Liver Flashcards
What divides the right and left hepatic lobes?
Plane between the GB and IVC
What are the right and left lobes divided by?
The hepatic veins
What are the right and left lobes further divided into?
Right posterior, Right anterior, Left lateral, Left medial
What vein is supplied by which lobe?
Right lobe - Right portal vein
Left lobe - Left portal vein
Caudate lobe - Both portal veins
Where is the caudate lobe specifically located?
Posterior to the ligamentum venosum and porta hepatis
Anterior and medial to the IVC
Lateral to the lesser sac
Where do the hepatic veins course?
Between the lobes and segments (interlobar and intersegmental)
Where do portal vessels course?
Center of each segment (intrasegmental)
What are the vessels of the portal triad?
Main portal vein, Proper hepatic artery, Common hepatic (bile) duct
What does the MLF divide?
The right and left hepatic lobes between the IVC and gallbladder fossa
Landmarks: GB, IVC, middle hepatic vein
What does the right intersegmental fissure divide?
The right lobe into anterior and posterior segments
Landmark: Right hepatic vein
What does the left intersegmental fissure divide?
The left lobe into medial and lateral segments
Landmarks: Left hepatic vein, asc left portal vein, falciform ligament, ligamentum teres
What does the ligamentum venosum divide?
Separates the left lobe from the caudate lobe
What are the remnants from fetal circulation?
Umbilical vein - ligamentum teres
Ductus venosus - ligamentum venosum
(Umbilical vein > LPV > Ductus venosus > IVC)
Describe the direction of bloodflow for the portal veins.
Hepatopetal - flow TOWARD liver
Hepatofugal - flow AWAY from liver
What is hepatic blood flow comprised of?
1500mL/min
25% Proper hepatic artery
75% Portal vein
What supplies hepatic oxygenation?
50% Proper hepatic artery
50% Portal vein (PV O2 Sat=85%)
What is the upper limit of the portal vein diameter?
13mm
Describe hepatic vein waveforms?
Triphasic - right atrial filling, contraction, and relaxation
What does the main hepatic artery run parallel to?
Main portal vein
Where does a replaced right hepatic artery originate from and where is it located?
SMA (11%)
Posterior to the head of the pancreas and main portal vein
What waveforms can be seen in the hepatic artery in a post-op liver transplant?
High-resistance hepatic artery waveform (venous congestion of liver or possible organ rejection)
Parvus tardus hepatic artery waveform (prox anastomotic stenosis)
What is the ligamentum teres a remnant of?
Umbilical vein from the umbilicus to the left portal vein
What is the falciform ligament?
Peritoneal reflection or fold from the passage of the embryonic umbilical vein from the umbilicus to the left branch of the portal vein
What is the coronary ligament?
Peritoneal reflections which suspend the liver from the diaphragm
What is the right and left triangular ligament?
Peritoneal reflections of the far right and left of the bare area
Where is the liver size measured?
Sup-inf dimension on the mid-clavicular sagittal or coronal mid-axial plane
When is hepatomegaly indicated?
Greater than 15.5 cm
What is Reidel’s lobe?
Inferior projection of the right lobe, commonly seen in women
What causes hepatic granulomas?
Histoplasmosis or TB
What is a hepatic granuloma?
Small organized collection of macrophages that appear as calcifications in the liver and spleen
What does acute hepatitis look like on ultrasound?
“Starry Night” (periportal cuffing)
Hypoechoic liver parenchyma
Liver enlargement
Hyperechoic portal vein walls
What does chronic hepatitis look like on ultrasound?
Hyperechoic liver parenchyma
Small liver
Decreased echogenicity of portal vein walls
Where is the most common source of pyogenic abscesses?
Biliary tract disease
Which lobe is affected more often with pyogenic abscesses?
Right > Left (2:1)
What are the 3 major forms of liver abscesses?
Pyogenic (polymicrobial) 80%
Amebic (Entamoeba histolytica) travel out of US
Fungal (Candida)
What do amebic abscesses look like on ultrasound?
Round hypoechoic/complex mass
Right lobe (dome)
Contiguous with liver capsule