Liver Vasculature Flashcards
what is the primary supplier of oxygen rich blood in the liver
Hepatic Artery
what percentage of blood does the hepatic artery supply to the liver
30%
where is the prox portion of the hepatic artery visualized best
in tranvesre @ the celiac axis level
where is the distal portion of the hepatic artery visualized best
intercostally @ the level of the MPV
what kind of flow pattern does the HA have
low resistance
why is there a fill-in of the spectral window on the HA
because of the small artery diameter
what causes the HA to have variable velocities
tortuosity
what is the RI of the HA
0.5-0.7
when is the intrahepatic artery evaluated
in liver duplex exams
pre and post liver transplant studies
to rule out veno-occlusive disease in bone marrow transplant patients
normal HA blood flow with a celiac artery occlusion would result in what
collateralization occurring through the pancreaticduodenal network of vessles
true or false: there are many varients of the HA circulation
true
IVC is formed by the union of which vessels
common iliac veins
what is the location of the IVC
anterior to the spine
to the right of the aorta
where do the HV empty into the IVC
just inferior to the diaphragm
what kind of window usually the best to visualize the intrahepatic portion of the IVC
intercostal
what kind of waveform does the IVC have
spontaneous
what kind of spectral waveform does the prox portion of the IVC have
pulsatile
what kind of spectral waveform does the distal portion of the IVC have
Phasic
size of the IVC will vary with what factors
size of the patient
respiration
right atrial pressure (CHF)
typically how many major hepatic veins are there
3
true or false: accessory HV are common
true
HV drain into where
IVC
what happens to HV as they approach the IVC
they enlarge
how does the RHV run
coronally between the anterior and posterior segments of the right lobe
how does the MHV lie
between the right and left lobes
how does the LHV run
between the medial and lateral segments of the left lobe
does the caudate lobe gave its own drainage into the IVC
yes
commonly what happens the left and middle HV before they enter the IVC
they join together
which HV is usually absent with agensis
RHV
to visualize all 3 HV what kind of scanning plane needs to be optimized
transverse in a subxiphoid scan plane
what kind of spectral tracing does the HV have
mutli-phasic
pulsatile flow pattern
are the walls more or less defined then the PV
less, because of no echogenic sheath
what are patency and distension a indication of
Budd Chiari or CHF
PV drain what kind of blood from the bowl and spleen to the liver
nutrient rich blood
what percentage of blood does the PV bring to the liver
70%
how is the PV formed
by the confluence of the splenic vein and SMV
what also forms the PV
IMV
coronary vein tributaries
where does the PV enter the liver
@ the porta hepatis
what are the branches of the PV
right
left
how is the PV visualized
sub or intercostal approach
what kind of velocity does the PV have
low
what is the range of PV velocity
15-40 cm/sec
what is the mean velocity of the PV
15-18 cm/sec
what kidn of signal does a PV spectral tracing produce
continuous
true or false: PV will have subtle phasic variations (slight undulations)
true
what kind of flow does the PV have
hepatopetal
what have to PV flow post-prandially
increases
with thrombosis in the PV what will be seen in the porta hepatis
numerous collaterals
with thrombosis what does the PV get termed
cavernous transformation
with the presence of thrombosis, sonographically what is the appearance of the PV
multiple small tortuous vessels in the porta hepatis with the MPV not visualized
what does a liver duplex exam determine
flow direction
normal waveform
a liver duplex exam includes the interrogation of which veins
hepatic veins
portal veins
splenic vein
what do you look for when looking for the cause of portal hypertension
collateral routes and indications
doppler assessment is assed during what kind of respiration
quiet
what are you looking for in the waveform prior to the alteration of flow direction
subtle changes
what position should the patient be in for a liver duplex exam
supine
the anterior subxiphoid window assesses what
LPV
LHV
SV
MPV
coronal (intercostal) assesses what
RHV MHV RPV MPV HA
colour and spectral doppler assesses what
flow direction
quality of flow
the hepatic veins should have what kind of flow and waveform
hepatofugal flow
multiphasic waveform
the portal veins should have what kind of flow and waveform
hepatopetal
subtle phasicity
when meausring the MPV where is the measurment taken
ap diameter
the MPV is located what to the IVC
anterior
how do you elongate the MPV
rotating the transducer counter clockwise
> towards the patients right shoulder
MPV 2D picture is taken in what window
anterior subcostal
the patient should have what kind of respiration when assessing the MPV
quiet
the normal measurement of the MPV is
less than 13mm
the colour and spectral tracing of the MPV should be taken in what window
coronal intercostal
the MPV should be sampled where
outside the liver
the coronal intercostal approch for assessing the MPV gives what kind of angle
zero angle
the anterior subcostal approach for assessing the MPV gives what kind of angle
