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56 Cards in this Set
- Front
- Back
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Abdominal vasculature exams
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renal artery-vein/ mesenteric arteries/ portal venous system/ hepatic vasculature/ abdominal aorta for aneurysms-stenosis
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What can fixed hypertension be caused by?
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chronic renal disease/ renal artery disease/ true renovascular hypertension
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Renovascular hypertension etiology
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atherosclerosis (most common)/ fibromuscular dysplasia (FMD)/ dissection and/or extension of aortic dissection
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Indications for renal doppler exam
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uncontrolled hypertension, especially in younger pts/ decreasing renal function/ abdominal bruit
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Main renal arteries arise from ____ just distal to the ____.
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aorta/ sma
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Right renal artery courses ____ to the IVC.
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posterior
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Right renal artery is ____ than the left renal artery.
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longer
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Left renal vein lies ____ to the SMA and ____ to the aorta.
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posterior/ anterior
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Right renal vein is ____ than left.
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shorter
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Normal renal veins should demonstrate ____ flow and maybe pulsatile flow transmitted from ____.
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phasic/ right atrium
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______ renal arteries course through the hilum and are branches of the _____.
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Segmental/ main renal artery
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_____ arteries arise from segmentals and lie between the ______ and penetrate the _____.
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Interlobar/ renal medullary pyraminds/ renal parenchyma
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_____ arteries branch from the interlobars and turn at the cortico-medullary junction to course ____ to the cortex surface.
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arcuate/ parallel
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____ arteries extend into cortex.
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Interlobar (cortical branches)
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_____ renal arteries are common and may arise from ____, above or below the main renal arteries. On the right side, they may pass ____ to IVC. They may also arise from the ____ or _____.
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Accessory (polar arteries)/ aorta/ anterior/ SMA, iliac arteries
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Purpose of renal doppler exam
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identify vascular etiology of hypertension/ prevent renal failure due to permanent parenchymal changes/ evaluate renal transplants for artery twists, kinks, stenosis, rejection, and renal vein thrombosis
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Evaluates the entire renal artery, bilaterally, from the aorta to the renal parenchyma. Spectral waveforms obtained from the prox, mid, distal renal arteries and from segmental renal arteries. Limited by obesity, bowel gas, previous abdominal surgery, and prolonged exam time.
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Direct color duplex renal artery exam
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Examine only the segmental and/or interlobar arteries. Wavefrom characteristics within kidney are analyzed for abnormality associated with main renal artery stenosis or occlusion. Short exam time and high technical success rate, but limited to detecting severe stenoses.
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Indirect color duplex renal artery exam
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How to identify renal artery stenosis
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Look for regions of velocity increase and post stenotic turbulence, carefully map these regions with spectral doppler/ record the peak systolic velocity from the waveform demonstrating max velocity/ calcualte the renal-aortic peak systolic velocity ration (RAR) from the highest velocity obtained in the renal artery with the velocity from the aorta
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Normal Renal Artery characteristics
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High flow velocity (PSV 100 +/- 20 cm/s)/ low resistance (RI < .75)/ high diastolic flow (EDV 30 +/- 5 cm/s)
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Criteria for >60% Renal Artery Stenosis
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Renal-aortic ratio > 3.5
Peak systolic velocity (PSV) > 180 cm/s Post-stenotic turbulence Low flow in distal renal artery |
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Renal Artery occlusion
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No flow detectable in a well visualized renal artery/ low amplitude color and spectral doppler signal from the parenchyma/ small kidney size (<9 cm)
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Renal parenchymal disease
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blood flow in the renal artery of a normal kidney is of low resistance/ in the presence of renal parenchymal disease velocity is reduced and resistance is high in the main renal artery and in the segmental and interlobar arteries
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Renal doppler physical limitations
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excessive depth of renal arteries/ motion of respiration/ intra-abdominal gas/ obesity/ previous abdominal surgery
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Technical limitations of Direct renal doppler
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high technical failure rate/ accessory renal arteries occur in some pts and are difficult, if not impossible/ to find/ poor doppler angles/ long exam time/ requires high skill
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Normal Indirect waveforms parameters
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presence of an ESP (early systolic)/ Acceleration Time less than .07 sec/ presence of diastolic flow
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Indirect criteria for > 60% stenosis
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increased acceleration time/ tardus-parvus waveform/ loss of early systolic peak/ flattened systolic upslope/ acceleration <3 m/s/ abnormality lower ipsilateral RI/ reduced color flow in kidney unilaterally
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Purpose of mesenteric doppler
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diagnose mesenteric ischemia
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very uncommon due to extensive collateral pathways/ usually caused by ather occlusive disease at vessel origins/ celiac, sma, and ima must all be involved for bowel ischemia to occur/ chronic or acute, usually caused by embolization
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mesenteric ischemia
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Mesenteric Ischemia symptoms
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abdominal cramps and pain after eating/ diarrhea, change in bowel habits/ weight loss/ fear of food syndrome
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Common hepatic artery branches
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hepatic artery, gastroduodenal artery, pancreaticoduodenal artery
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celiac axis branches
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lt. gastric artery, splenic artery, common hepatic artery
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supplies blood to the distal duodenum, small intestine, and colon
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sma
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arises from the aorta distal to renal arteries, supplies blood to the transverse descending, and sigmoid colong
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ima
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Celiac, hepatic, splenic arteries flow patterns
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low resistance
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sma & ima flow patterns
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high resistance when fasting, low resistance post prandium
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Criteria for >70% stenosis in mesenteric exam
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Celiac artery: PSV > 200 cm/s with post stenotic turbulence
SMA: PSV > 275 cm/s with post stenotic turbulence |
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drains nutrient rich blood from the bowel and spleen into liver/ has capillary bed on each end of system, one it gut and other in parenchyma of liver
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portal venous system
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portal vein is formed by:
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smv and splenic vein
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portal vein course ____ in liver
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intra-segmentally
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Portal vein normal flow
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low velocity (20-40 cm/s), continuous flow/ no filling defects with color doppler/ hepatopetal direction/ no varices/ normal flow direction in potential collaterals
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elevated pressure in the portal venous system due to increased impedence of flow through the liver
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portal hypertension
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Causes of portal hypertension
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prehepatic obstruction: thrombosis of portal or splenic vein
intrahepatic: cirrhosis (most common cause), hepatic fibrosis, lymphoma post hepatic: ivc obstruction, hepatic vein obstruction |
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Most common cause of portal hypertension
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cirrhosis
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Portal hypertension can lead to:
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ascites/ splenomegaly/ GI-esophageal bleeding/ jaundince/ signs of hepatic failure
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Porto-systemic shunts
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lt. gastric vein (coronary vein), gastric varices, recanalized paraumblical vein with hepatofugal flow, spleno-renal shunt
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Gastic varices often occur:
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near stomach (epigastrum), under lt lobe of liver, near the spleen
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Spleno-renal vein
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splenic vein to left renal vein
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Transjugular Intrahepatic Portosystemic Shunt (TIPS)
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stent placement in the liver parenchuma between the portal vein and hepatic vein/ purpose is decompression of the portal venous system/ does not address cause of portal hypertension
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drains right hepatic lobe
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right hepatic vein
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lies between left and right hepatic lobes
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middle hepatic vein
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courses between medial and lateral segments of left lobe
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left hepatic vein
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hepatic veins enlarge as they approach....
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the diaphragm
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How are hepatic veins best imaged?
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Trv, subcostally
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stenosis or obstruction of hepatic veins, may be caused by hepatomegaly, splenomegaly, ascites
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Budd-Chiari syndrome
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Normal hepatic veins flow
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respiratory variation, pulsatility
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