الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Hepatic focal lesions may be benign or malignant and some of the hypervascular focal lesions may be benign. Therapy requires an accurate diagnosis, which in turn relies primarily on appropriate imaging .
Triphasic CT was believed to be the standard in evaluating the hepatic focal lesions together with alpha fetoprotein but unfortunately, not all cases with HCC having high alpha fetoprotein & not all cases having typical imaging criteria of HCC by Triphasic CT scan & also not all lesions are detected by US or are seen in the dynamic CT study.
Biopsy of all lesions detected with MRI in the setting of liver cirrhosis would be impractical, extremely difficult, if not impossible, and likely to be of low yield also distinguishing between HCC and benign hypervascular lesions such as flash filling hemangiomas & pseudo lesions remain a major challenge in management of patients at risk for developing hepatocellular carcinoma.
MRI is the most sensitive modality in detection and characterization of hepatic focal lesions including small lesions (≤ 2 cm) also in follow up post locoregional therapy as TACE or RF ablation.
Summary and Conclusion
(134)
Most of HCC appear hypointense in T1-weighted images but they may appear hyperintense if it contains glycogen, fat or cupper. In follow up post intervention T1 hyperintensity denotes coagulative necrosis & hemorrhagic products.
For hepatic focal lesions detection and character-ization, conventional MRI relies on T1-weighted, T2-weighted, T1in-phase , T1 out-phase, dynamic gadolinium-enhanced T1-weighted imaging, DWI, ADC value .
MRI with intravenous contrast injection is a safe and well tolerated technique that is easily performed and is sensitive for early detection of malignant neoplastic hepatic lesions, and for differentiation between the premalignant and the malignant lesions. This technique is complementary to other imaging modalities and laboratory studies for full assessment of the hepatocellular lesions in cirrhotic livers.
DW MRI in the liver is a relative new and increasingly used imaging technique. It has the advantage that it can be obtained during a single breath-hold; it provides unique information that reflects tissue cellularity and organization. The ADC maps can also provide quantitative measurements of tissue water diffusibility, which can be used not only for disease assessment, but also for the evaluation of disease response to treatment, Moreover, because of the potential risk of nephrotoxicity in cirrhotic patients with hepatorenal syndrome, DWI as well
Summary and Conclusion
(135)
as T2 seems to be used as a substitute for dynamic imaging in the assessment of a variety of focal liver lesions in cirrhotic patients with poor renal function.
Finally we concluded that ;conventional MRI sequences combined with dynamic MRI and DWI provide further more accurate diagnoses for hepatic focal lesions , especially for hypervascular hepatic focal lesions in cirrhotic patient, which requires the necessity for injecting the contrast material and through the different pattern of enhancement and washout , we could be able to reach the definite diagnosis for these hepatic focal lesions and so starting management as early as possible which reflect on increasing the prognostic criteria for hepatic focal lesions