Clément O, Mühler A, Vexler V, Berthezène Y, Brasch R C
Department of Radiology, University of California San Francisco 94143-0628.
Invest Radiol. 1992 Aug;27(8):612-9.
Gadolinium-ethoxybenzyl-DTPA (Gd-EOB-DTPA) is a new hepatobiliary magnetic resonance imaging (MRI) contrast agent with a dual elimination: 70% via the liver and bile and 30% via the kidney in normal rats. The abdominal enhancement patterns of this new compound and the uptake mechanism by the liver were studied in rats using tissue relaxometry and MRI.
Twelve normal rats, 33 rats treated with agents designed to inhibit biliary excretion of the agent, and 6 rats with surgically ligated common bile ducts received Gd-EOB-DTPA intravenously. Distribution and excretion were measured by MR relaxometry. MR signal intensity was measured over time for liver, kidney, and bowel.
In normal animals, 0.1 mmol/kg Gd-EOB-DTPA induced a significantly greater (200%) and more prolonged liver signal enhancement (100% at 30 minutes) than Gd-DTPA at the same dose. Either hyperbilirubinemia, induced by common bile duct ligation, or bromosulfophtalein (BSP) infusion inhibited liver uptake of Gd-EOB-DTPA, resulting in a preferential elimination via the kidney. Taurocholate (TC), an inhibitor of the bile acid transporter, was unable to block the liver uptake of Gd-EOB-DTPA. Blood half-lives of Gd-EOB-DTPA in rats were 2.4 minutes for the first component and 8.2 minutes for the second.
Data indicate that transport of Gd-EOB-DTPA through the liver into bile is driven by the organic anion transporter. The relation between enhancement of liver and kidney may be diagnostically useful to indirectly evaluate liver excretory function. Yet, persistent enhancement of liver, even in the presence of severe hyperbilirubinemia, should be sufficient to identify focal mass lesions.
钆乙氧基苄基二乙三胺五乙酸（Gd - EOB - DTPA）是一种新型的肝胆磁共振成像（MRI）造影剂，在正常大鼠体内有双重清除途径：70%经肝脏和胆汁清除，30%经肾脏清除。本研究采用组织弛豫测量法和MRI研究了该新型化合物在大鼠体内的腹部增强模式及肝脏摄取机制。
12只正常大鼠、33只接受旨在抑制该造影剂胆汁排泄药物治疗的大鼠以及6只手术结扎胆总管的大鼠静脉注射Gd - EOB - DTPA。通过磁共振弛豫测量法测量其分布和排泄情况。随时间测量肝脏、肾脏和肠道的磁共振信号强度。
在正常动物中，0.1 mmol/kg的Gd - EOB - DTPA比相同剂量的Gd - DTPA能诱导出显著更强（200%）且更持久的肝脏信号增强（30分钟时为100%）。胆总管结扎诱导的高胆红素血症或静脉注射溴磺酞钠（BSP）均抑制了Gd - EOB - DTPA的肝脏摄取，导致其优先经肾脏清除。胆汁酸转运体抑制剂牛磺胆酸盐（TC）无法阻断Gd - EOB - DTPA的肝脏摄取。Gd - EOB - DTPA在大鼠体内的血液半衰期，第一成分是2.4分钟，第二成分是8.2分钟。
数据表明，Gd - EOB - DTPA通过肝脏进入胆汁的转运是由有机阴离子转运体驱动的。肝脏和肾脏增强之间的关系可能在诊断上有助于间接评估肝脏排泄功能。然而，即使在存在严重高胆红素血症的情况下，肝脏的持续增强也应足以识别局灶性肿块病变。
