Application Of Dynamic Contrast-enhanced MRI Combined With Diffusion-weighted Imaging In Differentiating Pulmonary Nodules

Objective:The aim of our study is evaluating the value of dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI), diffusion-weighted magnetic resonance imaging(DW-MRI) and the combination of two methods by differentiating pulmonary nodules.Materials and Methods:53 cases of pulmonary nodules which diameters covered from 8 mm to 30 mm finding by conventional chest CT are selected prospectively in Shandong Tumor hospital during 2014.1-2015.12. All of pulmonary nodules will be confirmed by biopsy or operation in later stage.All patients underwent conventional T1 WI, T2 WI, T2-FS, DW-MRI and DCE-MRI before biopsy or operation. The regions of interest(ROI) of pulmonary nodules and spinals were drawn after revising images of DW-MRI. And the value of lesion-to-spinal cord ratio(LSR) were calculated. The ROI were drawn in the images of DCE-MRI. And the time-signal intensity curve(TIC) and parameters were produced automatically.All of the parameters were analyzed by SPSS 19.0 statistical software. Compared to pathological results, the sensitivity, specificity, positive predictive value, negative predictive value, YI and diagnostic accordance rate were got for diagnosing malignancy pulmonary nodules of DCE-MRI, DWI-MRI and the combination of two methods. To evaluate the value of DCE-MRI, DW-MRI and the combination of two methods by differentiating pulmonary nodules.Result:There were 53 patients including 28 man and 25 woman. Their ages range from 48 to 77, the mean age is 62.34�8.82. There are 53 cases of pulmonary nodules including 23 benign pulmonary nodules and 30 malignant ones.(1) No significant difference of pulmonary nodules groups between ages, genders, and pulmonary lobes.(2) When b value are 200s/mm2, 400s/mm2, 600s/mm2, 800s/mm2, and 1000s/mm2, the LSR of malignancy pulmonary nodules are higher than inflammatory ones. When b value are 400s/mm2 and 600s/mm2, the LSR value of malignancy nodules are higher than inflammatory ones(P<0.05). While when b value are 200 s/mm2, 800 s/mm2 and 1000 s/mm2, no significant difference of LSR value between pulmonary nodules groups.When b value is 400 s/mm2, the sensitivity for diagnosing malignancy pulmonary nodules of DW-MRI is 63.33%, the specificity is 73.91%, the positive predictive value is 76.00%, the negative predictive value is 60.71%, the positive likelihood ratio is 2.43, the negative likelihood ratio is 0.50, the YI is 37.24%, and the diagnostic accordance rate is 67.92%.When b value is 600 s/mm2, the sensitivity for diagnosing malignancy pulmonary nodules of DW-MRI is 70.00%, the specificity is 65.22%, the positive predictive value is 72.41%, the negative predictive value is 62.50%, the positive likelihood ratio is 2.01, the negative likelihood ratio is 0.46, the YI is 35.22%, and the diagnostic accordance rate is 67.92%.(3) Inflammatory and malignancy pulmonary nodules just exist in A, B, C TIC types. Most of inflammatory and malignancy pulmonary nodules are A, B TIC types. No significant difference of pulmonary nodules groups between A, B, C three curve types.The steepest slope of inflammatory nodules is higher than malignancy ones(p<0.05). While no significant difference of relative enhancement, maximum enhancement, maximum relative enhancement, time to peak, wash out rate and area under the curve between pulmonary nodules groups. The sensitivity for diagnosing malignancy pulmonary nodules of DCE-MRI is 60.00%, the specificity is 78.26%, the positive predictive value is78.26%, the negative predictive value is 60.00%, the positive likelihood ratio is 2.76, the negative likelihood ratio is 0.51, the YI is 38.3%, and the diagnostic accordance rate is 64.2%.(4) There is no different about the value of diagnosing malignancy pulmonary nodules between DCE-MRI and DW-MRI.(5) When combined DCE-MRI with DW-MRI(b value is 400s/mm2), the sensitivity for diagnosing malignancy pulmonary nodules is 86.67%, the specificity is 69.57%, the positive predictive value is 78.79%, the negative predictive value is 80.00%, the positive likelihood ratio is 2.85, the negative likelihood ratio is 0.19, the YI is 56.24%, and the diagnostic accordance rate is 79.25%.When combined DCE-MRI with DW-MRI(b value is 600s/mm2), the sensitivity for diagnosing malignancy pulmonary nodules is 93.33%, the specificity is 47.83%, the positive predictive value is 70.00%, the negative predictive value is 84.62%, the positive likelihood ratio is 1.79, the negative likelihood ratio is 0.14, the YI is 41.16%, and the diagnostic accordance rate is 73.58%.Conclusion:There are some value for LSR to differentiating malignancy pulmonary nodules from inflammatory ones. There are some value for TIC parameters to differentiating malignancy pulmonary nodules from inflammatory ones. But the value of TIC types to differentiating malignancy pulmonary nodules from inflammatory ones is little. There are some value for DCE-MRI and DW-MRI to differentiating malignancy pulmonary nodules from inflammatory ones. There is no different about the value of diagnosing malignancy pulmonary nodules by DCE-MRI or DW-MRI. The diagnostic efficiency of DCE-MRI combined with DW-MRI in diagnosing malignancy pulmonary nodules is superior to those with only one method.