Flashcards in IVC Deck (111):
When does the venous return decrease and IVC decrease?
With deep inspiration
When does the venous return improve and the IVC diameter increase?
With deep expiration.
This is when the venous return is blocked and flow temporarily reverses in the IVC causing it to bulge?
When performing a Valsalva maneuver
When the blood flow in the IVC is obstructed, what is the normal response of the vessel?
To increase in caliber below the point of obstruction. Because of the elastic capacity of the veins, the expansion of the IVC can be quite dramatic.
What is the most common cause of IVC obstruction?
right sided heart failure
What are the other causes of IVC obstruction?
1. enlarged liver
2. para-aortic lymphnode enlargement
3. retroperitoneal masses or tumors
4. pancreatic tumors
5. a congenital IVC valve may also obstruct the lumen of the IVC
What are the signs and symptoms of IVC obstruction?
1. abdominal pain
3. tender hepatomegaly
4. lower extremity edema may also be present in the most severe forms of IVC blockage
Where does the IVC tend to dilate when there is obstruction?
below the level of the obstruction
What happens to the respiratory change when the IVC is obstructed?
They are decreased or absent below the obstructed segment.
What happens when there is right sided heart failure?
The distal IVC and hepatic veins become congested resulting in an increase in diameter. Respiratoy changes are markedly decreased or absent.
What is seen when the IVC is impinged?
Solid, complex, or echo poor tumors in the retroperitoneum or pancreas may be seen to impinge on the IVC. If large enough, they can obstruct the IVC, causing lower trunk and leg edema.
What else obstructs the flow within the IVC? Which area of the vein gets dilated?
Intravenous tumors, primary, or metastatic, also obstruct flow within the IVC. Dilation of the vein below the tumor mass will be identified.
Why does the overall enlargement of the liver cause the IVC to dilate?
Because it presses on the vessel
What is the most encountered intraluminal anomaly of the IVC?
From where does the thrombus spread?
usually from another vein in the pelvis, lower limb, liver or kidney
How is the IVC thrombosis seen sonographically?
as an intraluminal filling defect that usually expands the diameter of the vessel.
The echogenicity of the thrombus depends on its...
What happens to the doppler when there is thrombus in the IVC?
Doppler produces no signal.
Which organ is the most likely site of origin for thrombus to occur in the IVC?
The normal response of a vein below the point of obstruction will be ___ but above the obstruction the vein should remain ___ diameter.
What is an IVC filter made of?
A metal device made of either stainless steel or nitinol (nickel titanium).
Where is the IVC filter place in the body?
in the IVC
What does the IVC filter do?
It traps any blood clots that are 5mm in size or larger.
How is the IVC filter designed?
It is designed such that it will allow blood to flow back to the heart even if clots are trapped within it.
Can ultrasound see the IVC filters?
Sometimes they appear as echogenic structures within the IVC. Ultrasound can monitor complications that may occur at their site of insertion.
What are the fractures of IVC filter?
If the fragment migrate to adjacent tissues, *asymptomatic - no tx necessary
*symptomatic - confirm location with CT scan and consider surgical removal if feasible. If fracture results in compromise of filter function: place a 2nd filter.
What are the tumors of the IVC?
Primary, Metastatic, and an Extension of the primary
What are the primary tumors of the IVC?
Mostly leiomyomas or leimyosarcomas
When are the leiomyomas or leiomyosarcomas detected?
In women - the median age of detection is 61 years.
What happens if they have leiomyosarcoma tumors?
Possibly metastasis to the liver and lungs
What is the rare tumor of the IVC & where does it originate?
Chromaffin which is originated outside the adrenal gland.
Name the malignant invasions of the IVC.
1. Renal carcinoma
2. secreting and nonsecreting adrenal tumors
3. retroperitoneal sarcomas
4. hepatocellular carcinomas
Which is the most common malignant invasion?
renal cell carcinoma
What are the clinical signs & symptoms of IVC tumors?
Depends on tumor size and the degree of IVC obstruction. With large tumors, leg edema as well as ascites and abd pain may develop
How does tumors within the IVC tend to appear in sonographic appearance?
As echogenic foci. Occasionally, they may be isodense with blood in the lumen.
What does a larger primary tumor look like in sonographic appearance?
Heterogeneous with areas of necrosis.
Depending on the tumor size, what happens to the IVC?
If it's large, increased IVC caliber as well as loss of respiratory changes.
Why is the differential diagnosis larger in IVC?
Because of the similarity in echographic appearance of vascular tumor masses.
What are the differential diagnoses for IVC?
1. Primary vascular neoplasm
2. Malignant IVC mass
3. Chronic thrombus
4. larger primary tumors outside the vessel
What is important to identify when an IVC mass is seen?
