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Vascular sonography
Abdominal Doppler Hepatoportal and IVC
| Question | Answer |
|---|---|
| What is the most common imaging technique used to evaluate portal and hepatic venous systems? | Duplex ultrasound |
| What is duplex ultrasound used to determine? | Presence of flow, direction, velocity, and in characterizing flow hemodynamics |
| Duplex is useful in the detection of what? | Intraluminal thrombus, Hepatofugal flow, Collateral circulation, Absent flow, Increased or Decreased flow in both portal hepatic venous systems |
| The liver receives what kind of blood supply? | Dual blood supply |
| What does the Hepatic artery do? | Supplies approximately 30% of incoming blood, Source of oxygenated blood into the liver |
| What does the Portal Vein do? | Supplies the remaining 70% of incoming blood, and carries nutrient rich blood from the GI tract |
| What are the 3 Hepatic Veins? | Right, Middle, and Left |
| Where do Hepatic veins drain into? | Hepatic veins drain into the IVC |
| The 3 hepatic veins are the primary what? | Primary hepatic outflow vessels |
| Where does the Main portal vein begin? | Begins at the junction of the Splenic vein and the SMA |
| Where does the Main portal vein course? | Courses cephalad toward porta hepatis |
| What is the Porta Hepatis? | The largest area of the portal vein |
| Where is the Porta hepatis? | On the surface of the liver where the portal vein and hepatic artery enter and hepatic duct leaves, Lies anterior to the IVC |
| What does the Porta Hepatis divide into? | Divides into left and right portal veins |
| What do portal veins not contain? | Contain no valves |
| What kind of walls does the the Main portal vein have? | Bright, echogenic walls due to thick collagenous tissue |
| Left Portal Vein facts? | Smaller, more anterior branch, Branches into medial and lateral divisions |
| Right Portal Vein facts? | Larger, more posterior branch, Branches into anterior and posterior branches |
| The Hepatic veins are anatomically separate from what? | The Portal Venous System |
| Hepatic Veins characteristics | Thin-walled vessels, ↑ in size as they approach the diaphragm, Drain into the IVC near the RA |
| Which Hepatic vein is usually largest? | The Right Hepatic vein |
| The middle and left Hepatic veins often join to form what? | Common trunk before entering the IVC |
| The Hepatic artery is a branch of the what? | Celiac artery |
| Hepatic artery branches course with what? | Portal veins throughout the liver |
| Hepatic artery lies _________ to portal vein | Anteromedial |
| What are the indications for Hepatic exams? | Liver Cirrhosis, Portal Hypertension, Ascites, Portal vein thrombosis, History of abdominal malignancy, Pre/postintervention, Abdominal trauma, Budd-Chiari syndrome, Thrombosis of other veins |
| What are normal findings of the Portal vein? | Bright, echogenic walls, Diameter w/ quiet respiration is normally ≤13mm, Flow is normally directed toward the liver (hepatopetal), Slight variation (pulsatility) in flow vel due to cardiac activity and respiration; mostly continous, low vel flow |
| What is the mean flow velocity for normal Portal vein findings? | ~15-18 cm/s (peak from 10-30 cm/s) |
| What are some normal changes with Portal Vein? | ↑ in diameter with deep inspiration, Flow & velocity ↑ with expiration and ingestion of food |
| Post-prandially flow velocities do what? | Increase |
| Hepatic veins characteristics | Thin walls, less reflection than portal veins, Smaller vein diameters, Color flow will be both blue and red due to pulsatile flow |
| What does normal flow look like in Hepatic veins? | Triphasic with both antegrade and retrograde components, Corresponds to pressure changes in the heart |
| What is the peak velocities range for Hepatic veins? | 22-19 cm/s |
| Normal respiratory variation can augment waveforms with what? | inspiration |
| The Valsalva maneuver diminishes what? | Waveform pulsatility |
| The Hepatic artery has a smaller diameter than the? | Portal vein |
| Hepatic artery flow is _____? | Hepatopetal(toward the liver) |
| Hepatic artery spectral doppler waveforms demonstrate what flow pattern? | Low resistance flow with antegrade flow throughout entire cardiac cycle |
| Hepatic artery flow _____ when portal flow______(and vice versa) | Decreases, Increases |
| Hepatic artery flow decreases when portal flow increases is termed what? | Hepatic buffer response |
| What is the PSV in Hepatic artery ranges from? | 70-120 cm/s |
| What is the RI in the Hepatic artery? | Between 0.5 and 0.7 |
| Portal HTN etiology | Most common cause in North America is obstruction due to cirrhosis |
| What does Cirrhosis cause? | distortion of normal liver architecture |
| Portal HTN distorts what? | Distorts vascular channels which increases resistance to portal venous flow |
| What are the primary causes of cirrhosis? | Hepatitis C and alcohol abuse |
| What are the Duplex sonographic findings in Portal HTN? | ↑ Portal vein diameter(>13mm), ↑Splenic vein and SMV diameters (>10mm), ↓or absent respiratory variation (portal/splenic veins), <20% ↑in SMV or splenic vein diameter, quiet respiration to deep inspiration, Hepatofugal flow (away from liver) |
