Just by having a clean EMG with no muscle weakness is good enough sign that its not ALS (as what Wright stated below). Yes, you will always have doubts, its normal. But a piece of advice my friend, its unfair for to the good people at this forum for you to keep on pushing for an answer and when they give one to you, you just create more questions on your head. All of them (PALS) would do anything to change EMG results with you. Have you been to the BFS forum? Your symptoms point to BFS. Twitching starting with calves is a very classic BFS symptom. Enjoy life. I can relate to what you're undergoing because I think like you before I got my clean EMG. I still have my relapses of being anxious but I always go back to being rational. You'll be good. 100%
You have a clean EMG with no weakness. Why on earth would you think you have ALS? Is it the muscle twitching? My muscles are twitching as I write this. I'm not worried in the least, because everyone on the planet twitches. I get muscle cramps, too, and they can happen for a gazillion reasons (most of the time it's dehydration . . . drink more water). As far as your MRI: if your neuro's aren't concerned, why would you be concerned? They're the ones who went to school for many, many, many years and then did their residency and are experienced in those things medicine. You have done none of that. Be done with this and get-on with your life.