At least 30% of TBI are not discovered at first;[4] this number may be as high as 50%.[12] In about 10% of cases, TBI has no specific signs either clinically or on chest radiography, and its detection may be further complicated by concurrent injuries, since TBI tends to occur after high-energy accidents.[2] Weeks or months may go by before the injury is diagnosed, even though the injury is better known than it was in the past.[15]