Hepatocilliary System I (liver) Flashcards
radilogical modalities for hepatobiliary system:
- US, CT, MRI, SPECT
- MRCP (non invasive)
- ERCP (invasive)
- Percutaneous transhepatic cholangiogram
MRCP = MR cholangiopancreatography
ERCP = Endoscopic retrograde cholangiopancreatogram
examples for Diffuse liver diseases
- hepatic steatosis
- hepatic fibrosis
- infections
Uss of hepatic steatosis:
++ parenchymal echogenicity
Loss of visualization of the portal triads
Severe steatosis causes sound-beam attenuation, which will obscure visualization of the deep portions of the liver, & lesions like metastasis.
Hepatic steatosis on CT
decreased attention of hepatic parenchyma
HU is lower than the speen by more than 10 on non-contrast exams (and >25 HU with contrast)
Appearanceof Hyperdense vessels on non contrast exam
My obscure lesions that are normally hypodense compared to background liver
Moderate to severe steatosis if either (HU):
For non-contrast CT:
Liver attenuation < 40 HU
Liver attenuation > 10HU less than spleen
With IV contrast (portal venous phase):
Liver attenuation > 25 HU less than spleen
Steatosis on MRI
Loss of signal on out-of-phase imaging relative to in-phase imaging
describe hepatic steatosis radiologically (review)
- by US –> increased parenchymal echogenicity
- by CT –> Decreased attenuation (less than 40 HU)
- by MRI –> loss of signal on out-of-phase imaging relative to in-phase imaging.
review
HU of fatty liver compared to spleen ([HU of spleen] - [HU of fatty liver]) = …..
25 HU or more
Other MR techniques for hepatic steatosis
MR spectroscopy
MR Elastography
T1 mapping
the fatty liver may make the diagnosis of some diseases difficult radiologically, explain why?
- by US –> severe steatosis can cause sound-beam attenuation, which will obscure visualization of lesions like metastasis.
- by CT –> May obscure lesions that are normally hypodense
Role of imaging in cases of viral hepatitis
Image try to exclude biliary obstruction or neoplasm
Image evaluate parenchymal damage non-invasively
Image of …… usually sufficient to suggest dx of acute viral hepatitis and imaging surveillance of patients with hepatitis C prior to the development of heterogeneous nodular fibrotic, cirrhosis.
Ultrasound
Ultrasound has poor sensitivity and specificity for detection of:
Hepatocellular carcinoma in cirrhotic liver
Image …. or …. is mandatory for HCC surveillance among cirrhotic patients
Multiphasic Contrast-enhanced CT
MRI
Grayscale ultrasound of acute viral hepatitis
• ++ liver and spleen size
• decrease echogenicity of liver
• increase echogenicity of portal venous walls (starry sky)
• Thickened gallbladder wall
• periportal hypo-/anechoic area (hydropic swelling of hepatocytes)
Grayscale ultrasound of chronic viral hepatitis and cirrhosis
- increase echogenicity of liver and coarsening of parenchymal texture.
- “silhouetting” of portal vein wall(loss of definition of portal veins).
- Adenopathy un porta hepatis
review
US of acute viral hepatitis
- increase in size
- decrease in echogenicity of liver
- increase in echogenicity of portal venous walls (starry sky)
describe US of chronic viral hepatitis
silhouetting of portal vein walls (i know you like this word Silhouette)
Major screening tool for cirrhosis and its complications
Ultrasound
Gold standard for dx of liver cirrhosis
Ultrasound-guided liver biopsy
Ultrasound of liver cirrhosis
Nodular liver contour
Increased echogenicity
Rught hepatic lobe atrophy with caudate lobe hypertrophy
In advanced disease : shrunken liver
Ultrasound of portal hypertension
Collateral veins
Increased portal vein diameter
Decreased flow in the portal circulation (doppler)
review
which one of these goals, only US is sufficient:
1. suggestion of acute viral hepatitis
2. confirm the diagnosis diagnose
3. detection of HCC in cirrhotic liver
only 1 is correct
2. diagnosis is confirmed by serology + biopsy
3. for HCC in cirrhotic liver US has poor sensitivity and specificity
review
what is the most useful technique for diagnosis of liver cirrhosis
Ultrasonography elastography