60 degree angle
how is the peak velocity of the MPV assessed
with a generic caliper
what is the normal velocity range of the MPV
15-40 cm/sec
the splenic vein protocol consits of what
colour and spectral
long axis assessment
the LHV protocol consits of what
colour and spectral
long axis assessment
what window is the SV and the LHV assessed in
anterior subcostal
LPV protocol consists of what
colour and sepectral
long axis assessment
taken in the subxiphoid window
RHV protocol consists of what
colour and spectral
long axis assesment
taken from a right intercostal window
MHV protocol consists of what
colour and spectral
long axis assessment
taken from either a midline subxiphoid or intercostal at the anterior axillary line
RPV protocol consists of what
colour and spectral
taken from a coronal intercostal
> same window and area as MPV
HA protocol consists of what
colour and spectral
taken from a coronal intercostal window
> same window and as MPV colour and spectral image
can the patient hold there breath for the assessment of the HA
yes
why does the scale have to be adjusted accordingly when assessing portal venous flow whem compared to the hepatic vein flow
because it is slower
sweep speed should be should be adjusted to what
medium
for portal veins what should be done to the baseline
moved down slightly
for hepatic veins what should be done to the baseline
moved up slightly
all the images have quiet respiration except which one
HA
for intercostal scanning what should be done to the probe
rotate the transducer to go between the ribs
point transducer indicator towards patients right scapula
what is portal hypertension
elevated pressure in the portal venous system which impedes blood flow through the liver
what does PHT cause
volume overload
increased resistance to flow
what are the three classifications
pre-hepatic
intrahepatic
post-hepatic
what is the most common clssification of PHT
intrahepatic
which classifcations are extrahepatic PHT
pre-hepatic
post-hepatic
what are causes Pre-hepatic PHT
portal thrombosis splenic thrombosis portal vein invasion splenic vein invasion inflammation of the pancreas (pancreatitis) extrinsic compression by a tumor
what is pre-hepatic PHT
pathology that occurs to blood flow before it enters the liver
what is intraheptic PHT caused from
damage to the liver
sinusoids
hepatocytes
what is intrahepatic PHT
hepatocellular disease
what are the four main causes of intrahepatic PHT
cirrhosis
hepatitis
fatty infiltration
tumor invasion
can hepatitis, fatty infiltration anf tumor invasion lead to cirrohis
yes
what are the 3 steps of cirrhosis
- normal liver tissue becomes inflammed
- regeneration and scarring of liver tissue (fibrosis)
- increased risistance to blood flow at the sinusoid level
what are the cause of post-hepatic PHT
thrombosis of the hepatic veins
thrombosis of the IVC
CHF
right sided heart disease
what is post-hepatic PHT effect
drainage of blood from the liver (outflow)
what is Budd Chiari
thrombosis of the hepatic veins
can tumor invade into the portal vein
yes
what are the risk factors of chronic liver disease that proceeds fibrosis or cirrhosis
viral hepatitis: chronic hep B or C
alcoholic liver disease
autoimmune disorders: primary biliary cirrhoosis, primary sclerosing cholangitis
metabolic & geetic disorders: hemochromatosis, Wilson’s disease
schistosomiasis
non-alcoholic steatohepatitis (NASH)
sarcoidosis
what are the risk factors of heart diease that results in increased right sided heart pressure
tricuspid regurgitation
CHF
constrictive pericarditis
if these people have these risk factor are they at a higher risk to have PHT
yes, but it does not mean that they will get PHT
what are the clinical signs that are related to PHT
ascites: abdominal distension splenomagaly GI bleed jaundice abnormal LFT
what is jaundice common sign of
cirrhosis
can patients be asymptomatic if they have vascular liver disease
yes
manifestations of signs and symptoms associated with underlying disease is most common with which 2 diseases
pancreatitis
liver disease
what is hematemesis
blood in the vomit
what is melena
blood in the stool
what are other patient symtoms for PHT/vascular liver disease
variceal hemorrhage
bacterial peritonitis
what are the fidings of a physical examination when assessing for PHT
jaudice (if liver is sufficiently impaired)
splenomegaly (could lead to low platlet count)
dialted abdominal wall veins
hepatic encephalopathy (confusion due to poor liver function)
2-D sonographic evaluation includes documentation of what structures
portal vein diameter greater than 13mm
cavernous transformation (intra-abdominal collaterals)
portocaval anastomoses
dilation/recanalization of the umbilical vein
splenomegaly greater than 13cm
duplex evaluation of the patency of vessels including collaterals inculdes what kind of documentation
colour doppler assessinf for flow or the lack of flow
power doppler looking tortuous vessels and collaterals
duplex evaluation of the direction of flow inculdes what kind of documentation
colour and spectral
there is a possility of reverse flow in portal/splenic veins
assessing hepatofugal and hepatopedal flow
duplex evaluation of the loss of phasic variations inculdes what kind of documentation
spectral tracing
