Which phase of hepatic contrast enhancement occurs around 2-3 minutes post-injection?

The phase of hepatic contrast enhancement that occurs around 2-3 minutes post-injection is the equilibrium phase. In CT imaging, liver enhancement is characterized by various phases based on the timing of contrast administration.

During the equilibrium phase, the contrast agent has had enough time to distribute throughout the vascular and extravascular spaces in the liver tissue. This results in more uniform enhancement between the blood vessels and the surrounding liver parenchyma. Unlike the arterial phase, which occurs much sooner (about 20-30 seconds post-injection), and the portal phase, which typically happens around 60-90 seconds after injection, the equilibrium phase reflects a stabilization of the contrast in the liver tissue.

The delayed phase, which occurs even later, shows a gradual decrease in contrast enhancement as the contrast medium is cleared from the liver. Understanding these timing aspects is crucial for interpreting CT images effectively and recognizing the enhancement patterns of liver lesions.