IVC Physiology and Pathology Flashcards
CBD is _______ to the Portal Vein
Anterior
The CHD is _______ to the Portal Vein
Anterior
Portal Vein is _______ to the IVC
Anterior
SMV lies __________ to the Portal Vein
Inferior
SMV lies _________ to the Uncinate Process
Anterior
SMV lies _________ to the Pancreas Neck
Posterior
Pancreas Head lies______ to the IVC
Anterior
SMV and SMA lies________ to the 3rd portion of the duodenum
Anterior
MPV is a combination of
SMV Splenic and IMV
IVC displaced _________ by Right Liver Mass
Posterior
IVC displaced ________ by Right Renal Artery Aneurysm
Anterior
IVC displaced ______ by tortuous Aorta
Right
IVC displaced _______ by Right Adrenal Mass
Anterior/Medial
IVC displaced _______ by Right Renal Mass
Medial/ Left
Splenic Vein displaced _______ by left adrenal mass
Anterior
2 vessels in ventral cavity
Aorta and IVC
Whats the purpose of the IVC
Brings de-oxygenated blood back to the heart
What does the lumen of veins contain to help veins fight gravity
Valves
If valves are leaking or damaged what is it called when blood moves backwards
retrograde
Does venous system usually demonstrate a pulsatile flow
No
What happens when the valsalva maneuver is utilized
distends and dilates
Which vessels join to form the common iliac veins
External and Internal Iliac Veins
The IVC lies________ to the Liver
Medial and Posterior
What reason do we ultrasound the IVC
Look for thrombus and tumor invasion
What is rouleaux flow
The aggregation of RBCs
What are the 4 sections of the IVC
Hepatic
Pre-renal
Renal
Post-renal
If a tumor is in the renal veins what other vessel do you investigate
IVC
Where do the hepatic veins originate
Liver
What vessels drain all the blood from the liver
Hepatic Veins
The RHV empties which lobe
RLL
LHV empties which lobe
LLL
The MHV empties which lobe
Caudate Lobe
Do hepatic veins decrease in diameter as they approach IVC
No
What do you call blood flow toward the liver
hepatopedal
What do you call blood flow away from the liver
hepatofugal
What other vein enters the left renal vein besides the gonadal
left suprarenal
What does the right gonadal vein drain into
IVC
The major abdominal venous system constist of
IVC- from common iliac to diaphragm Splenic Vein IMV SMV Hepatic Veins Renal Veins Portal Veins
The proper hepatic artery shares circulatory supply with what
MPV
What does the IVC look like with Ultra Sound
Tube like
Well defined borders (echogenic)
Walls less echogenic and are thinner than arteries
How do you differentiate the artery from the vein
You can see pulsations of the arteries more than the veins. Also vein walls are collapsible
How do veins act during respiration
Inspiration - decrease size of lumen and blood flow decreases
Expiration - increases size of lumen and blood flow increases
How does Valsalva Maneuver affect the veins
Dilation/Distention and stops flow in the vessels
How are arteries affected by respiration and Valsalva
They aren’t
What two vessels combine to make the IVC
Left and Right common iliac
Where is the anatomical orientation of the IVC
Courses through retro-peritoneal
Right of Aorta
Anterolateral to vertebra
How does IVC relate to surrounding structures
Liver- posterior
Kidney- medial
Diaphragm- Anterior
What are the tributaries to IVC that can not be seen by ultrasound
Lumbar
Right suprarenal
Right gonadal vein
Is the venous system pulsatile
No
What is the Valsalva Maneuver
Patient takes deep breath and holds it and bears down, as if having a bowel movement
What shape is the lumen of the IVC
Elliptical
How should you measure the IVC
A/P
What is rouleaux formation
an aggrigation of the RBC in order to better facilitate the upward movement through the veins. Blood cells are stacked together. May make inner vessel appear complex.
