However, our search of the literature failed to disclose any report of FMD associated with fenestration of the cervicocephalic arteries; therefore, it is presumed that the association observed in the present patient was incidental. The clinical significance of fenestration of the vertebral artery has not been determined. An aneurysm susceptible to rupture may arise in the proximal portion of the fenestration as in the basilar, internal carotid, or intracranial arteries [5-7). Fenestration without an aneurysm is probably innocuous, although fenestration may become a nidus for clot formation [2).

A case of spontaneous pneumocephalus with progression to tension pneumocephalus is presented. It is unique because it occurred spontaneously via a sellar defect 5 years after resection and irradiation of a pituitary adenoma, without tumor recurrence. Computed tomography clarified the extent of the pneumocephalus and its progression to tension pneumocephalus.

A case of multiple saccular cerebral aneurysms in association with a left-sided inferior vena cava and hemiazygos continuation is presented. To our knowledge, this association has not previously been recorded in the literature.

Computed tomography was performed in two cases of blood-brain barrier (BBB) disruption due to cerebral arteriography. The first case showed diffuse contrast enhancement in the right frontotemporal region in the distribution of the middle cerebral artery; in the second case patchy contrast enhancement in both gray and white matter of both hemispheres was demonstrated. The possible mechanism for BBB disruption in these patients is discussed.