Cine gradient-echo MR imaging and MR velocity mapping in the evaluation of congenital heart disease.

Cine gradient-echo (GRE) magnetic resonance (MR) imaging and MR velocity mapping can be applied to assess cardiovascular function and to measure volumetric flow in patients with repaired and untreated congenital heart disease. GRE images, particularly when displayed in a cine loop, are very useful for visualizing surgical anastomoses and conduits and for detecting stenosis, regurgitation, and left-to-right shunts. Multisection cine GRE imaging is a suitable method for measuring global right ventricular function, an important issue in congenital heart disease. MR velocity mapping is used for quantitative assessment of hemodynamics. Pressure gradients can be estimated from peak blood flow velocities in stenotic pulmonary arteries or surgical conduits. Because flow volume can be measured with MR velocity mapping, main-, left-, and right pulmonary artery flow, valvular regurgitation, left-to-right shunts, and ventricular filling can all be quantified. The abilities to elucidate complex cardiac anatomy and to measure cardiac function and flow in one examination make MR imaging a useful comprehensive tool for follow-up of congenital heart disease.