title: Iterative reconstruction to preserve image quality and diagnostic accuracy at reduced radiation dose in coronary CT angiography: an intraindividual comparison.
abstract: OBJECTIVE
  This study sought to determine whether a 50%-reduced radiation dose protocol using iterative reconstruction (IR) preserves image quality and diagnostic accuracy at coronary computed tomography angiography (CTA) as compared with a routine dose protocol using traditional filtered back projection (FBP).
  
  
  BACKGROUND
  IR techniques show promise to decrease radiation requirements at coronary CTA. No study has performed a direct head-to-head, intraindividual comparison of IR algorithms with FBP vis-à-vis diagnostic accuracy and radiation dose at coronary CTA.
  
  
  METHODS
  Sixty consecutive subjects (45 men, 53.3 ± 9.4 years of age) prospectively underwent coronary catheter angiography (CCA) and 2 coronary CTA scans. One coronary CTA acquisition used routine radiation dose settings and was reconstructed with FBP. For another scan, the tube current-time product was reduced by 50%, and data were reconstructed with IR. Studies were blindly and randomly interpreted. Image quality, radiation dose, and diagnostic accuracy were compared using CCA as the reference standard.
  
  
  RESULTS
  Sensitivity and specificity for diagnosing ≥50% coronary artery stenosis on a per-segment level were 88.5% and 92.1% with FBP and 84.2% and 93.4% with IR, respectively. On a per-patient level, sensitivity and specificity were 100% and 93.1% with FBP and 96.8% and 89.7% with IR, respectively (all p > 0.05). With FBP versus IR, the area under the receiver-operating characteristic curve was 0.903 (95% confidence interval [CI]: 0.881 to 0.922) and 0.888 (95% CI: 0.864 to 0.909) on a per-segment level, and 0.966 (95% CI: 0.883 to 0.996) and 0.932 (95% CI: 0.836 to 0.981) on a per-patient level, respectively (p = 0.290 and 0.330). Compared with FBP, the iterative series showed no significant (p > 0.05) differences in image quality analyses. Median dose-length product was 52% lower for the IR protocol compared with the FBP protocol (109.00 [interquartile range: 82.00 to 172.50] mGy·cm vs. 52.00 [interquartile range: 39.00 to 84.00] mGy·cm, p < 0.001).
  
  
  CONCLUSIONS
  Compared with a routine radiation dose FBP protocol, 50% reduced dose acquisition using IR preserves image quality and diagnostic accuracy at coronary CTA.
authors.affiliation: Department of Radiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China.
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Yin
authors.affiliation: Department of Radiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China. Electronic address: blu@vip.sina.com.
authors.forename: Bin
authors.initials: B
authors.lastname: Lu
authors.affiliation: Department of Radiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China.
authors.forename: Nan
authors.initials: N
authors.lastname: Li
authors.affiliation: Department of Radiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Han
authors.affiliation: Department of Radiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China.
authors.forename: Zhi-Hui
authors.initials: ZH
authors.lastname: Hou
authors.affiliation: Siemens Healthcare, CT Division, Beijing, People's Republic of China.
authors.forename: Run-Ze
authors.initials: RZ
authors.lastname: Wu
authors.affiliation: Department of Cardiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China.
authors.forename: Yong-Jian
authors.initials: YJ
authors.lastname: Wu
authors.affiliation: Department of Cardiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China.
authors.forename: Hong-Xia
authors.initials: HX
authors.lastname: Niu
authors.affiliation: Department of Radiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China.
authors.forename: Shi-Liang
authors.initials: SL
authors.lastname: Jiang
authors.affiliation: Department of Radiology and Radiological Science and Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina.
authors.forename: Aleksander W
authors.initials: AW
authors.lastname: Krazinski
authors.affiliation: Department of Radiology and Radiological Science and Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina.
authors.forename: Ullrich
authors.initials: U
authors.lastname: Ebersberger
authors.affiliation: Department of Radiology and Radiological Science and Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina.
authors.forename: Felix G
authors.initials: FG
authors.lastname: Meinel
authors.affiliation: Department of Radiology and Radiological Science and Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina.
authors.forename: U Joseph
authors.initials: UJ
authors.lastname: Schoepf
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D019540:Area Under Curve; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D014057:Tomography, X-Ray Computed
keywords: BMI; CAD; CCA; CI; CT; CTA; DLP; ECG; FBP; IR; ROC; accuracy; body mass index; computed tomography; computed tomography angiography; confidence interval; coronary artery disease; coronary catheter angiography; coronary computed tomography angiography; dose–length product; electrocardiogram; filtered back projection; iterative reconstruction; radiation; receiver-operating characteristic