Fellow migraine sufferer/MRI aficionado here
The MRI facility you go to is so very important. I get MRI's all the time because of my migraines, and have a spot on my brain. They found the spot when I was about 19. Believe it or not some facilities give back reports missing the spot which pretty much tells me not to go back. Last year I had another one done and they told me another spot showed up and my Dr's office reported the 2 spots were unchanged from the previous study. I couldn't believe my ears and thought, umm what do you mean the 2nd spot is unchanged. Turns out the 2008 MRI Radiologist from local hospital St Lukes Bethlehem missed the second spot, but it was there because the 2009 Radiologist from Lehigh Valley Hospital saw it on both films.... nice. Now it turns out the spot isn't anything too horrible since I'm still here , sort of how the Neurologist explained it to me to calm me down

, but the fact that I've had stuff missed more than once doesn't exactly give me a great deal of confidence. Yes, the person administering the test should make sure it is perfect before sending you home but ultimately the Dr is the one who needs to make sure everything is absolutely clear. I think you should actually feel good and count yourself lucky that someone caught the trouble and has called you in to repeat the test. Someone in that facility is a really good Dr to do that for you

, you are probably in good hands.
Like you, I also have a great deal of trouble with word recall. It mostly happens with nouns and makes me feel terribly awkward sometimes as I just stand there unable to complete a thought. Not only do I forget words but i occasionally jumble my words up when I speak and use the wrong word without even realizing it. My kids point it out all the time and i almost never realize I've switched words so I don't really know how long I have been doing this since my kids are the only people who draw attention to it and they are 11 & 12, bless their honesty. On the other hand I am distinctly aware of the word loss, it's like i knew the word i wanted and mid sentence it just vanishes. For me the trouble got so bad that i asked my Neurologist to preform an early onset "Alzheimers Test" because I became convinced I was losing my mind. he had the test administered and I was relieved to learn that my mind is just fine. The neurologist thinks this is just another manifestation of my extremely weird migraines that can accompany pain, or not. I also have the worst memory ever, again the Dr tells me this is simply a part of how my particular brain is reacting to a migraine. Sometimes it just comes in waves but my Dr assures me it's just my version of normal. When it happens i just tell the people I am with "I'm sorry but my migraines are just acting up", I assume people are accepting of my explanation, they seem to be.
PS- since I mentioned it I should explain, severe migraine sufferers are known to have spots in their brains. It's not exactly run of the mill common but it's not unheard of either. They shouldn't be ignored but don't necessarily mean anything is wrong either.