Functional division of the liver
Right lobe
Left lobe
Caudate lobe
Main lobar fissure
- Separates right lobe of liver from left lobe
- passes from GB to IVC
- where middle hepatic vein located
Right lobe of the liver is further divided into:
Anterior/ posterior
By right intersegmental fissure
Left lobe of the liver is divided into
Medial/ Lateral
By left intersegmental fissure
Caudate lobe
- posterior aspect of the liver
- posterior border is IVC
- anterior border is LIGAMENTUM VENOSUM
Papillary process
- anteromedial extension of the caudate lobe
- may mimic lymphadenopathy
Middle hepatic vein
- within the main lobar fissure
- separates anterior right lobe from medial segment of the left lobe
Right hepatic vein
- runs within right intersegmental fissure
- divides right lobe into anterior and posterior segments
Right and left portal veins
Right and left portal veins run centrally within segments except ASCENDING PORTION of left portal vein
W/c runs in left intersegmental fissure
Left intersegmental fissure
- separates left lobe into medial/ lateral segments
- divided into cranial, middle and caudal sections
Fissure for ligamentum teres
Most caudal division of the left lobe
Hepatoduodenal ligament
- main portal vein
- proper hepatic artery
- common bile duct
Dual blood supply of the liver
- Portal vein- carries incompletely oxygenated venous blood (80%) from intestines and spleen
- Hepatic artery
Portal triad
- portal vein
- hepatic artery
- bile duct
Common hepatic artery variations (45% of population)
- Replaced left hepatic artery originating from left gastric artery 10%
- Replaced right hepatic artery originating from SMA 11%
- Replaced common hepatic artery originating from SMA 2.5
Congenital portal vein anomalies
- atresias
- strictures
- obstructing valves
Most common accessory veins
-drain the superoanterior segment of right lobe (segment 8)
Differential diagnosis for complex -appearing liver cyst (with thick septae or nodules)
- cystic metastases
- biliary cystadenoma
Four groups for hydatid cysts
- Simple cysts containing no internal architecture except sand
- Cysts with detached endocyst secondary to rupture
- Cysts with daughter cyst matrix (echogenic material between daughter cysts)
- Densely calcified masses
“Clay-pipestem fibrosis”
Schistosomiasis
Sonographic features of schistosomiasis
- widened echogenic portal tracts (up to 2cm)
- initially liver is enlarged
- periportal fibrosis—> contracted liver
Causes of cirrhosis
Micronodular cirrhosis
-mc cause is alcohol consumption
“mIcro”=Inom 🍺
Macronodular cirrhosis
-mc cause is chronic viral hepatitis
“mACro” =hepA, Ang dilAw! 😅
Sonographoc patterns associated with cirrhosis
- Volume redistribution
- Coarse echotexture
- Nodular surface
- Regenerating nodules
- Dysplastic nodules
Normal hepatic vein waveform
- triphasic
- two large antegrade diastolic and systolic waves
- small retrograde wave (atrial kick)
