Age determination of subdural hematomas with CT and MRI: a systematic review

To systematically review the literature on dating subdural hematomas (SDHs) on CT and MRI scans. We performed a systematic review in MEDLINE, EMBASE and Cochrane to search for articles that described the appearance of SDHs on CT or MRI in relation to time between trauma and scanning. Two researchers independently screened the articles, assessed methodological quality and performed data extraction. Medians with interquartile ranges were calculated. Differences were tested with a Mann-Whitney U or Kruskal-Wallis H test. We included 22 studies describing 973 SDHs on CT and 4 studies describing 83 SDHs on MRI. Data from 17 studies (413 SDHs) could be pooled. There were significant differences between time intervals for the different densities on CT (p <0.001). Time interval differed significantly between children and adults for iso- and hypodensity (p=0.000) and hyperdensity (p=0.046). Time interval did not differ significantly between abused and non-abused children. On MRI, time intervals for different signal intensities on T1 and T2 did not differ significantly (p=0.108 and p=0.194, respectively). Most time intervals of the different appearances of SDHs on CT and MRI are broad and overlapping. Therefore CT or MRI findings cannot be used to accurately date SDHs