Engelhardt R, Langkowski J H, Fischer R, Nielsen P, Kooijman H, Heinrich H C, Bücheler E
Abteilung Medizinische Biochemie, Universitätskrankenhaus Eppendorf, Hamburg, Germany.
Magn Reson Imaging. 1994;12(7):999-1007. doi: 10.1016/0730-725x(94)91230-t.
For the noninvasive liver iron quantification by MRI in human iron overload diseases, fundamental proton relaxation mechanisms were studied in aqueous solutions with ferritin and other iron compounds, in experimentally iron overloaded rats, and in patients with iron overload diseases. MR-relaxation rates as a function of iron concentrations in the range of 0-7.5 mg Fe/g aqueous iron solutions, 0-5.4 mg Fe/g rat liver in vivo, and 0.16-4.9 mg Fe/g human liver in vivo were determined from multi- and sets of single-spin echo sequences (1.5 T imager). As predicted by theory, transverse relaxation rates (1/T2) in aqueous iron solutions, in liver tissue of rats, and in human liver tissue increased linearly with the iron concentration. A preliminary calibration for the liver iron quantification by MRI was performed from in vivo measurements of liver 1/T2-relaxation rates and liver iron quantification by atomic absorption spectroscopy in biopsies from 13 patients. With the single spin-echo method, precise in vivo liver iron quantification in humans also above 2.0 mg Fe/g liver tissue (T2 < 15 ms) should be accomplished on any imager with shortest spin-echo time available, at least TE < 20 ms.
对于通过MRI对人类铁过载疾病进行无创性肝脏铁定量分析，我们在含有铁蛋白和其他铁化合物的水溶液中、实验性铁过载大鼠以及铁过载疾病患者中研究了基本的质子弛豫机制。通过多组和单组自旋回波序列（1.5T成像仪）测定了在0 - 7.5mg Fe/g水相铁溶液、0 - 5.4mg Fe/g大鼠肝脏活体以及0.16 - 4.9mg Fe/g人类肝脏活体范围内，作为铁浓度函数的磁共振弛豫率。正如理论所预测的，水相铁溶液、大鼠肝脏组织以及人类肝脏组织中的横向弛豫率(1/T2)随铁浓度呈线性增加。通过对13例患者活检样本中肝脏1/T2弛豫率的活体测量以及原子吸收光谱法进行的肝脏铁定量分析，对MRI肝脏铁定量分析进行了初步校准。使用单自旋回波方法，在任何具有最短可用自旋回波时间（至少TE < 20ms）的成像仪上，也应该能够在肝脏组织铁含量高于2.0mg Fe/g（T2 < 15ms）的人类中实现精确的活体肝脏铁定量分析。
