CAHE ABDOMEN II- ABDOMINAL VASCULAR PATHOLOGY

Terms in this set (98)

origin of the aorta
at the left ventricle
Aortic hiatus of diaphragm
where the aorta becomes the abdominal aorta
location/position of aorta
-retroperitoneal
-anterior to spine & left of midline
what is the best window to perform color flow of the renal vessels?
-coronal image
-transducer = slightly angled toward midline to see IVC anterior to aorta & renal arteries
what is the spectral waveform of the aorta dependent on?
where the waveform is obtained
proximal aorta waveform
lower-resistance waveform due to its low-resistance terminal bed, the liver, spleen and kidneys
distal aorta waveform & common iliac arteries
high-resistance waveform (triphasic) with reversal of flow in early diastole b/c they supply normally high-resistance lower extremities
aorta velocities
typically 40- 100 cm/speak systolic velocity (PSV)
atherosclerotic disease
occurs when arterial wall becomes thick & stiff from plaque buildup in arterial wall
what is atherosclerosis a specific form of?
arteriosclerosis
what does atherosclerotic disease lead to?
restriction of blood flow to organs and tissues in body resulting in high BP
normal healthy arteries
flexible and elastic
plaque
buildup of fats, cholesterol, calcium and other substances within arterial wall that can restrict blood flow
embolus
a small piece of a blood clot that breaks off from thrombus & travels through blood vessels until it reaches vessel too small to pass through
ultrasound features of atherosclerosis
-luminal irregularities
-aortic wall calcifications
-tortuosity (twisting)
luminal irregularities in sonogram of aorta
plaques
aortic wall calcification appearance
sharp, HYPERechoic, can display shadowing
causes of atherosclerosis
1. elevated BP
2. high cholesterol
3. high triglycerides
4. smoking
5. diabetes
6. inflammation from systemic diseases
7. family history of heart disease & lack of exercise
abdominal aortic aneurysm (AAA)
localized dilation of abdominal aorta
AAA diameter
usually greater than 3 cm

OR

more than 1.5 times diameter of proximal unaffected part of aorta
what might cause an aneurysm?
the force of blood pushing against walls of an artery COMBINED with damage/injury to artery's walls
location of aneurysm formation
majority of AAAs occur BELOW the kidneys (infrarenal)
AAA clinical findings
-evidence of pulsatile abdominal mass
-abdominal bruit
-back pain
-abdominal pain
-lower extremity pain
AAA complications
-distal embolism
-infection
-dissection
-rupture
what other aneurysm are commonly associated with aortic aneurysms?
-iliac & popliteal artery aneurysm
most common cause of aneurysm in united states
atherosclerosis
what type of aneurysms are most AAAs?
true aneurysms
AAA risk factors
-atherosclerosis (most common cause)
-tobacco use
-hypertension
-trauma
-COPD & positive family history for AAA
-marfan syndrome
-inflammation of media & adventitia (rheumatic fever etc.)
what should be measured if aneurysm is present?
measure length of dilation & note position of renal arteries in relation to aneurysm
what planes are used to measure aneurysm?
-transverse ( depth & AP)
-longitudinal (length & AP)
what should sonographer determine if there is an aneurysm?
-whether renal arteries & iliac arteries are involved in aneurysm
-clot or thrombus formation carefully assessed
what is important to distinguish between in the aorta?
between aortic ectasia & an aneurysm
when does aortic ectasia occur
when aorta increases both in transverse diameter & in vertical length
aortic ectasia
implies diffuse dilation of vessel
techniques to measure aneurysm
-measure max diameter of aneurysm outer to outer
-transducer = perpendicular to aorta
what is the correct plane to measure aortic aneurysm?
-sagittal plane, perpendicular to long axis of vessel @ widest point

-length x transverse x AP
3 classification of aneurysms
1. true aneurysm
2. false aneurysm
3. dissecting aneurysm
true aneurysm
involve all 3 layers of aorta & most common cause of artheriosclerotic disease
2 types of true aneurysms
1. fusiform
2. saccular
fusiform aneurysm (spindle shape dilation)
bulges out on BOTH sides of aorta & affects entire circumference of artery
most common presentation of AAA
is fusiform dilatation
saccular aneurysm
localized spherical out-pouching of vessel wall
false aneurysm (pseudoaneurysm)
a tear in vascular wall of aorta leading to hematoma which is walled off by surrounding tissue

*not lined by ALL 3 layers & very rare in aorta*
what does a pseudoaneurysm result from?
some type of injury to artery- interventional procedures, surgery or trauma
common site for pseudoaneurysm development
within groin @ level of femoral artery following heart catheterization
clinical findings of pseudoaneurysm
pulsatile mass in area of puncture location
sonographic findings of pseudoaneurysm
perivascular hematoma that contains swirling blood & has neck connecting it to vessel
Color Doppler with pseudoaneurysm
demonstrates turbulent flow within the mass

"ying-yang" sign
spectral waveform with pseudoaneurysm
-obtained from the neck of pseudoaneurysm

