title: Optimization of hybrid iterative reconstruction level and evaluation of image quality and radiation dose for pediatric cardiac computed tomography angiography.
abstract: BACKGROUND
  Hybrid iterative reconstruction can reduce image noise and produce better image quality compared with filtered back-projection (FBP), but few reports describe optimization of the iteration level.
  
  
  OBJECTIVE
  We optimized the iteration level of iDose4and evaluated image quality for pediatric cardiac CT angiography.
  
  
  METHODS
  Children (n = 160) with congenital heart disease were enrolled and divided into full-dose (n = 84) and half-dose (n = 76) groups. Four series were reconstructed using FBP, and iDose4levels 2, 4 and 6; we evaluated subjective quality of the series using a 5-grade scale and compared the series using a Kruskal-Wallis H test. For FBP and iDose4-optimal images, we compared contrast-to-noise ratios (CNR) and size-specific dose estimates (SSDE) using a Student's t-test. We also compared diagnostic-accuracy of each group using a Kruskal-Wallis H test.
  
  
  RESULTS
  Mean scores for iDose4level 4 were the best in both dose groups (all P < 0.05). CNR was improved in both groups with iDose4level 4 as compared with FBP. Mean decrease in SSDE was 53% in the half-dose group. Diagnostic accuracy for the four datasets were in the range 92.6-96.2% (no statistical difference).
  
  
  CONCLUSIONS
  iDose4level 4 was optimal for both the full- and half-dose groups. Protocols with iDose4level 4 allowed 53% reduction in SSDE without significantly affecting image quality and diagnostic accuracy.
authors.affiliation: Southern Medical University, Guangzhou, China.|Department of Radiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan Er Road, Guangzhou, 510080, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Yang
authors.affiliation: Department of Cardiac Surgery, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhuang
authors.affiliation: Department of Radiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan Er Road, Guangzhou, 510080, China.|Department of Catheterization Lab, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
authors.forename: Meiping
authors.initials: M
authors.lastname: Huang
authors.affiliation: Southern Medical University, Guangzhou, China. cjr.lchh@vip.163.com.|Department of Radiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan Er Road, Guangzhou, 510080, China. cjr.lchh@vip.163.com.
authors.forename: Changhong
authors.identifier: http://orcid.org/0000-0002-9101-8390
authors.initials: C
authors.lastname: Liang
authors.affiliation: Department of Radiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan Er Road, Guangzhou, 510080, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Liu
mesh_terms: D000072226:Computed Tomography Angiography / Q000592:standards*; D003287:Contrast Media; D017023:Coronary Angiography / Q000592:standards*; D005260:Female; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011446:Prospective Studies; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000592:standards*
chemical_list: D003287:Contrast Media
keywords: Angiography; Children; Computed tomography; Congenital heart disease; Hybrid iterative reconstruction; Radiation dose