Intravenous Contrast is basically, the bread-and-butter of CT imaging. While CT scans on their own are a wonderful source of detail and information, adding contrast to the mix just takes CT imaging to a whole new level. So what do we use Intravenous Contrast for? On a very basic level, Iodinated contrast allows us to visualise detail in soft-tissue structures that would otherwise remain hidden. It's more than just finding cancers or creating pretty CT Angiograms. To really understand Intravenous Contrast, you first have to understand how our body's circulatory system works.


The Circulatory System, in a Nutshell
The journey of Intravenous contrast all begins with a vein. And usually, it's the Basilic or Cephalic vein, right in the crease of the elbow joint. Having cannulated a nice (and hopefully size-able) vein, Iodinated contrast is injected into the venous system. From there, contrast makes its way to the Subclavian vein, then into the Superior Vena Cava, which in turn terminates at the heart. All that contrast is then pumped, along with the re-oxygenated blood, throughout the multitude of organs and soft tissues that make-up the human body. But just as every organ is unique and specific, so is its blood supply. This is where Arterial, Portal Venous & Delayed phases come in to play. All these phases, describe when specific organs uptake contrast and even in some cases, flush-out contrast. Let's investigate a little bit further about phases:

Arterial

Portal Venous

Delayed