Aorta, Illiac arteries & IVC
What is the normal anatomy of the aorta?
well defined walls
tapers below renals
mas diameter - 2 cm in adults
slightly to the left of midline
adjacent to spine
What are the branches of the aorta in order?
Where is the celiac axis?
What makes up the portal vein?
splenic & SMV
portal splenic confluence
What is the normal anatomy of the IVC?
right of midline
gradually moves away from spine
What is the importance of evaluation of the IVC?
determine patency or cause of obstruction
What happens to the IVC during the valsava manuever?
Where does the IVC enter the heart?
What should the blood flow be in the IVC?
What is the sonographic appearance of the Iliac arteries?
uniform in caliber
max 1 cm at common
bifurcates at umbilicus
EIA slightly small than the common
WHat is the measurement of the common iliac arteries
What is an aneurysm?
weakening of arterial wall
1.5 greater than adjacent
distal exceeds 3 cm
What are the different types of aneurysms?
mycotic & dissecting
What is a saccular aneurysms?
What is a fusiform aneurysms?
What is a diffuse aneurysms?
What are the majority of aneurysms?
true or false?
What is the problem with suprarenal aneurysms?
much harder to repair surgically
What is a true aneurysms?
walls are intact but stretched
involves all walls
Explain a Pseudoaneurysm?
a hole in the wall allowing escape of blood to surrounding tissue
may have circulation within the hematoma
common in groin, brachial & radial
What are the causes of a Pseudoaneurysm?
aortic puncture without stasis
leaky graft anastamoses
What is an aortic dissection?
What is the cause of arterial dissection?
torn tunica intima allows blood in the layers of the wall
What may occur with arterial dissection?
destruction of the tunica intima
What are the two requirements for an arterial dissection?
weakening of the tunica media
tearing of the tunica intima
What are the predisposing factors of an arterial dissection?
What is Marfans syndrome?
connective tissue disorder
tall, long extremities
What is the most common site for arterial dissection?
go to CT & angio
Where is the most common site for arterial dissection seen in U/S?
less common abdominal aortic dissection
What is the presentation of an aortic aneurysm?
pain - abd, back, leg
How many aortic aneurysms are incidental findings?
30 - 60% asymptomatic
What happens when an aortic aneurysm ruptures?
death 50% of the time
What increases the risk of rupture of an aortic aneurysm?
When is surgical repair recommended for an aortic aneurysm?
imperative at 6cm
What is the chance of rupture of an aortic aneurysm at 4.5 cm?
2% within 1 year
What is the chance of rupture of an aortic aneurysm at 4.5 cm - 6 cm?
10% within 1 year
An 4.5 cm aortic aneurysm grows at what rate?
1 cm per year
What is the average growth of an aortic aneurysm?
2 - 5 mm per year variable
How often should an aortic aneurysm be examined?
by U/S or CT
if no enlargement every year
Once an aneurysm be moved to CT?
Iliac 3 2 1 rule
An iliac aneurysm usually occurs in conjunction with what?
isolated are uncommon
What does a rupture of an iliac aneurysm cause
non specific symptoms
When does concern start for an iliac aneurysm?
found in common iliac arteris
can be palitated
What is the sonographic appearance of aneurysm?
focal increase in caliber 1.5 - 2 x greater
absence of tapering
frequently contains thrombus
What can be confused with an aneurysm?
Why does arteriography underestimates aneurysm?
by measuring only active lumen
How should the aorta be measured?
outer to outer
When looking at the aorta in coronal what is the easiest view?
from the left
aneurysm never decrease!
always check iliacs
above or below renals
What are the splanchnic arteries?
