Imaging Pearls ❯ Liver ❯ Vascular Pathology: Venous Thrombosis and Aneurysm
|
-- OR -- |
|
- Portal Vein Thrombosis: Causes
- Cirrhosis
- Cholangitis
- Pancreatitis
- Hepatoma
- Pancreatic cancer
- Hypercoagability states - Hepatic Artery Aneurysm: Facts
- Second most common type of splanchnic aneurysm and accounts for 20% of visceral aneurysms
- Causes include atherosclerosis. Fibromuscular dysplasia, collagen vascular disease, trauma, mycotic aneurysms, tumor related aneurysms
- Usually incidental finding but 20% present with abdominal pain or GI bleeding
"In conclusion, transient hepatic attenuation differences must be considered neither pitfalls nor nodular lesions. Instead they are imortant signs of an underlying liver disorder and for this reason they are useful to detect and characterize a large variety of liver diseases"
Transient Hepatic Attenuation Differences
Colagrande S et al.
AJR 2004;183:459-464- Transient Hepatic Attenuation Differences: Causes
- Increase in Hepatic arterial blood flow due to decreased portal venous flow
- Portal vein thrombosis
- Hepatic vein thrombosis
- Compression by adjacent masses
- Abscesses
- Long standing biliary obstruction
- Trauma
- Arterioportal shunt - Transient Hepatic Attenuation Differences: Causes
- Primary increase in arterial blood flow
- Focal hypervascular lesions Inflammation of adjacent organs (gallbladder or pancreas)
- Aberrant hepatic arterial supply - Transient Hepatic Attenuation Differences: Facts
- Defined as areas of increased CT attenuation typically seen on arterial phase imaging
- They can have both a range of causes and a range of CT appearances
- They can be a result of an underlying tumor (benign or malignant tumor) or can simulate a tumor (pitfall) - Hot Spot in the liver can also occur due to
- Budd Chiari syndrome
- Liver abscess
- Hemangioma
- Focal nodular hyperplasia
- Hepatoma
- These occur to areas beyond segment IV - Focal Hepatic Hot Spot Sign
- Focal area of increased CT attenuation on early phase imaging in segment IV of the liver
- Occurs typically in patients with SVC obstruction
- Due to portosystemic shunting of blood between the SVC and the portal vein
- The flow is via the internal mammary and left umbilical veins to the left hepatic lobe "HHT is a multiorgan vascular dysplasia that primarily affects the dermatologic, respiratory, central nervous, and gastrointestinal tract , although virtually every body system can be affected."
Imaging Hereditary Hemorrhagic Telangiectasia
Jaskolka J et al.
AJR 2004; 183:307-314- HHT: Liver Involvement
- Frequency of liver involvement is in the 8-30% range
- Half the patient are asymptomatic
- When symptomatic signs include high output heart failure, portal hypertension, biliary cystic disease
- CT findings include dilated and tortuous hepatic artery with diffuse parenchymal telangiectases, early enhancement of enlarged PV or hepatic veins - HHT: Lung Involvement
- 20-50% have PAVM and in 60% of cases it is multiple
- Most patients with PAVMs are asymptomatic
- When symptomatic presentation is usually dyspnea on exertion, but may include cyanosis, polycythemia, hemoptysis and spontaneous hemothorax - Hereditary Hemorrhagic Telangiectasia (HHT): Facts
Organs of interest
- Lung
- Brain
- Liver
- GI tract - Hereditary Hemorrhagic Telangiectasia (HHT): Facts
- AKA Osler-Weber-Rendu disease
- Autosomal dominant disorder with variable penetrance
- Definitive dx depends on presence of three of following symptoms: recurrent spontaneous epitaxis, mucocutaneous telangiectases, visceral AVMs or evidence of autosomal dominant inheritance - Portal Vein Thrombosis: CT Findings
Arterial phase imaging
- Perfusion changes in adjacent liver (usually increased)
Portal venous phase imaging
- Thrombus defined
- Collateral vessels well seen
- Perfusion chnages in the liver - Portal Vein Thrombosis: Etiologies
- Cirrhosis
- Pancreatitis
- Hepatoma (tumor invasion) or Pancreatic cancer
- Liver abscess
- Trauma - Portal Vein Thrombosis: Facts
- Occlusion of the portal vein may be partial or occlusive
- Occlusion of the portal vein may be acute or chronic and when chronic associated with cavernous transformation of the portal vein
- Can be due to a range of conditions from pancreatitis to hepatoma - Hepatic Vascular Pathologies
- Portal vein thrombosis
- Hepatic artery aneurysm
- Arterioportal shunting "MDCT with multiplanar reconstruction and volume rendered images is particularly well suited to demonstrating both the vascular and biliary abnormalities in HHT."
