Hemodynamic significance of renal artery stenoses from magnetic resonance imaging

Hemodynamically significant stenoses of the proximal renal artery reduce blood flow to the kidneys and cause result in ischemic nephropathy and hypertension. However, Conventional techniques for magnetic resonance (MR) renal artery imaging rely primarily on arterial illustration and its morphology. We propose a computational methodology to determine the functional impact of if a stenosis in the renal artery - specifically, if it is causing a significant obstruction to blood flow and, as such, will be likely to benefit from invasive angioplasty. We propose a finite-element methodology that incorporates vessel shape from contrast-enhanced magnetic resonance angiography (MRA) and blood flow rate from phase-contrast (PC) magnetic resonance imaging (MR). We demonstrate that an idealistic axisymmetric flow model produces average errors of 63% and 83% for measuring pressure drops with respect to the finite-element model. We conclude that estimation of pressure drops across renal artery stenoses from MR imaging may be possible but requires finite element modeling.