动态增强磁共振在肺孤立性结节灶中的定量化研究

The quantitative study of dynamic contrast enhanced MRI in solitary pulmonary nodules

目的:利用动态增强MRI的血流动力学参数评估孤立性肺结节,并探讨该方法在鉴别肺结节的良恶性的应用价值。方法:搜集2013年8月-2014年5月期间在本院行动态增强MRI扫描的孤立性肺结节的患者47例(其中恶性结节31例,良性结节16例)。先行全肺常规平扫,然后利用三维快速容积扫描技术(LAVA)对病灶和纵隔进行灌注扫描,测量注药前和注药后15期病灶的信号强度,拟合得到时间-信号曲线(T-SI曲线),计算注药后第1、2、4min信号增强比(SI1%、SI2%、SI4%)和最大信号增强比(MER),达到峰值信号的时间(Tmax),最大上升斜率(SS)以及廓清率(washout)。结果:恶性结节的平均强化量ME、SI1%、SI2%、SI4%、MER、SS、Tmax均与良性结节具有显著性差异(P<0.05),其中SI1%、SI2%、SI4%、MER、Tmax、SS具有非常显著统计学差异(P<0.01)。T-SI曲线可以分为4种类型,恶性结节以A型和B型为主,占30/31,良性结节主要是B型、C型为主,占12/16,D型曲线能够确定结节为良性。结论:利用DCE-MRI可以反映血流动力学参数,作为鉴别恶性病变、良性病变的有潜在前景的检查方法。

Objective：This study is to investigate if kinetic parameters of DCE-MR imaging may help to differentiate ma-lignant and benign SPNs.Methods：A total of 47 patients with SPNs （31 malignant nodules and 16 benign nodules）under-went routine SE/T1WI and FSE/T2WI scanning and liver acquisition of volume accelaration （LAVA）DCE-MRI exams. Two experienced radiologists measured the signal intensity of the mass in 15 phases,generating temporal signal curves.The following analysis were taken：signal at 1,2,4 minutes after bolus injection and the maximum enhancement ratio （MER）;time at the maximum enhancement ratio （Tmax）;the steepest rising slope of time-signal curves;mean enhancement value and washout ratio.Results：It was found that ME,SI1%,SI2%,SI4%,MER,SS,Tmax for the malignant group were signif-icantly different from those for the benign SPN group （P 〈0.05）and SI1%,SI2%,SI4%,MER,Tmax,SS were much sig-nificantly different （P 〈0.01）.The temporal-signal curves were classified into four types.The results showed that type A and B curves were main types for malignant nodules,whereas type B and C mainly occur in the case of benign nodules.In type D three were all benign tumors.Conclusion：DCE-MRI may be a viable tool in differentiating malignant SPNs from be-nign SPNs with the use of kinetic parameters.