title: Comparison of coronary computed tomography angiography image quality with high- and low-concentration contrast agents (CONCENTRATE): study protocol for a randomized controlled trial.
abstract: With the development of computed tomography (CT) technology, coronary CT angiography can be acquired with low doses of radiation and contrast agent without a loss of diagnostic performance. The primary objective of the CONCENTRATE study is to prove the noninferiority of the enhancement effect of low-concentration contrast agents compared to a high-concentration contrast agent of the coronary artery and myocardium with coronary CT angiography.
  
  
  
  The CONCENTRATE study is a prospective, multicenter, noninferiority, randomized trial evaluating the enhancement effect of low-concentration contrast agents (270 and 320 mg iodine/ml) compared with a high-concentration contrast agent (370 mg iodine/ml) in the coronary artery and myocardium of coronary artery CT angiography. The primary efficacy measurement is the enhancement of coronary arteries as measured in Hounsfield units. The target population comprises 318 patients with suspected coronary artery disease who have been referred for clinically indicated nonemergent coronary CT angiography. Eligible participants are randomized for three different concentrations of the contrast agent in a 1:1:1 allocation ratio to one of three arms. The CONCENTRATE trial is a double-blind study, where the subjects and the outcome assessor are blinded to the concentration of the contrast agent used for coronary the CT angiography. Eight clinical sites in Korea are participating in this trial.
  
  
  
  The CONCENTRATE study will determine whether low-concentration contrast agents are able to provide diagnostic image quality in coronary CT angiography.
  
  
  
  NCT02549794 . Registered on 14 September 2015.
authors.affiliation: Department of Radiology and Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Dong Jin
authors.initials: DJ
authors.lastname: Im
authors.affiliation: Department of Radiology, Chonnam National University Hospital, Chonnam University Medical School, Gwangju, Republic of Korea.
authors.forename: Yun-Hyeon
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Radiology, Pusan National University Yangsan Hospital, Pusan National University School of Medicine, Pusan, Republic of Korea.
authors.forename: Ki Seok
authors.initials: KS
authors.lastname: Choo
authors.affiliation: Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Joon-Won
authors.initials: JW
authors.lastname: Kang
authors.affiliation: Department of Radiology, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Jung Im
authors.initials: JI
authors.lastname: Jung
authors.affiliation: Department of Radiology, Uijeongbu St. Mary's Hospital, Catholic University of Korea, Uijeongbu, Republic of Korea.
authors.forename: Yoodong
authors.initials: Y
authors.lastname: Won
authors.affiliation: Department of Radiology, Yeouido St. Mary's Hospital, Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Hyo Rim
authors.initials: HR
authors.lastname: Kim
authors.affiliation: Department of Radiology, Bucheon St. Mary's Hospital, Catholic University of Korea, Bucheon, Republic of Korea.
authors.forename: Myung Hee
authors.initials: MH
authors.lastname: Chung
authors.affiliation: Department of Radiology and Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Kyunghwa
authors.initials: K
authors.lastname: Han
authors.affiliation: Department of Radiology and Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea. bchoi@yuhs.ac.|Department of Radiology, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea. bchoi@yuhs.ac.
authors.forename: Byoung Wook
authors.identifier: 0000-0002-8873-5444
authors.initials: BW
authors.lastname: Choi
mesh_terms: D002985:Clinical Protocols; D000072226:Computed Tomography Angiography / Q000379:methods*; D003287:Contrast Media / Q000008:administration & dosage*; D017023:Coronary Angiography / Q000379:methods*; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D004311:Double-Blind Method; D006331:Heart Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D007479:Iopamidol / Q000008:administration & dosage*; D061330:Multidetector Computed Tomography / Q000379:methods*; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted; D056910:Republic of Korea; D012107:Research Design; D014283:Triiodobenzoic Acids / Q000008:administration & dosage*
chemical_list: D003287:Contrast Media; D014283:Triiodobenzoic Acids; C044834:iodixanol; D007479:Iopamidol
keywords: CAD; CCTA; Computed tomography; Contrast agent; Coronary artery disease; Coronary computed tomography angiography; Radiation