The Value Of IVIM-DWI And The Quantitative DCE-MRI In The Diagnosis Of Soft Tissue Tumors

Objective:To explore the diagnostic value of Intravoxel incoherent motion-DWI(IVIM-DWI)and the quantitative Dynamic contrast enhanced-MRI(DCE-MRI)in soft tissue tumors.Materials and Methods:1.Case data: 20 cases of soft tissue tumors in limbs and trunk for conventional MRI,IVIM-DWI,and DCE-MRI from May 2016 to January 2017 in Second Affiliated Hospital of Dalian Medical University.10 males,10 females,age 20-83 years old,the average age is 55.4 years old,the median age was 54.5 years.All cases were manifested by surgical pathology with 10 cases of benign soft tissue tumors: 4 cases of lipoma,2cases of hemangioma,1 cases of cyst,1 cases of leiomyoma,1 cases of giant cell tumor of tendon sheath,1 cases of schwannoma.10 cases of malignant soft tissue tumor: 4cases of liposarcoma,2 cases of fibrosarcoma,1 cases of undifferentiated pleomorphic fibrosarcoma,1 cases of angiosarcoma,1 cases of leiomyosarcoma,1 cases of non-Hodgkin's lymphoma.2.MR scanning parameters and image post-processing:(1)Scanning parameters: Siemens Verio 3.0T MR(8 channel body phased array coil)was selected for all patients with conventional MRI,IVIM-DWI,DCE-MRI and conventional enhanced MRI.(2)Image post-processing: Multiple b DWI were sent to the MITK Diffusion software and both five variable flip angles and DCE-MR imaging were sent to Omni Kinetics(GE healthcare)software.We chose Double exponential model and ExtendedTofts Linear(ETL)model were fitted to obtain multiple b values DWI parameters of D,D*,f and DCE-MRI quantitative parameters: Ktrans,Kep,Ve,and took the pseudo color maps of every quantitative parameters.3.Observational indexes:(1)The MRI features of soft tissue tumor: conventional MRI,Multiple b DWI and DCE-MRI pseudo color value.(2)The parameters of IVIM-DWI: the pure diffusion coefficient(D),the pseudo-diffusion coefficient(D*),and the perfusion fraction(f).(3)The quantitative parameters of DCE-MRI: The volume transfer constant(Ktrans),the volume of extravascular extracellular space(EES)per unit volume of tissue(Ve),and the flux rate constant between EES and plasma(Kep).(4)The cut-off value,sensitivity,specificity of significance parameters(D,D*,f and Ktrans,Kep,Ve)were used to identify benign and malignant soft tissue tumor,and the correlation coefficient between each parameters.(5)The sensitivity,specificity and coincidence rate of IVIM-DWI,the quantitative DCE-MRI and the combination of the two methods in the diagnosis of benign and malignant soft tissue tumors.4.Statistical Analysis:(SPSS 24.0 software,?=0.05)(1)Student t test was compared with the parameters of IVIM-DWI and the quantitative parameters of DCE-MRI difference between benign and malignant soft tissue tumors,and the parameters were measured by(`?±s).(2)ROC curve was used for analyzing the cut-off value,sensitivity,specificity of the significance parameters,which can be used for identifying the nature soft tissue tumor,and evaluating the diagnosis ability of these parameters.(3)Pearson correlation test of two element correlation analysis was used for testing the correlation between each parameters of IVIM-DWI and the quantitative DCE-MRI.(4)Fisher's exact test was used for analyzing sensitivity,specificity and coincidence rate and comparing the diagnostic results of IVIM-DWI,the quantitative DCE-MRI and the combination of the two methods,which can be used for identifyingthe nature soft tissue tumor.Results:1.MRI of 20 cases of soft tissue tumors: MRI signal was not uniform,most of cases with T2 WI showed high signal intensity,strengthen the way showed significantly enhanced,multiple b DWI showed high signal intensity,DCE-MRI pseudo color map showed the area which obvious enhanced were red,slightly enhanced region revealed varying degrees of yellow,the area which did not enhanced were blue.2.There were significant differences for D,D* and f on IVIM-DWI between benign and malignant in 20 cases of soft tissue tumors(P=0.011,P=0.035,P=0.012).The D* and f in malignant tumors were higher than benign tumors of soft tissue tumors,while D in malignant tumors was lower than benign tumors.The cut-off value were1.120,9.940,12.264,sensitivity 50%,70%,100%,and specificity 100%,90%,70%respectively.3.There were significant differences for Ktrans ? Kep and Ve on the quantitative DCE-MRI between benign and malignant in 20 cases of soft tissue tumors(P=0.015,P=0.016,P=0.011).The Ktrans?Kep and Ve in malignant tumors were higher than benign tumors of soft tissue tumors.The cut-off value were 0.190,0.472,0.230,sensitivity90%,90%,80%,and specificity 90%,80%,70% respectively.4.There were a positive correlation between D*,f on IVIM-DWI and Ktrans,Kep,Ve on the quantitative DCE-MRI.D* was significantly correlated with Ktrans and Ve,f was significantly correlated with Ktrans,Kep and Ve,while there was no correlation between D with Ktrans,Kep,Ve and D* with Kep(P > 0.05).5.There was significant differences of IVIM-DWI combined with the quantitative DCE-MRI in the diagnosis between benign soft tissue tumors and malignant soft tissue tumors(P=0.033).There were no significant differences of IVIM-DWI and the quantitative DCE-MRI in the diagnosis between benign and malignant soft tissue tumors(P > 0.05).The sensitivity were 58.8%,62.5%,66.7%,specificity 100%,100%,100%,and coincidence rate 65%,70%,75% respectively.Conclusions:1.It is useful to the identification of benign soft tissue tumor and malignant soft tissue tumor with D,D* and f,of which D* has the highest diagnostic efficiency.The D*and f in malignant tumors were higher than benign tumors of soft tissue tumors,while D in malignant tumors was lower than benign tumors.2.It is useful to the identification of benign soft tissue tumor and malignant soft tissue tumor with Ktrans,Kep and Ve,of which Ktrans has the highest diagnostic efficiency.The Ktrans,Kep and Ve in malignant tumors were higher than benign tumors of soft tissue tumors.3.There were a positive correlation between D*,f on IVIM-DWI and Ktrans,Kep,Ve on the quantitative DCE-MRI.D* was significantly correlated with Ktrans and Ve,f was significantly correlated with Ktrans,Kep and Ve.4.The sensitivity and the coincidence rate of pathology results of IVIM-DWI combined with the quantitative DCE-MRI in the differential diagnosis of benign and malignant soft tissue tumors was higher than that of IVIM-DWI and the quantitative DCE-MRI.The sensitivity,specificity and coincidence rate respectively were 66.7%,100%,and 75%.