Capturing Dancing Bubbles in the Liver - USA

This course provides a discussion of normal vascular and surgical anatomy, vascular phases, filling patterns, and clinical usage while imaging focal liver lesions.   
Successful completion of this training is eligible for American Society of Radiology Technician (ASRT) Category A continuing education units (CEU).

Conventional 2D-mode ultrasound allows us to image the echo texture (homogeneity versus heterogeneity) of the liver. Spectral Doppler helps us determine flow direction and flow velocity while color and power Doppler provide a method to determine vessel filling. Contrast enhanced ultrasound (CEUS) adds another clue to liver morphology through imaging tissue and mass perfusion. During CEUS exams, slower flow within the microvascular beds of focal liver lesions image allow determination of vessel density, tissue structures, and mass characteristics.   This course provides a discussion of normal liver vascular and surgical anatomy, vascular phases, and filling patterns seen in focal liver lesions.    Congratulations! You have completed the Catching Dancing Bubbles in the Liver course. Listed below are the key points presented in this course. Take time to review the material before you try the final Assessment.   Download and print a copy of the detailed Course Review. In this course you have learned to: Identify the vascular and surgical anatomy of the liver, Describe the vascular phases of the liver, and Explain the importance of flow patterns within focal liver lesions. Upon completion of this course, the learner will be able to:        Identify the vascular and surgical anatomy of the liver      Describe the vascular phases of the liver      Explain the importance of flow patterns within focal liver lesions (FLL) The liver is the second largest organ in the body (the skin is the largest) and is in the right upper quadrant of the abdomen. The routine sonographic exam includes the right and left lobe as well as the caudate lobe. These lobes divide further when describing the surgical segments which use vascular and intersegmental fissures as landmarks for boundaries.1 The following sections describe the vascular anatomy and surgical segments used to localize masses within the liver.     The liver has a unique blood supply as two systems provide flow into this large organ. To understand the appearance and disappearance of the microbubble in the liver, we begin with an overview of liver vasculature. Learn More about Liver Vessels Learn more about liver vessels. Tab TitleTextHepatic ArteryThe hepatic artery originates at the celiac axis entering the liver at the porta hepatis. Running parallel to the common hepatic ducts and the portal vein, the hepatic artery supplies approximately a quarter of the oxygenated supply.2 Flow direction of the hepatic artery is into the liver (antegrade; hepatopetal).3   The common hepatic artery (red) lies between the aorta and the bifurcation to the right and left hepatic artery. Portal VeinThree-quarters of blood to the liver enters via the portal vein.1, 2 Flow, like the hepatic artery, is into the liver (antegrade; hepatopetal). The portal vein originates when the superior mesenteric and splenic vein merge.4   The portal vein (purple) lies slightly posterior to the hepatic artery. This vessel carries blood from the mesentery with nutrients absorbed via the small and large intestine.3  Liver AcinusThe hepatic artery and portal vein supply the hexagonal hepatocytes located within the sinus. This diagram shows the one of the microscopic acini which are the functional component of the liver. Flow from the vessels moves towards a central vein (orange arrows) into the hepatic veins.3 Blue – vein; Red – artery; Green -bile duct.Hepatic VeinsFlow out of the liver (hepatofugal) is via the hepatic veins which drain into the inferior vena cava (IVC).   The three hepatic veins exit the dome of the liver draining the right, middle, and left sections.4 In addition to the anatomic designation of the right and left liver, surgeons use a method based on the vascularity within the liver. A French physician, C. Couinaud, developed a method to identify liver segments in the late 1960’s. Now referred to as Couinaud’s anatomy, the liver divisions start in the posterior caudate lobe with segments numbered in a clockwise fashion.5, 6 Each segment has a portal vein branch, hepatic artery, and bile duct.5, 7 The hepatic veins designate the vertical boundaries while the right and left portal vein provide the horizontal division.4, 5, 7  These segments become important during surgery and when showing pathology locations with sonography. Keep in mind when imaging the liver that patient segmental anatomy varies. Learn More about Liver Segments Learn more about liver segments. Tab TitleTextLiver Segments Segment I – Caudate lobe.  