Background-Coronary allograft vasculopathy is the leading cause of late death after heart transplantation in children. It is poorly detected by conventional angiography. Intravascular ultrasound is invasive and costly. This study shows that magnetic resonance imaging (MRI) late gadolinium enhancement (LGE) of the coronary vessel wall can detect and grade coronary allograft vasculopathy. Methods and Results-Twenty-four children (10 male; age range, 9-17 years) underwent coronary angiography, intravascular ultrasound, and MRI.