The heart is the most common rather important organ of our body; abnormalities in such important organ can risk your life. That's why monitor working of heart is necessary to avoid future complication. But the problem is that blood vassals and heart muscles don't show up clearly in X-rays. So a substance (contrast medium) is injected to the part vessels being examined. This substance highlights the blood vessels within which the substance (Contrast Medium) was injected. This type of medical examination is known as catheterization. Some angiographies also carried out non invasively using Computerized Tomography (CT) and Magnetic Resonance Imaging (MRI) scanning. Which technique of angiography should used depends on number of factors.