What happens when the splanchnic arteries get occluded?
bowel ischemia (IBD)
What can prevent bowel ischemia with occluded vessels
What is the pancreaticoduodenal arcade?
collateral pathway links the celiac to the SMA
surrounds duodenum and pancreas
What is the Arc of Riolin?
collateral pathway links the SMA & IMA
What is the Marginal Artery of Drumond?
collateral pathway links the SMA and IMA
What is the two artery rule?
one vessel occlusion/stenosis is normally asymptomatic due to the collateral routes
normally IBD is clinically important when two of more vessels have been occluded
THIS IS NOT ABSOLUTE
What what percent must an occlusion be before surgery?
60% or higher
What is Medium arcuate ligament syndrome
medium arcuate ligament of the diaphragm extrinsically compresses the celiac axis - posteriorly
What are the symptoms of Medium arcuate ligament syndrome?
associated with psychosocial
Symptoms of Medium arcuate ligament syndrome become worse with ________.
pushes down on celiac
How do you determine whether a celiac obstruction is intrinsic or extrinsic?
have the patient inhale deeply during Doppler examination
if flow doesn't change - intrinsic
if flow changes between inspiration and expiration the stenosis is extrinsic
What does celiac flow occlusion result in 100% of time?
flow reversal through collaterals
The SMA and IMA vary with fasting
What is the resistance with preprandial?
The SMA and IMA vary with fasting
What is the resistance with postprandial?
timing causes increased flow 30 - 90 minutes after eating
What is the resistance of the celiac?
unaffected by fasting!!!
What are the SMA preprandial flow values?
PSV 96 -156 cm/sec
EDV 11 -16 cm/sec
What are the SMA postprandial flow values?
PSV 136 - 216 cm/sec
EDV massively increased
What are the Celiac flow values?
PSV < 122 cm/sec
EDV 32 -35 cm/sec
What is Acute Mesenteric Ischemia?
arterial occlusion of SMA & celiac
What are the symptoms of Acute Mesenteric Ischemia?
abdominal distension - from Air
What are the symptoms of Chronic Mesenteric Ischemia?
fear of food syndrome
What is the method of evaluation of Chronic Mesenteric Ischemia?
What is the diagnostic criteria for SMA stenosis?
preprandial SMA low resistance
splanchnic artery increased flow from (70% or greater stenosis) in 2 or more vessels
What is the celiac flow values if 70% occlusion?
PSV 200 cm/sec
EDV 55 cm/sec
What is the SMA flow values if 70% occlusion?
PSV 275 cm/sec
EDV 45 cm/sec
What is the pre-renal flow resistance in the abdominal aorta?
What is the post-renal flow resistance in the abdominal aorta?
The hepatic artery is
The portal vein is
The hepatic veins is
The hepatic artery is biphasic
What is the resistance of the splenic artery?
low resistance toward spleen
If a patient has uncontrolled hypertension what exam should be ordered?
renal Doppler exam
If a patient has ascites and/or cirrhosis what exam should be ordered?
Portal venous Doppler
If a patient has food fear what exam should be ordered?
IMA / SMA Doppler
If a patient has caudication what exam should be ordered?
What is caudication?
a condition in which cramping pain in the leg is induced by exercise, typically caused by obstruction of the arteries.
How many people in the USA have hypertension?
> 10 million with fixed hypertension
How many people in the USA have renal artery disease?
How many people in the USA have true renovascular hypertension?
stenosis in renal arteries
What is the direct method in renal Doppler?
interrogate entire renal artery, bilaterally
What is the indirect method in renal Doppler?
interrogate segmental renal arteries only, bilaterally
What is the purpose of a Renal Doppler exam?
identify vascular etology of hypertension
prevent renal failure due to permanent parenchyma changes
evaluate renal transplant (contour, thickness of cortex)
What is the causes of renovascular hypertension?
atherosclerosis - proximal renal arteries
fibromuscular dysplasia - distal renal artery
dissection - extension of aortic dissection
renal vascular anatomy consists of?
Main renal artery
segmental renal artery at hilum
How does the left renal vein course?
between the SMA and aorta
How does the right renal artery course?
posterior to IVC
Which renal artery is longer?
Which renal vein is longer?
