The image shows obvious mass effect throughout the left hemisphere. On close examination, there is evidence of an isodense subdural collection within the left frontoparietal region. This is causing a left-to-right shift of almost 11 mm.
This finding is most likely a subacute subdural hematoma, probably seven to 14 days old. Further questioning reveals that the patient had fallen in the shower approximately two weeks prior and hit his head. The patient was admitted for observation and subsequently underwent a craniotomy for evacuation of the subdural hematoma.