Phase contrast MR imaging to measure changes in collateral blood flow after stenting of recurrent aortic coarctation: initial experience.

Objective: To assess the feasibility of using phase contrast magnetic resonance (PC-MR) imaging to measure the change in collateral blood flow early after stenting of aortic coarctation.

Methods: A total of 10 consecutive patients with coarctation of the aorta underwent MR imaging, X-ray angiography, and stent placement. PC-MR at two sites in the descending aorta was performed before and early after stenting in order to estimate collateral inflow to the descending thoracic aorta. The collateral flow and collateral flow percentage before and after stent placement were compared.

Results: Before stenting, the mean proximal aortic flow = 43.9 +/- 14.6 mL/second; mean distal flow = 54.2 +/- 10 mL/second; collateral flow = 10.2 +/- 6.8 mL/second; and collateral flow percentage = 30.1 +/- 27.9%. After stenting, the mean proximal aortic flow = 62.1 +/- 17.9 mL/second; mean distal flow = 60 +/- 19 mL/second; collateral flow = -1.9 +/- 3.7 mL/second; and collateral flow percentage = -3.3 +/- 6.8%.

Conclusions: PC-MR can be used to measure changes in collateral circulation after stent treatment of coarctation of the aorta.