XFM targeting of endomyocardial injections according to infarct location (blue surface) and regional myocardial wall thickness (colored green for wall thickness >6 mm and red for wall thickness ≤6 mm) in an animal with a chronic LCX infarct. These surfaces were displayed over x-ray in orthogonal projections (A and B). The catheter is positioned where the wall thickness is ≤6 mm (arrow); this location was therefore rejected. C and D demonstrate relocation of the injection catheter to a “safe” peri-infarct location with wall thickness >6 mm. After deployment of the needle, orthogonal x-ray views allow reconstruction of the injection location in 3D (yellow spot, numbered 4). Previous injection locations (yellow spots, numbered 1 to 3) are also displayed to help avoid overlapping injections. The 3D injection locations are also displayed superimposed on the prior DHE MRI (E and G). A postmortem TTC-stained heart slice (F), located between the MRI slices displayed in E and G, shows tissue dye–staining patterns that correlate well with the XFM-derived injection locations.