الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
A wide spectrum of benign and malignant lesions other than HCC
may be found in the cirrhotic liver. MRI should be preferred over CT as
the primary imaging modality for the evaluation of cirrhotic patients due
to its greater ability to detect and characterize focal lesions. In this study, we noticed that the dynamic study of the majority of
HCC lesions displayed the typical early arterial enhancement and contrast
washout in the portal and delayed phases. The arterial enhancement
(hypervascularity) and delayed hypointensity are considered essential
characteristic features for HCC as the tumor recruits unpaired arteries and
sinusoidal capillaries with resultant avid arterial enhancement. Rarely,
HCC may remain hyperintense relative to adjacent liver parenchyma on
venous and delayed phase images. However, HCC may be hypovascular
to the surrounding liver parenchyma on the immediate gadoliniumenhanced
images, and this may be related to lack of arterialization of the
tumor and in these cases diagnosis by imaging is difficult and biopsy is
essential.
In the study, vascular invasion into the portal vein was not noticed
in any case of HCC lesions. However malignant portal vein thrombosis
in association with HCC is demonstrated by the same signal intensity and
contrast enhancement pattern as the primary tumor. In this study, we have seven cases of hemangioma, all of them
were relatively typical in appearance which is ” peripheral nodular
enhancement and progressive fill-in” is the most typical of cavernous
hemangiomas with contrast enhanced dynamic MR imaging.
Specific MR imaging findings that are important to recognize for
Characterization of cystic focal liver lesions are the size of the lesion; the
presence and thickness of a wall; the presence of septa, calcifications, or
internal nodules; the enhancement pattern; the MR cholangiographic
appearance; and the signal intensity spectrum. In addition, access to
critical clinical information remains extremely important. The most
important clinical parameters defined include age and gender, clinical
history, and symptoms.
The spectrum of multilocular cystic hepatic lesions includes
common and uncommon entities. A lesion’s cystic component and
internal septa usually reflect its underlying pathologic basis, although
imaging findings are not always specific. In this study there were four cases of hepatic cysts have
homogeneous very low signal intensity on T1-weighted images and
homogeneous very high signal intensity on T2-weighted images with no
enhancement is seen after administration of gadolinium chelates. One case of pyogenic liver abscess which is a multiseptated large
cavity showing rim and septa enhancement with a characteristic target
appearance (the “double target” sign).
The diagnosis of hypervascular metastatic lesions was more or less
easier by knowing that the patients have primary malignancy, so this
raises the importance of searching for a primary malignancy in cases we
find multiple hepatic nodular lesions even in cirrhotic patients. Malignant tumors were more common in males (76.2%) than in
females (23.8%), also benign tumors more common in males (63.2%)
than in females (36.8%).
In this study there is significant relationship between diagnosis of
patients and arterial phase. 78% of patients with hepatocellular carcinoma
showed early enhancement while and 100% of hemangioma cases showed
peripheral fill. Secondaries in liver showed early enhancement in (33.5%) &
peripheral enhancement in (66.5%). Moreover, there is significant relationship between diagnosis of
patients and portovenous phase. 78% of patients with hepatocellular
carcinoma showed washout while 100% of hemangioma cases showed
gradual fill. Secondaries in liver showed no washout.
In addition, there is significant relationship between diagnosis of
patients and delayed phase. 78% of patients with hepatocellular carcinoma
showed washout. 100% of hemangioma cases showed centripetal fill.
Secondaries in liver showed no washout.
So far MRI was found to be of great value in diagnosing and
differentiating between the different cirrhotic hypervascular nodules. This
technique can be implemented simply and reliably. It offers the
advantages of significantly shorter acquisition times, retrospective thinor
thick-section reconstruction from the same raw data, improved threedimensional
rendering, and high-quality liver imaging with high intrinsic
soft-tissue contrast. It also provides a global overview of the abdomen. Its
relative contraindications include renal impairment and sensitivity to IV
contrast.