Where is the Hepatic section of IVC
where hepatic dumps into IVC
Where is pre renal
Inferior to hepatic veins but superior to renals
Where is renal
Where renal veins are
Where is post renal
Proximal to the Renal veins to the bifurcation
Where does tumor invasion most likely occure
renal veins and extend into the IVC
Most common renal tumor
Renal Cell Carcinoma
What are the normal variants of IVC
Double IVC, IVC on left, absent portion
Hepatic Veins originate in
Liver
Where do hepatic veins empty
superior to renal veins
Do the hepatic veins increase or decrease as they approach IVC
Increase
Are hepatic Veins pulsatile
Yes
Are hepatic Veins hepatofugal or hepatopedal
hepatofugal
What are caudate lobe veins
Small veins that drain directly into the IVC, occasionally seen with ultrasound
Which renal veins is longer
Left
Left renal vein receives which two veins
Left Suprarenal Vein and Left Gonadal Vein
The Renal Veins are ______ to the Renal Arteries
Superior (VAU)
What is the nutcracker
LRV is caught between aorta and SMA
Where does the Right suprarenal vein and maybe also left gastric vein feed into
IVC
What is another name for the gonadal veins
Ovarian veins and gonadal veins
What are Azigos and Hemi Azigos
They are veins that run parallel to the IVC and can bypass the IVC if need be.
Left - Hemi azygos
Right - Azygos
What structure may be mistaken for the RRA or RRV
Right Crus of the Diaphragm
Will left and right veins be symmetrical
No because they collapes
Can you always see the vein
No my be collapsed
Are Renal veins anterior or posterior to renal arteries
anterior but crossover can frequently occur. Doppler is helpful
Do the Portal Veins enter the IVC
NO
What is the function of the Portal Veins
It delivers blood from the spleen, gastrointestinal tract to the liver
Is the portal vein system similar to the arterial system
No different from the arterial and venous blood supply to the liver
What vessels make up the portal system
Portosplenic confluence
Main portal vein
Right portal vein and branches
Left portal vein and its branches
Which is more tortuous splenic vein or artery
Artery
Where does the splenic vein begin
Helium of the spleen
How does splenic vein travel
Travels transversely across posterior abdominal wall inferior inferior to splenic artery and posterior to the pancreas tail
What are the landmarks that are anterior and posterior to pancreas
Anterior- splenic artery
Posterior- Splenic vein
What vein joins the Splenic vein as it drains distal colon and rectum
IMV
Is IMV normally seen by ultrasound
No
When is IMV seen by ultrasound
When it dilates with Portal HTN may be confused for Splenic Vein
Where does SMV originate
Ileocecal valve where the ilium and small intestines join the cecum of the large intestines
How does SMV travel
Superiorly near midline
When does it become the portosplenic confluence
When SMV joins the Splenic vein and IMV
Portosplenic confluence then travels laterally and becomes
MPV
MPV passes____________ to the 1st portion of the duodenum CBD, PHA and GDA
posteriorly
How much blood does main portal vein supply to the IVC
80% or 4/5
Where does MPV begin
Posterior to the neck of the pancreas
Where does MPV enter the liver
Porta hepatis
What are the division of the MPV
Left and right portal veins inside the liver
What is the portal veins connected to GB by the main lobar fissure
Right portal vein
What 3 vessels make up the Porta Hepatis
Main Portal Vein
Common Hepatic Duct
Proper Hepatic Artery
What sign is the porta hepatis made of
Mickey Mouse Sign-Mashed (main portal vein) Potatoes (Proper Hepatic Artery), and Corn (Common Bile Duct)
What scanning plane can you find mickey mouse
Oblique
Which is longer R portal vein or L portal vein
Left and has smaller diameter
What does Left portal vein branches feed
Caudate lobe and Left lobe of liver
How does Left portal vein travel
Origin- MPV and courses medially
What are two segments of Left portal vein
MEDIAL AND Lateral
What sign does Left portal vein make when it branches
Steer sign
What veins originates from the Right Portal Vein
Cystic vein
Cystic vein gives branch to
Caudate lobe before entering into the right lobe of the liver
What does Right portal veins branch into
Anterior and posterior
What makes Portal Veins stick out
Highly echogenic walls- due to high collagen in the walls
Why do we evaluate the portal veins
Tumor or thrombus which causes portal HTN