1. The presence of a primary tumor and its site
2. The cranial extent of the tumor mass
3. Possible tumor involvement or invasion of the wall of vessel
What will aid in the diagnosis of IVC obstruction by tumors?
doppler and color flow
How is the normal blood flow of the IVC?
Normally, blood flow in the IVC is steady. Near the heart, effects of cardiac pulsations cause some reversal of flow.
What happens to the blood flow when the IVC is partially obstructed?
They change and the velocity at the narrowed segment increases.
With deep inspiration, venous blood flow ___ and the IVC ___.
When performing a Valsalva maneuver, venous return is blocked and flow temporarily ___ in the IVC causing it to ___.
When blood flow in the IVC is obstructed, the normal response of the vessel is to...
increase in caliber below the point of obstruction.
In right-sided heart failure, the distal IVC and hepatic veins become ___ resulting in ___ diameter.
T/F? Primary tumors of the IVC tend to be a very common finding.
False. Only about 2% of vascular incidences are primary IVC tumors.
What is one clinical sign or symptom of an IVC tumor invasion that is seen most often?
When an IVC mass is identified it is important to attempt to identify?
1) Does it involve the hepatic veins or the right atrium?
2) Is there tumor involvement or inasion of the wall of the vessel?
What are the reasons for renal vein enlargement?
1) Increased flow due to a splenorenal or gastrorenal shunt in patients
2) with portal HTN or portal thrombosis
3) tumor involvement from renal cell carcinoma
4) increased flow from an AV malformation in the kidney
What are the clinical signs & symptoms of renal enlargement?
1. Symptoms are generally associated with the inital disease process, not the venous enlargement.
2. Tumor involvement usually produces no specific symptoms
Sonographically, an enlarged renal vein is defined as one with a diameter in excess of...
What is another sonographic finding suggesting of increased flow volume into the renal vein?
Abrupt IVC dilation at the level of the renal insertion point.
What is useful in differentiating the types of disease processes that may cause venous enlagement?
Evaluation of symmetry between the renal veins
If enlargement of the renal veins is bilateral or symmetric, the disease process most likely involves the ___ at a level ___ the insertion of the ___ ___.
IVC, above, renal vein
What could unilateral renal vein enlargement indicate?
1. tumor involvement
2. portal venous HTN
3. with renal vein collateral anastomosis
4. AV fistula
In portal HTN, what are apt to develop as the pressure in the portal system increases?
What happens to the blood flow when blood is diverted to the collaterals?
They could fistulize to the left renal vein as a means of relieving the increased pressure.
What is involved in portal veins HTN?
isolated left renal vein involvement
What is involved by tumor invasion or AV fistula?
Either left or right renal vein
What happens to the renal vein when renal cell carcinoma occurs?
The renal vein dilates.
What happens to the vein during AV malformation?
The increased blood volume causes the vein to dilate.
When does an AV malformation occur?
1. Blunt or penetrating trauma
2. biopsy complications
3. tumor involvement
5. idiopathic causes
Blood flow patterns can be determined with ___ and may be useful in diffferentiating the varous types of ___.
doppler, renal vein enlargement
What is evident in the presence of a gastrorenal or splenorenal shunt associated with portal HTN or in the presence of an AV malformation?
disturbed or turbulent venous flow signals are evident in the enlarged renal vein; velocities may also be abnormally rapid
With tumor involvement ___ focus is usually present in the vessel lumen.
If there is tumor involved in the renal veins, what else must be done?
The IVC should be searched carefully to identify the extension for the tumor beyond the renal veins.
What are the pitfalls during the exam of a renal tumor?
1. In a tumor free vessel, reverberation artifact may mimic a tumor or possible a thombus.
2. It is also possible that some metastatic tumors may appear isoechoic with the surrounding blood, mking hem very dificult to identify.
3. The left renal vein may appear enlarged at the point where it crosses over the aorta before entering the IVC. This is a normal finding in many persons. Dilations should be suspected only if the entire length of the renal vein is enlarged.
When does a renal vein thrombosis occur?
1. nephrotic syndrome
2. renal tumors
3. renal transplants
5. infant dehydration
7. compression of the renal vein secondary to tumor
What are the clinical signs & symptoms for acute renal venous thrombosis?
1. loin or flank pain
3. leg swelling
Where does the dilation occur when there is renal vein thrombosis?
The renal vein is dilated at a point proximal to the occlusion.
Where can the thrombus be visualized?
both in the renal vein and the IVC
What happens to the renal vein when there is thrombosis?
1. renal size generally increases in the acute phase and a loss of normal renal structure may be identified
2. doppler flow decreases
Thrombus can appear in what different ways?
