ROLE OF THREE DIMENSIONAL DYNAMIC, GADOLINIUM ENHANCED MR ANGIOGRAPHY IN DIAGNOSIS OF RENAL ARTERY STENOSIS

Abstract

Renal artery stenosis (RAS) is an important cause of renal ischemia and hypertension. The methods of investigations of patients with suspected renal artery stenosis are controversial ranging from screening patients with color Doppler US up to digital subtraction angiography (DSA) as the sole definitive test (Rickards and Jones, 1995). Color Doppler US is an operator dependent method, it also suffers from the problem of anatomic limitations such as bowel gases , obesity and wall calcification .(Correas et al., 1999). The usefullness of renal scintigraphy as a diagnostic test for renal artery stenosis has recently been questioned because of diminished sensitivity and specificity especially in patients with bilateral renal artery stenosis (Katz et al.,1998). Digital subtraction angiography (DSA) is currently the gold standard imaging technique and gives excellent spatial resolution. However, its disadvantages include a necessary exposure to radiation and the need for iodinated contrast media beside complications of arterial catheterization (Knopp et al., 1999). MR. Angiography is already able to demonstrate a clinical utility to that of invasive procedures but without the risks associated with nephrotoxic contrast agents, ionizing radiation or arterial catheterization (Schoenberg et al., 1999) In addition, recent development in renal MRA, specifically 3- D gadolinium enhanced MRA methods have been shown to provide a more reliable assessment of renal morpholgy and allow accurate determination of hemodynamic significance of RAS (Grist, 1999). The administered contrast agent (gadolinium) is free of clinically detected nephrotoxicity and has a low incidence of allergic reactions. (Matos et al., 1999) .· The aim of this work is to emphasis the role of 3-D dynamic gadolinium enhanced MR. Angiography in diagnosis of various renal artery stenosis lesions.