<qa>  What is the size of the ulcer?At study Week 4, the size of the ulcer will be compared to the size at study Day 0 to determine if the ulcer is demonstrating Predicted to Heal PTH, defined as 40 reduction in ulcer surface area compared with study Day 0, or Not Predicted to Heal NPTH, defined as 40 reduction in ulcer surface area compared with study Day 0. 