Triple phase CT / Triphasic CT
Focal lesions in the liver are common. Characterizing a liver lesion as benign (safe) or malignant (cancerous) is essential for optimal treatment. Ultrasound is used as a screening test for detection of liver lesions, but lacks accuracy. Conventional CT with only one phase of scanning has certain limitations including its inability to detect lesions which enhances in arterial phase like Hepatocellular carcimoma / neuroendocrine tumors and those enhancing in delayed phase like Cholangiocarcinoma. Triple phase CT (scanning in 3 different phases after giving IV contrast, triphasic CT) offers a comprehensive and accurate determination of liver lesions. It involves a dedicated late arterial phase, portal venous phase and delayed phase acquisition. It is also useful in assessment of pathologies involving the gall bladder, pancreas, spleen and the kidneys.
Dynamic three-phase CT scan of the liver. (A) Non-contrast image showing a isodense mass (arrow) in the left lobe of the liver. (B) Arterial phase showing encapsulated mass (arrow) with heterogeneous enhancement and central necrosis (small arrows). (C) Fast washout of the tumor mass (arrow) in the portal venous phase. (D) Delayed phase showing an isodense area of the mass (arrow).