title: Targeted transendocardial therapeutic delivery guided by MRI-x-ray image fusion.
abstract: OBJECTIVE
  To validate a multi-modality image fusion approach to guide catheter-based, targeted transendocardial therapeutic delivery in a swine myocardial infarction (MI) model.
  
  
  BACKGROUND
  Biologic agents such as stem cells may curb post MI adverse ventricular remodeling if delivered by a transendocardial catheter directly into the infarct border. 3D visualization of the infarct and other cardiac surfaces is required to perform this task. We propose registering and overlaying magnetic resonance imaging (MRI) roadmaps onto live x-ray fluoroscopy (XRF) to guide targeted transendocardial delivery.
  
  
  METHODS
  Custom software was used to register and overlay MRI models of the endocardium and infarct on live XRF by aligning common endocardial border features. In a swine MI model, transendocardial injections of co-localizing imaging labels were performed, targeting a 20 mm perimeter around the infarct. Directed targeting error (DTE) was defined as the difference between the predicted injection site-to-infarct distance calculated by the image fusion system, to the actual distance determined by postprocedure in vivo MRI. The mobile image fusion system was designed to be vendor-independent for imaging systems and transendocardial catheters.
  
  
  RESULTS
  Transendocardial injections were performed in all animals without complications. Mean DTE was 0.9 ± 5.0 mm (n = 8 swine). Time to register the images and establish a high quality roadmap was less than 12 min in all animals. Custom imaging tools to display injection sites and distribution were useful adjuncts during targeted injection procedures.
  
  
  CONCLUSIONS
  Multi-modality image fusion is a feasible and accurate platform technology to guide transendocardial injections precisely to the discrete infarct border.
authors.affiliation: Department of Biomedical Engineering, University of Wisconsin, Madison, USA.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Tomkowiak
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Klein
authors.forename: Karl K
authors.initials: KK
authors.lastname: Vigen
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Hacker
authors.forename: Michael A
authors.initials: MA
authors.lastname: Speidel
authors.forename: Michael S
authors.initials: MS
authors.lastname: VanLysel
authors.forename: Amish N
authors.initials: AN
authors.lastname: Raval
mesh_terms: D000818:Animals; D006328:Cardiac Catheterization; D003287:Contrast Media / Q000008:administration & dosage; D003911:Dextrans / Q000008:administration & dosage; D004195:Disease Models, Animal; D004699:Endocardium / Q000000981:diagnostic imaging* / Q000473:pathology*; D005240:Feasibility Studies; D005471:Fluoroscopy; D007090:Image Interpretation, Computer-Assisted; D007267:Injections; D007472:Iohexol / Q000008:administration & dosage; D053783:Magnetic Resonance Imaging, Interventional; D058185:Magnetite Nanoparticles / Q000008:administration & dosage; D023421:Models, Animal; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000628:therapy; D011237:Predictive Value of Tests; D015641:Radiography, Interventional; D015203:Reproducibility of Results; D012984:Software; D013552:Swine
chemical_list: D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D007472:Iohexol; C065507:ferumoxides