Liver lesion classification

Density of the lesion compared to surrounding liver:
Arterial phase: Hyperdense  Isodense  Hypodense
Delayed phase: Hyperdense  Isodense  Hypodense

Hounsfield unit measurements:

PhaseAortaPortal veinLiver lesion
Arterial
Portal venous
Delayed

Lesion classification:

Notes:
  • This calculation has a sensitivity of 76% and specificity of 97% for detecting malignancy (HCC or hypervascular metastasis). Lesions are classified as malignant if they are (hypervascular with washout OR hypodense on all phases) AND hepatic artery coefficient (HAC)>-0.03 AND HAC<0.3 AND portal vein coefficient (PVC)<0.4.
  • This calculation has only been validated on pre-treatment scans of hepatocellular carcinoma, hypervascular metastases, regenerative nodules, focal nodular hyerplasia, transient hepatic attenuation differences, hemangiomas, and adenomas. It should not be applied to cysts, hypovascular metastases, or cholangiocarcinoma.
  • Hounsfield unit measurements should be made in the aorta (at the level of the celiac artery), and portal vein (near the bifurcation). For heterogeneous lesions, measurements should be made in the most arterially enhancing portion of the lesion, and in the same location on the other phases. Avoid large intrahepatic vessels when drawing ROIs in the liver.
Important limitations:
This is a research and educational tool, and should not be used to make medical decisions.

Reference:
Boas FE, Kamaya A, Do B, Desser TS, Beaulieu CF, Vasanawala SS, Hwang GL, Sze DY. (2015) "Classification of hypervascular liver lesions based on hepatic artery and portal vein blood supply coefficients calculated from triphasic CT scans." Journal of Digital Imaging. 28: 213-23.