Tanimoto A, Kreft B P, Baba Y, Zhao L, Finn J P, Compton C C, Stark D D
Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston.
J Magn Reson Imaging. 1993 Sep-Oct;3(5):786-93. doi: 10.1002/jmri.1880030515.
The hepatocyte-specific paramagnetic magnetic resonance (MR) contrast agents manganese-DPDP [N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'bis-(phosphate)] and gadobenate dimeglumine were used for diagnosing chemically induced hepatitis in rats. Ex vivo liver tissue relaxation times and in vivo MR image signal-to-noise ratios were compared before and after contrast agent administration. Ex vivo relaxometry and in vivo MR imaging showed that Mn-DPDP enhanced normal and diseased livers to the same degree at all time points from 5 to 120 minutes. Gadobenate dimeglumine showed reduced T1 and T2 enhancements in hepatitis relative to those of normal liver, in the early phase (5-30 minutes). However, these effects are offsetting, and as a result, MR imaging failed to allow distinction of diseased from normal livers. This surprising result observed in vivo was in fact predicted by applying the Bloch equation to our ex vivo data. Our results show that detection and quantitation of hepatitis with MR imaging enhanced with paramagnetic cell-specific contrast agents will be more difficult than anticipated.
肝细胞特异性顺磁性磁共振（MR）造影剂锰-二乙烯三胺五乙酸二吡啶盐[N，N'-二吡啶氧基乙二胺-N，N'-二乙酸5，5'-双（磷酸盐）]和钆贝葡胺被用于诊断大鼠化学诱导性肝炎。在给予造影剂前后，比较了离体肝脏组织的弛豫时间和体内MR图像的信噪比。离体弛豫测量和体内MR成像显示，在5至120分钟的所有时间点，锰-二乙烯三胺五乙酸二吡啶盐对正常肝脏和患病肝脏的增强程度相同。在早期阶段（5至30分钟），相对于正常肝脏，钆贝葡胺在肝炎中显示出T1和T2增强作用减弱。然而，这些影响相互抵消，结果，MR成像无法区分患病肝脏和正常肝脏。在体内观察到的这一惊人结果实际上是通过将布洛赫方程应用于我们的离体数据预测出来的。我们的结果表明，使用顺磁性细胞特异性造影剂增强的MR成像检测和定量肝炎比预期的更困难。
