Table 3.
Diagnosis of hepatocellular carcinoma
| Imaging modality | Role in HCC diagnosis | Assessment of “washout” appearance |
||
|---|---|---|---|---|
| Timing | Degree | Preconditions | ||
| Multiphasic contrast-enhanced CT | First- and second-line imaging study | Portal venous phase or delayed phase | All | No targetoid appearance on contrast-enhanced images |
| Multiphasic MRI using extracellular contrast agent | First- and second-line imaging study | Portal venous phase or delayed phase | All | Neither marked T2 hyperintensity nor targetoid appearances on diffusionweighted images or contrastenhanced images |
| Multiphasic MRI using hepatocyte- specific contrast agent | First- and second-line imaging study | Portal venous phase or delayed phase or hepatobiliary phase | All | |
| Contrast-enhanced US using blood-pool contrast agent | Second-line imaging study | Late vascular phase (≥60 seconds) | Mild | No rim or peripheral globular enhancement on arterial phase; no early washout (<60 seconds); no punch-out pattern washout within 120 seconds |
| Contrast-enhanced US using Kupffer cell-specific contrast agent | Second-line imaging study | Late vascular phase (≥60 seconds) or Kupffer phase | Mild (if late vascular phase) | |
1. Imaging diagnosis: in high-risk patients (chronic hepatitis B, chronic hepatitis C, and cirrhosis), a liver nodule ≥1 cm detected by surveillance test can be diagnosed as an HCC if it shows radiological hallmarks of HCC. When an imaging diagnosis of HCC cannot be made with confidence on a first-line imaging study, an additional second-line imaging study can be applied. (1) Major imaging features are defined as arterial phase hyperenhancement and washout appearance on portal venous, delayed, or hepatobiliary phases on dynamic contrast-enhanced CT or dynamic contrast-enhanced MRI (extracellular contrast agent or hepatocyte-specific contrast agent). These criteria should be applied only to a lesion that does not show either marked T2 hyperintensity or targetoid appearances on diffusion-weighted images or contrast-enhanced images. (2) When contrast-enhanced ultrasound (blood-pool contrast agent or Kupffer cell-specific contrast agent) is performed as a second-line imaging study, arterial phase hyperenhancement and mild and late (≥60 seconds) washout are radiological hallmarks of HCC. These criteria should be applied only to a lesion that does not show rim or peripheral globular enhancement on the arterial phase. 2. Pathologic diagnosis: if the patient does not have any risk factor for HCC or the nodule does not show typical radiological hallmarks of HCC, a biopsy can be performed for confirmative diagnosis. HCC, hepatocellular carcinoma; CT, computed tomography; MRI, magnetic resonance imaging; US, ultrasonography.