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Vascular: Hepatic Artery Imaging Pearls - Learning Modules | CT Scanning | CT Imaging | CT Scan Protocols - CTisus
Imaging Pearls ❯ Vascular ❯ Hepatic artery
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  • “The liver is the largest organ in the adult human body, weighing approximately 1.5 kg. It is divided into eight independent segments on the basis of the fact that each segment has a separate vascular inflow and outflow. The hepatic inflow consists of the hepatic artery and portal vein in the center of each hepatic segment, and the outflow consists of the hepatic veins in the periphery of the segment. The portal vein, which supplies 75% of the blood supply to the liver, provides deoxygenated blood that has drained from the spleen, pancreas, and gastrointestinal tract. The hepatic artery, a branch of the celiac artery, supplies 25% of the blood to the liver and provides the liver with oxygenated blood.”

    
A Comprehensive Approach to Hepatic Vascular Disease
Khaled M. Elsayes et al.
RadioGraphics (in press)
  • “The portal vein and hepatic artery each divide into right and left lobar branches, which further divide into segmental, then lobular branches. The smallest portal vein and hepatic artery branches are located at the corners of hepatic lobules. The hexagonal hepatic lobules represent the small microscopic units of the liver. Each lobule is formed of radiating hepatocytes and many specialized capillaries, known as sinusoids. In the sinusoids, the blood is processed by hepatocytes, which can absorb or release nutrients and metabolize toxic chemicals. Deoxygenated blood flows out of the lobules through the central veins (located at the center of each lobule) to, in order, the hepatic veins, IVC, and right atrium.”


    A Comprehensive Approach to Hepatic Vascular Disease
Khaled M. Elsayes et al.
RadioGraphics (in press)
  • “Portal vein thrombosis can be seen with many conditions, including cirrhosis, abdominal tumors, intraabdominal inflammatory processes such as Crohn disease, diverticulitis and appendicitis, hypercoagulable states, and trauma . Recently, portal vein thrombosis was found to be associated with metabolic syndrome, especially with central abdominal obesity. A thrombus may be either bland or tumoral, with venous invasion from adjacent malignancies.”


    A Comprehensive Approach to Hepatic Vascular Disease
Khaled M. Elsayes et al.
RadioGraphics (in press)
  • “Transient hepatic attenuation differences (THADs) and THIDs refer to perfusional changes usually resulting from portal venous occlusion, with THAD being seen at CT and THID at MR imaging. These perfusional changes generally appear as segmental wedge-shaped areas of enhancement during the arterial phase, which become isoattenuating/isointense during the portal venous phase. This results from an increase in hepatic arterial inflow in response to decreased portal venous flow, resulting in relative hyperenhancement during arterial-phase imaging. Causes of THAD and THID include bland and tumor thrombi, extrinsic compression (such as from adjacent tumors), surgical ligation, flow diversion from shunts or anomalous blood supply, and inflammation of the biliary ducts or adjacent organs.”

    
A Comprehensive Approach to Hepatic Vascular Disease
Khaled M. Elsayes et al.
RadioGraphics (in press)
  • “A portal venous aneurysm, or varix, is a localized fusiform or saccular dilatation of the portal vein measuring greater than 2 cm in diameter. This cutoff was derived from a sonographic study by Doust and Pearce in which no portal vein measured more than 1.5 cm in diameter in patients with healthy livers, or more than 1.9 cm in patients with cirrhotic livers. Intrahepatic portal veins are considered to be aneurysmal when there is a diameter of greater than 0.7 cm in a patient with a healthy liver and 0.85 cm in a patient with a cirrhotic liver. The extrahepatic portal vein is the most commonly involved vein in the portal venous system to form aneurysms, followed by the splenomesenteric venous confluence, intrahepatic portal vein, splenic vein, superior mesenteric vein, and inferior mesenteric vein. Although a portal venous aneurysm is often incidentally discovered during imaging, the most common presentation is abdominal pain . Complications of aneurysms include thrombosis, compression of the biliary tree or duodenum, and rupture.”


