Diffuse axonal injury (DAI) is axonal and small vessel injury produced by a sudden acceleration of the head by an extal force,and is a major cause of death and severe disability (Paterakis et al.,2000).Prognosis is poorer in patients with apparent hemorrhage than in those without (Paterakis et al.,2000).Therefore,it is important to identify the presence and precise position of hemorrhagic foci for a more accurate diagnosis.CT and magnetic resonance imaging (MRI) have long been applied in the diagnosis of DAI,but they are not sensitive enough for the detection of small hemorrhagic foci,and cannot meet the requirements for early diagnosis.A major advance in MRI has been the development of susceptibility weighted imaging (SWI),which has greatly increased the ability to detect small hemorrhagic foci after DAI (Ashwal et al.,2006).In this study,we retrospectively analyzed MRI data for 25 patients with hemorrhagic DAI verified by clinical imaging,and we explored whether SWI was sufficiently sensitive to evaluate hemorrhagic DAI and help accurately assess the severity of the disease.