| Other Duplex sonographic findings with Portal HTN | Diminished, static, altered pulsatility or portal & hepatic venous flow, Portosystemic collateral (varices), Ascities and splenomegaly, Liver parenchymal pathology (cirrhosis, tumor, Budd-Chiari), Portal vein obstruction (thrombus, tumor), ↑HA flow |
| What is the most specific finding of Portal HTN? | Detection of varices |
| What are commonly seen collaterals with Portal HTN? | Paraumbilical vein (recanalized w/ hepatofugal flow), Coronary vein, Gastroesophageal veins, Splenorenal vein |
| What does TIPS stand for? | Transjugular Intrahepatic Portosystemic Shunt |
| The treatment of portal HTN involves techniques to compress what? | The portal venous system |
| TIPS is a stent that does what? | Connects the portal vein to the hepatic vein, typically the right portal vein connected to the hepatic vein |
| How is the TIPS placed via? | Placed via jugular vein into liver |
| What does TIPS do? | Reroutes blood away from the liver, out through the stent, into the hepatic vein, and back to the heart |
| What does the TIPS not do? | TIPS does not correct the cause of portal HTN |
| Where should direction of flow be noted with TIPS? | Within the shunt, and adjacent portal veins, splenic vein and superior mesenteric vein |
| Should flow be toward or away from shunt? | Flow should be noted toward shunt |
| What is the normal velocities range for TIPS? | 90-190 cm/s |
| Main portal vein and hepatic artery velocities ↑ with the presence of the shunt, T/F? | TRUE |
| When should TIPS occlusion be suspected? | In echogenic material visualized within the stent (no flow detected with spectral and color doppler) |
| What can Portal Venous Thrombosis be caused by? | Stasis secondary to cirrhosis & portal HTN, Inflammatory processes, hypercoagulable states, Surgical intervention, Abdominal malignancy, Sepsis and Trauma |
| what are clinical findings with Portal Venous Thrombosis? | Acute abdominal pain, Sudden onset of ascitites, Elevated D-dimer |
| Obstruction can be caused by what? | True thrombus or by intravascular tumor |
| What is an intravascular tumor associated with? | Hepatocellular carcinoma or pancreatic carcinoma |
| What is Budd-Chiari syndrome? | Obstruction of hepatic venous outflow due to thrombus or tumor invasion |
| What are the clinical features of Budd-Chiari syndrome? | Right upper quadrant pain, Jaundice, Ascites, Hepatomegaly, Splenomegaly, and Liver function abnormalities |
| What are some of the causes of Budd-Chiari syndrome? | Cirrhosis, Hypercoagulable disorders, use or oral contraceptives, Abdominal trauma, Tumor invasion (extrinsic compression), and IVC occlusion or stenosis (thrombus) |
| Where does the IVC begin? | The level of the 5th lumbar vertebra |
| The IVC is what? | Retroperitoneal and lies to the right of the abdominal aorta |
| Where does the IVC course? | Courses posterior to the liver and it terminates into the right atrium |
| Where does the IVC receive blood? | From organs and tissues below the diaphragm |
| Does the IVC return oxygenated blood or deoxygenated blood back to the heart? | DEOXYGENATED |
| What should be the diameter of the IVC in a well hydrated patient? | 17-20 mm |
| What can occur with the IVC if there is congestive heart failure? | Megacava |
| Small diameter IVC can occur in _______ patients? | Dehydrated patients |
| What TD to scan the IVC? | 2-5 MHz TD |
| What type of walls will a normal IVC and iliac veins have? | Echogeinic, muscular walls, Lumen should be anechoic, and Diameter my change with respiration |
| What should a normal IVC show? | Respiratory phasic & may show slight pulsatility from cardiac cycle, ↑ pulsatility noted closer to ♥ , Flow pattern becomes more resp phasic in lower abdomen, & severe fluid overload may cause ↑ in cardiac pulsatility |
| Lack of respiratory phasicity &/ or cardiac pulsatility is an indication of what? | IVC and/or iliac obstruction |
| What is the peak velocites range for normal IVC? | 40-120 cm/s |
| What does Valsalva Maneuver do? | Blocks venous return and flow is temporarily reverse in IVC, also causes dilation of IVC |
| With obstruction what happens with the IVC? | IVC dilates below the level of obstruction, and Respiratory changes are decreased or absent |
| What is an IVC interruption device? | A device used to protect patients from pulmonary emboli, Trap thromboemboli from lower extremity DVT |
| Where is the IVC interruption device typically placed? | Distal to the renal veins |
| What does the IVC interruption device consist of? | Thin metal struts joined at one end (cone shaped) |
| What does the IVC interruption device look like in the transverse scan plane? | Filter appears as central echogenic dot in IVC lumen |
| What does the IVC interruption device look like in the sagittal scan plane? | Linear, echogenic structures are seen in IVC lumen |
Created by:
EmilyGriffin
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