 |
|
|
|
|
 |
|
| |
HEPATOCELLULAR CARCINOMA IMAGING
Category: Diagnostic Radiology
Abstract : Hepatocellular carcinoma (HCC) This primary carcinoma of the liver is more
common in Africa and the Far East than in the UK. Most HCCs arise in diseased
livers, hence the strong association with alcoholic cirrhosis and hepatitis, and
one of the main reasons for ultrasound referral in these patients is to try to
exclude focal liver lesions which could represent carcinoma. HCC is also
a
Hepatocellular carcinoma (HCC)
This primary carcinoma of the liver is more
common in Africa and the Far East than in the UK. Most HCCs arise in diseased
livers, hence the strong association with alcoholic cirrhosis and hepatitis, and
one of the main reasons for ultrasound referral in these patients is to try to
exclude focal liver lesions which could represent carcinoma.
HCC is also
associated with metabolic disorders and drug-related liver disease. Clinically,
small tumours are asymptomatic but cause a raised serum alpha-fetoprotein (AFP).
The relationship between cirrhosis and HCC prompts screening of such patients
with AFP and ultrasound.
The ultrasound appearances of HCC vary from
hypoechogenic to hyperechogenic or mixed echogenicity lesions. It is often
particularly difficult to locate small HCCs in a cirrhotic liver which is
already coarse-textured and nodular. CT and MRI may be useful in these cases.
These lesions may be solitary or multifocal. Colour and spectral Doppler can
demonstrate vigorous flow, helping to distinguish HCCs from metastases or
haemangiomas, which demonstrate little or no flow. All carcinomas demonstrate
neovascularization: the formation of numerous new blood vessels to supply the
growing lesion.
The vascular characteristics of such new vessels are
different from those of the normal, established vessels. The lesion usually
demonstrates a knot of short, tortuous vessels with an irregular course. Because
these new vessels have a paucity of smooth muscle in the intima and media, they
exhibit a low resistance to blood flow, having relatively high end diastolic
flow (EDF). They are able to multiply relatively quickly, causing arteriovenous
shunting within the mass which may result in high
velocities.
Increasingly, contrast ultrasound is used to detect and
characterize HCCs in patients with a background of liver disease. HCCs tend to
demonstrate an early enhancement of tortuous vessels, followed by a ‘blush’ of
arterial enhancement compared to normal liver.
Hit: 220 times
Related Articles in Diagnostic Radiology :
|
| |
|
|
|
|
|
Advertise with Health Information Encyclopedia