Whats the difference between a spinal mri and brain mri for ms? do they tell different things? would a brain mri only be needed for ms eye issues and random muscle twitches?

A brain MRI is of the brain and a spinal cord MRI is of the spinal cord, usu. only the C-spine because most spinal MS occurs there. Your doctor will choose brain, C-spine, or both depending on your symptoms. Don't try to 2nd-guess the doc. You'll just slow down the process.

Since MS can involve both brain and spinal cord in various combinations, and other disorders such as NMO can mimic MS, the two areas of imaging can be useful in making clinical decisions. Diagnostic confirmatory criteria may require imaging in both brain and spinal cord. Your neurologist will decide what additional information is needed to arrive at therapeutic interventions.