Cat scan and MRI indicate a shadow on the brain. Dr. indicates small stoke happened 6 months ago, however there were no symptons. Recently there were 2 events of memory loss and several hours of not remembering recent events. What could this be?

I heard this happen w/ a friend of mine who had some bleeding going on in her brain . She did have miniature strokes ? Tiny ones . A shadow on the brain too huh ? That sounds like someone I know who had a Tumor , she had so much memory loss , and would not remember things that happened when she usually remembered everything!!
I hope its not either of these things yet I think you should mention to your doctor.

There are often no symptoms for mini strokes. But the recent discovery of memory loss could be related to the bleed in the brain. You much get another scan to detect any potential damage.