Evaluating The Value Of Diffusion Tensor Imaging And Fiber Tractography In Describing The Relations Of Soft Tissue Tumors And The Peritumoral Muscle

Objective:To investigate the Value of diffusion tensor imaging and fiber tractography used for describing the relations of soft tissue tumors and the peritumoral muscle on 3.0 T MRI.Materials and methods:1.General informations30 patients with soft tissue mass were collected and divided into three groups:intermuscular malignant tumor group(12 cases), intermuscular benign tumor group(12cases),And intramuscular tumor group(6 cases).2. MR technology(1)All patients were underwent conventional MRI(FS-T1 WI,FS-T2 WI,FS-T1 WI enhancement)and axial DTI(b=600 s/mm2,NEX =4, diffusion gradient directions=15).(2) Regions of interest(ROIs)Intramuscular tumor group:ROIs were choosed as both of the proximal and distal peritumoral muscle.Distal peritumoral muscle was defined as far away from the tumors more than 3cm.Intermuscular benign and malignant tumor group:ROIs were was choosed both of the proximal and distal peritumoral muscle,distal peritumoral muscle was defined far away from the tumors more than 3cm.(3)The DTI and fiber tractography pictures of peritumoral muscles were reconstructed by GE AW 4.4 workstation and Functional tool software..3.Observational indexes(1)The signal value of conventional MR( FS-T1 WI,FS-T2 WI,FS-T1 WI enhancement)of the proximal and distal peritumoral muscle(2) The value of FA and ADC of the proximal and distal peritumoral muscle(3)The r ADC and r FA value:rFA value =(FA1- FA2)/FA2; r ADC value=(ADC1-ADC2)/ADC2.FA1 and ADC1 were the FA and ADC values of proximal muscle, FA2 and ADC2 were the FA and ADC values of distal peritumoral muscle;(4) The FTI of peritumoral muscles were classified into four types.Type Ⅰ: Only displacement changed, muscle fiber continuous, T2 WI signal normal. Type Ⅱ :Edema or inflammatory changed, T2 WI sequences signal increased, muscle fiber bundle was still continuous. Type Ⅲ: Tumor invasive peritumoral muscle fibers, but some of fiber bundles were continuous, T2 WI sequence signal unevenly increased.Type Ⅳ: Tumor destroyed peritumoral muscle, muscle fiber bundle interruption.4. Statistical analysis(1) Wilcoxon Rank Sum Test was used to analyse the differences between the signal value of conventional MR(FS-T1 WI,FS-T2 WI,enhancement FS-T1WI)of proximal and distal peritumoral muscle;(2) Wilcoxon Rank Sum Test was used to analyse the differences between the FA and ADC value of proximal and distal peritumoral muscle;(3) Mann Whitney U Test was used to analyse the differences between the r ADC and r FA value of malignant tumor group and benign tumor group;(4) Fisher’s Exact Test was used to analyse the differences between the FTI of malignant tumor group and benign tumor group;(5) The application of the measurement results of two researchers Intraclass Correlation Coefficient(ICC)conformance testing.Results:1.The conventional MR signal values:(1)Intramuscular tumor group:The enhancement FS-T1 WI signal values of proximal peritumoral muscle was higher than the distal peritumoral muscle(p= 0.028).(2) Intermuscular malignant tumor group:Intermuscular malignant tumor group:ntermuscular malignant tumor group:The FS-T2 WI signal values of proximal peritumoral muscle was higher than the distal peritumoral muscle(p= 0.028).2.The FA value:(1)Intramuscular tumor group:FS-T1 WI enhancement signal values of proximal peritumoral muscle higher than the distal peritumoral muscle.(2)Intermuscular malignant tumor group:The FA values of proximal peritumoral muscle lower than the distal peritumoral muscle(p= 0.030).3. The r FA value:The of r FA value of malignant tumor group higher than thebenign tumor group(p=0.000).4.FTI Used for describing the relations of soft tissue tumors and the peritumoral muscle:83.33% of intermuscular benign tumor group tumor showed the type I; 41.67% of intermuscular malignant tumor group showed type III,25% of intermuscular malignant tumor group showed type IV;100% intramuscular tumor group showed type IV;The difference between the FTI of intermuscular benign and malignant group had statistical significance(p = 0.000).5. All of the ICC were greater than or equal to 0.90.Conclusion:1.The conventional MR could’t intuitive describing the relations of soft tissue tumors and the peritumoral muscle.2.FA values could reflect the shape and structure of muscle fibers.3.RFA values could reflect the different results of Tumors impact the peritumoral muscles to.4.The fiber Fiber Tractography was valuable to display the relationship between tumor and peritumoral muscle which can provide evidences for its diagnosis andbiological behavior.