MEASUREMENT OF COLLATERAL BLOOD-FLOW IN A PORCINE MODEL OF AORTIC COARCTATION BY VELOCITY-ENCODED CINE MRI

The purpose of this study was to investigate the time course of develo pment of collateral blood now in an animal model of aortic coarctation . A juxtaductal aortic stenosis (model coarctation) was surgically cre ated in five juvenile pigs. MRI was performed preoperatively, 1 to 2 d ays postoperatively, and 2 to 10 weeks postoperatively. Aortic blood f low was measured by velocity-encoded cine MR (VENC-MR). The percent ch ange in aortic blood now (Delta BF) from proximal to distal descending thoracic aorta was calculated, and a multiple-comparison paired t tes t used to assess changes in Delta BF over time. Invasive now measureme nts were obtained in one animal before sacrifice using an ultrasonic p robe, Delta BF preoperatively was -2 +/- 8% (mean +/- SE), Delta BF in creased to 32 +/- 7% (mean +/- SE, P =.022) 2 days postoperatively and 55 +/- 19% (P =.032) 2 to 8 weeks postoperatively. Invasive measureme nts were In qualitative agreement with the VENC-MR data. VENC-MR is an accurate noninvasive method of measuring collateral blood now in aort ic coarctation, Recruitment and development of collateral flow pathway s occur rapidly in an animal model.