What flow should portal veins show
Hepatopedal
What are all the hepatic arteries
Common hepatic which branches into the Proper hepatic and GDA
The Common Hepatic Arteries pass _________ to the MPV just proir to bifurcation
Anteriorly
How does the proper hepatic flow
Bifurcates from CHA and enters through portahepatis within the folds of the hepatoduodenal ligament
Proper Hepatic artery divides into
Left Hepatic Artery and Right Hepatic Artery, the Right Hepatic Artery gives rise to the cystic artery
What does cystic artery feed
GB, hepatic ducts and part of CBD
Will CBD have color on doppler
NO
Does portal venous system enter the IVC
No
Function of the portal system
Brings oxygenated blood from spleen and gastrointestinal tract to liver for oxygenation and detoxification
Name 4 segments of the portal vein system
Portasplenic confluence
Main Portal Vein
Right Portal Vein
Left Portal Vein
What is vessel that landmarks the Pancreas
Splenic Vein
Name the ligament that crosses the celiac axis
Medain Arcuate Ligament
3 vessels of the portasplenic confluence
SMV IMV and splenic vein
What supplies 80% of the Liver blood supply
MPV
What is the steer head sign
The branches of the Left Portal Vein (median and lateral
What makes up porta hepatis
MPV, PHA, CHD - MICKEY MOUSE SIGN if in oblique
Cystic originates in
R portal and branches to Caudate lobe
What are Azygo and Hemi Azygo
Back up for IVC
How does inspiration affect IVC
Smaller diameter
Less venous return
How does expiration affect IVC
Larger diameter
Greater venous return
How does valsalva maneuver affect IVC
Venous return is blocked because flow is temporarily reversed causing it to bulge
How should exams be done in order to be consistent
Examine as patient examines on suspended inspiration
How does an obstruction affect the IVC
Increases in diameter BELOW (proximal) the point of obstruction
What is the most common cause of IVC occlusion
Right sided heart failure
What is right sided heart failure
When the right side of the heart can’t pump out blood in an efficient manner
The blood isn’t pumped out and it gets backed up into the IVC
What is it indicative of when the IVC does not collapse at least 50% with deep breath
A right sided filling pressure issue- Right sided Heart Failure
Other causes of IVC obstruction
Enlarged liver (crushed from the front)
Para-aortic lymph node enlargement (crushed from the left)
Retroperitoneal mass or tumors (crushed from all sides)
Pancreatic tumors (crushed from the front)
Congenital IVC valve issues
What are the signs of IVC obstruction
Abdominal pain
Ascites
Tender hepatomegaly
Lower extremity edema
How does IVC obstruction appear on ultra sound
With all causes- Dilation below obstruction
With CHF- Decreased collapse with breath,
congestion of hepatic veins, Ascites, Hepatomegaly
How do tumors appear in ultrasound
Irregular borders
internal echoes
What can be the result of any impinging tumor or structure on the IVC
Thrombus
What is the most encountered intraluminal anomaly of the IVC
Thrombus
Where will the thrombus usually spread from
Vein in pelvis
Lower Limb
Liver
Kidney
How is thrombosis sonographically diagnosed as
an intraluminal filling defect that usually expands the diameter of the vessel
Why is important to look at the IVC from thrombus or obstruction
To avoid a fatal PE
How do you determine the age of a thrombi
Echogenicity- more echogenic the older it is
How does doppler appear on an occluded IVC
No signal
What is the most like place from a thrombus to occure
Kidneys
What is an IVC filter
metal device placed in the IVC which will filter out any blood clots over 5mm. May be permanent or temporary
What complication can occur with an IVC filter
Filter fracture
What are the symptoms and intervention of IVC filter fracture
Asymptomatic- do nothing
symptomatic- CT and consider surgery
What are the three types of IVC tumors
Primary
Metastatic
Extension from primary
What is a primary tumor
Leiomyomas or leiomyosarcomas (2%)
Usually in women around 61
With leiomyosarcoma 40-50% spread to liver or lung
Where can metastasis of tumors occur from
Renal Carcinoma Adrenal Tumors Retroperitoneal sarcoma Hepatocellular Carcinoma Teratoma Lymphomas
Signs and symptoms of tumor (primary/metastatic)
Symptoms are unremarkable but depends on tumor size
Leg edema
Ascites
Abdominal Pain
Sonographer apprearence of tumor
Echogenic foci but maybe isodense and hard to see.
