Shuter B, Wang S C, Roche J, Briggs G, Pope J M
Department of Nuclear Medicine, The Royal North Shore Hospital, St. Leonards, NSW, Australia.
J Magn Reson Imaging. 1998 Jul-Aug;8(4):853-61. doi: 10.1002/jmri.1880080415.
After injection of Gd-EOB-DTPA, T1 and T2 were determined on a clinical MR scanner (1.5 T) in the liver and kidneys of sacrificed but intact guinea pigs with normal and obstructed biliary systems and in bile, urine, and blood collected postmortem. Tissue [Gd] was determined by radioassay of 153Gd and relaxivities (R1 and R2; units of s(-1) x mmol(-1) x kg) of Gd-EOB-DTPA calculated. Compared with R1 in 2% agarose gel (4.49 +/- 0.03), in normal animals R1 was increased in liver (9.3 +/- 0.5), similar in kidney cortex (4.1 +/- 0.5), but reduced in kidney medulla (2.5 +/- 0.4) and papilla (2.7 +/- 0.4). Chronic biliary obstruction did not change R1 in liver (9.7 +/- 4.3) but reduced R1 further in kidney tissues (1.0-0.4). In normal animals, R2 values of all tissues (9.5-18.4) were greater than R2 in gel (5.72 +/- 0.12). Biliary obstruction possibly elevated R2 in liver (40.1 +/- 63.5), severely depressed R2 in kidney cortex (-4.2 +/- 6.2) and medulla (-2.3 +/- 5.4), and reduced R2 in papilla (5.4 +/- 4.6). Obstruction had little effect on R1 and R2 in bile and urine. Water content, macromolecular binding, microviscosity, compartmentalization, and susceptibility effects can readily account for the R1 and R2 observed in liver and kidney. Negative R2 could be a result of several factors, including reduced endogenous magnetic field gradients due to "susceptibility matching" as [Gd] increased, changes in tissue T2 with period of ligation, or a physiological effect of EOB-DTPA. These results show that disease can alter both R1 and R2 from their values in normal tissues.
注射钆塞酸二钠（Gd-EOB-DTPA）后，在临床磁共振扫描仪（1.5T）上测定正常和胆道梗阻的处死但完整的豚鼠肝脏和肾脏中的T1和T2，并测定死后收集的胆汁、尿液和血液中的T1和T2。通过对153Gd进行放射性测定来确定组织中的[Gd]，并计算Gd-EOB-DTPA的弛豫率（R1和R2；单位为s(-1)×mmol(-1)×kg）。与2%琼脂糖凝胶中的R1（4.49±0.03）相比，正常动物肝脏中的R1升高（9.3±0.5），肾皮质中的R1相似（4.1±0.5），但肾髓质（2.5±0.4）和乳头中的R1降低。慢性胆道梗阻未改变肝脏中的R1（9.7±4.3），但进一步降低了肾脏组织中的R1（1.0 - 0.4）。在正常动物中，所有组织的R2值（9.5 - 18.4）均大于凝胶中的R2（5.72±0.12）。胆道梗阻可能会升高肝脏中的R2（40.1±63.5），严重降低肾皮质中的R2（-4.2±6.2）和髓质中的R2（-2.3±5.4），并降低乳头中的R2（5.4±4.6）。梗阻对胆汁和尿液中的R1和R2影响很小。含水量、大分子结合、微粘度、分隔和磁化率效应很容易解释在肝脏和肾脏中观察到的R1和R2。负的R2可能是多种因素的结果，包括随着[Gd]增加由于“磁化率匹配”导致内源性磁场梯度降低、结扎期组织T2的变化或EOB-DTPA的生理效应。这些结果表明，疾病可使R1和R2与正常组织中的值发生改变。
