Hounsfield unit changes over time in contusions of the brain

In the United States, traumatic brain injuries are an important cause of death and disability, often with significant financial and legal consequences. Although it is generally accepted by neuroradiologists that the density of cerebral contusions decreases over time, previous research has not addressed this phenomenon directly. In the current study, we reviewed charts of patients who had suffered cerebral contusions and had at least two subsequent computed tomography scans in order to determine whether Hounsfield Units, a measure of density, decreased over time. We found that 100% of contusions decreased in Hounsfield Units over time. In addition, we found that the rate of decrease in density appears to be higher in the first 100 days after the injury. These findings are especially applicable in the area of forensics. For example, they could be used to determine the relative age of two separate brain contusions in the same patient.