For patients with liver nodules larger than 1 cm who are at risk for HCC, diagnosis should be established. The tests required to diagnose HCC may include radiology, biopsy, or both.
Alpha-fetoprotein (AFP) levels
AFP is insufficiently sensitive or specific for use as a diagnostic assay. AFP can be elevated in intrahepatic cholangiocarcinoma and in some metastases from colon cancer. The finding of a mass in a liver with an elevated AFP does not automatically indicate HCC. If the AFP level is high, it can be used to monitor for recurrence.
In patients with cirrhosis, liver disease, or other risk factors for HCC, triple-phase, contrast-enhanced studies (dynamic computed tomography [CT]-scan or magnetic resonance imaging [MRI]) can be used to establish diagnosis of HCC for nodules larger than 1 cm.
During the arterial phase of the study, HCC enhances more intensely than the surrounding liver because the arterial blood in the liver is diluted by venous blood that does not contain contrast, whereas the HCC contains only arterial blood. In the venous phase, the HCC enhances less than the surrounding liver, which is referred to as the venous washout of HCC, because the arterial blood flowing through the lesion no longer contains contrast; however, the portal blood in the liver now contains contrast.
The presence of arterial uptake followed by washout in a single dynamic study is highly specific (95%–100%) for an HCC of 1 to 3 cm in diameter and virtually diagnostic of HCC.[20,21,22][Level of evidence: 3ii] In these cases, the diagnosis of HCC may be considered established without the need for a second imaging modality, even in the absence of a biopsy confirmation.[5,22,23][Level of evidence: 3ii]
If, on the other hand, a first imaging modality, such as either a contrast-enhanced CT or MRI, is not conclusive, sequential imaging with a different modality can improve sensitivity for HCC detection (from 33% to 41% for either CT or MRI to 76% for both studies when performed sequentially) without a decrease in specificity.