title: Feasibility of Selective Catheter-Directed Coronary Computed Tomography Angiography Using Ultralow-Dose Intracoronary Contrast Injection in a Swine Model.
abstract: OBJECTIVE
  Selective catheter-directed intracoronary contrast injected coronary computed tomography angiography (selective CCTA) has recently been introduced for on-site evaluation of coronary artery disease during coronary artery catheterization. In this study, we aimed to develop a feasible protocol for selective CCTA using ultralow-dose contrast medium as compared with conventional intravenous CCTA (IV CCTA).
  
  
  METHODS
  A novel combined system incorporating coronary angiography and a 320-detector row computed tomographic scanner was used to study 4 swine (35-40 kg) under animal institutional review board approval. A selective CCTA scan was simultaneously performed with an injection of 13.13 mgI/mL of modulated contrast medium at multiple different injection rates including 2, 3, and 4 mL/s and different total injection volumes of either 20 or 30 mL. Intravenous CCTA was performed with 60 mL of contrast medium, followed by 30 mL of saline chaser at 5 mL/s. Coronary mean and peak intensity, transluminal attenuation gradient, as well as 3-dimensional maximum intensity projections were obtained.
  
  
  RESULTS
  Attenuation values (mean ± standard error, in Hounsfield units [HUs]) of selective CCTA for the left anterior descending (LAD) and right coronary artery (RCA) using the various combinations of injection rates and total injection volumes were as follows: 20 mL at 2 mL/s (LAD, 270.3 ± 20.4 HU; RCA, 322.6 ± 7.4 HU), 20 mL at 3 mL/s (LAD, 262.9 ± 20.4 HU; RCA, 264.7 ± 7.4 HU), 30 mL at 3 mL/s (LAD, 276.8 ± 20.4 HU; RCA, 274.0 ± 7.4 HU), 20 mL at 4 mL/s (LAD, 268.0 ± 20.4 HU; RCA, 277.7 ± 7.4 HU), and 30 mL at 4 mL/s (LAD, 251.3 ± 20.4 HU; RCA, 334.7 ± 7.4 HU). The representative protocol of the selective CCTA studies produced results within the optimal enhancement range (approximately 250-350 HU) for all segments, and comparison of transluminal attenuation gradient data with selective CCTA and IV CCTA studies demonstrated that the former method was more homogenous (-1.5245 and -1.7558 for LAD as well as 0.0459 and 0.0799 for RCA, respectively). Notably, the volume of iodine contrast medium used for selective CCTA was reported to be 1.09% (0.2 g) of IV CCTA (24 g).
  
  
  CONCLUSIONS
  The current findings demonstrate the feasibility of selective CCTA using ultralow-dose intracoronary contrast injection. This technique may provide additional means of coronary evaluation in patients who may require strategic planning before a procedure using a combined modality system.
authors: From the *Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul; †Division of Cardiology, Department of Internal Medicine, National Health Insurance Service Ilsan Hospital, Goyang-si, Gyeonggi-do; ‡Cardiovascular Center, Myongji Hospital, Goyang-si; §Division of Cardiology, Department of Internal Medicine, Severance Cardiovascular Hospital, Yonsei University College of Medicine; ∥Division of Cardiology, Department of Internal Medicine, Heart Center, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea; ¶Division of Cardiology, Cedars-Sinai Medical Center, Los Angeles, CA; #Dalio Institute of Cardiovascular Imaging, New York-Presbyterian Hospital and the Weill Cornell Medical College, New York, NY; **Cardiovascular Product Evaluation Center, College of Medicine, Yonsei University, Seoul; ††Department of Biostatistics, Bundang CHA Medical Center, Graduate School of Health and Welfare, CHA University, Seongnam; ‡‡Cardiovascular Research Institute; §§Cardiovascular Product Evaluation Center, Yonsei University College of Medicine, Seoul; ∥∥CHA University Graduate School of Health and Welfare, Seongnam-si; and ¶¶Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, South Korea.
authors: Youngtaek
authors: Y
authors: Hong
authors: Sanghoon
authors: S
authors: Shin
authors: Hyung-Bok
authors: HB
authors: Park
authors: Byoung Kwon
authors: BK
authors: Lee
authors: Reza
authors: R
authors: Arsanjani
authors: Bríain
authors: B
authors: ó Hartaigh
authors: Seongmin
authors: S
authors: Ha
authors: Yeonggul
authors: Y
authors: Jang
authors: Byunghwan
authors: B
authors: Jeon
authors: Sunghee
authors: S
authors: Jung
authors: Se-Il
authors: SI
authors: Park
authors: Ji Min
authors: JM
authors: Sung
authors: Hackjoon
authors: H
authors: Shim
authors: Hyuk-Jae
authors: HJ
authors: Chang
mesh_terms: D000818:Animals; D006328:Cardiac Catheterization / Q000379:methods*; D003287:Contrast Media / Q000008:administration & dosage; D017023:Coronary Angiography / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D005240:Feasibility Studies; D005260:Female; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007479:Iopamidol / Q000008:administration & dosage / Q000031:analogs & derivatives*; D011835:Radiation Protection / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014920:Wine
chemical_list: D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol