No, you need to see the spine specialist first. The spine specialist will order the MRI if he/she feels it is needed.
The spine surgeon will order the type and area of MRI that is needed, and all the details that will be needed, including the use of a contrast dye if that will be needed.
If you go with the chiro order for the MRI and it is not what should be done, you've wasted your time, ins money and the ins may not be willing to pay for another MRI.
Best to not use a chiro, in my opinion. they have a tendency to not be of much help, but can sure make spine problems worse.
Good luck
Fran