Interesting article: "Blood-fluid levels in the brain"
"17 cases reviewed prospectively over a period of 4 months highlight then varied appearance of blood–fluid levels in intracranial cystic lesions of different aetiologies; a finding which has not featured significantly in the medical literature. Four types of intracranial cysts demonstrating blood–fluid levels have been categorised according to the nature of the pathology, i.e. primary neoplasms of the brain, metastatic deposits to the brain in cases of extraneural malignancies, lesions of vascular aetiology and intraparenchymal bleeds secondary to trauma......"
Blood-fluid levels in the brain - BJR