Segment II – Superior lateral left lobe Segment III – Inferior lateral left lobe Segment IVA – Superior medial left lobe Segment IVB – Inferior medial left lobe Segment V – Inferior anterior right lobe Segment VI – Inferior posterior right lobe Segment VII - Superior posterior right lobe Segment VIII – Superior anterior right lobe. Upper Segments This transverse image of two of the three hepatic veins shows segments IVA, VII, and VIII. The right hepatic vein (asterisk) courses between the right intersegmental fissure dividing the anterior and posterior portions of the right lobe. The main hepatic vein (dot) courses through the main lobar fissure dividing the right and left portions of the liver. The left hepatic vein (not shown) travels through the left intersegmental fissure dividing the medial and lateral segments of the left lobe at the cephalic aspect.5Lower Segments This transverse image of the liver, taken at the level of the liver hilum shows segments III, IVB, V, and VI. The proper portal vein (dot) divides into the right and left portal vein. The anterior branch of the right portal vein, lies in the intrasegmental, anterior part of the right lobe coursing in the central anterior segment. The posterior branch of the right portal vein lies in the intrasegmental, posterior part of the right lobe coursing in the central posterior segment. The horizontal segment of the left portal vein lies anterior to the caudate lobe separating this lobe from the medial part of the left lobe.4 IVC – asterisk Segment IV   This transverse image of a normal liver demonstrates the medial part of the posterior right lobe (segment VI). Right kidney – arrow; IVC – dot; Gallbladder - asterisk Segment III   This midsagittal image of the left lobe of a normal liver shows segment III. Your Turn Your turn. Instructions:Flash File:HTML5 File:/content/generator/Course_90022444/2019-YT-01-Liver_Contrast/index.htmlPDF File: Contrast enhanced ultrasound (CEUS) has a unique set of terminologies describing the appearance of contrast within the liver. Divided into time-based stages, the arterial phase, portal venous phase, and late phase, show the enhancement occurring within the liver vasculature.8   Keep in mind, timing varies due to each patient’s circulatory status and disease process. Cardiac diseases or contrast injection into a small vessel may slow contrast clearing while intracardiac or pulmonary shunting, or hyperdynamic circulation may increase contrast clearing.9   Acquire a cine loop to capture arterial, portal venous, and late phase flow.10 Learn More about Liver Vascular Phases Learn more about liver vascular phases. Tab TitleTextArterial Phase The arterial phase (AP), also known as the hepatic arterial phase or wash in, begins as early as 10 seconds or as late as 45 seconds post injection.8, 11 During this phase the blood supply for the liver is via the hepatic artery.12 This phase lasts approximately 45 seconds.8  Portal Venous Phase During the second stage, the portal venous phase (PVP), the portal vein supplies the liver parenchyma.12  Vascular enhancement steadily increases from 30-45 seconds, until contrast saturation peaks, finally beginning to decrease (washout).8, 11 Lasting as long as six minutes post-injection,8, 12  the portal venous phase may overlap the arterial phase.12   Late Phase Passing of the contrast via hepatic veins into the inferior vena cava (IVC) signals the beginning of the late phase (LP) of the liver. Beginning as early as two minutes, the hepatic vein enhancement begins to decrease; however, the liver parenchyma remains enhanced.12   In the normal liver the Kupffer cells hold the contrast with the damaged areas of the liver showing a decrease in flow resulting in what we call a filling defect. The LP lasts until all the microbubbles clear from imaged vessels.11   Your Turn Your turn. Instructions:Flash File:HTML5 File:/content/generator/Course_90022444/2019-YT-02-Liver_Contrast/index.htmlPDF File: Focal liver lesions show characteristic flow patterns in the arterial, portal, and late phases during the CEUS exam. The enhancement capabilities of CEUS results in a high sensitivity for microvasculature within focal liver masses. We can accurately describe perfusion, describing flow patterns by the number of microbubbles within an area, appearance of vascularity, as well as flow patterns and direction in vessels of all sizes.   Focal liver mass filling patterns change throughout the phases of the liver; however, they have characteristic vascular patterns.   Centrifugal fill describes the mass that fills with contrast from the center toward the outer edges.   