1. As an echogenic fous, esp in longstanding cases
2. In more acute cases, isoechoic to the surrounding blood.
What are the causes of a venous aneurysm?
1. weakening of a vessel wall by pancreatitis
2. portal HTN
3. embryonic malformations (congenital anomalies)
What is the sonographic appearance for venous aneursym?
1. anechoic areas in the porta hepatis. There may or may not be thrombus
2. Doppler dectecting a turbulent signal in the lesion
3. Other venous aneursyms are rare, but they all resemble a portal vein aneurysm sonographically.
Where does the portal venous system drain blood from?
The small and large intestine, stomach, spleen, pancreas, and gallbladder
What unites to form the portal vein?
SMV, IMV, and splenic vein unite behind the neck of the pancreas to form the portal vein.
Which vein does the right branch drain?
the cystic vein
Which veins does the left branch receive?
the left branch receives the umbilical and paraumbilical veins that enlarge to form umbilical varices in PHTN.
Which vein runs along the lesser curvature of the stomach?
Which veins does the coronary vein receive?
distal esophageal vein
What usually beings intrahepaticaly and spreads to the extrahepatic portal vein?
cirrhosis, hepatic malignancies, and thrombosis
In most other etiologies, where does the thrombosis usually start?
at the site of origin of the portal vein
What is the normal portal vein caliber?
Portal vein thrombosis can be caused by...
1. portal HTN
2. inflammation - appendicitis, peritonitis, pancreatitis
4. postsurgical complications
5. hypercoagulability states
6. abd neoplasms
7. renal transplant
8. benign ulcer disease
What is the potential complication of the portal vein thrombus?
bowel ischemia and perforation
What are the clinical signs & symptoms?
1. abd pain
2. low grade fever
6. abd rigidity
7. elevated liver function tests
What is the sonographic appearance of portal vein thrombus?
A varying appearance with each stage...
1. echogenic thrombus in vessel lumen
2. thrombus and small collaterals
3. large collateral and no identifiable portal vein (cavernomatous transformation)
What are the direct signs of portal venous thrombosis?
1. visualization of a clot in the lumen
2. clot appears echogenic
3. if acute, clot may be difficult to identify
4. local bulge of the vein at clot level
5. total occlusion: no venous doppler signals
6. portial occlusion: normal doppler but decreased flow in vein
What's the indirect evidence of portal vein clot?
1. no portal vein landmarks
2. collateral vessel formation
3. increased SMV and splenic vein caliber
What is cavernomatous transformation?
multiple worm like serpiginous vessels in the region of the portal vein; a network of vessels that replace the obliterated portal vein
Cavernomatous transformation is the result from what?
results from longstanding thrombus and subsequent collateral vessel formation
What is portal HTN?
acute or chronic hepatocellular disease blocks the flow of blood throughout the liver, causing it to back up into the hepatic portal circulation, leading to an increase of blood pressure in the hepatic circulation
What is formed in an effort to relieve the pressure from PHTN and what do they connect to? What is it called?
collateral veins are formed that connect to the systemic veins. This is known as varicose veins.
Where do these varicose veins occur?
Most frequently occurs in the area of the esophagus, stomach and rectum.
What happens if these varicose veins rupture?
possibly fatally massive bleeding
What is the most common cause of portal HTN in the western world?
What are the clinical signs and symptoms in advanced cases?
2. GI bleeding
3. poor renal function
4. impaired coagulation
Under extreme pressure, the round ligament (aka ligamentum teres) reopens to allow the passage of blood. Such recannalization is common in patients with cirrhosis and PHTN. Patients with cirrhosis experience rapid growth of scar tissue in and around the liver, often functionally obstructing nearby vessels.
What is the sonographic appearance of PHTN?
Portal vein may be enlarged, but it may be normal or small due to development of collaterals; look for secondary effect of increased pressure within the venous system like collateral channel developent or recannalization and abnormal respiratory responses.
Collateral network may involve...
1. coronary vein
2. gastroesophageal vein
3. umblical vein
4. pancreatic duodenal vein
5. gastrorenal and splenorenal veins
What is a good indicator of PHTN?
What is a useful landmark in the location of the recannalized?
How is the coronary vein located?
The coronary vein is imaged by locating the splenic vein in a midline sagittal view and moving the probe to the right. It is recognized as a small vessel coursing cephalad from the splenic vein near the portal splenic confluence.
When a person gets PHTN which blood flow does that person have?
What is the most significant clinical consequence of PHTN?
What doe sthe presence of caput medusae indicate?
posthepatic or intrahepatic PHTN
How is capu medusae formed?
By recannalization fo the umbilical vein which connects with the left hepatic branch of the portal vein