 If there is an associated localized mass effect that may explain the clinical symptoms, or concern for a potential chronic SDH that could rebleed, then an MRI, with or without neurologic consultation, may be useful.It is not uncommon for chronic subdural hematomas (SDHs) on CT reports for scans of the head to be misinterpreted as subdural hygromas, and vice versa.Magnetic resonance imaging (MRI) should be done to differentiate a chronic SDH from a subdural hygroma, when clinically warranted.