The MRI is very good at looking at the disc complex. The MRI was originally developed for imaging the brain and tumors. It is excellent for soft tissues, but cortical bone is not its strong suit. With newer sequencing, this has improved significantly.
I am not sure what you mean by a wedged disc. This would be an extremely uncommon deformity. However, wedging of the vertebral body due to trauma, congenital, and developmental causes is not uncommon.
Hope you find answers to your questions. Good luck.