Sacral Insufficiency Fractures?

Since the summer of 2006, I have suffered continuous pain (5 or 6 on a 1 to 10 scale) in my right Sacroiliac Joint. The diagnostic work I received since then has revealed a chronic mild compression of the superior end plate at L2 and a suggestion of anterior wedging in T12. Also, I have been diagnosed with Osteoporosis (T -2.1 in the spine, T -2.5 in Femoral Neck, and T -1.8 in the total hip). An MRI taken in the Fall of 2006 revealed a non-specific lesion in my Sacrum. However, several subsequent CT scans did not show a Sacral mass. Is it possible that I may have an undiagnosed Sacral Insufficiency Fracture(s)? Could the non-specific lesion seen on the MRI actually have been bone marrow edema?