Abdominal Vasculature - Part 7

Question 1

Thrombus

Answer 1

Stationary blood clot along the wall of a blood vessel, frequently causing vascular obstruction

Question 2

What causes IVC thrombus? (7)

Answer 2

Extrinsic compression from

1. Tumours
   - sarcomas —> renal or adrenal
2. Lymph nodes
3. AAA
4. Polycystic kidneys
5. Trauma
6. DVT from lower extremities
7. Retroperitoneal fibrosis

Question 3

What is a sign of IVC thrombus?

Answer 3

Bilateral leg swelling

- this is not a cause

Question 4

What is bilateral leg swelling caused by with IVC thrombus?

Answer 4

Pooling of blood

Question 5

IVCFs

Answer 5

Inferior Vena Cava Filters

Question 6

Inferior Vena Cava Filters

Answer 6

Devices that can be deployed into the IVC to block the passage of thrombi from the lower extremities and pelvis into the lungs

Question 7

What do IVCFs help with?

Answer 7

In preventing embolization

Question 8

What is the most common cause of IVC thrombosis?

Answer 8

The presence of an un-retrieved IVC filter

Question 9

Renal artery stenosis

Answer 9

Narrowing of a renal artery

- occurs slowly over time

Question 10

What forms in renal artery stenosis?

Answer 10

Collateral vessels

- supply the kidney

Question 11

What does collateral vessels lead to in a renal artery stenosis?

Answer 11

Secondary hypertension

Question 12

What is the most common cause of renal artery stenosis?

Answer 12

Atherosclerosis

Question 13

What segment of the renal artery is most common for a stenosis?

Answer 13

The proximal segment

Question 14

What is the second most common cause of renal artery stenosis?

Answer 14

FMD

- fibromuscular dysplasia

Question 15

What indicates a renal artery stenosis?

Answer 15

Anything larger than a 3.5 ratio renal artery to aortic ratio

Question 16

What is tardus parvus an indicator of?

Answer 16

An upstream significant renal artery stenosis

Question 17

What do renal ratios do?

Answer 17

Assess the main renal artery for stenosis

- must be compared to the proximal aorta flow using a ratio between the aorta and the renal artery

Question 18

What is the formula for the renal ratio?

Answer 18

Renal artery / aorta

Question 19

How high can the renal artery PSV be for it still to be considered normal?

Answer 19

180cm/s

Question 20

Where do you measure on the aorta PSV for the renal ratio?

Answer 20

Just above the renal artery takeoff

Question 21

Where do you measure on the renal artery for the renal ratio? (2)

Answer 21

1. At the origin
   - sometimes covered by gas

Or

2. Measure the PSV of the distal renal artery at the hilum
   - easy to identify

Question 22

RI

Answer 22

Resistive indices

Question 23

When is resistive indices used?

Answer 23

What a renal artery stenosis is suspected

Question 24

If a renal artery stenosis is suspected, what should you want to assess?

Answer 24

The intrarenal vessels

Question 25

What is the resistive indices formula?

Answer 25

RI = PSV - EDV / PSV

Question 26

What is considered normal for RI?

Answer 26

< 0.7

Question 27

What is the RI when you need to get a transplant that has been rejected?

Answer 27

> 0.9

Question 28

What is RI a common parameter for?

Answer 28

The flow analysis within the segmental and interlobar vessel

Question 29

What is RI a good indicator of?

Answer 29

The hemodynamically significant stenosis in MRA

Question 30

Is angle correct used when calculating RI?

Answer 30

No

- the angle is independent