Lecture 19: Abdomen Vascular Duplex Imaging Flashcards
what is the seagull sign on ultrasound in regards to the abdominal vessels?
in TRV, sonographer can see the splenic artery & CHA
what is the celiac trunk composed of?
left gastric artery, CHA, splenic artery
what are you evaluating when scanning the aorta or the iliacs?
stenosis/occlusion
follow up on bypass grafts, aneurysms
what are you evaluating when scanning the renal arteries?
stenosis of 60%
renovascular HTN
what are you evaluating when scanning the kidneys?
transplants
nephrosclerotic disease
what are you evaluating when scanning the SMA & IMA?
stenosis of 70% related to mesenteric angina/ischemia
what are you evaluating when scanning the liver?
portal HTN
pre & post liver transplants
3 patient positions for abdominal imaging techniques?
- supine
- RLD
- LLD
transducer used for abdominal scanning?
curvilinear 2.5-5.0 MHz
what is true renal vascular hypertension?
when the renal artery is the cause for hypertension
when is duplex imaging ordered for renal arteries?
for patients with controlled/uncontrolled hypertension
what is the most common reason for reno-vascular hypertension?
renal artery stenosis
3 indications for a renal artery exam?
- uncontrolled hypertension
- decreased renal function
- abdominal bruit
what are 2 renal doppler exam methods?
- direct method
- indirect method
what is the pathway of blood from the renal artery to the renal vein?
renal artery –> segmental a –> interlobar a –> arcuate –> interlobular a –> interlobular v –> arcuate v –> interlobar v –> segmental v –> renal vein
where can you find the segmental arteries of the kidneys?
hilum
where can you find the interlobar arteries of the kidneys?
pyramids
where can you find the arcuate arteries of the kidneys?
cortico-medullary junction
where do accessory renal arteries arise from? (3)
- may rise from AO above or below the main RA
- accessory RT RA may pass anterior to IVC instead of posterior
- may rise from SMA or iliac arteries
patient prep for renal artery exam
- fasting
- bisacodyl (10mg) for anti-gas (optional)
- AM exam
- hydrated
how to complete a renal artery direct method scan?
- scan kidneys SAG & TRV w/ measurements
- scan AO LONG (DIST to SMA & with waveform)
- scan main RA PROX, MID, DIST, waveform with PSV & EDV
what is the normal PSV for renal artery
100 +- 20 cm/s
what is the normal EDV for renal artery?
30 +- 5 cm/s
what is the flow resistance for the renal artery?
low resistance: high systole & high diastole
what is the resistive index for the renal arteries?
< 0.75
what is an abnormal PSV for the renal arteries?
> 180 cm/s
what is diagnostic criteria for renal artery stenosis?
> 60% diameter reduction
stenotic profile of the renal arteries?
- spectral broadening
- post-stenotic turbulence
- tardus parvus waveform
- increased resistance to flow
what does RAR stand for?
renal to aorta ratio
what is the RAR equation?
RAR = RA PSV/AO PSV
what is a normal RAR?
< 0.35
what does EDR stand for?
end diastolic ratio
what is the equation for EDR?
EDR = EDV/PSV
what is a normal EDR?
> = 0.33
what is another name for pourcelot’s ratio?
resistivity index
what is pourcelot’s ratio used for?
to determine if resistance is increasing
equation for the resistivity index?
RI = PSV - EDV/PSV
normal range for the RI?
< 0.7
a pitfall in imaging the renal arteries includes a high technical failure rate. T/F?
true
it’s difficult to image renal arteries with early kidney failure. T/F?
false – late kidney failure
poor doppler angles in the renal artery can lead to ___ ___
different resistivity index
how to complete an indirect method of scanning the renal arteries?
evaluating the segmental & interlobar artery waveforms to indirectly assess the main renal artery
4 patient positions for the indirect method for scanning the renal arteries?
- flank approach
- supine
- slightly oblique
- RLD or LLD
a normal waveform for the indirect method for scanning the renal arteries has an ___ systolic peak
early (ESP)
what is the AT/RT for the indirect method of scanning the renal artery?
< 0.7 sec
what is the purpose for assessing the mesenteric arteries?
to assess for mesenteric ischemia/angina
what is mesenteric ischemia caused by?
stenosis or occlusion of 2 of 3 of the mesenteric arteries
S&S of mesenteric angina?
dull, achey, crampy abdominal pain 15-30 minutes after a meal
1st part of scanning the mesenteric arteries?
- patient is NPO
- get PSV & EDV for mesenteric arteries & aorta
2nd part of scanning the mesenteric arteries?
- give patient high caloric meal
- document how much is ingested
- document how long between ingestion & onset of symptoms
- study repeated after 20-30 minutes (sooner if patient experiences symptoms)
when do the SMA & IMA high resistance flow?
pre-prandially
when do the SMA & IMA have low resistance flow?
post-prandially
when is stenosis diagnosed in the mesenteric arteries?
> 70% DR
celiac axis PSV with stenosis?
> 200 cm/sec
SMA PSV with stenosis?
> 275 cm/sec