I was diagnosed with a syndesmotic liagament injury do a distal fibular fracture...why would my dr not order an mri, only after i requested one?

Not needed: MRI scan of a syndesmotic injury is not necessary. Often diagnosed with plain Xray, this injury can best be imaged by CT scan if clinically indicated and Xrays are negative.

X-rays are enough: An injury to the syndesmosis is picked up by X-rays and even though mris are helpful for many other types of soft tissue injuries, a doctor can tell that the syndesmosis is disrupted by the alignment if the bones on xray.