--really doesn't tell you much (but you know that).

It would be more useful if the doctor or technician can get you a copy of the report so you can see which nerves are most damage, whether the damage involves slowing of neural impulses or an actual conduction block, or whether the result pattern suggests demyelination (damage to the insulating sheath around the larger motor and sensory nerves) or damage to the axons (nerve fibers) themselves, as these can possibly point to causes.

What part of the body is the MRI to be done on? If it is your lower back, that implies the medical people suspect the damage to your nerves starts in the spine or at the spinal nerve roots (which can involve bulging discs, arthritic spurring of the vertebrae, etc. compressing nerves). The EMG patterns might reveal that by indicating where "blocks" or "slowdowns" appear to begin, if all parts of your leg and lower back were tested. But an MRI could be ordered for pelvis or hips, problems within which might also lead to lower extremity symptoms. Or, your spine/hips/pelvis may be fine and this may something more systemic. There are hundreds of causes of lower extremity neurologic symptoms and often the investigation into them is long and very process of elimination, as many different conditions may result in exactly the same symptoms.

Do get copies of the report (we're pretty good at deciphering them here).