A computed tomography (CT) scan uses X-rays to take detailed cross-sectional images of the body, including the arteries and beating heart, of children and adults. A contrast dye is injected into a vein. As this dye moves through the heart and blood vessels, the CT scan will take detailed pictures. These pictures can create a 3D reconstruction of the heart and major blood vessels. You or your child's doctor can use these images to identify problems with the heart or blood vessels and develop a treatment plan, if necessary.