| Objective: The purpose of this study is to evaluate the role of the Intravoxel Incoherent Motion Diffusion-weighted MR imaging in presurgically assessing the pathological grade of soft tissue sarcomas.Materials and Methods: 1.case data: A hospital-based prospective study was carried out comprising 19 patients with soft tissue sarcomas in limbs and trunk who underwent MRI examinations from June 2016 to March 2018.All the examinations were agreed.8 males,11 females,age from 31 to 67 years old,the average age is 55.8years old,the median age is 60 years old.All cases were approved by surgical pathology.Among them,8 cases of liposarcoma,3 cases of fibrosarcoma,2 cases of osteosarcoma,2 cases of pleomorphic undifferentiated sarcoma,1 case of leiomyosarcoma,1 case of malignant peripheral schwannoma,1 case of epithelioid sarcoma,1 case of malignant myofibroblastic tumor.2.MR equipment and scanning parameters:(1)examination method:All the patients were underwent Siemens 3.0 T MRI(8 channel body phased array coil)with conventional MRI,IVIM-DWI and conventional enhanced MRI.(2)Post-processing: All the DWI with multi-b value were sent to the post-processing software(MITK Diffusion)for analysis and processing,and ROI(region of interest,ROI)was drawn in the highest signal area of tumor in DWI.The standard ADC value is obtained by the calculation of the single-exponential model Sb = S0 × exp(-b × ADC),and the IVIMDWI parameters: D,D * and f values were obtained by the calculation of doubleexponential function Sb = S0 [(1-f)exp(-b × D)+ fexp *].3.The production of the pathological specimens corresponding with MR imaging(1)The position line on body surface(2)MR imaging and the acquisition of ROI(3)Surgery and mounting specimens(4)The acquisition of the pathological specimens corresponding with MR imaging(5)The observation the HE slices 4.Observation index(1)The Conventional MRI manifestations of soft tissue sarcomas: tumor location,morphology,size,border,signal,intra-tumor hemorrhage and peritumoral edema and enhancement.(2)The IVIM-DWI parameters in 19 patients with soft tissue sarcomas: ADC,D,D*,f(3)Histopathological grading of the soft tissue sarcomas: according diagnostic criteria of the French Cancer Center(FNCLCC),in which the degree of cell differentiation,necrosis area and mitosis were observed respectively to score the tumor.19 cases of soft tissue sarcoma were divided into I ~ III grade.5.Statistical analysis:(SPSS 24.0 software,?=0.05)(1)The differences of ADC,D,D * and f values of IVIM-DWI parameters in 19 STS patients and their histopathological grading were analyzed by one-way ANOVA and Newman-keula q test.(2)The correlation between IVIM-DWI parameters in 19 STS patients and their histopathological grading was tested by spearman correlation test of binary correlation analysis.(3)The ADC thresholds,D thresholds,and corresponding sensitivities and specificities that were significant for identifying STSs were statistically analyzed by receiver operating characteristic curve(ROC).Results 1.The MRI findings of 19 cases of soft tissue sarcoma(1)Conventional MRI manifestations: 1.Morphology: 4 cases of round shape,15 cases of irregular shape;2.Size: 11 cases of tumor diameter <5cm,8 cases of ? 5cm;3.Boundary: clear in 14 cases,fuzzy in 5 cases;4.Signal: uniform or non-uniform,hypoisointense on T1 WI in 15 cases,hyperintense in 4 cases;hyperintense on T2 WI in 20 cases;5.Enhancement: heterogeneous enhancement in 13 cases,moderately uniform enhancement in 2 cases,mild uneven enhancement in 2 cases,mild ring enhancement in 2 cases.(2)Multi-b value DWI: hyperintense in 17 cases,slightly increased and hypointense in 2 cases,and the contrast of the tumor and surroundings is increased with the increasing b value;with the increasing b value,there is lower diffusion signal within the tissue.2.19 cases of soft tissue sarcoma: 7 cases in grade?,6 cases in grade ?,6 cases in grade ?.3.The correlations of IVIM-DWI parameters and pathological grading of the 19 cases of soft tissue sarcoma(1)The correlations of IVIM-DWI parameters and pathological grading of soft tissue sarcomas In 19 cases of soft tissue sarcoma,with the lower ADC and D values,there is the higher corresponding histopathological grade.The ADC and D values are significantly:different(p <0.01)in?-? grade soft tissue sarcoma.It is able to identify soft tissue sarcomas between grade I and II,grade II and III,grade I and III(p <0.01)according to the ADC and D values.According to D * and f values of grade ?,? and ? of soft tissue sarcoma can't be identified(p> 0.05).(2)There was a negative correlation between ADC,D and histopathological grading of soft tissue sarcoma,of which D had the best correlation with histopathological grading(r =-0.846).There was no correlation between D * and f with histopathological grade > 0.05).(3)In 19 cases of soft tissue sarcoma,the area of the ADC and D values of grade ? and ?,? STSs under the curve were 0.949,0.974,and the threshold of differential diagnosis of grade ? and ?,? soft tissue sarcoma is 1.317×10-3mm2/s,1.200×10-3mm2/s.The sensitivity of the threshold to diagnosis soft tissue sarcoma between grade ? and grade ?,? was 100%,100%,and specificity was 76.9% and 92.3% respectively.the area of the ADC and D values of grade? and?,? STSs under the curve were 0.881?0.974,and the threshold of differential diagnosis of grade ? and ?,? soft tissue sarcoma is 1.600×10-3mm2/s?1.848×10-3mm2/s.The sensitivity of the threshold to diagnosis soft tissue sarcoma between grade ? and grade ?,? was 91.7%?100%,and specificity was 71.4%?71.4% respectively.Conclusions 1.The IVIM parameters ADC and D value of soft tissue sarcoma were negatively correlated with histopathological grade.D had a higher correlation with histopathological grade comparing with ADC value,and ADC and D values could reflect histopathological grade.2.It is able to identify soft tissue sarcomas between grade I and II,grade II and III,grade I and III(p <0.01)according to the ADC and D values.When the ADC and D value of the STSs is less than 1.317 × 10-3mm2 / s,1.200 × 10-3mm2 / s,the STSs is considered as grade ?,the diagnostic sensitivity is 100%,100%,the specificity is 76.9 %,92.3% respectively;when the ADC value and D value of soft tissue sarcoma are more than 1.600 × 10-3mm2 / s and 1.848 × 10-3mm2 / s respectively,the STSs is considered as grade I.The diagnostic sensitivity is 91.7% and 100% The specificity is 71.4% and 71.4% respectively. |
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