MR imaging of intracranial fluid levels.

Six patients with seven intracranial fluid levels were evaluated with both CT and MR at 1.5 T. A surgical diagnosis was obtained in six of the seven instances. MR was found to be superior to CT in detecting intracranial fluid levels, and the MR signal characteristics were helpful in identifying their contents. These cases demonstrate the necessity for a slightly different approach to lesions with fluid levels. In one patient, imaging in the prone position allowed detection of a solid component; in several others, detection of the fluid level was dependent on the selection of nonroutine windows and levels. Fluid levels are classified with respect to their components and MR features. MR is superior to CT in imaging fluid levels. The appearance of fluid levels on MR varies with their composition, the ratio of the components, the sequence parameters, and the position of the patient.