Abdominal Vasculature (pre)

what type of resistance waveform does this show (arterial)?

low resistance

• high diastolic flow

• renal artery

what type of resistance waveform does this show (arterial)?

high resistance

• low diastolic flow

• distal AO

what type of resistance waveform does this show (venous)?

pulsatile

• hepatic veins

what type of resistance waveform does this show (venous)?

continuous

• renal veins

how do you calculate resistive index?

RI = (peak sys - end diast) / peak systole

what is considered high RI?

1.0

what vessels are evaluated in abdominal vasculature scans?

• mesenteric vasculature

• aortoiliac vessels

• renal arteres

• renal veins

• portal vein

• hepatic artery

• IVC

• hepatic veins

what are the symptoms of abdominal aortic aneurysm (AAA)?

abdominal pain

back pain

leg pain

pulsatile abdominal mass

what diameter measurement of abd aorta indicates AAA? risk of rupture?

>3cms

rupture risk : >5cms

how do you measure aorta diameter?

outer to outer

which layer of the aortic wall does blood enter in an aortic dissection?

media layer

where does the SMA arise from?

anterior surface of aorta

what does the SMA supply blood to?

large and small bowel

how do SMA doppler signals vary pre vs post prandial (before vs post meal)

pre : high resistance

post : low resistance

• sends more blood to bowel

• EDV should double

what are symptoms of small bowel/mesenteric ischemia?

post prandial pain

• SMA evaluated

weight loss

change in eating habits

which vessels should be evaluated in the presence of atherosclerotic disease?

• origins of celiac axis

• SMA

• IMA

they will be evaluated for stenosis (disease significant if 2/3 vessels are diseased)

SMA/aorta ratio of - is suggestive of >70% stenosis

3.5

what is the criteria for atherosclerotic disease of SMA? Celiac?

• syst velocity

• EDV

SMA

• syst : >275cm/s

• edv : >45cm/s

celiac

• syst : >200 cm/s

• edv : >45 cm/s

what is median arcuate ligament syndrome (MAL) and which vessel does it affect?

MAL is a fibrous band that extends from the diaphragmatic crura and passes superior to the celiac artery

• can cause celiac artery compression during expiration which could mimic stenosis

what are the normal ranges of velocties for SMA? Celiac? IMA?

celiac : 98-105 cm/s

SMA : 97-142cm/s

IMA : 93-189 cm/s

patients with renal artery stenosis usually present with

uncontrollable hypertension

renal artery protocol

• prox ao (PSV)

• renal arteries from origin of ao to hilum of kidney in trv (2D, color)

• MRA prox, mid and distal (PSV &EDV)

• sag kidney (PSV & EDV)

• segmental arteries in UP and LP of each kidney

• accessory renal arteries

• calculate RAR ratio (renal to aortic ratio)

  • RAR = renal artery PSV

what is a normal arterial waveform for the kidney?

low resistance

what is a normal arterial waveform for the aorta?

high resistance

what is a normal & abnormal aortic PSV value?

normal : <3.5

abnormal : >3.5

RAS if PSV of main renal artery is

180-200cm/s

what are looking for when evaluating renal veins?

renal vein thrombosis (partial or complete)

where does the IVC lie in relation to the aorta?

IVC lies to the right of the aorta

what kind of doppler signal is seen in the IVC?

continous with respiratory variation

why do we evaluate the IVC?

• pts with history of DVT

• history of cancer (esp wilm’s tumor or renal cell CA)

• pts with IVC filter

• post op liver transplant

how does CHF affect the IVC?

increases IVC diameter

IVC exhibits pulsatile doppler waveform

what are the causes of IVC thrombosis?

• extension of thrombus from tributary vein (renal/iliac)

• compression from external mass

  • abd/pelvic mass

  • enalrged lymph nodes

• tumor invasion

  • renal cell carcinoma

what is the purpose of an IVC filter?

catch cloths from lower leg(s) to prevent pulmonary embolism

• placed in infrarenal location

what is the purpose of the portal venous system?

transport blood from bowel and spleen into the liver

where is the MPV formed?

at junction of splenic vein and SMV

what percentage of blood in the liver is received by the portal vein?

75% (50% oxygenated)

what does doppler look like in the portal vein?

continous hepatopetal flow with slight respiratory variation

• flow is pulsatile/biphasic with cardiac issues

what are the causes of portal vein thrombosis?

• cirrhosis

  • alcohol (most common)

  • biliary

• tumor invasion

  • hepatocellular carcinoma (HCC)

  • pancreas

  • metastatic

• hypercoagulable states

• intraperitoneal inflammation

  • pancreatitis

  • appendicitis

what does acute portal vein thrombosis look like on US?

• enlarged vein with echoes

• lack of flow by CDV/CDE

what does chronic portal vein thrombosis look like on US?

• small echogenic vein (difficult to detect)

• enlarged hepatic artery

what is cavernous transformation of the portal vein?

multiple small, tortuous collaterals around MPV in porta hepatis

what causes cavernous transformation of the portal vein?

• complete portal vein thrombosis

• extrahepatic portal vein thrombosis

what is portal hypertension?

increased pressure in portal venous system resulting in impdence of blood flow through the liver

what casues portal hypertension?

• alcoholic cirrhosis

• pancreatitis

• hepatitis

• sickle cell anemia

• coagulative disorders

• hepative vein thrombosis

what are clinical signs of portal hypertension?

ascites

splenomegaly

GI bleeding

hepatic encephalopathy

underlying liver disease

what ultrasound criteria indicates portal hypertension?

• hepatofugal flow

• portal vein diameter >13mm

• decreased splenic vein flow

• recanalized umbilical vein (originates from left portal vein)

what is the purpose of hepatic veins?

return blood back into systemic circulation

normal hepatic vein waveform

how does CHF affect hepatic veins?

causes hepatic veins to dilate

what is budd chiari syndrome?

narrowing or blockage of HV → hepatic vein thrombosis

what causes budd chiari?

hypercoagulable states

compression by tumors or masses

what are the sonographic signs of budd chiari syndrome?

• non visualization of one or more hepatic veins

• continous/flattened doppler signal

• IVC obstructed

• enlarged caudate lobe (volume overload)

• PV flow sluggish or reversed (due to outflow obstruction)

where is the hepatic artery located? where does it go?

it is the right branch off the celiac axis

follows portal vein into liver via porta hepatis → divides into right and left branch

where is the hepatic artery in relation to the main PV?

hepatic artery is superior to the main PV

normal hepatic artery views

what is SVC syndrome?

collection of clinical signs resulting from partial/complete obstruction of blood flow through SVC

• obstruction most commonly from thrombus formation or tumor infiltration