    A Comprehensive Approach to Hepatic Vascular Disease
Khaled M. Elsayes et al.
RadioGraphics (in press)
  • “The most common cause of portal venous gas is bowel ischemia, which can result from arterial or venous mesenteric thrombosis, hypoperfusion, aortic dissection, embolic disease, or intestinal obstruction. Bowel distention and intra-abdominal sepsis have also been implicated as sources of portal venous gas . At CT, portal venous gas appears as linear branches of air coursing in the expected location of the portal venous system to the periphery of the liver . The feature of peripheral branching air at CT helps differentiate portal venous gas from pneumobilia, which typically is more central. The sonographic appearance of portal venous gas is multiple tiny high-amplitude transient intraluminal echogenic foci, resulting in characteristic high-amplitude spikes at Doppler spectral analysis. The air bubbles in the portal vein are strong acoustic reflectors, which cause blooming of the color flow in the portal vein and are noted to move during real-time imagings.”


    A Comprehensive Approach to Hepatic Vascular Disease
Khaled M. Elsayes et al.
RadioGraphics (in press)
  • Vascular Mapping of the Liver
    • Celiac Artery
       • Hepatic artery
       • Splenic artery
       • Left gastric artery
    • SMA
  • “Hepatic arterial thrombosis (HAT) is a potentially devastating arterial complication following transplantation and also the most common vascular complication. Undetected HAT can result in biliary ischemia, necrosis, bilomas, sepsis, fulminant hepatic necrosis, and graft failure. Although early diagnosis of HAT may enhance the success of attempts at revascularization with surgical thrombectomy or thrombolysis, most patients with HAT will require retransplantation. Absence of hepatic arterial flow on Doppler ultrasonography should raise concern for hepatic arterial thrombosis and prompt further evaluation with CTA, magnetic resonance angiography, or catheter angiography.”

    Computed Tomography Angiography of the Hepatic, Pancreatic, and Splenic Circulation 
Price M, Patino M, Sahani D
Radiol Clin N Am 54 (2016) 55–70
  • “MDCT serves as an excellent noninvasive imaging modality for diagnosis and surveillance of hepatic artery aneurysms (HAAs). HAAs are the second most common type of visceral artery aneurysm, after splenic artery aneurysms. Most HAAs are incidentally detected with cross-sectional imaging and patients will be asymptomatic unless the aneurysm ruptures. Unlike splenic artery aneurysms, HAAs most frequently occur in men.25 When imaging HAAs, it is critical to assess for the presence of any anatomic vascular variants, particularly in the presence of planned endovascular or surgical intervention.”


    Computed Tomography Angiography of the Hepatic, Pancreatic, and Splenic Circulation 
Price M, Patino M, Sahani D
Radiol Clin N Am 54 (2016) 55–70
  • “Pancreaticoduodenal aneurysms are felt to be at higher risk for rupture, and all of these aneurysms should be considered for surgical or endovascular treatment.”

    Managing Incidental Findings on Abdominal and Pelvic CT and MRI, Part 2: White Paper of the ACR Incidental Findings Committee II on Vascular Findings

    Khosa F et al
    J Am Coll Radiol. 2013 Oct;10(10):789-94
  • “Treatment is generally recommended for aneurysms >2 cm in diameter, possibly with a smaller threshold for nonatherosclerotic aneurysm. For hepatic aneurysms, Abbas et al  established that multiplicity and nonatherosclerotic origin were linked to increased rupture rate. Criteria for which it is safe to observe visceral arterial aneurysms have not been clearly established. In the study of Abbas et al, of 21 patients with a mean follow-up interval of 68.4 months and mean diameter of 2.3 cm, none required intervention during the follow-up period.”

    Managing Incidental Findings on Abdominal and Pelvic CT and MRI, Part 2: White Paper of the ACR Incidental Findings Committee II on Vascular Findings

    Khosa F et al
    J Am Coll Radiol. 2013 Oct;10(10):789-94
  • Hepatic Artery Aneurysms: Facts

    - 20% of splanchnic artery aneurysms
    - More frequent in men than woman
    - Risk of rupture is 20-30%
  • Hepatic Artery Aneurysms: Facts

    "Paragangliomas of the aortic body and the great vessels have a characteristic imaging appearance. They originate from known sites of the branchiomeric paraganglia such as in the aortic body."

    Cross-Sectional Imaging of Paragangliomas of the Aortic Body and Other Thoracic Branchiomeric Paraganglia
    Balcombe J et al.
    AJR 2007; 188:1054-1058
© 1999-2017 Elliot K. Fishman, MD, FACR. All rights reserved.