Diagnosis and evaluation of hepatocellular carcinoma and precancerous states using magnetic resonance imaging

1.肝细胞癌的诊断：磁共振成像（MRI）在评价肝细胞癌（HCC）方面与常规CT一样有效。横向弛豫时间（T2）的测定对HCC与海绵状血管瘤的鉴别诊断准确率在90%以上. HCC和癌前状态的病理生理学; T2加权或梯度回波图像上的MRI可以检测到肝硬化（HCC的高危状态）的再生结节为无数微小的低强度结节。它不仅有助于与微小肝癌（如检出，T2加权像上总是高信号）的鉴别诊断，而且有助于肝硬化的评价和观察。肝癌常因癌栓或直接压迫门静脉而引起门静脉阻塞。门静脉阻塞远端的边缘区在T2加权像上表现为高信号区，这是由于门静脉血流阻塞的继发性改变。3.对比剂：肝脏肿瘤采用钆-DTPA动态MRI，海绵状血管瘤表现为长时间明显强化，易于与HCC鉴别。

1.Diagnosis of hepatocellular carcinoma; Magnetic resonance imaging(MRI) was as effective as conventional CT in the evaluation of hepatocellular carcinoma(HCC). Differentiation of HCC from cavernous hemangioma was accurate in over 90% by measurement of transverse relaxation time(T2).2. Pathophysiology of HCC and precancerous states; MRI either on T2-weighted- or gradient echo image could detect regenerating nodules of liver cirrhosis (high risk state for HCC) as innumerable tiny low intensity nodules. It is useful not only in the differential diagnosis from tiny HCC(always high-intensity on T2-weighted image,if detected) but also in the evaluation and observation of liver cirrhosis. HCC often causes portal vein obstruction either by tumor thrombus or by direct compression. Peripheral zone distal to portal obstruction appeared as high intensity area on T2-weighted image due to secondary change of portal blood flow stoppage.3.Contrast agent; Dynamic MRI using gadolinium-DTPA was applied in liver tumors, where cavernous hemangioma showed prolonged,marked enhancement and was easily differentiated form HCC.