Object: The dating of inflicted head injuries in infants is a recurrent and difficult problem in the forensic evaluation of child abuse. The dating of hemorrhagic lesions when using magnetic resonance (MR) imaging is delicate because many confusing factors interact. In particular, infants frequently develop subdural hematomas (SDHs), which are generally composed of a supernatant, similar to cerebrospinal fluid (CSF), and a sediment, similar to blood clots. In the absence of a validated theoretical model predicting the evolution of blood signal in head-injured infants, clinical data are much needed; however, reliably dated information regarding head injuries in infants is scarce.
Methods: The authors prospectively studied infants who presented with dated and corroborated head injury to investigate the temporal modifications of computerized tomography (CT) and MR imaging in relation to the delay since trauma. In cases of SDH, the authors distinguished between sediment and supernatant based on their CT scanning appearance. They then studied the MR imaging signal of these two components in T1- and T2-weighted, fluid-attenuated inversion recovery (FLAIR), and gradient-echo sequences. Whereas the signal of the supernatant showed little difference from that of the CSF and did not yield information about the date of trauma, the signal in the sediment, especially on the T1-weighted and FLAIR sequences, showed time-related modifications that could be used to date the trauma.
Conclusions: The authors propose a method by which to develop a time scale for the dating of head injuries in infants based on the modifications of signal and location of blood on CT and MR images.