MRI evidence for preserved regulation of intracranial pressure in patients with cerebral arteriovenous malformations.

Purpose: The purpose of this study was to investigate intracranial pressure and associated hemo- and hydrodynamic parameters in patients with cerebral arteriovenous malformations AVMs.

Methods: Thirty consecutive patients with arteriovenous malformations (median age 38.7 years, 27/30 previously treated with radiosurgery) and 30 age- and gender-matched healthy controls were investigated on a 3.0T MR scanner. Nidus volume was quantified on dynamic MR angiography. Total arterial cerebral blood flow (tCBF), venous outflow as well as aqueductal and craniospinal stroke volumes were obtained using velocity-encoded cine-phase contrast MRI. Intracranial volume change during the cardiac cycle was calculated and intracranial pressure (ICP) was derived from systolic intracranial volume change (ICVC) and pulse pressure gradient.

Results: TCBF was significantly higher in AVM patients as compared to healthy controls (median 799 vs. 692 mL/min, p=0.007). There was a trend for venous flow to be increased in both the ipsilateral internal jugular vein (IJV, 282 vs. 225 mL/min, p=0.16), and in the contralateral IJV (322 vs. 285 mL/min, p=0.09), but not in secondary veins. There was no significant difference in median ICP between AVM patients and control subjects (6.9 vs. 8.6 mmHg, p=0.30) and ICP did not correlate with nidus volume in AVM patients (ρ=-0.06, p=0.74). There was a significant positive correlation between tCBF and craniospinal CSF stroke volume (ρ=0.69, p=0.02).

Conclusions: The elevated cerebral blood flow in patients with AVMs is drained through an increased flow in IJVs but not secondary veins. ICP is maintained within ranges of normal and does not correlate with nidus volume.