Noninvasive assessment of the infarct-related coronary artery blood flow velocity using phase-contrast magnetic resonance imaging after coronary angioplasty

This study assesses infarct-related coronary artery blood flow velocity usi ng phase-contrast magnetic resonance imaging (MRI) in patients with reperfu sed acute myocardial infarction (AMI) and compares these results with flow measurements obtained nonsimultaneously by intracoronary Doppler ultrasound . MRI examination was performed in 17 patients with AMI within 1 to 4 days (mean 2.5 days) after direct or rescue coronary angioplasty using a 0.014-i n Doppler guidewire. MRI was performed on a 1.5-T clinical imager. The fast gradient echo segmented k-space phase-contrast pulse sequence was employed during breath-hold. The MRI and Doppler parameters of average peak velocit y and maximum peak velocity were measured. Mean phase contrast MRI average peak velocity was 13.3 +/- 10.7 cm/s, and mean phase-contrast MRI maximum p eak velocity was 27 +/- 16.6 cm/s. Mean Doppler average peak velocity was 1 7.1 +/- 5.1 cm/s, and mean Doppler maximum peak velocity was 35.5 +/- 10.1 cm/s. At the same anatomic levels, phase-contrast MRI average peak velocity correlated significantly to Doppler average peak velocity (r = 0.52; p <0. 006) and Doppler maximum peak velocity (r = 0.42; p <0.03). Phase-contrast MRI velocity measurements were correlated with the same heterogeneity of Th rombolysis In Myocardial Infarction 3 flow velocity observed during Doppler examination. Thus, by comparing phase-contrast MRI with invasive intracoro nary Doppler flow measurements, the measured MRI values showed significant correlation with Doppler data. Phase-contrast MRI has the potential to noni nvasively quantify coronary flow velocity and to evaluate quality of reperf usion in patients with AMI after reperfused therapy. (C) 1999 by Excerpta M edica, Inc.