With just that amount of information, it would be hard to really conjecture what might be going on. The lesion locations, particularly periventricular, would be suspicious of MS.
Your neuro looks not just at your MRI, but should also listen closely to your history and do a thorough neurological exam. The LP results don't prove or disprove MS, it is just used as supporting evidence. Then the doctor pieces it all together.
I hope you get some answers and the next LP goes better.
~Laura
I'm curious, what do you mean "closer to your skull"? Doesn't the LP have to be done below the level of the spinal cord?
(I got stuck twice in 2003, no fluid; again in 2011, FIVE times or more UNDER X-RAY and they still couldn't withdraw fluid...I hope you have much better luck!)
Do you have spinal problems such as scoliosis? I think that is what interfered with my attempted LPs.
I don't know what the odds are that you don't have MS, but a negative spinal tap wouldn't necessarily rule it out. Mainly they go by the MRI.
Good luck.