Abdominal Vasculature Flashcards
What are the major parts of the abd venous system?
- IVC
- IMV
- Renal veins
- SMV
- splenic vein
- portal veins
- hepatic veins
How do the venous vessels look in u/s?
tube-like structions with well-defined, echogenic walls and an echofree lumn, but the wall of arteries and portal venous structures will be more echogenic than the thinner walled veins.
What are the great vessels of the ventral cavity?
IVC and aorta
What is the function of the IVC?
to transport deoxygenated blood towards the heart
In real time imaging arteries show…
pulsations.
The lumens in the veins open and close with…
respiration.
What produces a more variable response with respiration?
valsalva maneuver
What happens when a patient does a valsalva maneuver?
The vessel distention may be greater when the patient holds his breath after a deep inspiration.
Why are arteries not influenced by respiration?
Arterial walls are thick and strong which enables the vesssel to withstand alterations in intra-abdominal pressure.
How is the IVC formed?
The IVC arises from the union of the two common iliac veins.
How are the common iliac veins formed?
From the union of the internal and external iliac veins
Where does the IVC course?
through the retroperitoneum, to the right of the aorta, and anterolateral to the vertebral processes
The IVC lies ___ to the right kidney and ___ to the liver.
medial, posterior
What multiple tributaries does the IVC give rise to which can be accessible with u/s through vascular exams?
lumbar veins, right suprarenal vein, right gonadal vein
What’s the only vessel posterior to the IVC?
right renal artery
What does the venous system contain within the lumen of the vessel that helps the blood move forward?
valves
If the valves leak or are damaged, what do we call the flow of blood in those vessels when it goes in reverse or backwards?
retrograde flow
T/F? The venous system usually demonstrated pulsatile flow.
False. The only time the venous system demonstates pulsatile flow is close to the heart or in right-sided CHF patients.
How does the IVC look in u/s?
The IVC is more elliptical than round with smaller AP measurement.
Where does the IVC begin to widen?
at the level of the renal veins
What is rouleaux formation?
red cell aggregation causing internal echos
When is rouleaux formation observed?
rouleaux formation may be observed in any large vein as larger veins have slower flow. Slow flow enhances rouleaux formation.
What are the sections of the IVC?
hepatic, pre-renal, renal, post-renal
What is the hepatic section?
where the hepatic veins empty into the IVC
Which is the prerenal section?
inferior to the hepatic veins, but suprerior to the renal veins
Which is the renal section?
where the renal veins and the multiple tributaries are
Which is the post-renal section?
extends just inferior to the renal veins until the bifurcation
Why do we look at the IVC?
to detect introluminal thrombus or tumor invasion
THe tumor invasion most commonly ocurs in the ___ ___ and extends into the ___.
renal veins, IVC
What is the most common tumor to involve the IVC?
renal cell carcinoma
What are some normal variants of the IVC?
double IVC or left-positioned IVC, or a portion of the vessel may be absent (these are uncommon)
Where do the hepatic veins originate and where do they empty into?
originates in the liver and empties into the IVC
the hepatic veins are located ___ to the renal veins.
superior
What are the three major hepatic veins?
right, middle, and left
Which vein is responsible for draining all the venous blood out of the liver?
hepatic vein
Which lobes do the right, left and the middle hepatic vein empty?
right lobe, left lobe, and the caudate lobe
The hepatic vein ___ in diameter as they approach the IVC.
increases
What causes the playboy bunny/moosehead sign?
Transversely the hepatic veins look like anechoic linear structures that empty into the IVC
The hepatic veins exhibit ___, which is a reflection of ___ and ___ activity.
pulsatility, cardiac, and respiratory
The flow direction away from the organ is called…
hepatafugal
What are the small veins that drain directly into the IVC?
caudate lobe veins (occasionally seen on u/s)
Suprarenal veins are also called…
adrenal veins (not normally seen on u/s)
From where does the renal vein return blood and where does it empty?
kidney, IVC
Renal veins lie ___ to the level of the renal arteries.
superior
Left renal vein is ___ than the right renal vein.
longer
Which other veins does the left renal vein receive?
Left renal vein receives the left gonadal vein and the left suprarenal vein.
THe left renal vein passes posterior to the ___ vein and ___ ___ & ___ prior to entering the IVC.
splenic vein, pancreas body & tail
The LRV courses anterior to the ___ and lies between the ___ ___ and the ___.
aorta, aortic wall and the SMA
Why does the left renal vein engorge?
compression by the SMA and aorta
Where does the LRV appear dilated?
prior to crossing inbetween the SMA and aorta
Which renal vein is shorter?
right renal vein
Where does the right gonadal vein drain into?
the IVC
THe right renal vein may also receive the ___ ___ ___.
right suprarenal vein
Representing the gender, the gonadal veins are also known as…
testicular and ovarian veins
Where do the left and right gonadal veins drain into?
Left - into the left renal vein
Right - into the IVC inferior to the right renal vein
What does the azygos and hemi azygos vein provide?
alternate pathway for venous return in the case of IVC obstruction
Where is the azgyos vein located?
right
Where is the hemi azygos vein located?
left
What can be mistaken for the right crus? How must this mistake be checked?
For either the right renal artery or vein, follow the vessels
Why won’t the left and right veins be symmetrical?
veins’ diameter is very variable
Why would the veins appear as large as the IVC?
prior to entering the IVC
Why would the renal veins and arteries be confusing and what must we do?
Renal veins are generally anterior to the renal arteries, however crossing over is not uncommon; using pulsed wave or color doppler would be helpful.
What are the reasons for the IVC to get displaced?
