Ordered ct scan brain mri for lumbar spine after fall stairs lft leg has been numb 3yr prior to stairs spine not bad brain chronic microvascular ishemic white matter disease ms? autoimmune?

You need diagnosis: The left leg issues may be peripheral nerve or due to lumbar nerve compression, but would wonder about prior stoke or even spinal cord compression in neck. This is not ms or any autoimmune process. See a neurosurgeon or a spine specialist and get this addressed.

Ischemic Brain: Not likely. At your age, the vascualr ischemia is more apt to be due to chronic high blood pressure or diabetes. It is important to follow up on this with your doctor to avoid small lesions called "lacunar" infarcts. Often, medication can be prescribed which will improve your micro vascualr integrity and avoid further damage.