الفهرس 
Introduction & aim of the studyOnly 14 pages are availabe for public view
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Abstract
The objectives of liver imaging in oncology are the detection of the liver disease, the characterization of liver lesions, the staging of neoplasms, the evaluation of biliary ductal status, the evaluation of treatment response, and the assessment of vascular anatomy for surgical planning and chemotherapy placement . Diagnostic Approach: A detailed history should be obtained from a patient with a lesion of the liver, and a physical examination should be performed to assess whether underlying liver disease or malignancy may be present (Figure 58). Comorbid illnesses, medications, and the use of oral contraceptives should be recorded. If the patient has a history of cancer and a liver lesion is found on follow-up, the lesion will most often be a metastasis. Tumor markers should be obtained and enhanced dynamic CT performed. Spiral arterial phase CT allows small lesions less than 1.5 cm in diameter to be defined. CT also allows an evaluation of other intraabdominal tissues. Metastases usually appear hypodense around the enhanced liver parenchyma. Vascular metastatic lesions exhibit peripheral enhancement during the arterial phase and then may become isodense . CT with arterial portography (CTAP) is a very effective modality in the detection of small lesions 172. Ferumoxides-enhanced MRI is more accurate than unenhanced MRI and at least as accurate as CTAP for the detection of hepatic metastases . If the patient has cirrhosis or serologic markers of viral hepatitis and a solid or new lesion is found, HCC is likely, especially if the lesion appears hypervascular on dynamic CT. Angiographically assisted helical CT was superior to MRI in one study. If the patient does not have a history of malignancy, no clinical evidence of malignancy or underlying liver disease is found, and the tumor markers and results of serology for viral hepatitis are negative, a solid lesion of the liver is most often benign . The most common benign solid lesions of the liver are hemangiomas (~4%), FNH (0.4%), and adenomas (<0.004%). Small hemangiomas and FNH are usually incidental findings, whereas most adenomas present with abdominal pain or a mass effect. The liver chemistries are usually normal unless a complication such as hemorrhage (usually an adenoma) is present. Ultrasonography and CT provide useful information about the size, number, and location of lesions (Table 1). Ultrasonography should be used as a screening technique because of its excellent sensitivity and low cost. However, it is not specific for tumor differentiation except perhaps in the case of a small hemangioma. When a solid lesion is diagnosed by another imaging modality, ultrasonography adds little to the differential diagnosis. Dynamic CT may conclusively establish the diagnosis of hemangioma and FNH without any further workup. Biphasic and triphasic spiral CT may characterize a wide range of focal liver lesions 172 . Calcification inside a lesion suggests fibrolamellar carcinoma, and hemorrhage within a tumor is more suggestive of adenoma. MRI may help in the differential diagnosis of small tumors and can also detect the central scar of FNH and bleeding in adenoma. Magnetic resonance imaging offers high intrinsic soft tissue contrast and detailed anatomic information owing to its multiplanar capabilities. The clever selection of appropriate MR sequences, as well as the introduction of dynamic scanning and DWI has helped to characterize focal hepatic masses.