ASSESSMENT OF HEMODYNAMIC-CHANGES IN PATIENTS WITH RENAL-ARTERY STENOSIS BY MEANS OF THE CINE MR PHASE-CONTRAST TECHNIQUE

Purpose: To evaluate the use of high-temporal resolution cine MR phase -contrast flow measurements for assessment of flow dynamics in renal a rtery stenosis (RAS). Material and methods: In a dog model, cine MR fl ow measurements were validated by comparing the MR flow data to an inv asive transit-time ultrasound reference technique for different degree s of RAS. Cardiac-gated MR flow curves were recorded in 56 renal arter ies of 28 patients with a temporal resolutions of at least 32 ms. In a ll cases RAS was confirmed by digital subtraction angiography (DSA). A bnormalities of flow dynamics were assessed in the calculated flow cur ves using the MR parameters mean flow, maximum velocity, and time to s ystolic maximum. Results: By means of the MR blood flow parameters hig h-grade stenoses (>50%, n=23) were detected with sensitivity of 100% a nd specificity of 94% with reference to DSA. The overall differentiati on between stenoses (n=37) and non-stenosed vessels (n=19) revealed a sensitivity of 87% and a specificity of 100%. Conclusion: Analysis of cardiac-gated MR flow curves provides a non-invasive method to assess the hemodynamic significance of RAS and thus allows a functional evalu ation in relation to the morphologic characteristics of the stenosis.