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90 Cards in this Set
- Front
- Back
what is the most cephalad branch of the abdominal? what does it bifercate into? What is the doppler signal like in this artery?
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Celiac artery/axis.
-bifercates 1-3cm from origin into common hepatic and spenic arteries -doppler signal is low resistance with continuous flow through diastole. -the splenic(lt branch) and hepatic(rt branch) arteries also exibit a low resistance flow pattered caused by the low flow resistance within the microcirculation of the liver and spleen. |
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What happens if the celiac artery is occluded?
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Collateralization occurs through the pacreaticoduodenal arterial arcade(vessels surrounding pancreas and duodenum)
-These vessels enlarge, and feed into the gastroduodenal artery reserving flow for the common hepatic artery. -The hepatic artery, or splenic artery may appear normal even if the origin of the celiac axis is occluded. |
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Explain the course of the splenic artery, and its doppler signal?
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-tortuous
-runs along the posteriosuperior pancreatic margin, branching, and terminates in the hilum of the spleen. -Becaus it is tortuos, it often has turbulent flow. |
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Explain the course of the common hepatic artery until it enters the liver?
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-runs superior to pancreaic head
-gastroduodenal artery branches off -common hepatic artery becomes proper hepatic artery which follows the portal vein tothe porta hepatis (refer to image A on pg. 516 of zwibel) |
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Explain the course of the hepatic arteries in the liver?What is the doppler flow like?
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At the porta hepatis, it is divided into left and right hepatic arteries which branch off through the liver.
-Flow is low-resistant with large amount of continuous forward flow through diastole. |
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Explain some variations of the hepatic arteries?
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1)common hepatic artery arising from SMA(4%)
2)RHA arising from SMA(11%) 3)LHA arising from left gastric artery. |
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What is the second branch of the abdominal AO? What does it supply?
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SMA supplies:
-jejunum -ileum -cecum -ascending colon -Prox 2/3 of trx colon -portions of the duodenum and pancreatic head |
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Describe the anatomical location of the SMA?
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-surrounded by distinct layer of echogenic fat
-panc is ant. -AO is post. |
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describe the doppler waveform of the SMA?
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-turbulent near origin, but more uniform distally
-high resistant in fasting patient -low resistant within 30-90 minutes of eating with broad systolic peaks and continuous diastolic flow. |
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Where does the portal venous system transfer blood from?
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bowel and spleen to the liver.
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Explain the course of the portal vein?
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Begins at junction of splenic and superior messenteric veins.
-courses oblique and to the rt to terminate at the porta hepatis -branches into rt and lt branches with supply their corrisponding lobes |
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Explain the course of the splenic vein
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follows the course of the body and tail of the panc.
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explain the course of the superior messentericvein?
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extends posteriorly from the portal vein junction and parallels the SMA
-best seen in longitudinal |
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Where can the IMV empty?
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-Splenic vein(38%)
-Splenic/SMV junction(32%) -SMV(25%) |
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HOw can the coronary vein be helpful?
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It may shunt blood from the portal to systemic circulation in cases of portal hypertension
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What is the normal direction, and doppler of portal vein flow
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Hepatopedal(toward the liver)
-normal flow demonstrates a windstorm sound -w/ right heart failure, and fluid overload, RA pulsitations may be transfered through the liver to the portal vein which then exhibits pulsatile doppler flow. |
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What happens to the splenic and superior messenteric arteries with respiration?
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the are increased in calebre, and do not change with respiration.
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Where are the hepatic veins in comparisin to the liver?
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Rt-btw ant and post segments
Middle-btw rt and left segments Lt-btw med and lat The caudate lobe has separate drainage from the rest of the liver (directly into the IVC) |
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What are some variations of hepatic vein anatomy?
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-LHV is duplicated
-accessory hepatic veins -absent of one of the 3 main HV's |
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Name some dfferences btw hepatic and portal veins
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1)course-hepatic=longitudinal
portal=trx 2)Convergence-HV-converge @IVC PV-converge at porta hepatis 3) change is size: HV-larger toward diaphragm PV-larger towards hepatis 4)Margins: HV-naked PV-surrounded by echogenic sheath |
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What is the doppler signal like in the HV's?
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chaotic and pulsitile resulting from transmission of RA pulsitations
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Describe the normal doppler signal of the IVC?