If primary- may be heterogeneous, with areas of necrosis
Increase in IVC diameter before Block and decrease change with respiration
What different diagnosis can the Radiologist contribute to invading tumor
Primary Vascular Neoplasm
Malignant IVC Mass
Chronic Thrombus
Large primary tumors outside the vessel
What is in alternative to a tumor in the vessel
A tumor out of the vessel but distorting into the vessel and may be hard to tell the difference
What do you need to ID when you locate an IVC mass
Presence of a primary tumor and its site
The cranial extent of the tumor mass (hepatic veins or right atrium)
Possible tumor involvement or invasion of the wall of the vessel
What happens to the blood flow pattern when there is an obstruction
They are changed
Speeds where it is narrowed
What is the symptom seen most often which an IVC tumor invasion
Leg Edema
When an IVC mass is identified what 2 things must be identified
Involvement of hepatic mass or right atrium
Involvement of tumor or invasion of the wall of the vessel
What are the most common causes of renal vein enlargement
1) Increased blood flow do to a splenorenal or gastrorenal shunt
2) Thrombus or portal htn
3) Tumor involvement from renal cell carcinoma
4) Increased flow from an AV malformation in the kidney
What are sign and symptoms of a renal vein enlargement
1) Associated with another disease process
2) No specific systems that would make suspicious of tumor extension
3) Renal veins are enlarged past 1.5cm
4) IVC enlargement around the renal veins
Sonographer appearance of enlarged renal veins
1) Evaluation symmetry between renal veins (ID causing disease
If bilateral- IVC
If only one veins- portal htn, tumor involvement, AV fistula
What will happen in the kidney veins if patient has portal htn
Formation of collateral pathways cause Left Kidney vein fistula
What other problems may cause isolated kidney vein enlargement
AV fistula
Tumor
How prevalent is renal cell carcinoma in renal vein enlargement
21-55%
What happens in AV fistula
Connection of artery in vein causes artery to force blood into the vein
Why might an AV fistula occur
1) Blunt trauma
2) Biopsy complication
3) Tumor
4) Nephrectomy
5) Idiopathic (unknown)
How does doppler appear in portal htn which causes AV fistula associated with a gastrorenal or splenorenal shunt
Turbulent blood flow in veins
Increased velocity
If a sonographer finds an echogenic area in the lumen what should he/she then do
Closely inspect IVC from extension of the tumor
What pitfall might one experience when examining the renal veins
1) In tumor free- reverberation artifact which mimics tumor or thrombus
2) Isogenic tumors
3) Left renal vein may appear enlarged when crossing the aorta which is normal
4) Duplicate IVC could appear as left renal enlargement
What disorder may cause renal vein thrombus
1) Nephrotic syndrome
2) Renal tumors
3) Renal transplants
4) Trauma
5) Infant dehydration (common)
6) Compression of the renal vein secondary to tumor
Signs and symptoms of renal vein thrombus
1) Loin or flank pain
2) Hematuria
3) Leg swelling
4) Protenuria
What is the sonographic appearance of a renal vein thrombus
1) Dilation proximal to thrombus
2) Visible thrombus in renal vein or IVC
3) Increased renal size and loss of structure
4) Doppler flow increases
How does thrombus appear (staging of a blood clot)
Echogenic foci- especially old thrombus
Acute phase- isochoic to surrounding blood
How common are venous aneurysms
Very RARE
What causes venous aneurysms
1) Weakened vessel wall by pancreatitis
2) Portal HTN
3) Embryonic malformations
What are signs and symptoms of venous aneurysm
None associated with small ones in portal venous system
Sonographic appearance of portal vein aneurysm PVA
1) PVA anechoic in portal hepatis- may or may not be thrombus
