Ch 16 IVC + iliac veins

Question 1

What is a confluence?

Answer 1

Union of 2 or more veins to form a larger vein (same as a bif in the arterial system)

Question 2

What is an IVC filter?

Answer 2

-Cone shaped medical device that prevents pulmonary embolism
-Placed in IVC to trap embolisms from the lower extremities before they travel to the heart + lungs

Question 3

What is a pulmonary embolus?

Answer 3

An obstruction of the pulmonary arteries, due to detached fragments of a blood clot that travels from the LEVs

Question 4

What is the retroperitoneum?

Answer 4

Space b/w abdo cavity + the muscles/bones of posterior abdo wall

(includes IVC, iliac veins + abdo Ao)

Question 5

Is the abdominal IVC in the peritoneal cavity?

Answer 5

No, retroperitoneal cavity

Question 6

The IVC begins at what level of the spine?

Answer 6

L5: at the confluence of the RT + LT CIVs

Question 7

The IVC ascends to the right or left of the Ao?

Answer 7

RT

Question 8

The IVC passes through the diaphragm at what level of the spine?

Answer 8

T8

Question 9

The EIVs is a continuation of the ___ veins?

Answer 9

Common femoral veins

Question 10

___ joins the EIVs to form the CIVs?

Answer 10

IIVs

Question 11

The left CIV passes superficial or deep to the right CIA at the level of the Ao bif?

Answer 11

Deep

Question 12

___ veins join to form the IVC?

Answer 12

LT + RT CIVs

Question 13

What veins drain into the IVC?

Answer 13

Hepatic, adrenal, renal, gonadal + lumbar veins

Question 14

The diameter of the IVC depends on what?

Answer 14

The hydration status of the pt

Question 15

What is the average IVC diameter at the level of the renal veins?

Answer 15

17-20mm

Question 16

What defines mega cava?

Answer 16

-Enlarged IVC >28mm
-Occurs in pt’s with a large stature or with congestive heart failure

Question 17

When does a duplicated IVC + left-sided IVC terminate?

Answer 17

Duplicated: terminates when the LT IVC drains into the LRV

Left-sided: terminates in the LRV or extends cranially to drain into the azygos vein in the chest

Question 18

List 3 normal variants of the IVC?

Answer 18

-Duplicated IVC
-Left sided IVC
-Absence of intrahepatic portion of IVC

(these have normal doppler signals)

Question 19

How does blood get returned to the heart if there is an absence of the intrahepatic portion of the IVC?

Answer 19

Via the azygos or hemiazygos veins

Question 20

SF of an absent intrahepatic IVC?

Answer 20

HVs are seen draining directly into the RA

Question 21

IVC protocol?

Answer 21

IVC: prox, mid, dist, CIV confluence + EIVs

Also: assess hepatic + renal veins

Question 22

Course of the LRV?

Answer 22

Anterior to Ao, posterior to SMA

Question 23

What is the nutcracker syndrome?

Answer 23

Compression of LRV

Question 24

Where does blood flow during inspiration + expiration?

Answer 24

Inspiration: to chest
Expiration: to abdomen

Question 25

Waveform for prox + dist IVC?

Answer 25

Prox: pulsatile (near RA) Dist: phasic

Question 26

SF of a partial IVC obstruction?

Answer 26

Loss of normal respiration + cardiac variation in IVC + iliac veins

Question 27

What does a loss of respiratory phasicity + inability to augment with compression indicate?

Answer 27

Prox obstruction with iliac vein thrombosis

Question 28

What is the m/c pathologic finding?

Answer 28

Thrombosis resulting from propagation of a lower extremity venous thromboembolism

Question 29

SF of a thrombosis?

Answer 29

-Distended IVC or iliac vein with echogenic materal in lumen -Acute thrombus can be anechoic + is hard to detect in 2D

Question 30

Differentiate b/w a fully + partially occlusive thrombus?

Answer 30

Fully: -Distended vein with echogenic material in lumen -Absent flow -No doppler signal Partially: -Echogenic material is partially free floating + attached to vessel wall -Flow is present but diminished -Continuous doppler signal (loss of respiratory + cardiac variation)

Question 31

Is neoplastic obstruction of the IVC + iliac veins rare?

Answer 31

Yes!

Question 32

Intraluminal tumors arise from what veins?

Answer 32

Hepatic or renal veins (can obstruct IVC)

Question 33

SF of tumors?

Answer 33

Moderately echogenic + will have CD flow within the mass

Question 34

What does extrinsic tumors result in?

Answer 34

Dilated collateral veins + distention of distal IVC + iliac veins (can completely obstruct)

Question 35

What is iliac vein compression syndrome (aka may thurner syndrome)?

Answer 35

When the CIV gets compressed b/w the iliac artery above + the vertebral body below

Question 36

May thurner syndrome m/c affects with CIV?

Answer 36

LT

Question 37

How does may thurner appear on spectral doppler?

Answer 37

-Increased velocity at point of compression -Monophasic flow w/o respiratory variation distal to compression

Question 38

Treatment for may thurner?

Answer 38

Balloon angioplasty + stent placement

Question 39

What is a caval fistula?

Answer 39

Abnormal connection b/w IVC + other vessels Spontaneous: aortocaval Surgical: portocaval

Question 40

Where is an IVC filter placed?

Answer 40

Just below level of renal veins

Question 41

SF of an IVC filter?

Answer 41

SAG: echogenic line in lumen (near renal veins) TRV: central echogenic dot

Question 42

How does a physician put in an IVC filter?

Answer 42

Maintains SAG IVC image with the RRA in view, the tip should be just below the RRA

Question 43

Benefits to intravascular u/s (IVUS)?

Answer 43

-Can diagnose iliac vein stenosis -Accurately measure vein diameter -Evaluate the effect of endovascular intervention

Question 44

What is IVUS?

Answer 44

-Real time imaging of vein lumens, with more detail + accuracy than duplex u/s or contrast venography -Helps differentiate the flow lumen from the vessel wall

Question 45

Flexible IVUS catheters have u/s ___ embedded at their tip?

Answer 45

Crystals (they emit sound waves covering 360 degrees of the vessel)

Question 46

IVUS has high sensitivity in detecting ___ + ___ vein segments?

Answer 46

Stenotic + obstructed