Can a MRI Tech detect an abnormality?

I know the Radiologist has to look at it and the tech is not supposed to say anything. But can they usually tell if there is something abnormal beforehand? And is it customary if they don't see anything for them to say everything looks fine?
Answer:
You can usually tell during the MRI if something is abnormal and it really stands out. If they don't see anything they can say everything is fine. After the MRI is done the radiologist looks over the films very carefully to make sure he/she didn't miss anything.

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