Advantages of blood pooling in pediatric MR angiography.

slice misregistration artifacts. As scanner technology improved, short-echo-time 3D gadoliniumenhanced acquisitions (using phase encoding for 2 dimensions) reduced flow artifacts and reduced artifacts from surgical clips, stents, sternal wires, embolization coils, and other ferromagnetic hardware commonly found in congenital heart disease patients. The 3D acquisition can have a single center of k-space for capturing the brief arterial phase of a gadolinium bolus injection that is shorter than the scan duration. Alternatively, the center of k-space can be repeated multiple times (5) or even sampled with every repetition time using projection or spiral imaging (6,7) to obtain time-resolved MR angiography at temporal resolutions that are faster than what is possible based on the desired spatial resolution. However, gadolinium-enhanced MR angiography still has limitations. Timing the gadolinium bolus for a perfect arterial phase can be challenging