- liver mass
- right renal artery aneursym
- lymphadenopathy
- a tortuous aorta
- right renal or adrenal mass
What would be a reason to u/s the IVC?
to detect intraluminal thrombus or tumor invasion
If a tumor is seen in the renal veins, what other vessel would one interrogate and why?
Renal vein tumors are most likely to invade the IVC, so look for at the IVC for tumor extension.
What is the name of the flow of blood if it’s flowing away from the liver?
hepatofugal
What is the opposite of hepatofugal?
hepatopetal (towards the liver)
What 2 veins enter the left renal vein instead of the IVC?
left gonadal and left suprarenal veins
The ___ ___ system does not enter the IVC.
portal venous
What is the function of the portal venous system?
to deliver blood from the spleen and the gastrointestnal tract to the liver metabolism and detoxification
What is the portal venous system made up of?
- portosplenic confluence
- main portal vein
- right portal vein with branches
- left portal vein with branches
Which is the largest vein of the portal venous system?
splenic vein
T/F? Splenic vein is less tortuous than the splenic artery.
True.
Where does the splenic vein begin?
at the hilum of the spleen
The splenic vein passes tranversely to the ___ across the posterior abdominal wall ___ to the splenic artery and ___ to the body and tail of the pancreas.
right, inferior, posterior
What does the splenic vein drain?
Part of the pancreas and stomach, and the spleen
What is used as a landmark for locating the pancreas?
splenic artery and vein
The splenic vein is located ___ to the pancreatic body and tail.
superior
What vessels form teh portosplenic confluence?
SMV, IMV, splenic vein
What vessel joins the splenic vein to form the portosplenic confluence?
IMV
What organs does the IMV drain?
The IMV drains the inferior part of the large itestines, primarily the area along the rectum, sigmoid area and the dexcending colon.
From its origin, the IMV courses ___.
superiorly
When is the IMV seen with u/s?
When IMV dilates with PHTN
Where does the SMV orginiate?
SMV originates at the ileocecal valve where the ileum and small intestine join the cecum of the large intestine
Where does the SMV course?
SMV courses superiorly towards the midline
The main portal vein ascends obliquely to the ___ passing posterior to the superior portion of ___, ___, ___ and ___ and anerior to the ___.
right, duodenum, common bile duct, proper hepatic artery and GDA, IVC
How much blood does the main portal vein supply to the liver?
80%
How much blood does the hepatic artery supply to the liver?
20%
How long is the main portal vein and where does it begin?
8 cm long, posterior to the pancreatic neck
What landmark is used for the pancreatic neck?
porto-splenic confluence/SMV
The MPV courses ___ and ___ about ___ before it enters the liver.
superiorly, laterally, 5-6 cm
Where does the MPV enter the liver?
porta hepatis
After the MPV enters the liver it divides into ___ and ___ ___ ___.
right and left portal veins.
What vessels make up the porta hepatis?
MPV, PHA, CHD
Why is the porta hepatis called the mickey mouse sign?
In the oblique scanning plane, the three vessels look lke the head and ears of mickey mouse
Which portal vein is longer and has a smalled diameter?
The left portal vein is longer and has smaller diameter than the RPV.
Before entering the left lobe of the liver the LPV gives branches to which lobe?
caudate lobe
What is the origin of the LPV and where does it course?
the MPV, medially
The LPV branches into the ___ and ___ segment.
medial and lateral
WHat does the LPV and its medial and lateral branches look like in a transverse scanning plane? What is the sign called?
Horns of a steer - the steer head sign
What portal vein is shorter and larger?
RPV
Which vein originates from the RPV? What does it do before entering the right lobe of the liver?
The cystic vein originates from the RPV and gives a branch to the caudate lobe before entering the right lobe of the liver.
The RPV courses ___ ___ and then divides into branches called the ___ and ___ segments.
right, laterally, anterior and posterior
How can the portal vein be distinguished from other structures, especially the hepatic vein?
it has highly echogenic walls
Why does the portal vein have echogenic walls?
high collagen content in the walls
Why are the portal veins evaluated?
for thrombosis and tumor invasion and for PHTN
How must the portal ven be evaluated?
with color doppler and duplex doppler and should show blood flowing into the liver (hepatopetal flow)
Where does the common hepatic artery arise from? What does it bifurcate into?
the celiac axis, the GDA and proper hepatic artery
Just prior to the bifurcation the CHA passes ___ to the MPV.
anterior
Where does the proper hepatic artery begin? Where does it ascend to ?
at the bifurcation, the porta hepatis of the liver within the folds of the hepatoduodenal ligament
What does the PHA divide into?
into the right and left hepatic arteries within the porta hepatis
What does the right hepatic artery give rise to?
the cystic artery
What does the cystic artery supply?
the gallbladder, hepatic ducts and part of the CBD
T/F? The portal venous system enters the IVC.
False
What vessel is a definate landmark for locating the pancreas?
splenic vein
What is the name of the ligament that crosses over the celiac axis?
median arcuate ligament
What vessel supplies the liver with 80% of its blood supply and originates behind the pancreas neck?
MPV
What is the steerhead sign?
the medial and lateral branches of teh left portal vein
What is the mickey mouse sign?
the portal triad oblique
What segments do the right portal vein branch into?
anterior and posterior
What does the proper hepatic artery divide into?
right and left hepatic artery
What vessel does the right hepatic artery give rise to?
cystic artery which feeds the gallbladder
Where does the cystic vein originate and what does a branch of that vessel feed?
It comes off the right portal vein and the branch of the cystic vein feeds the caudate lobe.
