FIGURE 3. When ¹⁵O-water washout images are superimposed on extravascular images and analyzed with semiautomated edge-detection routine, a whole myocardial ROI is determined. Program extracts 3D region enclosing the whole myocardial wall; process is performed in the 3D matrices. Positioning of whole LV wall ROI on ¹⁵O-water washout images is evident. (A) Circles are placed semiautomatically inside and outside myocardial edges. (B) Program defines endocardial and epicardial borders of LV wall (B).