MR-guided PTA in experimental bilateral rabbit renal artery stenosis and MR angiography follow-up versus histomorphometry

Purpose: To assess in vivo 1) MR-guided percutaneous transluminal renal ang ioplasty (PTRA) in experimental bilateral rabbit renal artery stenosis (RAS ); 2) postprocedural follow-up by gadolinium-enhanced MR angiography versus histomorphometry. Methods: Fifteen male NZW rabbits of mean weight 4.0 kg (range 3.5-4.2 kg) underwent bilateral RAS induction by combined overdilation-deendothelializa tion with a gadolinium-filled balloon, passively MR-guided by the artifact of a 0.014-inch guidewire. After 4 weeks the rabbits were randomized into t wo groups: group A (n = 8) underwent right-sided PTRA for treatment of RAS, group B (n = 7) underwent left-sided PTRA. After another 4 weeks the rabbi ts were killed to assess by histomorphometry recurrent stenosis and contral ateral induction injury stenosis lesions. Each step was preceded by gadolin ium-enhanced three-dimensional MR angiography, and the carter-to-aorta (C/A ) signal intensity ratio was calculated. Results: RAS induction was successful in all cases. Fourteen arteries devel oped restenosis and 13 only initial stenosis. MR-guided PTRAs were feasible in 22 arteries (73%). For a successful catheterization of the ostium (20 a rteries, 66%, success rate), 10-25 steps were required. Five to eight steps were required for balloon localization and inflation for each PTRA. The re stenosis effect was reflected by a 16% (12%-27%) decrease in C/A values on MR angiograms (p < 0.05). Conclusion: MR guidance and MR angiography represent a feasible, less invas ive alternative for performing and assessing experimental PTRA in RAS.