磁共振DCE和DWI联合评价孤立性肺结节的临床意义

The clinical significance of joint evaluating solitary pulmonary nodule by DCE and DWI of MRI

目的:研究MRI动态对比增强(DCE)联合扩散加权成像(DWI)对孤立性肺结节(SPN)的鉴别诊断价值。方法:收集SPN患者62例,其中恶性35例,良性27例,全部先行MRI胸部常规T1WI、T2WI和DWI检查,再行DCE检查。在工作站测量SPN在不同b值时的ADC值;根据Schaefer分型标准观察动态增强曲线类型,并计算曲线最大斜率(Steepest slope,SS)和廓清率(Washout ratio,WR)。评价诊断恶性SPN的敏感性、特异性及准确率。结果:良、恶性SPN曲线类型之间差异无显著统计学意义(P>0.05);B型曲线在良、恶性SPN之间有重叠,SS在二者间有显著统计学意义(P<0.05);以SS>2.5%/s作为诊断恶性SPN的依据,DCE诊断恶性SPN的敏感性、特异性、准确率分别为64%、60%、62%。B型曲线类型SPN在b值为800 s/mm2和1 000 s/mm2时,其ADC值差异有显著统计学意义(P<0.05),以ADC值<1.34×10-3mm2/s作为诊断依据,DCE联合DWI诊断恶性SPN的敏感性、特异性、准确率分别为80%、75%、78%;结论:DCE和DWI对良、恶性SPN的鉴别诊断分别有意义,综合运用DCE和DWI参数能提高恶性SPN的诊断准确率。

Objective： To study differential diagnosis value in the benign and malignant solitary pulmonary nodule（SPN） by dynamic contrast-enhanced（DCE） and diffusion weighted imaging（DWI） of magnetic resonance imaging（MRI）. Methods： The 62 SPN patients were firstly examined by routine T,WI, T2WI and DWI, secondly by DCE-MRI, including 35 malignant and 27 benign lesions. The ADC values were measured of different b values at work station, the curve types were observed according to Schaefer standard, steepest slope（SS） and washout ratio（WR） were calculated. The sensitivity, specificity and accuracy in the diagnosis of malignant SPN were evaluated. Results： The curve types were not significantly different between benign and malignant SPNs（P〉0.05）; The B type curve was overlap, the SS was significantly different between them（P〈0.05）; It had a sensitivity of 64%, a specificity of 60% and a accuracy rate of 62% for malignant SPN diagnosis according to SS value being more than 2.5%/s; The ADC values of SPNs were significantly different at b 800 s/mm^2 and 1 000 s/mm^2 with B curve type（P〈 0.05）. Combination of DCE and DWI, it had a sensitivity of 80%, a specificity of 75% and a accuracy rate of 78% for malignant SPN diagnosis according to ADC value being less than 1.34×10^-3 mm^2/s. Conclusion： The differential diagnosis of benign and malignant SPN is significant by DCE and DWI respectively. Combined application of DCE and DWI can improve the accuracy of diagnosis of malignant SPN.