Reevaluation of CT findings of epidural hematomas

Homogeneous high density (01 biconvex shape) has been the CT hallmark 01 epidural hematomas. High res이u­ tion CT demonstrates the structural detail 01 hematomas and as a result all the hematomas are no longer homogeneous. Authors reviewed CT lindings 01 27 les ions os epidural hematomas within 72 hours, 01 head injury and Irouped into 4 types according to the density homogeneity type 1: well-delined low density area within hematoma type 2: ill -delined low density area within hematom (Iaminar, hole, or irregular) type 3‘ homogeneous high density hematoma with or w ithout internal mottling type 4: marginal low density area along hematoma Types and time interval between head injury and CT examination are well co rrelated; The mean time dura tions 01 each typeare 2hr, 7.6hr, 15hr, and 53 hr in order. The lucency in type 1 represents active bleeding lrom meningeal artery or dural sinus. The inhomogeneity in type 2 is due to liquid blood within clots. The homogeneity in type 3 means complete clot lormation. The marginal low density in type 4 rellects retraction 。1 blood clot.