Brainstem and related structures: normal CT anatomy using direct longitudinal scanning with metrizamide cisternography.

A method for direct longitudinal imaging of the cisternal spaces surrounding the brainstem and related structures by CT was developed for use with metrizamide. Multiple 1.5-mm or 5-mm sections were obtained at a 70 degrees angle to the anthropologic baseline, allowing excellent visualization of the brainstem, the cranial nerves, the parasellar structures, and the cerebellum. Thin section, high resolution CT scans of a formalin-fixed normal cadaver head were obtained, and the specimen was then dissected in the same tomographic plane for correlation with normal anatomy. The technique described produces a simple, highly accurate evaluation of the normal and pathologic anatomy of the brainstem and adjacent structures. The method of study allows for visualization of structures and relationships previously unattainable by any other clinical radiographic imaging technique.