Research on MRI Contrast Agents for the Liver.

1. 使用Gd-DTPA，我们评估了其在肝脏肿瘤中的鉴别诊断准确性，并研究了肝细胞癌（HCC）治疗的评估。在自旋回声延迟期，HCC与肝海绵状血管瘤（HCH）的鉴别准确率为94%。为了评估晚期发现的微弱强化的诊断作用，Gd-DTPA给药剂量从0.05增加到0.2m mol/kg。然而，HCC显示典型的HCH模式从7%上升到15%。动态MRI与动态CT相比，两者的研究基本相同，尽管扫描间隔和时间不同，使用的成像方向不同，但只有3%的病变诊断不同。因此，MRI在微弱增强区域的检测上优于CT，不良反应的发生频率和严重程度也较低。然而，我们尚未证实在肝癌治疗后早期发现复发方面优于CT的优势，以及迄今为止治疗效果的评价。MRI造影剂在弥漫性肝病（如肝硬化和放射性肝炎）中的应用也被评估。非铁沉积型再生结节在平面上表现为相对高强度，增强后因Glisson氏鞘增强明显而变为等强度或低强度。然而，由于空间分辨率较差，MRI对CT所获得的结果没有任何补充。放射性肝炎在肝细胞癌增强峰后呈渐进性、显著性增强。强化峰出现的时间和程度不同，推测与照射剂量、照射后时间和肝炎组织状态有关。我们首先用氧化铁MRI报道了土旱鼠高分化肝细胞癌中网状内皮系统的存在，随后，在人类受试者中也发现了这一现象，我们用DAB诱导的肝肿瘤大鼠比较了氧化铁和戊二醛的剂量和峰值时间。少

1. Nonspecific Contrast Agents Using Gd-DTPA, we evaluted its differential diagnostic accuracy among liver tumors and investigated the evaluation of treatment in hepatocellular carcinoma (HCC). In delayed phase of spin echo, differentiation of HCC from hepatic cavernous hemangioma (HCH) was achieved with accuracy of 94%. In order to evaluate the diagnostic role of subtle ehancement noted in the late phase, the dose of Gd-DTPA administered was increased from 0.05 to 0.2m mol/kg. However, HCC revealing the typical HCH pattern was in creased from 7% to 15%. Comparing dynamic MRI with dynamic CT, both studies were essentially same and only 3% of lesions had different diagnoses despite different scanning interval and time as well as different direction of imaging used. Thus MRI was superior to CT in the detection of feebly enhanced areas and in less frequent and severe adverse effects. However, we failed to confirm the advantage over CT in the early detection of recurrence in treated HCC an … More d the evaluation of treatment effect so far. The utility of MRI contrast agent was also evaluated in diffuse liver diseases such as liver cirrhosis and radiation hepatitis. Regenerating nodules of non-iron deposit type appeared as relatively hyperintense on plain Tl-weighted image and became isointense or hypoinse after contrast enhancement because of prominent enhancement of Glisson's sheath. However, due to inferior spatial resolution, MRI did not have anything adding to findings obtained with CT. Radiation hepatitis showed gradual, prominent enhancement behind the enhancement peak of HCC. The time and degree of enhancement peak were varying and were inferred to be related with radiation dose, period after irradiation and histological state of hapatitis.2. Specific Contrast Agents We first reported the presence of reticulo-endothelisl system in well-differentiated HCC of woodchuck with MRI using iron oxide, and later, this phenomenon was also noted in human subjects, Iron oxide and Glutal were compared in terms of dose and peak time using rat having hepatic tumors induced by DAB. Less