A systematic review of magnetic resonance imaging and spectroscopy in brain injury after drowning

Primary objective: To report Magnetic Resonance Imaging (MRI) and/or Magnetic Resonance Spectroscopy (MRS) findings in subjects with hypoxic encephalopathy caused by drowning in recent literature and to compare them with non-specific hypoxic encephalopathy. Method: Systematic review of the Medline Database for bibliographic citations from1996 to 2008. Results: The studies included in this review described a total of 68 victims of drowning. From those, 58 performed MRS with a decrease of N-Acetyl-Aspartate/Creatine ratio in 75.86% (n = 44), and presence of lactate in 65.52% (n = 38) of the cases. MRI data was available in 46 cases. The main finding was brain edema in 78.26% (n = 36) and abnormalities of MRI signal in basal ganglia in 75% (n = 27) of the cases. Worse clinical outcomes were reported in conjunction with degree of MRI and MRS alterations. The findings were more consistent in the latter. Comparing these results with literature from non-specific hypoxic brain injury, the drowning process is apparently more variable. Conclusions: We found a trend to a more variable pattern of brain injury as seen by MRI/MRS in victims of drowning, which may reflect the nature of the aggression. Possibly there are different mechanisms involved in aquatic submersion, such as temperature, not present in pure hypoxic injury.