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-near the heart, it can be somewhat pusitile
-distally, flow is phasic and similar to the pattern seen in extremity veins |
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What are some anomolies that can occur with the IVC?
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-duplication(0.2%)
-transposition(0.2-0.5%) |
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Describe the course of the right and left renal arteries? What is the doppler flow pattern of them?
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RIGHT:
-comes of the AO anteriolaterally -passes post. to IVC LEFT: -Comes of the AO laterally, and courses to the renal hilum Doppler: Low resistance |
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What are some anomolies associated with renal arteries?
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1/3 of knys are supplied by 2 ore more arteries arising from the AO:
-main renal artery can be duplicated -extra arteries may arise fro AO, and attach to the hilum, or poles -accessory arteries may also arise from the ipsilateral iliac artery, AO, or other arteries. -accessory renal arteries |
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Explain the courses of the LT and RT renal veins? What is the doppler signal?
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Left:
-receives adenal vein(from above),and left gonadal vein(from below). Passes ant. to AO and pos. to SMA RT: -Shorter than LT -directly to IVC from hilum. Doppler: shows same phasic flow variations as IVC |
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What are some variations of renal veins?
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LT:
-circumaortic w/ separate vein passing ant. and post. to the AO -retroaortic, w/ single branch passing posterior to the aorta rather than anterior. Rt: -Accessory renal veins draining directly into IVC |
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What can the greater saphenous vein and/or lesser saphenous vein be used for?
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conduit for coronary and peripheral arterial reconstruction
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Explain the difference btw accute, subaccute, and chronic trombus
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acute=<14 days
subacute=14days-6 months chronic->6 mo. |
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What features does blood flow in normal veins have?
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1)spontaneous
2)phasic 3)ceases w/ valsalva 4)augmented by distal compression 5)unidirectional(towards the heart) |
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What are the causes of renovascular hypertension?
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-Atherosclerosis(in the prox renal artery)(most common)
-Fibromuscular dysplasia(in mid-dis renal artery)(More frequent in women) -dissection&/or extension of aortic dissection |
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Why would renal doppler need to be done?
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-uncontrolled hypertension(esp. in younger patients)
-Decreasing renal fx -abdominal bruit |
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Segmental and interlobar renal arteries
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segmental-course through the hilum and are branches of the main renal artery
interlobar-arise from segmentals and lie btw renal medullary pyramids and penetrate parenchma |
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what is the order of renal artery branches
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main renal artery
segmental arteries interlobar interlobular |
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What is the purpose of renal doppler
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-identify cause of hypertension
-prevent renal failure -evaluate renal transplants for artery twists, kinks, stenosis, and rejection |
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Differentiate btw direct and indirect renal artery doppler
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direct-sample renal artery from prox to distal and sample segmental renal arteries bilaterally.
Indirect-only sample segmental and/or interlobar arteries. Quick exam time, but limited in detecting >70% stenosis |
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What transducer should be used for renal artery doppler?
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2.25-3mhz
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Explain the technique for doppler of the renal arteries?
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-Measure doppler of the ao 2-3cm disto=al to xiphoid process
-obtain doppler waveforms from multiple sites from the renal artery origin to the hilum bilaterally. Also, sample segmental arteries |
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RAR
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renal/aortic peak systolic velocity ratio
highest velocity in renal artery compared to velocity of the aorta 2-3 cm distal to xiphoid process |
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What is the criteria for >60 renal artery stenosis?
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RAR>3.5
peak systolic velocity >180cm/s post-stenotic turbulence low flow in distal renal artery |
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what are the characteristics of renal artery occlusion?
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no flow in a well visualized renal artery
low amplitude color and spectral doppler signal from the parynchma small kny size(<9cm) |
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Renal parynchal disease
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Normal renal artery=low resistance
Parenchymal disease=reduced velocity, high resistance in main renal artery, segmental and interlobar arteries. |
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what are the limitations of direct renal doppler?
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-high technical failure rate(12-25%)
-accessory renal arteries occur 20% of the time -poor doppler angles -long exam time -requires very skilled tech |
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WHAT is the normal wave form for indirect renal testing?
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-presence of an ESP
-AT <0.07sec -diastolic flow |
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What is the criteria for >60% stenosis with indirect testing?
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-increased AT(>0.07 sec)
-tardus-parvus waveform -loss of early systolic peak(ESP) -flattened systolic uplsope -AT<3m/s -Low RT(<0.75) -Reduced color flow unilaterally |
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What is RI used for in the kidneys? What are the normal and abnormal values?
