Multiphasic hepatic imaging includes all except
Answer: d) Capillary phaseWith the triple-pass technique, multidetector CT can be used to image during three distinct hepatic circulatory phases.The first pass provides an image of the arterial phase, which exquisitely displays the hepatic arterial system, though it may be too early to see some hypervascular neoplasms.The second pass corresponds in timing to initial opacification of the portal venous system and is labeled the parenchymal or portal vein inflow phase. The enhancement of hypervascular neoplasms is maximized during this phase.In both primary and metastatic hypervascular neoplasms (eg, hepatocellular carcinoma, islet cell tumor, carcinoid, sarcoma), approximately 30% more lesions are detectable during this phase than during the later portal venous phase.During the third imaging pass, conventionally labeled the portal venous phase but also known as the hepatic venous phase, the hepatic veins are enhanced, having been unenhanced during both the early arterial and parenchymal phases.During this phase, enhancement of background hepatic parenchyma is maximized.Tumors that are hyperattenuating on the arterial-phase and parenchymal phase images may appear iso- or hypoattenuating on the hepatic venous-phase image.Though all three phases are often useful in the initial detection and characterization of liver lesions, CT arteriography is usually not necessary in patients who are undergoing posttherapeutic care, and only the second and third imaging passes may be performed.
Early arterial phase
Hepatic parenchymal phase
Portal venous inflow phase
Capillary phase
G.I.T.