagnostic accuracy and reduced radiation dose. Online supplemental material is available for this article.
authors.affiliation: From the Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea.
authors.forename: Young Joo
authors.initials: YJ
authors.lastname: Suh
authors.forename: Young Jin
authors.initials: YJ
authors.lastname: Kim
authors.forename: Sae Rom
authors.initials: SR
authors.lastname: Hong
authors.forename: Yoo Jin
authors.initials: YJ
authors.lastname: Hong
authors.forename: Hye-Jeong
authors.initials: HJ
authors.lastname: Lee
authors.forename: Jin
authors.initials: J
authors.lastname: Hur
authors.forename: Byoung Wook
authors.initials: BW
authors.lastname: Choi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D003287:Contrast Media; D017023:Coronary Angiography / Q000295:instrumentation*; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007479:Iopamidol; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011835:Radiation Protection; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*
chemical_list: D003287:Contrast Media; D007479:Iopamidol