Hypoxic-ischemic brain injury(HI-BI) is one of the most common causes of severe neurological disability.Some studies have reported diffusion tensor imaging(DTI) findings of neonatal patients with HI-BI.However,very little is known about DTI in the adult brain.The present study reports on a 15-year-old male patient with HI-BI,who exhibited no specific focal lesions on conventional brain MRI at 5 weeks.However,neural tract injuries were revealed by DTI.Seven control subjects were also evaluated.The patient suffered from cardiac arrest due to ventricular fibrillation for a period of 10-15 minutes.At 4 weeks after onset of cardiac arrest,although he was conscious and alert,he exhibited mild quadriparesis and severe cognitive dysfunction.DTI was acquired at 5 weeks after HI-BI onset.Decreased fractional anisotropy or voxel number of neural tracts suggested partial injury of the corticospinal tract,fornix,and cingulum.Disruptions of the fornix and cingulum on DTI confirmed neural tract injury.DTI could serve as a useful tool for evaluating the state of neural tracts in patients with HI-BI. Hypoxic-ischemic brain injury (HI-BI) is one of the most common causes of severe neurological disability. Home studies have reported diffusion tensor imaging (DTI) findings of neonatal patients with HI-BI. However, very little is known about DTI in the adult brain. The present study reports on a 15-year-old male patient with HI-BI, who with no specific focal lesions on conventional brain MRI at 5 weeks. However, neural tract injuries were revealed by DTI. It also evaluated the patient suffered from cardiac arrest due to ventricular fibrillation for a period of 10-15 minutes. At 4 weeks after onset of cardiac arrest, although he was conscious and alert, he showed mild quadriparesis and severe cognitive dysfunction. at 5 weeks after HI-BI onset. Decreased fractional anisotropy or voxel number of neural tracts suggested partial injury of the corticospinal tract, fornix, and cingulum. Disruptions of the fornix and cingulum on DTI confirmed neural tract injur y.DTI could serve as a useful tool for evaluating the state of neural tracts in patients with HI-BI.