超顺磁性氧化铁(SPIO)对比剂肝脾MR成像的比较研究

A Comparative Study of the Relaxation Effects of Two Superparamagnetic Iron Oxide Agents in MRI of the Liver and Spleen

目的 比较两种超顺磁性氧化铁 (superparamagneticironoxide ,SPIO)对比剂 ,Ferumoxides及SHU 5 5 5A在肝脾MR成像中的效应。材料与方法 3 6例已知为肝转移癌患者于SPIO造影前后进行T2 WI快速自旋回波成像 (T2 WITSE)及T1WI梯度回波快速去相位成像 (T1WIFLASH)。扫描仪为 1.0TMR机。 18例患者行Ferumoxides增强后 90分钟进行MR成像 ;另 18例行SHU 5 5 5A快速团注增强 ,注药后即刻、3 0秒及 480秒行T1WIFLASH成像 ,10分钟行T2 WITSE成像。测量肝脾、肝转移癌SPIO增强前后的信号强度(signalintensity ,SI) ,计算两种SPIO对比剂在肝脾、肝转移癌增强前后SI变化的百分比 (percentagesignalintensitychange ,PSIC)及病灶 肝脏对比噪声比 (lesion to livercontrast to noiseratio ,CNR)及其变化 (ΔCNR)。结果 在T2 WITSE图像上 ,两种SPIO对比剂造成的肝实质SI下降无显著性差异 (P >0 .0 5 )。Ferumoxides引起的脾信号下降显著大于SHU 5 5 5A(P <0 .0 5 )。两种SPIO对比剂均导致肝转移癌CNR显著增高。T1WIFLASH图像上 ,两种对比剂均可导致延迟像上肝脏SI的轻度下降及肝转移癌CNR下降 ,两者肝脏PSIC之间无显著性差异。T1WI上两种对比剂均可导致脾脏SI显著升高 ,两者脾脏PSIC之间无显著性差异 (P >0 .0 5 )

Objective To compare the enhancement effectiveness of two superparamagnetic iron oxide (SPIO) contrast agents, Ferumoxides and SHU 555A, in MRI of the liver and spleen.Materials and Methods T 2W TSE and T 1WI FLASH scanning were performed in 36 cases with hepatic metastases before and after SPIO contrast injection with a 1.0T MR unit. Post Ferumoxides images were obtained 90 min. After the infusion of the agent with a dose of 15 μmol Fe/kg in 18 cases. In the other 18 cases, T 1W FLASH images were obtained at 0, 30, and 480 sec. After a bolus injection of SHU 555A with a dose of 7.0～12.9 μmol Fe/kg, while T 2W TSE images were obtained at 10 min. After the injection. Signal intensity of the liver, spleen and hepatic metastatic lesions was measured with an operator defined region of interest both before and after SPIO admistration. The enhancement effects of Ferumoxides and SHU 555A were expressed as the percentage of signal intensity change (PSIC) of the liver and spleen, the PSIC of the malignant liver lesions, and the changes in lesion to liver contrast to noise ratio (ΔCNR).Results No significant difference in signal loss of liver parenchyma between the two agents was found on T 2W TSE images, (P> 0.05). Both SPIO agents produced a significant increase in the CNR of malignant liver lesions. ΔCNR in Ferumoxides group was slightly greater than that in SHU 555A group (P< 0.05). On T 1W FLASH images, a slight decrease of liver SI induced by the two agents was seen on late post SPIO images. No significant difference in liver PSIC between two groups was noted onT 1W images. The CNR of hepatic metastatic lesions was decreased in both groups on T 1W images. The SI of spleen was significantly increased in both groups on T 1W images and no difference in PSIC of spleen was noted (P>0.05).Conclusion Ferumoxides and SHU 555A have similar T 1 and T 2 enhancement effects for the liver, while Ferumoxides carries a stronger T 2 enhancement effects for the spleen than SHU 555A does.