Computed tomography may be useful for the evaluation and diagnosis of liver masses. The evaluation of liver mass should be performed with a triphasic CT, this modality includes 3 phases: non-contrast, arterial phase, and portal venous phase. On CT, characteristic findings of liver mass, may include: solitary or multiple lesion, solid or cystic consistency, and normally a rounded lesion. The evaluation of liver mass will depend on several characteristics, such as: vascular pattern, size, location, size, distribution, margins, attenuation, and contrast enhancement.

Computed tomography may be useful for the evaluation and diagnosis of liver masses.^[1][2]

• The evaluation of liver mass should be performed with a triphasic CT, this modality includes 3 phases:
  • Non-contrast
  • Arterial phase
  • Portal venous phase

• On CT, characteristic findings of liver mass, include:^[1]
  • Solitary or multiple lesion
  • Solid or cystic
  • Rounded lesion
  • Bright dot sign: Presence of a bright dot within a lesion which remains hyper-attenuating on arterial and portal venous phase CT, corresponding to early nodular enhancement seen on liver hemangioma.

Hepatic Diseases	CT Scan Findings
Hepatocellular carcinoma	Early arterial phase enhancement and then rapid wash out Rim enhancement of capsule may persist Malignant liver mass, particularly hepatocellular carcinoma, can have a variety of appearances, such as: Massive (focal) Large mass May have necrosis, fat and /or calcification Nodular (multifocal) Multiple masses of variable attenuation May also have central necrosis Infiltrative (diffuse)
Hemangioma	Discontinuous, nodular, peripheral enhancement starting in arterial phase Gradual central filling Enhancement must match blood pool in each phase, or not a hemangioma (i.e. similar to the aorta in arterial, portal vein in portal phase, etc) Small hemangiomas (< ~1.5 cm) may demonstrate “flash filling” – complete homogenous enhancement in arterial phase (no gradual filling in)
Focal nodular hyperplasia	Bright arterial phase enhancement except for central scar Isodense/isointense to liver on portal venous phase Central scar enhancement on delayed phase
Hepatic adenoma	Large, well circumscribed encapsulated tumors The distribution of hepatic adenoma 80% solitary 20% multiple Arterial phase: transient homogenous enhancement Returns to near isodensity on portal venous and delayed phase image
Liver metastases	Hypodense and enhance less than the surrounding liver Metastases from certain primaries demonstrate an increase in the number of vessels Rim enhancement as a feature of malignant lesions especially metastases