Air-fluid level

When obstruction occurs, both fluid and gas collect. They produce a characteristic pattern called “air-fluid levels”. The air rises above the fluid and there is a flat surface at the “air-fluid” interface.

A hypodense area with an air fluid level within it of approximately 4.4 cm x 3.6 cm is visualized, in the left cerebellar hemisphere, which enhances after IV contrast and causes a mass effect on the fourth ventricle and an increase in the ventricular size of the lateral horns, in relation to cerebellar abscess with secondary hydrocephalus. Content is visualized inside the left mastoid. Hypodense foci in subcortical white matter, predominantly bilateral frontoparietal, in semioval centers, corona radiata, and periventricular, nonspecific, which could be related to small vessel ischemia, being very numerous for the patient's age. Hypodense foci in the left external capsule suggest Virchow-Robin spaces vs. chronic lacunar infarction.

Findings in relation to an abscess in the left cerebellar hemisphere that causes hydrocephalus, especially of the lateral ventricles.