Diagnostic Value Of DTI And DKI In The Evaluation Of Soft Tissue Sarcoma Infiltration Boundary Based On MRI-Pathology Correlation

Objective:To explore the application value of Diffusion Tensor Imaging(DTI)and Diffusion Kurtosis Imaging(DKI)in evaluating soft tissue sarcomas(STSs)infiltration boundary.Materials and Methods:1.Case Information A total of 20 patients with a total of 21 lesions(there is 1 patient with 2independent lesions)were collected verified from 20 patients who underwent MRI examinations from August 2018 to December 2019 in the Second Hospital of Dalian Medical University.Enrollment criteria:(1)Patients with soft tissue sarcoma of the extremities and trunk;(2)Patients without any treatment and with planned surgery(surgical resection within 1 week after MRI examination);(3)Sign the informed consent.Exclusion criteria:(1)Measurable diameter of solid tumor components is less than1.0cm;(2)tumors of the thoracic cavity,abdominal cavity and pelvic cavity;(3)inability to perform MRI scans or poor quality of MRI images,unable to analyze the lesions effectively.There are 9 males and 12 females in all cases,aged 28-85 years,mean age60.38 years.The lesion locations were 12 in the lower limbs,6 in the back,and 3 in the hips.Among them,9 were liposarcomas(4 cases of myxoid liposarcoma,2 cases of pleomorphic liposarcoma,2 cases of dedifferentiated liposarcoma,and 1 case of highly differentiated liposarcoma),2 cases of undifferentiated pleomorphic sarcoma,2 cases of leiomyosarcoma,1 case of myxoid fibrosarcoma,1 case of malignant peripheral schwannoma,1 case of angiosarcoma,1 case of malignant giant cell tumor of tendon sheath,and dermatofibrosarcoma protuberans in 4 cases.2.MRI scanning technology and image post-processing2.1 Scanning method Using the US GE Discovery 750 W 3.0T superconducting MRI scanner,according to the choice of tumor location,16-channel phased array abdominal coil,large flexible coil,etc.,equipped with GE-ADW4.7 workstation,the workstation comes with Functool software,conventional MRI examination uses fast Spin echo sequence(FSE).The scanning sequence includes T1 WI,T1WI-FS,T2 WI,T2WI-FS,DTI,DKI.2.2 Image analysis and post-processing The DTI and DKI raw data of all cases were imported into the GE ADW4.7 postprocessing workstation,and the original image was post-processed using Functool software to obtain FA values,ADC values,MK values,MD values,and Fiber Tractography Image(FTI).Manual selection of Region of interest(ROI): Taking T 2 WI as a reference,select three regions of interest in the tumor proximal and distal muscles respectively,and outline the area of 30 ~ 50 mm 2 Take the average value.To measure the maximum infiltration diameter,first mark the infiltration area with a black marker under a microscope and measure the length with a scale.3.The image pathology correlated method The research group’s MRI-pathological correlated(three-step control method)research method is used,the steps are as follows:(1)palpation of the tumor before MRI examination,drawing a horizontal line,perpendicular to the frontal axis of the body,on the body surface to mark the position of the tumor.Next,three vitamin AD capsules were placed on the line.MRI scan was performed to locate the vitamin AD capsules as an imaging reference.(2)During the operation,the incision perpendicular to the body surface marker line was made to expose the tumor.Three surgical marker lines(left,middle and right)were attached to the exposed surface of the tumor that overlapped with the body surface marker line,and a surgical marker line was attached to the top of the tumor to identify the upper and lower positions of the tumor.