Flow and pressure measurements in aneurysms and arteriovenous malformations with phase contrast MR imaging

Abstract

PurposeTo explore phase contrast (PC) magnetic resonance imaging of aneurysms and arteriovenous malformations (AVM). PC imaging obtains a vector field of the velocity and can yield additional hemodynamic information, including: volume flow rate (VFR) and intravascular pressure. We expect to find lower VFR distal to aneurysms and higher VFR in vessels of the AVM. Materials and MethodsFive cerebral aneurysm and three AVM patients were imaged with PC techniques and compared to VFR of a healthy cohort. VFR was calculated in vessel segments in each patient and compared statistically to the healthy cohort by computing the z-score. Intravascular pressure was calculated in the aneurysms and in the nidus of each AVM. ResultsWe found that patients with aneurysm had z<−0.48 in vessels distal to the aneurysm (reduced flow), while AVM patients had z>6 in some vessels supplying and draining the nidus (increased flow). Pressures in aneurysms were highly variable between subjects and location, while in the nidus of the AVM patients; pressure trended higher in larger AVMs. ConclusionThe study findings confirm the expectation of lower distal flow in aneurysm and higher arterial and venous flow in AVM patients.