Spectrum of biliary abnormalities in hepatic hereditary hemorrhagic telangiectasia: demonstration by multidetector computed tomography
Lin E, Stall L
Emerg Radiol (2007) 14;461-463- HHT or Hereditary Hemorrhagic Telangiectasia: Liver Involvement
- Occurs in 8-31% of cases of HHT
- Range of abnormalities includes arterioportal shunts, arteriosystemic shunts, small telangiectases, and larger confluent vascular masses
- Patients may be symptomatic (high output heart failure or portal hypertension) or asymptomatic
- May have ductal abnormalities as well with multiple stenosis and focal dilatations
- Biliary cysts
- May resemble sclerosing cholangitis, Caroli’s disease, or biliary cysts - HHT or Hereditary Hemorrhagic Telangiectasia: Facts
- Also known as Rendu-Osler-Weber disease
- Frequency of 1-2 cases per 10,000 individuals
- Telangiectases and arteriovenous malformations most commonly involve the skin, lung, GI tract and brain "By substantially increasing the tumor to liver CNR (contrast to noise ratio), a low tube voltage, high tube current CT technique improves the conspicuity of malignant hypervascular liver tumors during the late hepatic arterial phase while significantly reducing patient radiation dose."
Hypervascular Liver Tumors: Low Tube Voltage, High Tube Current Multidetector CT during Late Hepatic Arterial Phase for Detection-Initial Clinical Experience
Marin D et al.
Radiology 2009; 251:771-779- "Although splanchnic artery aneurysms are relatively rare, they are being diagnosed with increased frequency given the widespread availability of MDCT and 3D imaging capabilities."
MDCT and 3D CT Angiography of Splanchnic Artery Aneurysms
Horton KM, Smith C, Fishman EK
AJR 2007;189:641-647
- "Although splanchnic artery aneurysms are relatively rare, they are being diagnosed with increased frequency given the widespread availability of MDCT and 3D imaging capabilities. It is important that these aneurysms be diagnosed accurately because they can carry a high morbidity and mortality, even in asymptomatic patients."
MDCT and 3D CT Angiography of Splanchnic Artery Aneurysms
Horton KM, Smith C, Fishman EK
AJR 2007;189:641-647
- "Although splanchnic artery aneurysms are relatively rare, they are being diagnosed with increased frequency given the widespread availability of MDCT and 3D imaging capabilities. It is important that these aneurysms be diagnosed accurately because they can carry a high morbidity and mortality, even in asymptomatic patients."
MDCT and 3D CT Angiography of Splanchnic Artery Aneurysms
Horton KM, Smith C, Fishman EK
AJR 2007;189:641-647
- Splanchnic Artery Aneurysms: Facts
- Incidence of 0.01-0.2% in autopsy series
- Most common is splenic artery aneurysm (60%), with hepatic artery aneurysm being second most popular (20%)
- Aneurysm rupture is associated with high morbidity and mortality
- Splanchnic Artery Aneurysms: Frequency
- Splenic artery (60%)
- Hepatic artery (20%)
- SMA (5.5%)
- Celiac artery (4%)
- Pancreatic arteries (2%)
- Gastroduodenal artery (GDA) 1.5%
- Splenic Artery Aneurysms: Facts
- 4x more common in woman than men
- In woman association with pregnancy and multiparity
- Although more common in woman more likely to rupture in men
- Risk of rupture (2-3%) increases with pregnancy, portal hypertension, and after liver transplantation
- Portal Vein Aneurysms: Facts
- May be associated with liver cirrhosis and portal hypertension
- Most cases are asymptomatic
- Most frequent site of aneurysm is the main portal vein
- Aneurysm size is over 20 mm (normal usually 15 mm)