Kumar Pratik, Jagannathan N R, Choudhry V P
Medical Physics Unit, IRCH, All India Institute of Medical Sciences, New Delhi 110029.
J Indian Med Assoc. 2007 Oct;105(10):561-4, 591.
The patients of thalassaemia major need repeated blood transfusion which leads to excess iron deposition in various organs like liver, heart, pituitary etc. This iron accumulation causes various complications and ultimately organs' failure. There is no non-invasive, standard and reliable method to know the status of iron overload in various organs of the body. This paper attempts to use magnetic resonance imaging to know the liver iron overload in 8 thalassaemic patients as a pilot study. Eight children suffering with thalassaemia and 3 controls who were the normal siblings of the patient group underwent magnetic resonance imaging of the abdomen using spin-echo T, weighted sequence. Blood serum ferritin levels in the patients' group were also determined on the same day of magnetic resonance imaging examination. It was observed that the ratio of magnetic resonance imaging signal intensity (in spin-echo T1 weighted image) in paraspinous muscle to liver was significantly different in normal control (0.65) compared to that in thalassaemia patients (2.1 to 11.4 depending upon extent of iron deposition). The magnetic resonance signal intensity ratio correlated with the blood serum ferritin level of patients (p = 0.01) which is generally taken as indirect measure of body iron burden. Spin-echo sequence is the simplest imaging sequence and it increases the chance of its routine use. The study concludes that magnetic resonance imaging has good potential to quantify the liver iron deposition non-invasively and may denote the efficacy of iron-chelation therapy which is used to reduce the body iron burden in these patients.
重型地中海贫血患者需要反复输血,这会导致铁在肝脏、心脏、垂体等多个器官中过量沉积。这种铁的积累会引发各种并发症,最终导致器官衰竭。目前尚无一种非侵入性、标准且可靠的方法来了解身体各器官中铁过载的状况。本文尝试通过磁共振成像来了解8例地中海贫血患者的肝脏铁过载情况,作为一项初步研究。8例患地中海贫血的儿童以及3名作为患者组正常同胞的对照者,采用自旋回波T1加权序列进行腹部磁共振成像检查。在磁共振成像检查当天,还测定了患者组的血清铁蛋白水平。结果观察到,正常对照组中脊柱旁肌肉与肝脏的磁共振成像信号强度比(自旋回波T1加权图像中)为0.65,与地中海贫血患者(根据铁沉积程度,该比值在2.1至11.4之间)相比有显著差异。磁共振信号强度比与患者的血清铁蛋白水平相关(p = 0.01),血清铁蛋白水平通常被视为身体铁负荷的间接指标。自旋回波序列是最简单的成像序列,这增加了其常规使用的可能性。该研究得出结论,磁共振成像具有良好的潜力,可以非侵入性地量化肝脏铁沉积,并可能表明用于减轻这些患者身体铁负荷的铁螯合疗法的疗效。