(3)The tumor was cut open along the surgical marker line to obtain the pathological sampling surface.The image localization surface was printed on paper according to the actual size of the tumor at 1:1,and the region of interest was selected on the surface.The region of interest on the printing paper was completely deducted to form a transparent region.Then the printing paper containing the transparent region was matched with the pathological sampling surface,and the exposed tissue block was taken as the sampling point.4.Observation indicators:4.1 Conventional MRI Performance of STSs(1)Tumor size(2)Tumor morphology(3)Tumor signal homogeneity(4)Tumor strengthening method(5)Tumor margin(6)Presence or absence of edema around the tumor4.2 DTI fiber tracer image(FTI)of STSs,4.3 DKI and DKI parameters of STSs(1)DTI: ADC value of apparent dispersion system,FA value of partial anisotropy(2)DKI: average kurtosis MK value,tissue average dispersion MD value4.4 Histopathological results: whether peritumoral infiltration and extent of infiltration5.Statistical analysis The statistical software SPSS 22.0 was used to analyze the data.The ADC values,FA values,MK values,and MD values of 21 STSs parameters were first tested by the method of normality of the samples using the method of moments,and the data consistent with the normal distribution were expressed as mean ± standard deviation.Non-normally distributed data are expressed as a median of 21(interquartile range).(1)The DTI parameter FA value,ADC value,DKI parameter MK,value MD value of the proximal muscle ROI and the distal muscle ROI were tested by t test.Checking whether each parameter value is meaningful for the diagnosis of peritumoral muscle.(2)Receiver Operator Characteristic Curve(ROC curve)was used for each value between the infiltration positive and negative groups to test the diagnostic efficacy of each value.(3)Chi-square test was performed to determine whether DTI-FTI infiltration was related to pathological infiltration in the positive and negative groups,and the correlation was tested.(4)Linear regression was performed between the maximum diameter of tumor infiltration and each value.Results:1.21 cases of conventional MRI manifestations of STSs The cases of maximum tumor diameter less than 5cm was 7 and more than or equal to 5cm was 14;7 were round-like masses and 14 were irregular masses;7 cases of uniform signals and 14 cases of uneven signals;6 cases of uniformly enhanced and 15 cases of unevenly enhanced;9 cases had clear edges,12 cases had blurred edges;13cases had peritumoral edema,and 8 cases had no edema.2.21 cases of STSs quantitative analysis of DTI,DKI parameters and tumor infiltration positive and negative comparison(1)The DTI parameter FA value was significantly different between the proximal and distal muscles of soft tissue sarcoma(p <0.05),and there was no significant difference in ADC value(p> 0.05).(2)The DKI parameter MK value and MD value were significantly different between the proximal and distal muscles of soft tissue sarcoma(p <0.05).(3)The FA,MK,and the area under the MD curve(AUC)with significant differences in the observed parameters were 0.782,0.79,and 0.895.3.Among the 21 cases of soft tissue sarcoma,9cases showed peritumoral muscle infiltration in FTI,and 12 cases did not see peritumoral infiltration.There was significant difference between DTI-FTI and pathological diagnosis of STSs.4.Correlation analysis between the maximum infiltration diameter of 10 STSs positive infiltration and DTI parameter FA value,ADC value,DKI quantitative parameter MD value,MK value(1)The DTI parameter FA value is significantly negatively correlated with the infiltration boundary.(2)There is a significant positive correlation between the DKI parameter MK value and the infiltration boundary.Conclusion:Based on the MRI-pathological control method,the following conclusions can be drawn from the comparative study of DTI and DKI parameters and pathological results of perioma muscle infiltration of soft tissue sarcomas in 21 cases:(1)DTI-FTI can directly reflect the position of peritumor muscle infiltration in soft tissue sarcomas.(2)The FA value of DTI parameter and the MK value and MD value of DKI parameter were measured according to the ROI of the proximal muscle of soft tissue sarcoma,which can be used to differentiate the positive and negative peritumor muscle infiltration of soft tissue sarcoma,among which the MD value has the best diagnostic efficacy.(3)According to the positive values of DTI and DKI parameters of the peritumor proximal muscle of soft tissue sarcoma,the corresponding ROI position of the MRI sequence was found to determine the boundary of peritumor muscle infiltration of soft tissue sarcoma.