The Application Value Of Multi-parametric Magnetic Resonance Imaging In The Diagnosis Of Benign And Malignant Paranasal Sinus Lesions

Objective: MRI has played an important role in the diagnosis of benign and malignant paranasal sinus lesions now,especially diffusion-weighed imaging(DWI),dynamic contrast-enhanced imaging(DCE-MRI),which has developed much faster.To evaluate the clinical value of multi-modality magnetic resonance imaging on paranasal sinus lesions,this study was carried out.Materials and Methods: From March,2014 to March,2017,with 76 cases with paranasal sinus lesions collected,age 12-73 average age 47,all cases were post-surgery or puncture pathology.All patients performed MR routine,diffusion and dynamic enhancement check,retrospective analysis of the imaging findings.(1)conventional MRI,including axial and coronal T1 WI,T2WI fat suppression sequence,observe the lesions’ location,shape,signal intensity characteristics,edge,growth pattern and adjacent tissue structure,metastasis.(2)DWI using se echo planar(echo planarimaging,EPI)sequence,the value of b is 0,800/ mm2.Measure the apparent diffusion coefficient(ADC)value of lesion area.(3)DCE-MRI using vibe sequence,paranasal sinus lesions obtained the time-signal intensity curves(TIC)and summarized the type of TIC,then obtained enhanced signal intensity(SIpre),maximum signal strength(SImax),peak signal intensity SIpeak,peak time(Tpeak),maximum rising slope(Slope),Rrim-center analysis.Three TIC sinus tumor types were classified as follows: Type A: flat type-gradual enhancement;Type B:rapid enhancement,slow clearance;Type C: rapid intensification and rapid clearance.Pairwise comparison was dealed with two-group independent t-test,and analyzed with x2 test data.Statistical software SPSS19.0 was used to analyze to determine whether differences(P<0.05)were significant between groups.The receiver-operating curve(ROC)wasused to confirm the threshold value of ADC、Slope、Rrim-center and Ktrans.Results: Conventional MRI is mainly for morphology.35 benign lesions often showed regular without infiltrating into the surrounding tissue,the boundary was clear,compressive bone changes,mild to obvious homogeneous or inhomogeneous enhancement.41 cases of malignant lesions,the main manifestations in the conventional MRI were irregular shape,infiltrating into the surrounding tissue in a large area,the border of the disease was not clear,the signal of the necrosis was more common,and the surrounding tissue structure was seriously affected.(2)ADC value has statistically significant differences between some benign and malignant lesions.The average ADC value of nasosinusitis(1.74±0.39×10-3mm2/s),the average ADC value of nasal polyps(1.58±0.26×10-3mm2/s)and malignant tumor value(1.24±0.92×10-3mm2/s)were statistically significant(P < 0.01);The average ADC value of paranasal sinus benign and malignant tumors is 1.46±0.89×10-3mm2/s,1.24±0.92×10-3mm2/s,respectively.The two value did not have significant differences(P > 0.05).(3)There are 29 benign lesions intype A,but 4 benign lesions in type B,2 benign lesions in type C.There are 29 malignant lesions in type B,12 lesions in type C without in type A.Statistical differences are significant in TIC curve type between that of benign and malignant tumors.The benign and malignant lesions of Tpeak,Slope,Rrim-center and Ktrans have statistical differences(P < 0.05),and SIpeak,Ve and Kep have no statistical difference(P > 0.05).(4)The average Tpeak of benign and malignant lesions were respectively(92.0±53.8)s、(47.5±23.41)s.The average Slope of TIC curve of benign and malignant lesions were respectively 15.75±6.20×10-3 、 10.51±10.2×10-3.There are statistically significant differences(P<0.05)between two groups.Slope=10.58×10-3 was made as benign and malignant tumors diagnosis threshold,and the sensitivity,the specificity,the area under the curve were 73.2%,78.1%,0.741.(5)The average Rrim-center value of benign and malignant lesions were respectively 0.12±0.085 、 0.26±0.065.There are statistically significant differences(P<0.01)between two groups.Rrim-center=0.21 was made as benign and malignant tumors diagnosis threshold,and the sensitivity,the specificity,the area under the curve were 74.5%,91.6%,0.779.(6)The average Ktrans value of benign and malignant lesions were respectively 0.115±0.104 、 0.411±0.189.There are statistically significant differences(P<0.05)between two groups.Ktrans =0.121 was made as benign and malignant tumors diagnosis threshold,and the sensitivity,the specificity,the area under the curve were 65%,75%,0.733.Conclusions:(1)DWI displayed ADC values of sinusitis,nasal polyps and mucus cyst were significantly lower than that of paranasal sinus malignant tumor.Therefore,the techniqueof DWI can be used to identify sinus malignant lesions with benign lesions(sinusitis,nasal polyps and mucus cyst).(2)DCE-MRI played an important role in the diagnosis of benign and malignant paranasal sinus lesions and can get TIC curves.Benign lesions had type A(flat type)and type B(speed up flat type).In type B,benign lesionswere vascular tumor with rich blood supply.And malignant tumor performed for type B or type C(speed up and downhill type).(3)Tpeak,Slope,Rrim-center and Ktrans of benign and malignant lesions were significantly different(P < 0.05).They had a certain practical value on differentiating benign and malignant sinus lesions.