Hepatic Ultrasound: Anatomy, Pathology, and Imaging Findings

Normal Liver Parenchymal Echogenicity

Homogeneous, moderately echogenic smooth parenchyma containing anechoic tubular structures representing vessels and ducts; normally more echogenic than the adjacent renal cortex and less echogenic than the spleen.

Main lobar fissure

Anatomical sonographic landmark running between the gallbladder fossa and the inferior vena cava (IVC), utilized to divide the right and left hepatic lobes.

Liver length indicative of hepatomegaly

A measurement exceeding $15.5\,\text{cm}$, observed in approximately $75\%$ of individuals with true organ enlargement.

Adult polycystic kidney disease (ADPKD) liver involvement

An autosomal dominant disorder causing hepatic cysts in $75\text{--}85\%$ of patients, typically exhibiting preserved liver function tests without associated fibrosis or portal hypertension.

Periportal cuffing

Pronounced thickening and hyperechogenicity of the connective tissues encasing the intrahepatic portal vein branches, commonly identified in acute hepatitis.

Water-lily sign

Sonographic appearance of a transitional hydatid cyst (WHO-IWGE CE3a) demonstrating a collapsed, undulating endocyst membrane floating inside the lumen.

WHO-IWGE CE2 cyst appearance

Active, fertile hydatid lesion featuring a multivesicular 'honeycomb' or 'rosette' internal architecture caused by multiple daughter cysts.

Metabolic dysfunction-Associated Steatotic Liver Disease (MASLD)

The consensus clinical designation replacing NAFLD, defined as imaging- or biopsy-confirmed hepatic steatosis alongside at least one of five defined cardiometabolic risk factors.

Severe diffuse steatosis on ultrasound

Marked hepatic parenchymal hyperechogenicity with profound posterior acoustic beam attenuation, resulting in poor or absent delineation of intrahepatic vessels and the diaphragm.

Hepatic lobar redistribution in cirrhosis

Morphologic volume change characterized by shrinkage and atrophy of the right hepatic lobe combined with compensatory hypertrophy of the caudate lobe and left lobe.

Liver shear-wave elastography cutoff for F4 fibrosis (cirrhosis)

Quantitative tissue stiffness values reaching approximately $12\text{--}14\,\text{kPa}$ using standard reference metrics.

Cavernous hemangioma classic sonographic appearance

A small ($<3\,\text{cm}$), well-circumscribed, homogeneous, hyperechoic focal liver lesion exhibiting acoustic stability across routine surveillance.

Spoke-wheel vascular pattern

Color Doppler sign distinctive of focal nodular hyperplasia (FNH), demonstrating prominent central stellate arterial branches radiating outward within a fibrous scar.

Hepatic adenoma acute complication

Spontaneous intralesional hemorrhage leading to capsule rupture, hemoperitoneum, and acute hemodynamic collapse, often associated with estrogen or oral contraceptive use.

CEUS LI-RADS LR-5 criteria

Nonrim arterial-phase hyperenhancement paired with late and mild washout occurring at $\ge 60\,\text{seconds}$ in an at-risk liver, definitively establishing hepatocellular carcinoma without requiring biopsy.

Hypoechoic halo around a hepatic mass

A distinct hypoechoic peripheral rim encircling a focal solid parenchymal lesion, considered an ominous sonographic indicator suggestive of malignancy or metastasis.