The purpose of this study was to compare Tc 99m HMPAO SPECT with MRI aft,er acute and subacute closed head injury. There were thirty two focal lesions in all cases of these, Fifteen lesions(47%) were seen on both MRI and SPECT. Fourteen lesions(44%) were seen only on MRI. Three lesions(9%) were seen only on SPECT. Of the 14 lesions seen only on MRl, one was epidural hematoma, two were subdural hematoma, three were subdural hygroma, one was intracerebral hematoma, four were contusion, and three were diffuse axonal injuries. SPECT detected 52% of the focal lesions found on MRI. For the detection of lesions, MRl was superior to SPECT in fourteen cases, while SPKCT was superior to MRI in three cases. In conclusion, there was a tendency that detection rate af the traumat,ic lesions was higher on MRI, but the SPECT could delineate more wide extent, of lesion.