2) Doppler can be used to see if there is an echo free structure
- Portal htn resembles all other venous aneurysms
Where does Portal vein drain blood from
Spleen, pancreas, stomach, gallbladder, small and large intestines
What does the left portal vein receive
umbillical and paraumbillical vein
What does the coronary vein receive
Distal esophageal veins- enlarge with portal htn
How does coronary vein run
Along lesser curvature of stomach
Where do thrombus usually occur in portal vein during cirrhosis and hepatic maglignancies
Intrahepacally and will spread to extrahepatically
Where do all other etiologies cause portal vein thrombus
starts at the point of origin
What vessel can clot and leaded to thrombus in portal vein
Splenic vein- results from an adjacent inflammatory process such as the pancreas
What is the normal size of the portal vein
13mm
What causes portal venous thrombus
1) Portal htn
2) Inflammatory - appendicitis, peritonitis, pancreatitis
3) Trauma
4) Postsurgical complications
5) Hypercoagulability states
6) Abdominal neoplasm
7) Renal transplant
8) Benign ulcer disease
9) Idiopathic
What is a complication of portal vein thrombus
Bowell ischemia and perforation
Signs and symptoms of portal vein thrombus
Abdominal pain Low grade pain Leukocytosis Hypovolemia Shock Abdominal Rigidity Elevated LFTs N & V Hematemesis Melena
Sonography appearance of portal htn
Stage 1- Echogenic thrombus in vessel lumen
Stage 2- Thrombus and small collaterals
Stage 3- Large collaterals and no identifiable portal veins
Direct signs of portal venous thrombus
- Visualization of a clot in the lumen
- Clot appears echogenic
- If acute, clot may be hard to identify
- Local bulge of the vein at clot level
- Total occlusion: no venous doppler
- Partial occlusion: normal doppler but decreased flow
Indirect evidence of portal vein clot
- No portal vein landmarks
- Collateral vessel formation
- Increased SMV and splenic vein caliber
What is cavernomatous Transformation
Multiple worm like serpiginous vessels in the portal region- will replace clotted portal veins
What causes cavernomatous transformation
long standing portal thrombus and collateral vein formation
What is portal htn
Increase in pressure in the portal veins
What features accompany portal htn
- Superficial collateral vessels- Cruveilhier- Baumgarten syndrome
- Left gonadal vein varix
- Spontaneous splenorenal shunt
What are steystemic vein connection to collateral veins to relieve pressure
Varicose veins
What are varicose veins most frequent
Esophagus
Stomach
Rectum
Rupture may cause death
What is the most common cause of portal htn
Cirrhosis
Sign and symptoms of cirrhosis
Ascites Gastrointestinal bleeding Poor renal function Impaired coagulation Recannalization
What is recannalization
Under extreme pressure the round ligament (tere) will reopen to move blood
- Common in cirrhosis or portal htn
- Results in rapid growth of scar tissue in liver
How does recannalization occur
So much pressure on vessels surrounding the liver that it forces the round ligament open
Sonographer’s appearance
- Portal vein enlarged/or normal or small due to collaterals
- Secondary effect of increased pressure results in collateral channel development and recannalization and abnormal respiratory responses
Collateral network may involve
- Coronary vein
- Gastroesophageal vein
- Umbilical vein
- Pancreatic duodenal vein
- Gastrorenal and splenorenal vein
How often does identifying coronary dilation and esophageal varices indicate portal htn
80-90% of the time
How often will umbilical vein recannalization be present
10-20% of the time
How can you locate the coronary vein
Locate the splenic vein in midline sagital veiw and move the probe right. It courses cephalad from the splenic vein near the porto-splenic confluence
Portal htn from is
