IVC Flashcards
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?
- enlarged liver
- para-aortic lymphnode enlargement
- retroperitoneal masses or tumors
- pancreatic tumors
- a congenital IVC valve may also obstruct the lumen of the IVC
What are the signs and symptoms of IVC obstruction?
- abdominal pain
- ascites
- tender hepatomegaly
- 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?
thrombus
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…
age.
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?
kidney
The normal response of a vein below the point of obstruction will be ___ but above the obstruction the vein should remain ___ diameter.
dilation/normal
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.
- Renal carcinoma
- secreting and nonsecreting adrenal tumors
- retroperitoneal sarcomas
- hepatocellular carcinomas
- teratomas
- lymphomas
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?
- Primary vascular neoplasm
- Malignant IVC mass
- Chronic thrombus
- larger primary tumors outside the vessel
What is important to identify when an IVC mass is seen?
- The presence of a primary tumor and its site
- The cranial extent of the tumor mass
- 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 ___.
decreases, compresses