mesenteric vessel sonographic evaluation

indications for mesenteric vessel evaluation:

• post-prandial pain

• abdominal bruit

• recent weight loss

• “fear” of food/eating → sitophobia

• diarrhea

• nausea and vomiting

limitations of mesenteric vessel evaluation:

• open abdominal wounds, drains, sutures or staples

• pt not NPO

• overlying bowel gas → Simethicone may be administered to reduce gas

• obesity

• pt cooperation, inability to comply with holding breath

what vessels are evaluated during a mesenteric vessel exam?

• prox abdominal aorta

• celiac axis (CA)

• common hepatic A (CHA)

• splenic A (SA)

• SMA and IMA → prox, mid, distal portions and with doppler

exam techniques for celiac axis:

• 2.5-4 MHz curvilinear array - adult

• 4-8 MHz curvilinear array - peds

• pt must be NPO

• trans view: origin and bif → looks like “T”, bird, seagull signs

• long view: for doppler

doppler evaluation of the celiac axis:

• low resistance waveform

• flow pattern does NOT normally change after eating

• evaluated at the origin from the aorta, usually in long plane

normal PSV of the celiac axis:

<2.0 m/s

abnormal PSV of the celiac axis:

>2.0 m/s which indicates 70-99% stenosis

abnormal EDV of the celiac axis:

>0.55 m/s which indicates > 50% stenosis

occlusion of the celiac axis leads to:

• retrograde flow through the GDA to supply blood to the CHA to maintain blood supply to the liver and spleen

• common hepatic trunk may also demonstrate retrograde flow as it sends blood to maintain blood supply to the spleen

indications for a CHA scan:

• chronic liver disease

• liver transplant (pre- or post-)

• trauma

exam techniques for CHA:

• best visualized in trans plane, anterior approach to view the area around the porta hepatis

• travels along the superior border of the head of the pancreas

doppler evaluation of the CHA:

• low resistance

• tortuous

• flow velocities increase with cirrhosis, metastasis and lymphoma

• RI >0.78 implies portal HTN

exam techniques for splenic A:

• origin and prox portion best visualized in trans

• distal segment best evaluated through the splenic hilum from a left lateral window

• left wing of seagull

• travels posterior and superior to the pancreas body/tail

doppler evaluation of the SA:

• low resistance

• tortuous, may normally find areas of high PSV

exam techniques for SMA:

• 2.4-4 MHz curvilinear array → adult

• 4-8 MHz curvilinear array → peds

• pt must be NPO

doppler evaluation of the SMA:

• long → tubular structure coursing parallel to anterior aorta

• trans → circular structure anterior to the aorta and post to the pancreas body

• if no resistance changes occur, pre- vs post- prandial, then stenosis is present

• PSV can increase normally after eating

pre-prandial waveform of the SMA:

• high resistance flow with minimal flow in late diastole

• peaked waveform

post-prandial waveform of the SMA:

• low resistance flow with continuous flow in late diastole

• more rounded waveform

exam techniques for the IMA:

• gas artifact usually impedes visualization

• can be found by finding the renal arteries and sliding inferiorly

• can be found by findings the aortic bif and sliding superiorly

• if IMA is easily identified, SMA stenosis or occlusion should be suspected

doppler evaluation of the IMA:

high resistance with minimal late diastolic flow