This graphic shows flow in a liver mass beginning in the central portion extending to the periphery. View these instructions for information on navigating through the self-evaluation tools we call ‘Your Turns’. These questions help you gauge your understanding of key topics. Click the icon below to start the self-evaluation instructions. Note: This is not part of the final Assessment. Learn How to Navigate the Your Turns Learn how to navigate the Your Turns. Instructions:Flash File:HTML5 File:/content/generator/Course_90022444/Navigation_Instructions_Liver_Contrast-V1/index.htmlPDF File: Centrifugal, hypervascular filling begins in the central portion of the mass extending to the borders in a spoke-like manner. One type of liver mass showing this type of radial filling pattern is focal nodular hyperplasia (FNH).13 FNH has few 2D-mode characteristics; however, contrast images often show this type of filling in the arterial phase.13, 14   This graphic demonstrates the classic spoke pattern with a large feeding vessel.13     Centripetal fill describes the mass that fills with contrast from the outside toward the center. A hemangioma shows this type of filling pattern in the portal venous and late phase.13    This graphic shows filling of a mass from the periphery to the central portion. View these case studies to see how contrast imaging helps visualize benign liver lesion flow characteristics. Case 1 Case 1. Tab TitleText2D-modeThe following series of images and video clip show a well-defined, hyperechoic lesion with centripetal filling in the arterial phase.  These findings suggest the presence of a hemangioma.13, 14     This image shows a hyperechoic lesion (yellow calipers) within the liver.Color Doppler Velocity   Color Doppler Velocity (CDV) image showing a vascularity within the area of concern. Video   This mass fills from the center to periphery (centrifugal). The right kidney, located in the lower right of the image, enhances first followed by the liver mass. Case 2 Case 2. Tab TitleText2D-modeThese images show two anechoic lesions within the liver.   Two anechoic areas (calipers) show posterior enhancement on the 2D-mode characteristic of cysts.  Contrast Image   The two anechoic areas lack contrast filling during the exam.Portal Vein   The portal vein images posterior to the common bile duct (CBD).  Contrast enhancement files the vein during the portal venous stage.Video   This video shows the two anechoic areas during a contrast study.   Case 3 Case 3 Tab TitleText2D-mode   The 2D-mode shows a heterogeneous liver seen in focal nodular hypoplasia (FNH). Color Doppler Velocity VideoInitial Injection VideoPeak Hold Case 4 Case 4. Tab TitleText2D-modeContrast Image View these case studies to see how contrast imaging helps visualize malignant liver lesion flow characteristics. Case 1 Case 1. Tab TitleText2D-mode   The 2D-mode shows a hypoechoic area within the liver shown to be a biopsy proven hepatocellular carcinoma (HCC). Arterial Phase Video   This video clip, taken during the arterial phase, shows the feeder vessels to the mass.10  Portal Phase Video Case 2 Case 2. Tab TitleText2D-mode   This liver metastasis images as a hypoechoic area within the liver. Video Case 3 Case 3. Tab TitleText2D-modeVideo 1Video 2 Explore the links below for the Glossary, References, and Further Reading opportunities. Glossary Glossary. Acinus – The functional unit of the liver.   Arterial phase (AP) – Time when the contrast microbubbles enter the liver via the hepatic artery.   Arterial phase hyperenhancement (APHE) – Increased enhancement of a focal liver lesion during the arterial phase.   Centrifugal – Flow in a mass from the center to periphery.   Centripetal – Flow in a mass from the periphery to the center.   Contrast enhanced ultrasound (CEUS) – The use of gas-filled microbubbles to increase (enhance) blood flow visualization within a vessel.   Enhancement – Comparison of signal intensity and the surrounding tissue.  May be used to describe a mass that has equal signal intensity (isoenhancing), an increased signal intensity (hyperenhancing), decreased signal intensity (hypoenhancing), or complete absence of signal intensity (nonenhancing).   Hepatofugal – Flow away from or out of the liver.   Hepatopetal – Flow towards or into the liver.   Heterogeneous – Liver tissue or mass with a mixed echo texture.   Homogeneous – Liver tissue or mass with an even echo texture.   Kinetics – Relating to motion of blood flow within vessels.   Late phase (LP) – Circulatory phase where the microbubbles exit the liver into the inferior vena cava via the hepatic veins.   Portal venous phase (PVP) – Circulatory phase when the microbubbles enter the liver via the portal vein.   Sustained enhancement – Continuing enhancement of a focal liver lesion throughout the CEUS exam. References / Further Reading References / Further Reading. 1. Wilson, S.R. and Withers, C.E. (2011). The liver. In Rumack, C.M., Wilson, S.R., Charboneau, J.W., et al., (Eds.), Diagnostic Ultrasound (pp. 78-145). Philadelphia, PA: Elsevier Mosby.   2. Middleton, W.D. and Robinson, K.A. (2012). Ultrasound assessment for the hepatic vasculature. In Pellerito, J.S. and Polak, J.F., (Eds.), Introduction to Vascular Ultrasonography (pp. 495-515). Philadelphia, PA: Elsevier Saunders.   3. Kline, T., Zamir, M., and Ritman, E. (2011). Relating function to branching geometry: a micro-CT study of the hepatic artery, portal vein, and biliary tree. Vol. 194. 