Liver Doppler: Mastering the Maze
Marsha M. Neumyer, BS, RVT, FSDMS, FSVU, FAIUM
Liver Doppler: Mastering the Maze
Marsha M. Neumyer, BS, RVT, FSDMS, FSVU, FAIUM International Director Vascular Diagnostic Educational Services Vascular Resource Associates Harrisburg, PA
Objectives
Define the vascular
anatomy of the hepato-portal hepatosystem
Discuss the most common
vascular hepato-portal hepatocomplications
Describe the alterations in
blood flow patterns that occur with hepato-portal dysfunction hepato-
Abdominal Sonography
High resolution ultrasound system 2-5 MHz transducers Color and power Doppler, compound, harmonic, and panoramic imaging
Abdominal Sonography
Transducers Linear Curved
5-2 MHz 12-5 MHz 7-4 MHz
Phased
Hepato-Portal Duplex HepatoExam Objectives Assessment of quality and direction of flow Identification of portal and/or hepatic vein thrombosis Documentation of portal vein diameter Evaluation of blood flow patterns in porto-systemic and portospleno-renal shunts splenoConfirmation of portal vein-hepatic vein fistulae vein-
Examination Guidelines
8-12 hour fast Transducer frequency range 2.0 MHz 5 MHz Adjust the color imaging set-up for slow venous flow setCheck the PRF (Velocity Scale) and wall filter settings Confirm identification of all vessels with pulsed Doppler spectral waveforms Consistently optimize the size of the Doppler sample volume
Hepato-Portal System HepatoPortal vein feed the liver; hepatic veins drain this organ Portal vein carries 70% of oxygenated blood to the liver Remaining 30% carried by hepatic artery
Hepatic Veins
Hepatic Venous Flow Pattern
Bi-directional flow BiHepatofugal direction Pulsatile due to cardiac influence Flow toward the heart during ventricular systole Flow reversal during atrial systole
Hepatic Veins
Normal Examination No significant flow disturbance at the hepatohepatocaval confluence Flow throughout the right, middle, and left hepatic veins No evidence of extrinsic compression No intraluminal echoes
Hepatic Vein Thrombosis
Budd-Chiari syndrome Budd Rare disorder Obstruction of the hepatic veins DVT, Congenital web, trauma, malignancy, hypercoagulable states Visualization of major veins does not exclude thrombosis Vein distension, wall thickening, collaterals Difficult ultrasound diagnosis
Hepatic Vein Stenosis/Compression
Hepatic Veins
Abnormal Examination
Continuous, nonpulsatile flow Hepatopetal or to-fro flow pattern toSignificant flow disturbance at hepato-caval confluence hepatoSegmental absence or reduction of flow Extrinsic compression (Dense cirrhotic tissue, mass, etc.) Intraluminal echoes
Confirmation of Budd-Chiari Budd-
Absence of flow in the hepatic veins; all veins may not be involved Identification of collateral vessels, particularly intrahepatic collaterals Concurrent thrombosis of the portal vein (20% of cases) or IVC Extrinsic compression of veins from enlarged caudate lobe or hepatic mass.
Portal Veins
Main Portal Vein
Flow is similar to the lower extremity veins Nonpulsatile; minimally phasic Hepatopetal flow direction Low velocity
Portal Vein
Normal Examination Diameter < 13 mm at the level of the IVC Nonpulsatile, minimally phasic flow in hepatopetal direction No significant flow disturbance in any segment No intraluminal echoes No evidence of extrinsic compression
Pulsatile Portal Venous Flow
TricuspidRegurgitation,CHF,FluidOverload
Portal Vein
Normal-Hepatopetal Flow Abnormal-Hepatofugal Flow
Portal Vein Thrombosis
Portal Vein
Abnormal Examination Continuous or markedly pulsatile flow Hepatofugal flow direction; diameter > 13 mm Segmental absence of flow Significant flow disturbance in the main portal, at the confluence, or anastomosis (transplant) Extrinsic compression Intraluminal echoes ( may be segmental thrombosis)
Portal Hypertension
Formation of varices due to increased vascular resistance Hepato-fugal flow through Hepatocollateral pathways Porto-systemic Portoanastomoses Flow seeks pathways to inferior vena cava
Portal Hypertension
Gastroesophageal varices Paraumbilical veins Spleno-renal shunts SplenoRetroperitoneal shunts
Portal Hypertension
Portal Hypertension
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Cavernous Transformation of the Portal Vein
Results from prior portal vein thrombosis Formation of a complex collateral network that replaces the portal vein Mass of tortuous vessels in porta hepatis Low velocity venous signals
Confirmation of Portal Hypertension
Hepatofugal portal venous flow Portal vein diameter > 13 mm No respiratory variation noted in portal vein Cavernous transformation of portal vein Collateral veins imaged in the region of gallbladder, porta hepatis, splenic hilum Paraumbilical vein imaged; collaterals in region of umbilicus; apparent coronary vein Enlarged caudate lobe, > 8 cm in length
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Hepatic Artery
When portal venous flow is compromised, hepatic artery flow / velocity may increase Rule out hepatic artery stenosis
Hepatic Artery
Normal Examination Low resistance waveform Peak systolic velocity approximates 100 cm/sec; may increase with portal vein thrombosis or portal hypertension Minimal spectral broadening
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Spleno-renal Shunt
Transjugular Intrahepatic Portosystemic Shunt
Relief of portal hypertension Expandable metal stent Inserted via jugular vein through hepatic vein into portal vein- drains veinthrough IVC Diverts portal flow through hepatic veins and IVC Ultrasound is used to monitor patency and assess complications
TIPS
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Normal TIPS
Velocity ranges from 100-200 cm/sec 100Hepatofugal flow direction Increased hepatic artery peak systolic velocity ranges from 80-130 cm/sec 80Portal vein velocity ranges from 22-42 cm/sec 22FOSHAGER, AJR 1995; 165: 1-7 1-
TIPS
TIPS Dysfunction
Maximum peak systolic velocity less than 50 cm/sec Change in peak systolic velocity > 50 cm/sec compared to baseline Focal stenosis with at least doubling of the peak systolic velocity
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Liver Doppler Summary Know the anatomy Know the pathology Know the examination technique Know the pitfalls Know the solutions
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