BREATHHOLD GADOLINIUM ENHANCED MR-ANGIOGRAPHY INLIVING (UN)RELATED RENAL DONORS: A NEW TECHNIQUE WITH ARTERIAL PITFALLS

Abstract

566 Purpose: Gadolinium enhanced MR-angiography has become an important imaging procedure for the assessment of the suitability of renal organs for donation. The purpose of this study is to compare the diagnostic accuracy of gadolinium enhanced MRA with DSA in living (un)related renal donors. Material and Methods: 13 potential renal donors underwent MRA and intra-arterial DSA within a 3 days interval. Gadolinium enhanced MRA was performed on a 1.5T scanner with a phased array bodycoil. A 17 sec. 3D Flash fatsuppressing pulse sequence (TR/TE 3.8/1.3, 30°, FOV of 350mm, 256 matrix, slab thickness of 96mm) with a slice interpolation technique was repeated 4 times. DSA consisted of an aortogram and, if the aortogram was inconclusive, selective renal artery injections. Qualitative and quantitative comparison of the arterial and venous supply, the parenchymal phase and excretory system was made. Results:arterial: In the series of 26 kidneys 5 identical accessory arteries were depicted on both MRA and DSA. However, both techniques failed in one case of an accessory artery. Four early branching renal arteries (< 1.5 cm from the origin) were seen on MRA and DSA, one early branching artery on DSA was considered a double renal artery on MRA. One severe stenosis (>50%) on MRA was not confirmed on DSA, a mild stenosis (<50%) on MRA happened to be a severe long segment of unilateral fibromuscular dysplasia. No assessment of renal arteries distally from the renal hilum was possible on MRA, DSA showed these arteries in all selective renal studies (18). Venous: MRA identified more renal veins than DSA (30 versus 21). Parenchyma: Both MRA and DSA showed complete parenchymal perfusion in all cases. Excretory system: 6 out of 30 pyelocalyceal systems were inadequately depicted to analyze on MR, on DSA all were considered normal. In one donor the ureteral system was unclear on DSA, in three donors on MRA. A small bladder tumor was only seen on MR. Conclusion: Although MRA is superior in visualizing the venous system and of equal value in analyzing the number of renal arteries, there are problems with the accurate depiction of the arterial integrity and the pyelocalyceal system. This may lead to an unwanted acceptance or rejection of a potential renal donor. Until the spatial resolution in MRA is improved, all possible arterial "abnormalities" on MRA should be proved or disproved by a DSA.