碘油在磁共振上信号特点的探讨

目的探讨碘油在磁共振上信号特点。方法收集2例肝癌插管化疗栓塞（TACE）患者，于0．5T的MR仪行常规腹部磁共振检查，包括SE序列T1WI、T2WI。制备样品：碘油样品取作肝栓塞剂的碘化油，并各取12ml的蒸馏水、泛影葡胺、碘海醇、碘（分析纯）、大豆色拉油、菜子油、血清置试管内作为对照。将试管顺序排列，于0．5T的MR仪进行多参数扫描；同时，将各制备品试管置于随机选取的常规扫描者体侧，获得试管与身体组织共同扫描图象，计算SNR值进行对比。结果在不同的磁场强度中碘油产生的信号强度不同，但可以通过调整扫描参数使信号强度趋于一致。碘油在体外SE序列T1WI上呈高信号，T2WI上低信号。体内成像的表现与周围环境的信号对比有关，在与正常肝脏对比中均为低信号。碘在MRI各个序列上均不成像，并且影响其他物质的碘油的信号强度低于油脂的信号强度。自旋回波长TR多回波的图像上信号强度SNR，TE30=6．3、TE60=2．8，TE90=1．6。结论可以用在自旋回波长TR多回波的图像来区分碘油，判断碘油的沉积情况，同时显示残存肿瘤的信号。

Study on charactoristic image of lipiodol in nuclear magnetic resonance signal

Objective To study the characteristic image of lipiodol in nuclear magnetic resonance signal. To aqurie T1 WI and T2 WI signal of SE sequence in MRI and study the model＇s imaging of T2 WI ,multiple long TR spin echo , the change patten of the signals and its comparison with signals of other materials , as well as the signal intensity＇ s change under different field. Methods Two patients with HCC were studied retrospectively. CT and MRI scans were performed both before and 1 month or 3 week after TACE . the CT as a gold standard was performed to check whether embolized mdules contained lipiodol and how lipiodol was distributed within them. Standard SE T1WI and T2WI were obtained with use of a routine protocol for liver imaging on a 0.5T whole body scanner, on the same samples. SNR of lipiodol was also compared with that of liver tissues and vegetable oil. Results The lipiodofshowed lower signal intensities than the liver parenchyma in both T1 - weighted images （T1WI） and T2 - weighted （T2WI）. On T1WI we observed that the lipiodol increased the SNR , on T2WI signal intensity of lipiodol and noise at the same level. On multiecho images MR signal decreased with extend TE time. Lipiodol accumulationragions shows lower signal intensities than the normal hepatic parenchyma, on SE T1WI and T2WI, by SNR data analysed after TACE. Conclusion On multiecho images , image of multiple long TR spin echo could be used to distinguish lipiodol , therefore judging the status of deposition and showing the signal of remant tumor at the same time .