Posterior fossa arteriovenous pial fistula: diagnostic and endovascular therapeutic features. A case report.

Intracranial arteriovenous fistulas (AVFs) are rare vascular cerebral lesions composed of one or more cortical-pial arterial feeders directly connected with a single draining vein. They differ from the other AV malformations in that they lack a nidus and are located outside the dural leaflets. Because of high flow and pressure AVFs have a high risk of hemorrhage and if untreated cause death in up to 63% of cases.

Quantitative assessment of cerebral vascular reserve by means of transcranial Doppler ultrasound and rebreathing maneuver: bedside test and mathematical modeling.

Cerebral vascular reserve was measured by means of the transcranial Doppler (TCD) technique from carbon dioxide (CO2) tests, in healthy individuals and patients with unilateral internal carotid artery (ICA) occlusion. The percentage changes in middle cerebral arteries blood flow velocity (VMCA) per mmHg of pCO2 variations (reactivity index, RI) were separately computed during hypocapnia and hypercapnia, the latter obtained by a rebreathing maneuver. Clinical data have been compared with predictions obtained using an original mathematical model of intracranial dynamics, in order to search a theoretical explanation of the hemodynamic events observed during clinical testing.