431-42.   4. Moore, K.L., Dalley, A.F., and Agur, A.M.R. (2010). Abdomen. In Moore, K.L., Dalley, A.F., and Agur, A.M.R., (Eds.), Clinically Oriented Anatomy (pp. 181-325). Philadelphia: Wolters Kluwer Health | Lippincott Williams & Wilkins.   5. Barr, R.G., Ferraioli, G., Palmeri, M.L., Goodman, Z.D., Garcia-Tsao, G., Rubin, J., . . . Levine, D. (2015). Elastography assessment of liver fibrosis: Society of Radiologists in ultrasound consensus conference statement. Radiology. 276(3): 845-861.   6. Theise, N.D. (2014). Liver cancer. In Stewart, B.W. and Wild, C.P., (Eds.), World Cancer Report 2014 (pp. 403-412). Geneva: World Health Organization International Agency for Research on Cancer.   7. Grube, J.A. (2012). The liver. In Kawamura, D.M. and Lunsford, B.M., (Eds.), Diagnostic medical sonography: Abdomen and superficial structures (pp. 101-164). Philadelphia: Wolters Kluwer Health | Lippincott Williams & Wilkins.   8. Claudon, M., Dietrich, C.F., Choi, B.I., Cosgrove, D.O., Kudo, M., Nolsøe, C.P., . . . Xu, H. Guidelines and good clinical practice recommendations for contrast enhanced ultrasound (CEUS) in the Liver - Update 2012. Ultrasound in Medicine and Biology. 39(2): 187-210.   9. Piscaglia, F., Nolsøe, C., Dietrich, C.F., Cosgrove, D.O., Gilja, O.H., Bachmann Nielsen, M., . . . Weskott, H.P. (2012). The EFSUMB guidelines and recommendations on the clinical practice of contrast enhanced ultrasound (CEUS): Update 2011 on non-hepatic applications. Ultraschall in Med. 33(01): 33-59.   10. Bracco. (2016). Clincal review of NDA 203684 supplement; Characterization of focal liver lesions, in 3894336, Association, U.S.F.a.D., Editor, FDA: Silver Spring, MD.   11. Wilson, S.R., Lyshchik, A., Piscaglia, F., Cosgrove, D., Jang, H., Sirlin, C., . . . Kono, Y. (2017). CEUS LI-RADS: algorithm, implementation, and key differences from CT/MRI. Abdominal Radiology: 1-6.   12. Chami, L., Chebil, M., Clevert, D., Lassau, N., E, L., Low, G., . . . Xu, H. (2013). Liver. In Weskott, H., (Eds.), Contrast-enhanced ultrasound (pp. 49-120). Bremen: Uni-Med.   13. Stock, K.F. (2013). Benign focal liver lesions. In Wescott, H., (Eds.), Contrast-enhanced ultrasound (pp. 50-59). Bremen: UNI-MED Verlag AG.   14. Yang, H., Liu, G., Lu, M., Xu, H., and Xie, X. (2013). Evaluation of the vascular architecture of focal liver lesions using micro flow imaging. Journal of Ultrasound in Medicine. 32(7): 1157-1171.   15. Bertin, C., Egels, S., Wagner, M., Huynh-Charlier, I., Vilgrain, V., and Lucidarme, O. (2014). Contrast-enhanced ultrasound of focal nodular hyperplasia: a matter of size. European Radiology. 24(10): 2561-2571. The reproduction, transmission or distribution of this training or its contents is not permitted without express written authority. Offenders will be liable for damages.   All names and data of patients, parameters and configuration dependent designations are fictional and examples only.   All rights, including rights created by patent grant or registration of a utility model or design, are reserved.   Please note that the learning material is for training purposes only!   For the proper use of the software or hardware, please always use the Operator Manual or Instructions for Use (hereinafter collectively “Operator Manual”) issued by Siemens Healthineers. This material is to be used as training material only and shall by no means substitute the Operator Manual. Any material used in this training will not be updated on a regular basis and does not necessarily reflect the latest version of the software and hardware available at the time of the training.   The Operator Manual shall be used as your main reference, in particular for relevant safety information like warnings and cautions. Note: Some functions shown in this material are optional and might not be part of your system. The information in this material contains general technical descriptions of specifications and options as well as standard and optional features that do not always have to be present in individual cases.   Certain products, product related claims or functionalities described in the material (hereinafter collectively “Functionality”) may not (yet) be commercially available in your country. Due to regulatory requirements, the future availability of said Functionalities in any specific country is not guaranteed. Please contact your local Siemens Healthineers sales representative for the most current information. Copyright © Siemens Healthcare GmbH, 2019.

  • ASRT
  • CEU
  • CME
  • Contrast
  • Contrast Agents
  • Bubbles
  • Liver
  • CEUS
  • contrast enhanced ultrasound
  • surgical segments
  • Couinaud
  • Couinaud Anatomy
  • liver segments
  • hepatopetal
  • hepatofugal
  • arterial phase
  • portal venous phase
  • late phase
  • wash-in
  • wash-out
  • centrifugal
  • centripetal
  • hemangioma
  • focal nodular hypoplasia
  • FNH