The anatomy of the posterior fossa in relation to positive contrast cisternography

High resolution CT of Meckel's cave

High resolution CT of the parasellar region was carried out in 50 patients studied for suspected pituitary microadenoma, but who showed normal pituitary gland or microadenoma on CT. This control group of patients all showed an ellipsoid low-density area in the posterior parasellar region. Knowledge of the gross anatomy and correlation with metrizamide cisternography suggest that the low density region represents Meckel's cave, rather than just the trigeminal ganglion alone. Though there is considerable variation in the size of Meckel's cave in different patients as well as the two sides of the same patient, the rather constant ellipsoid configuration of the cave in normal subjects will aid in diagnosing small pathological lesions, thereby obviating more invasive cisternography via the transovale or lumbar route. Patients with "idiopathic" tic douloureux do not show a Meckel's cave significantly different from the control group.

Cisternography with the non-ionic water-soluble contrast medium metrizamide. A preliminary report

In 11 patients the basal cisterns in the posterior cranial fossa were examined with the new water-soluble compound metrizamide. Promising results were obtained when the medium was administered suboccipitally or through the foramen ovale but less favourable after lumbar administration. The clinical tolerance of the compound with regard to short term effects was good.

Anatomy of the cranial nerves in the basal cisterns. A radiologic post-mortem investigation

A post-mortem radiologic investigation of the basal cisterns has been made with special regard to the cranial nerves. The cisterns were removed in one piece together with the adjacent brain structures and the skull base. The anatomy of the cranial nerves as seen at cisternography and the frequency of their identification have been analysed. The application in clinical cisternography of the information obtained is discussed.

Cerebellopontine angle myelography

✓ Review of more than 1400 positive-contrast myelograms of the posterior fossa performed at the Mayo Clinic indicates that this is an excellent method for depicting normal and pathological anatomy in the basal cisterns, if an adequate amount of medium and a precise technique are used. However, the technique is not without its sources of diagnostic error and these are discussed.