title: Multimodality infarct identification for optimal image-guided intramyocardial cell injections.
abstract: BACKGROUND
  Intramyocardial cell injections in the context of cardiac regenerative therapy can currently be performed using electromechanical mapping (EMM) provided by the NOGA®XP catheter injection system. The gold standard technique to determine infarct size and location, however, is late gadolinium enhanced magnetic resonance imaging (LGE-MRI). In this article we describe a practical and accurate technique to co-register LGE-MRI and NOGA®XP datasets during the injection procedures to ultimately perform image-guided injections to the border zone of the infarct determined by LGE-MRI.
  
  
  METHODS
  LGE-MRI and EMM were obtained in three pigs with chronic myocardial infarction. MRI and EMM datasets were registered using the in-house developed 3D CartBox image registration toolbox consisting of three steps: 1) landmark registration, 2) surface registration, and 3) manual optimization. The apex and the coronary ostia were used as landmarks.
  
  
  RESULTS
  Image registration was successful in all datasets, and resulted in a mean registration error of 3.22 ± 1.86 mm between the MRI surface mesh and EMM points. Visual assessment revealed that the locations and the transmural extent of the infarctions measured by LGE-MRI only partly overlap with the infarct areas identified by the EMM parameters.
  
  
  CONCLUSIONS
  The 3D CartBox image registration toolbox enables registration of EMM on pre-procedurally acquired MRI during the catheter injection procedure. This allows the operator to perform real-time image-guided cell injections into the border zone of the infarct as assessed by LGE-MRI. The 3D CartBox thereby enables, for the first time, standardisation of the injection location for cardiac regenerative therapy.
authors.affiliation: Department of Cardiology, University Medical Center Utrecht, E03.511, PO Box 85500, 3508 GA, Utrecht, the Netherlands, f.j.vanslochteren@umcutrecht.nl.
authors.forename: F J
authors.initials: FJ
authors.lastname: van Slochteren
authors.forename: R
authors.initials: R
authors.lastname: van Es
authors.forename: S
authors.initials: S
authors.lastname: Koudstaal
authors.forename: T I G
authors.initials: TI
authors.lastname: van der Spoel
authors.forename: J P G
authors.initials: JP
authors.lastname: Sluijter
authors.forename: J
authors.initials: J
authors.lastname: Verbree
authors.forename: R H R
authors.initials: RH
authors.lastname: Pruim
authors.forename: J P W
authors.initials: JP
authors.lastname: Pluim
authors.forename: T
authors.initials: T
authors.lastname: Leiner
authors.forename: P A
authors.initials: PA
authors.lastname: Doevendans
authors.forename: S A J
authors.initials: SA
authors.lastname: Chamuleau