Anzai Y, Prince M R
Department of Radiology, University of Michigan Medical Center, Ann Arbor 48109-0030, USA.
J Magn Reson Imaging. 1997 Jan-Feb;7(1):75-81. doi: 10.1002/jmri.1880070111.
Accurate diagnosis of cervical lymph node metastasis is challenging, even with the latest computed tomography or MR equipment and technique. The lack of definitive criteria for distinguishing metastatic from benign nodes is a serious shortcoming of current imaging options. Dextran-coated, ultrasmall superparamagnetic iron oxide is a new MR contrast agent, which accumulates in the reticuloendothelial system of lymph nodes. Small iron oxide particles are taken up by macrophages within normal functioning nodes, reducing their signal on postcontrast MR because of the magnetic susceptibility effects of iron oxide. Metastatic nodes, on the other hand, remain high in signal on postcontrast T2*-weighted gradient echo images. Early clinical experience in cancer patients suggests that iron oxide-enhanced MR lymphography is a valuable imaging technique that may improve diagnostic accuracy for nodal metastases. This article reviews development of superparamagnetic iron oxide compounds, their imaging characteristics, and clinical experience for evaluating head and neck cancer metastases.
即使采用最新的计算机断层扫描或磁共振成像设备及技术，准确诊断颈部淋巴结转移仍具有挑战性。缺乏区分转移性淋巴结与良性淋巴结的明确标准是当前成像方法的一个严重缺陷。葡聚糖包被的超小型超顺磁性氧化铁是一种新型磁共振造影剂，它会在淋巴结的网状内皮系统中蓄积。正常功能的淋巴结内，巨噬细胞会摄取小的氧化铁颗粒，由于氧化铁的磁化率效应，会降低其在造影后磁共振成像上的信号。另一方面，转移性淋巴结在造影后T2*加权梯度回波图像上信号仍然很高。癌症患者的早期临床经验表明，氧化铁增强磁共振淋巴造影是一种有价值的成像技术，可能会提高淋巴结转移的诊断准确性。本文综述了超顺磁性氧化铁化合物的发展、其成像特征以及评估头颈部癌转移的临床经验。
