My previous neuros used open MRIs. My current neuro is an MS specialist-he insists on closed Tesla3 mri machiines, which are more sensitive.
Contrast, as explained above, show active lesions.

I do get claustrophobic in the machine, but I don't want to take a narcotic so that I am able to drive myself home (that way husband doesn't have to take time off of work to take me there and home).
As soon as I lie down on the platform, I close my eyes and I don't open them again until they tell me it's time to stand up. I don't want to hear them tell me how long each picture is going to take- I tell them to just tell me when they are going to inject the contrast, and then tell me when I'm done.
If the place doesn't have earphones with music, I bring my earplugs.

It took several years for me to get a diagnosis of MS...even though I had lesions. Patience is the buzzword when trying to figure out what causes all the strange symptoms.

Good luck and keep us informed