title: Co-registration of angiography and intravascular ultrasound images through image-based device tracking.
abstract: OBJECTIVE
  To determine the feasibility of automated co-registration of angiography and intravascular ultrasound (IVUS) to facilitate integration of these two imaging modalities in a synchronous manner.
  
  
  BACKGROUND
  IVUS provides cross-sectional imaging of coronary arteries but lacks overview of the vascular territory provided by angiography. Co-registration of angiography and IVUS would increase utility of IVUS in the clinical setting.
  
  
  METHODS
  Forty-nine consecutive patients undergoing surveillance for cardiac allograft vasculopathy with angiography and IVUS of the left anterior descending artery (LAD) were enrolled. A pre-IVUS angiogram of the LAD was performed followed by an ECG-triggered fluoroscopy (ECGTF) during IVUS pullback at 0.5 mm/s using an automatic pullback device. ECGTF was used to track the IVUS catheter during pullback and establish a spatial relationship to the pre-IVUS angiogram. Angio-IVUS co-registration was performed with a research prototype (Siemens Healthcare, Germany) and accuracy was evaluated by distance mismatch between angiography and IVUS images at vessel bifurcations.
  
  
  RESULTS
  Median age was 54 (44.5, 67) years. The population was 82.6% male with minimal risk factors. The median (IQR) co-registration distance mismatch measured at 108 bifurcations in 42 (85%) patients was 0.35 (0.00-1.16) mm. Seven patients were excluded due to inappropriate data acquisition (n = 3) and failure of tracking (n = 4), e.g., due to overlapping sternal wires. Estimated effective radiation dose for ECGTF was 0.09 mSv.
  
  
  CONCLUSIONS
  This study demonstrates the feasibility of angio-IVUS co-registration which may be used as a clinical tool for localizing IVUS cross-sections along an angiographic roadmap. © 2015 Wiley Periodicals, Inc.
authors.affiliation: Mayo Clinic School of Medicine, Division of Cardiology, Rochester, Minnesota.
authors.forename: Megha
authors.initials: M
authors.lastname: Prasad
authors.affiliation: Mayo Clinic School of Medicine, Division of Cardiology, Rochester, Minnesota.
authors.forename: Andrew
authors.initials: A
authors.lastname: Cassar
authors.affiliation: Mayo Clinic School of Medicine, Division of Cardiology, Rochester, Minnesota.
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Fetterly
authors.affiliation: Mayo Clinic School of Medicine, Division of Cardiology, Rochester, Minnesota.
authors.forename: Malcolm
authors.initials: M
authors.lastname: Bell
authors.affiliation: Siemens Corporate Research and Technology, Germany.
authors.forename: Heike
authors.initials: H
authors.lastname: Theessen
authors.affiliation: Siemens Corporate Research and Technology, Germany.
authors.forename: Olivier
authors.initials: O
authors.lastname: Ecabert
authors.affiliation: Mayo Clinic School of Medicine, Division of Cardiology, Rochester, Minnesota.
authors.forename: John F
authors.initials: JF
authors.lastname: Bresnahan
authors.affiliation: Mayo Clinic School of Medicine, Division of Cardiology, Rochester, Minnesota.
authors.forename: Amir
authors.initials: A
authors.lastname: Lerman
mesh_terms: D000328:Adult; D000368:Aged; D001331:Automation; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000209:etiology; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005240:Feasibility Studies; D005260:Female; D016027:Heart Transplantation / Q000009:adverse effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D011237:Predictive Value of Tests; D011829:Radiation Dosage; D000069079:Radiation Exposure; D011857:Radiographic Image Interpretation, Computer-Assisted; D018084:Ultrasonography, Interventional
keywords: coronary artery disease; imaging; integration; novel