1. Purpose:
A comprehensive triphasic CT scan of the liver is used to evaluate liver lesions, such as hepatocellular carcinoma (HCC), hemangiomas, and metastases. This type of scan provides detailed images of the liver in different phases to assess the characteristics and extent of these conditions.

2. Phases of Imaging:
The triphasic CT scan includes three phases:
– Arterial Phase: Captures images shortly after contrast injection to visualize the liver’s arterial blood supply and identify       hypervascular lesions like HCC.
– Portal Venous Phase: Taken a few minutes after the arterial phase to show the liver’s portal vein and hepatic veins, highlighting lesions that may show contrast uptake in this phase.
– Delayed Phase: Performed after a longer interval to assess how the contrast is washed out and to evaluate the residual enhancement of liver lesions, useful for characterizing various types of tumors and metastases.

3. Contrast Administration:
Contrast material is injected intravenously to enhance the visibility of liver structures and lesions. The scan relies on the timing of contrast enhancement in different phases to differentiate between types of liver lesions.

4. Preparation:
Patients may be required to fast for a few hours before the scan. Additionally, they will need to receive the contrast material through an intravenous line during the procedure.

5. Imaging Procedure:
The patient lies on a motorized table that moves through the CT scanner. Multiple cross-sectional images of the liver are taken in each of the three phases to provide a comprehensive view of the liver’s blood supply and any lesions.

6. Radiologist Analysis:|
A radiologist reviews the triphasic images to identify and characterize liver lesions based on their enhancement patterns across the different phases. This helps in distinguishing between HCC, hemangiomas, and metastatic lesions.

7. Post-Procedure Care:
After the scan, patients are advised to drink plenty of fluids to help flush the contrast material from their system. They should also be monitored for any potential reactions to the contrast dye.