Figure 7. CT and MRI images showing blood–fluid levels in cases of primary intracranial malignancies and metastases to the brain. Cystic secondary deposits from an ovarian malignancy in a 46-year-old woman are widely seeded throughout the brain on (a) a pre-contrast CT. The cystic lesions have imperceptible walls and show fluid interfaces. (b) Lower attenuation values of the dependent components of two of these lesions (one in the midline posterior fossa; the other in the high parietal deep white matter on the right side) suggest sedimentation of particulate matter rather than the presence of frank blood.