I have a question about how to interpret the blood volume (with papillars) in short axis MRI images. I observe that always almost the endocardial heartwall is defined as a convex contour. It almost never get concave shape. Why it the endocard always indicated in this way? I see in some typical SA MRI images of the left ventricle that there is no contrast at cases where papillars are located. This seems resonable because there is no MRI signal originating from this location. However in most cases the endocardial heart wall is defined as a circular object, which isn't the cases conform the pixel (voxel) intensities. So why are the papillars then so large?