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Used to evaluate for transplant rejection
NORMAL=<0.73+-0.04 ABNORMAL=>0.8+-0.7 |
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what are the limitations of indirect renal sampling?
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-stenosis in accessory renal arteries is hard to find(doppler in upper, mid, and lower poles of segmental arteries helps reduce false negative)
-not efficient at detecting stenosis <60% -positive study in segmental arteries cannot differentiate stenosis from occlusion in the main renal artery -parynchmal disease with main renal artery stenosis may cause segmental waveform to become more resistive leading to a false negative |
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What is the purpose of messenteric doppler?
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To diagnose messenteric ishemia
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mesenteric ishemia
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-uncommon due to colalteral
-usually due to athero occlusive disease -The celiac, SMA, and IMA have to all be involved for bowel ishemia to occur. -can be chronic or acute(due to embolization) |
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What are the symptoms of mesenteric ischemia?
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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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Pancreaticoduodenal artery
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-branch of the gastroduodenal artery
-allows communication btw the celiac axis, and the SMA |
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Explain the technique for mesenteric doppler?
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-patient supine
-3 mhz trans. -identify Ao and obtain doppler -obtain spectra from all measenteric vessels and measure peak systolic and diastollic velocities. |
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What is the mesenteric criteria for >70% stenosis?
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Celiac artery-PSV>200cm/s w/ post stenotic turbulence
SMA-PSV>275cm/s w/ post stenotic turbulence |
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what are some other applications for mesenteric doppler?
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celiac compression syndroem
SMA compresion syndrome |
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what is normal portal vein flow?
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-low velocity(20-40 cm/s)
-no filling defects -hapatopedal direction -no varices -normal flow direction in potential collaterals |
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What is portal hypertension? What can it be caused by?
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-elevated preassure in the portal venous system due to increased impedence of flow through the liver. Due to:
Prehepatic obstrucion intrahepatic Post hepatic |
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Explain prehepatic, intrahepatic, and post hepatic obstruction?
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prehepatic:
Thrombosis of portal vein or splenic vein extrinsic compression of portal v Intrahepatic: -cirrhosis(most common) -hepatic fibrosis -lymphoma Post hepatic: -IVC obstruction -Hepatic vein obstruction |
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What can portal hypertension lead to?
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-Ascites
-splenomegaly -GI-esophageal bleeding -jaundice -signs of hepatic failure |
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what is the technique for portal doppler?
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-Measure portal vein diameter
-Measure velocity and direction -Measure vein and branches for patency, and flow direction -measure spleen -R/O extrinsic compression by mass -evaluate IVC for obstruction |
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what are some common porto-systemic shunts?
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-Lt gastric vein(coronary vein):
regrograde in 80-90% of PHT increased pressure in this vessel may cause esophageal varices -Gastric varices: near stomach under left lobe of liver near spleen |
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other porto-systemic shunts
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-recanalized paraumbilical vein with hepatofugal flow
-spleno-renal shunt(spleniv vein to left of renal vein) |
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TIPS shunts
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Transjugular intrahepatic portosystemic shunts:
-stent in the liver btw the portal vein and hepatic vein -purpose is decompression of the portal venous system -doesn't address cause of portal hypertension |
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Budd-chiari syndrome
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-Stenosis or obstruction of the hepatic veins. May be caused by:
Hepatomegaly splenomegaly ascites |
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what does normal hepatic flow look like?
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-respiratory variation
-pulsitile |
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When are patients chosen for a liver transplant?
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When their life expectancy without transplantation is lower than there life expectancy with a transplant
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What are the most common diseases requiring liver transplant?
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1) hep c
2)alcoholic liver disease 3)cryptogenic cirrhosis |
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Why were hep b patients considered poor transplant candidates? has that changed?
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because of the high recurrence rate of infection resulting in rapid progression to cirrhosis
-this has changed due to the use of hyperimmunoglobulins and nucleoside analogs |
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What is the standard for liver transplants of patients with HCC?
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no lesion >5cm or no more than 3 lesions >3cm
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What will be seen on U/S with a normal liver transplant patien?
