mASTOID An imaging test that studies, diagnoses, and examines the mastoid bone, that is located behind the ear is known as Mastoid X-Ray.It creates images of the internal part of the back of the ear.It is advised by doctors to do when symptoms like discharge from the ear, redness behind the ear, headache, hearing loss is experienced.Mastoiditis is caused due to infection in the mastoid bone.It takes only about 15-30 minutes to perform the same.It is a safe technique that does not harm the human body.