This paper might be useful [0]. It measures the thickness of a tissue. If you do that over time you can detect the parts that aren't moving. I studied under Yezzi for a while. Cool dude.
Awesome, thank you for the reference. That's the essence of finding regional wall motion abornomalities. When looking at the ultrasound I look for parts of the myocardium that don't change in size relative to their neighbors during the cardiac cycle.