Normal renal veins should demonstrate phasic flow but can have pulsatile flow from right atrium
Describe the accessory renal arteries
May arise from aorta above or below the main renal arteries
on right side they may pass anterior to IVC
may arise from the SMA or iliacs
What is the patient prep for a renal Doppler?
NPO after mid
What can be the cause of a high velocity without PST?
Why should you not invert spectral Doppler in the abdomen?
to check flow direction
What is the main renal arteries flow velocity?
High flow velocity
PSV 100 +- 20 cm/sec
What is the main renal arteries resistance?
RI < 0.75
What is the main renal arteries diastolic flow velocity?
High flow velocity
EDV 30 +- 5 cm/sec
What is the criteria for diagnosis of a 60% stenosis in the Renal arteries?
Renal - aortic ratio (RAR) >= 3.5
Peak systolic velocity (PSV) . 180 cm/sec
post stenotic turbulence
Low flow in distal renal artery
What is the criteria for diagnosis of an occlusion in the Renal arteries?
low amplitude signal from parenchyma
small kidney size (<9 cm)
Renal prenchymal disease
high resistance flow in kidney and main renal artery
velocity is reduced
What are the physical limitations of Renal Doppler?
Depth of renal arteries
motion of respiration
previous abdominal surgery
What are the technical limitations of Renal Doppler?
high technical failure rate (12 - 25%)
accessory renal arteries (polar artery)
Poor Doppler angle
Long exam time
requires very skilled tech
Renal transplants evaluation
R/O kinks / twists in renal artery
normal 0.73 +- 0.04
abnormal 0.8 +- 0.07
RI not universally accepted
What is the Purpose of a Mesenteric Doppler scan?
diagnose mesenteric ischemia
chronic or acute
What are the symptoms of mesenteric ischemia?
pain after eating (food fear)
What is the resistance of the renal arteries?
What is the resistance of the pre renal?
What is the resistance of the post renal?
Eating does not affect the celiac
What provides blood to the liver?
portal vein (80%)
What is the purpose of the Portal system?
drains nutrient rich blood from bowel and spleen and takes it to the liver
What is portal hypertension?
elevated pressure in the portal venous system due to increased impedance of flow through the liver
What are the prehepatic causes of portal hypertension?
thrombosis of portal vein & splenic vein
extrinsic compression of Portal V
What are the intrahepatic causes of portal hypertension?
What are the post hepatic causes of portal hypertension?
hepatic vein obstruction
What forms the Portal vein?
splenic vein and SMV
The right portal vein has what branches?
anterior and posterior
The left portal vein has what branches?
medial and lateral
What are techniques used for the Portal hypertension exam?
measure portal vein > 13 cm BAD
Doppler use low PRF and wll filters
Portal vein velocity & direction
evaluate portal vein and branches for thrombus
spleen enlarged? > 13 cm BAD
13 is magic number for what?
portal vein > 13 cm BAD
spleen > 13 cm BAD
How does the portal vein course?
ontra-segmentally in liver
What is the normal measurement for the main portal vein?
Portal vein has echogenic walls
Explain the flow in the main portal vein.
20 - 40 cm/s
normal flow direction in collaterals
What are technques used in a portal hypertension exam?
R/O extrinsic compression of portal vein by tumor or mass
evaluate IVC for obstruction
Porto-sysstemic collaterals present
use low Doppler PRF and low wall filters
intercostal windopw = good Doppler angle
appropriate Doppler frequency
What is the porto-systemic shunts Lt. Gastric vein?
AKA coronary vein
retro flow occurs in 80-90% of PH
may cause esophageal varices
What are the gatric varices located?
under lt lobe of liver
What is flow when the paraumbilical vein recanalizes?
What is flow of the splenorenal shunt?
splenic to lt renal vein
What is a TIPS?
Transjugular intrahepatic portosystemic shunts
stent placement in liver parenchyma between portal vein and hepatic vein
decompression of portal system
does not address cause of portal hyper tension (bandaide)