 - Magnetic resonance imaging if one has not been done within the previous 6 months: MRI uses a magnetic field and radio waves to produce images of body tissues and organs. For this procedure, the patient lies on a table that is moved into the scanner a narrow cylinder and wears earplugs to muffle loud knocking and thumping sounds that occur during the scanning process. The procedure lasts about 45 to 90 minutes, during which the patient lies still up to a few minutes at a time. 