Hepatofugal- away from the liver, supposed to be hepatopedal
What is the most significant clinical consequence of portal htn
Variceal Hemorrhage
What are pericholecystic varices
They are vascular areas of increased flow within the gallbladder wall- associated with portal htn
What does Caput Medusae describe
Distended and engorged umbilical veins which are seen radiating from the umbilicus across the abdominal wall to join the splenic vein
What does the presence of caput medusae indicate
Posthepatic and intrahepatic portal htn due to recannalization of the umbilical vein which connects with left portal vein. Wont occur if obstruction if below the umbilical vein
What is Caput Medusae and indication of
Portal htn which shunting through umbilical veins
Where did Caput Medusae derive its name
Medusa’s hair of snakes
How do normal Portal veins appear
- No intralumenal echoes
- low velocity and respiratory variation
- Smooth fill with color
How do Portal vein with thrombus appear
- Enlarged or normal with low lever echoes in the lumen, may be isoechoic in the liver
- Decreased low velocity to absent Doppler
- Hepatofugal flow
- No color
How does Portal HTN appear
- Enlarged Portal Veins with recannalization of the umbilical vein
- Look for Hepatofugal flow
- Hepatofugal flow with good color flow
How does Cavernous Transformation look
- Multiple vascular channels near the poral hepatis or splenic hilum
- Thrombus of the extrahepatic portal vein
- Recannalized umbilicus
- Continuous velocity flow
- Color fills dilated collateral vessels
- Portal vein hard to fill with color
How does a normal Hepatic artery appear
- Hepatic artery should be anterior to portal vein
- Should be level with the celiac axis
- Distal HA should seen in intercostal coronal view level with MPV and CBD
How does a thrombosis in the hepatic artery appear
- Increased low level echoes
- Obstruction causes increased waveforms
- Turbulence or absence of flow if completely obstructed
How does normal IVC appear
- Low level echoes that changes with respiration
- Returns to right atrium
- Coninuous triphasic waveform with respiratory variation
- Color filled lumen
How does a thrombosis in the IVC appear
- Increase echogenicity within the lumen returning to the Right Atrium
- Evaluate Renal Veins for extension of thrombus
- Decreased Doppler waveform for secondary to degree of thrombus
- Decreased color in the lumen
- Color will outline the walls of the thrombus
How does the IVC appear in right sided heart failure
- Dilation of lumen that does not change in respiration
- Multiphasic, pullsatile flow
- Color fills lumen of hepatic veins and IVC
How does a thrombosis associated with Budd Chiari appear
- Low level echoes within the lumen of the hepatic veins
- May restrict blood flow into the IVC
- Caudate enlargement may mean hepatic vein thrombosis
- Decreased flow signal
- Decreased color fill in hepatic veins
- IVC collapsed with decrease bloodflow
What is normal size of portal vein
13mm
What is the cavernomatous transformation
Multiple worm-like vessels in the regions of the portal veins that result from long standing thrombus and collateral vessel formation
What is portal hypertension
Acute or chronic blocks flow through the liver- causing portal back up. Causes portal blood pressure to increase
What helps relieve the high pressure in the portal system
Collateral vein formation and varicose formation
Where do these collateral vessels usually form
Esophagus, stomach, rectum
Advances portal HTN can cause what signs and symptoms
- Ascites
- Gastrointestinal bleeding
- Poor renal function
- Impaired Coagulation
What is the most significant clinical sign or portal htn
Varicose Hemorrhage
What kind of blood flow is observed with portal htn
Hepatofugal or retrograde
Average measurement of IVC
2-3.7 cm above 3.7 is considered abnormal