Jensen P D, Jensen F T, Christensen T, Ellegaard J
Department of Medicine and Haematology, Amtssygehuset, Denmark.
Br J Haematol. 1994 May;87(1):171-84. doi: 10.1111/j.1365-2141.1994.tb04888.x.
We investigated the clinical usefulness of a standard magnetic resonance imaging (MRI) system for non-invasive determination of the liver iron concentration in 38 patients with iron overload and 15 normal controls by measurement of the signal intensity ratio between liver and skeletal muscle (SIR). However, SIR was found dependent on the applied repetition time (TR) of the MRI system, which led us to investigate this relationship in autopsy material of liver and muscle tissue specimens with various iron content. Based on these results, adjustment of SIR measurements to a constant value of TR was achieved. By use of this technique we found a close correlation between MRI and chemically determined liver iron concentration (r2 = 0.98) as well as the serum ferritin concentration (r2 = 0.86). The reproducibility was sufficiently good for the use of MRI in the follow-up of iron reductive treatment. The use of iron store parameters in serum was found insufficient as indicators of endpoint for venesection therapy, if 20 mumol Fe/g dry weight was applied as the upper reference limit of the liver iron concentration. It is concluded that MRI based on SIR measurements offers a precise and reproducible non-invasive method for the determination and follow-up of iron overload within a wide range of liver iron concentrations. Our findings may increase the clinical use of MRI in haematological patients with iron overload.
我们通过测量肝脏与骨骼肌的信号强度比（SIR），研究了标准磁共振成像（MRI）系统对38例铁过载患者和15例正常对照者进行肝脏铁浓度无创测定的临床实用性。然而，发现SIR取决于MRI系统所采用的重复时间（TR），这促使我们在具有不同铁含量的肝脏和肌肉组织标本的尸检材料中研究这种关系。基于这些结果，实现了将SIR测量值调整到恒定的TR值。通过使用该技术，我们发现MRI与化学测定的肝脏铁浓度（r2 = 0.98）以及血清铁蛋白浓度（r2 = 0.86）之间存在密切相关性。对于铁还原治疗的随访，MRI的可重复性足够好。如果将20 μmol Fe/g干重作为肝脏铁浓度的上限参考值，则发现血清中铁储存参数作为放血疗法终点指标并不充分。结论是，基于SIR测量的MRI为在广泛的肝脏铁浓度范围内测定和随访铁过载提供了一种精确且可重复的无创方法。我们的发现可能会增加MRI在铁过载血液病患者中的临床应用。
