The pathological finding of multiple small hemorrhagic brain lesions of traumatic origin was first identified by Cassaca. Subsequently, cases of this pathology were reported only by Tomlinson, Strich, and Adams et al., who named it diffuse vascular injury. A more thorough knowledge of DVI is appropriate, since this type of lesion is relatively frequent in victims of severe head trauma caused by road traffic accidents. Since DVI and diffuse axonal injury are lesions produced by acceleration of the head, and the axon injury occurs at lower acceleration levels than those required to cause vascular rupture, this study hypothesized that DVI should always be associated with DAI in road traffic accidents. A total of 120 victims of road traffic accidents who had sustained either a motor vehicle accident (n=51) or an auto-pedestrian injury (n=69) were autopsied in the period between 1989 and 1993. Both the victims that had died after being admitted to the hospital and those whose death had occurred at the site of the accident or before admission were included. DVI was found in 14 of the 120 patients (11.7 percent). All had died within 24 hours after the accident. The frequent association between DVI and DAI was in accord with the short period of survival and low consciousness level on hospital admission. These results confirm the hypothesis advanced by Adams that DVI is a primary, diffuse brain lesion, i.e., it occurs at the moment the trauma is sustained. Similar to DAI, DVI apparently depends on long-duration, high-level acceleration and is practically restricted to road traffic accidents. The degree of axonal and vascular disruption is determined by the intensity of the acceleration rupture. The study results thus show a relationship between DVI and DAI that suggests there may be a spectrum or at least a continuum between these conditions rather than DVI being a separate condition. 4 figures, 2 tables, and 22 references