IN-VITRO MODEL OF ARTERIAL-STENOSIS - CORRELATION OF MR SIGNAL DEPHASING AND TRANS-STENOTIC PRESSURE-GRADIENTS

Purpose: Turbulent how just distal to stenoses causes signal loss (dep hasing) on magnetic resonance angiography (MRA). This study correlates dephasing with trans-stenotic pressure gradients in an in vitro model of arterial stenosis. Materials and methods: Three-dimensional (3D) p hase contrast, 2D time-of-flight, and 3D spoiled gradient echo MRA wit h/without gadolinium and varied echo time were performed for a system consisting of a peristaltic perfusion pump and a silastic vessel with stenoses of varying caliber. Length and diameter of dephasing jets wer e measured, and volumes calculated at varying pressure gradients and e cho times, then correlated with percentage cross-sectional area stenos is as measured by conventional angiography. Results: Dephasing occurre d in all sequences at pressure gradients of greater than or equal to 4 mmHg (1 mmHg = 133 Pa) and stenoses of greater than 70%, and varied d irectly with pressure gradient. The dephasing was greatest for 3D phas e contrast (PC). Gadolinium did not diminish dephasing. Conclusions: M RA signal dephasing at stenoses varies directly with pressure gradient . MRA may provide a non-invasive means for determining the hemodynamic significance of arterial stenoses. (C) 1998 Elsevier Science Inc.