HIGH-RESOLUTION CT OF MECKEL 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 mitrizamide 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 configutation 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 douloreux do not show a Meckel''s cave significantly different from the control group.