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normal, or slighly heterogenous liver echotexture
-may bee intraperitoneal fluid, or small serosas, or hamatomas(resolve by 10dys) -normal appearance of the billiary tree. biliary anastamosis should be inspected for changes in caliber -normal to have pneumobilia -assess vascular patency(of hepatic artery, portal veins, hepatic veins, IVC, esp. anastamosis areas) |
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Billiary stricture
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may be difficult to diagnose early because due to poor nerve supply, patients do not typically experience colic.
Symptoms: -assymptomatic -painless obstructive jaundice -Abnormal LFT's Classified into anastamotic, and intrahepatic |
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Anastomotic strictures
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-most common cause of biliary obstruction after transplantation
-Scarring results in retraction of duct wall , and narrowing of luminal diameter |
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Intrahepatic strictures
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-proximal to anastamosis
-either unifocal, or multiocal -the hepatic artery is the only lood supply to the CBD and intrahepatic bile ducts, so most intrahepatic duct strictures are due to ischemia caused by hepatic artery occlusion/ |
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what may echogenic intraluminal material within the billiary tree represent.
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ominous sign
-sometimes caused by severe billiary ischmia resulting in sloughing billiary epithelium. |
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recurrent sclerosis cholangitits
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-happens 20% for those transplanting for sclerosis cholagitis
-diffuse mural thickening of intrahepatic and/or CBD -Diverticulum-like outpouchings of the CBD -occasionally, patients with ascending cholagitis may present with an identical ultrasound appearance |
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biliary sludge
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10-29% of liver transplant pts.
-once sludge is present, it has the potential to produce biliary ostruction and lif-thretening ascending cholagitis -should evaluate the CBD to exclude leision or leaks -should evaluate hepatic artery to ensure optimal arterial supply |
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Dysfunction of the schincter of oddi
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hepatic dysfuction due to diffuse dialation of bile ducts in the absense of biliary stenosis
-devascularization or denervation of the ampulla of vater resulting in dysfunction of the sphincter of oddi |
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Arterial complications with liver transplant
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results in transplanted hepatic artery becoming the only arterial blood supply to intrahepatic biliary epithelium. Early detection before biliary necrosis is paramount in managing liver trx patiets.
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Hepatic artery thrombosis
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can present clinically with delayed biliary leak, fulminant hepatic failure, or intermittent episodes of sepsis
-Doppler shows absense of flow in the hepatic artery, or tardus parvus arterial waveform - |
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what are the risk factors for hepatic artery thrombosis with liver transplatation
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-complex vascular reconstruction
-rejection -severestenosis -increased cold ischemic to of donor liver -ABO blood type incompatability |
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False positive for hepatic artery thrombosis
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severe hepatic edema
systemic hypotension high grade hepatic arterty stenosis if unsure, confirm on CT because it is very NB |
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Hepatic artery stenosis
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-most common at anastamosis
-clinically:biliary ischemia, or abnormal LFT's -doppler provides either diect evidence(identifying and localizing narrowed segment), or indirect evidence(tardus parvus waveform anywhere in the hepatic artery) of hepatic artery stenosis |
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Hepatic artery pseudoaneurysm
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shows as a cystic periportal structure with intense swirling flow on color doppler and a disorganized spectral waveform
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celiac artery stenosis
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-may be due to atheromatous disease or impingement of the celiac axis by the medial arcuate ligament
-patients often are asymptomatic prior to trasplantation, but post transplant, they become symptomatic, presenting with evidence of biliary ischemia and abnormalities in serum LFT's |
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Portal vein stenosis or thrombosis
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clinical=hepatic failure / signs of portal hypertension
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Stenosis of IVC
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May occur at either the suprahepatic or infraheptaic anastamosis
-IVC shows obvious narrowing at the site of anastamosis, associated with focal region of aliasing on color dopppler -hepatic veins may show reversal of flow |
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Extrahepatic fluid collections
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common in the areas of bascular arnastamosis
-bare area of the liver |
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Adrenal hemorrhage
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-right sided adrenal hemorrhage from venous engorgement or coagulaopathy caused by patient's preexisting liver disease
|
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inctrahepatic fluid collections
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-along the falciform ligament and ligamentum venosum
-bilomas may present as hypoechoic and round or complex -intraparenchymal hematoas may occur |
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ABSCESS VS INFARCT
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Infarcts-hypoechoic areas reflecting liquifaction and necrosis. Doppler evidence of hepatic arterial compromise
Abscess-a complex cystic structure with thick, irregular walls |
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Recurrent HCC
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-most common site=lungs
-2nd most common=within allograft |