-displays a high velocity, bidirectional or "to-and-fro" signal
correction of pseudoaneurysm techniques
1. surgical repair
2. prolonged compression repair
3. ultrasound guided thrombin injection repair
thrombi- blood clots
-commonly seen in very large aneurysms
-eccentric in location
-causes narrowing of vessel lumen
appearance of acute vs. chronic clots
-acute clots (fresh clots) = hard to see, less echogenic

-chronic clots = more echogenic
rupture of aortic aneurysm classic symptoms
- sever abdominal pain
-hypotension
-DECREASED heamtocrit
-expanding abdominal mass
mortality rate of an aortic aneurysm rupture
50%
sonographic appearance for aortic rupture
an abdominal aneurysm with an adjacent hematoma
when should intervention be considered for an AAA?
once AAA reaches size of 5.5 cm
dissecting aneurysm (aortic dissection)
a separation of the intima from aorta wall creating a flap causing blood flow on both sides
how many lumens are there in an aortic dissection?
2- a true one & false one divided by the "intimal flap"
true lumen of aortic dissection appearance
-round or oval
-strong systolic doppler velocity
-thrombus = rare
false lumen of aortic dissection appearance
-shaped like a crescent
-sluggish or no doppler velocity
-thrombus = common
where does a dissection most often occur?
in the thoracic aorta
what might an aortic dissection be associated with?
stenosis
what happens to the outer diameter in a aortic dissection?
diameter of aorta is increased & false lumen opens in the media layer
causes of aortic dissection
-most idiopathic
-hypertension
-connective tissue disorders (marfan's)
-coarctation of the aorta
-takayasu arteritis
-trauma
coarctation
congenital narrowing of a short section of the aorta
takayasu arteritis
-an idiopathic, progressive obliterative arteritis involving chronic inflammation of aortic arch
-fibrosis & marked luminal narrowing of aorta/branches
aortic dissection clinical findings
-intense chest pain
-hypertension
-abdominal pain
-lower back pain
what needs to be identified sonographically for an aortic dissection?
2 channels of flow using 2D or color flow doppler
what may be noted sonographically for an aortic dissection?
a linear intimal flap within aortic lumen & might be visualized swaying in current of passing blood
what needs to be determined sonographically for an aortic dissection?
-extent of dissection in either direction
-the velocity of flow & existence of turbulent flow
mycotic aneurysms
aneurysm caused by infection
berry aneurysm
small saccular aneurysm commonly located in cerebrum (brain vessels)
surgical repair of AAA
repaired surgically with resection or grafts
endovascular repair of AAA
with percutaneous insertion of aortic stent grafts where residual aneurysm sac remains- surrounding aortic stent graft
aortic endograft appearance
echogenic walls
median arcuate ligament syndrome
a vascular compromise due to compression "pinching" of celiac trunk by the low attachment of median arcuate ligament of diaphragm resulting in vascular narrowing
location of vessel in median arcuate ligament syndrome
-the median arcuate ligament of diaphragm lies anterior to abdominal aorta
-just proximal to origin of the celiac truck
how can the pinching be relieved for median arcuate ligament syndrome
patient assumes upright position or takes a deep breath
ruling out median arcuate ligament syndrome
obtain Doppler readings during inspiration/expiration & in supine and upright positions
SMA syndrome
-characterized by compression of 3rd (transverse) portion of duodenum against aorta by the SMA

-results in complete or partial duodenal obstruction
what angle does the SMA form with abdominal aorta?
approx 45 degrees
sonographic findings of SMA syndrome
-measure angle b/w vessels to see if reduced
-use color doppler of SMA
formation of IVC
union of common iliac veins near level of umbilicus @ level of 5th lumbar vertebra
IVC measurement
less than 2.5 cm
doppler waveform of distal IVC
-demonstrates pulsatility from reflected right atrial pressure

-proximal IVC = phasicity similarly seen in lower extremity veins
doppler waveform of proximal IVC
demonstrates phasicity similar to lower extremity veins
what does color-flow imaging of the IVC reveal?
directional variations associated with respirophasicity in the distal segment of vein
dilation of IVC
caused by obstruction leading to enlargement of IVC
most common cause of dilation of IVC
right-sided heart failure
IVC thrombosis
-most common vascular problem affecting IVC
most common findings of IVC thrombosis
-IVC enlargement
-absence of flow
-thrombus noted with IVC lumen
acute thrombus sonographic appearance
-completely anechoic or HYPOechoic
-free-floating tail may be seen
sonographic appearance of IVC thrombus over time
becomes more echogenic & may calcify producing acoustic shadowing
what does the doppler spectral waveforms demonstrate for IVC thrombus
-continuous, nonphasic flow patterns with partial obstruction of the caval lumen
tumor thrombus
may be associated with renal cell carcinoma & carcinomas of adrenal gland
IVC filter
used for pulmonary embolus to trap emboli that could travel upstream
preferred location of IVC filter
in the iliac bifurcation below renal veins
nutcracker syndrome
compression of LRV between the aorta and SMA
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