A Preliminary Study Of The Quantitative DCE-MRI In Soft Tissue Tumors

Objective: To explore the feasibility and application value of quantitative Dynamic contrast-enhanced MRI?DCE-MRI?in soft tissue tumors.Materials and Methods: 1.Case data: 14 cases of soft tissue tumor for surgical treatment were recruited from June 2015 to February 2016 in Second Affiliated Hospital of Dalian Medical University.7 women,7 men;mean age,53.2 years.All cases were proved by pathology with 2 cases of liposarcoma,2 cases of malignant schwannoma,1 case of epithelioid sarcoma,3 cases of lipoma,1 case of schwannoma,4 cases of lymphangioma,1 case of giant cell tumor of tendon sheath.2.MR equipment and scanning parameters: All patients underwent conventional MRI and DCE-MRI at 3.0T MR?Magnetom Avanto,Siemens Healthcare?.Conventional precontrast images and a total of five variable flip angles?VFAs?precontrast images with five angles of 5°,8°,10°,15°and 20°were obtained with threedimensional volumetric interpolated breathhold examination?3D-VIBE?sequence first,and then continuous scanning 40 phase of DCE MR imaging,and scanning 5 phase before the injection of the contrast,finally,conventional contrast imaging with 3D-VIBE sequence were scanned.3.DCE-MRI post-processing:All datasets?both DCE-MRI and VFAs?were sent to Omni Kinetics?GE healthcare?software.First,A region of interest?ROI?was defined in the blood vessels of the tumor or nearby the tumor on the axial slice to extract the individual arterial input function?Ind-AIF?,and measured the quantitative pharmacokinetics parameters of Extended Tofts model and Extended Tofts Linear model with Ind-AIF,include the volume transfer constant(K^trans),the volume of extravascular extracellular space per unit volume of tissue?Ve?,and the flux rate constant between extravascular extracellular space and plasma?Kep?.Then measured K^trans,Ve and Kep of Extended Tofts model and Extended Tofts Linear model with population average AIF?Avg-AIF?.Last,measured K^trans of Reference Region model with the function of reference muscle.We took the pseudo colour maps of every pharmacokinetics parameters separately right after measured their value.4.Observational indexes:?1?The quantitative pharmacokinetics parameters of soft tissue tumors : K^trans,Ve and Kep.?2?The cut-off value of quantitative parameters used for identify the nature of soft tissue tumors: K^trans cut-off value and Ve cut-off value.?3?The pseudo colour maps features of K^trans,Ve,and Kep of soft tissue tumors.5.Statistical Analysis: SPSS statistical analysis software?version 17.0?were used for analyze the data.?1?The Wilcoxon rank-sum test was used for compare the pharmacokinetics parameters difference between Avg-AIF and Ind-AIF.?2?The Friedman rank-sum test was used for compare the pharmacokinetics parameters difference between Extended Tofts model,Extended Tofts Linear model and Reference Region model.?3?Student t test and Mann-Whitney U test were used for compare the pharmacokinetics parameters difference between begin soft tissue tumors and malignant soft tissue tumors.?4?Receiver operator characteristic curve?ROC?was used for analyzing the cut-off value,diagnostic sensitivity and specificity of the pharmacokinetics parameters,which can be used for identify the nature of soft tissue tumors.Results: 1.The comparison of soft tissue tumors pharmacokinetics parameters between Avg-AIF and Ind-AIF For Extended Tofts Linear model,there were no significant difference between K^trans,Ve,Kep which caculated with Avg-AIF and K^trans,Ve,Kep which caculated with Ind-AIF?P=0.791;P=0.791;P=0.424?.For Extended Tofts model,there was no significant difference between K^trans which caculated with Avg-AIF and K^trans which caculated with Ind-AIF?P =0.180?.2.The comparison of soft tissue tumors K^trans among Extended Tofts model,Extended Tofts Linear model and Reference Region model There was no significant difference of the K^trans calculated from Avg-AIF among Extended Tofts model,Extended Tofts Linear model and Reference Region model?P=0.145?.There was significant difference of the K^trans calculated from Ind-AIF among Extended Tofts model,Extended Tofts Linear model and Reference Region model?P=0.002?.3.The comparison between begin soft tissue tumors pharmacokinetics parameters and malignant soft tissue tumors pharmacokinetics parameters There were significant differences of the K^trans and Ve which calculated from Avg-AIF of Extended Tofts Linear model between begin soft tissue tumors and malignant soft tissue tumors?P=0.006;P=0.020?,and the cut-off value were 0.009 and 0.036,sensitivity were 100% and 100%,specificity were 78% and 44%.There was significant difference of the K^trans which calculated from Avg-AIF of Extended Tofts model between begin soft tissue tumors and malignant soft tissue tumors?P=0.009?,and the cut-off value were 0.016,sensitivity were 100% and specificity were 78%.Kep calculated from Avg-AIF and K^trans,Ve,Kep calculated from Ind-AIF of Extended Tofts Linear model,K^trans calculated from Ind-AIF of Extended Tofts model,and K^trans of Reference Region model were no significant difference between begin soft tissue tumors and malignant soft tissue tumors?P>0.05?.4.The pseudo colour map features of K^trans,Ve and Kep of soft tissue tumors On pseudo colour map,the lesions displayed different colours from blue to red,which related to the degree of enhancement.The area which obvious enhanced were red,slightly enhanced region revealed varying degrees of yellow,the area which did not enhanced were blue.Conclusions: 1.Both Ind-AIF and Avg-AIF can be used for DCE-MRI quantificative analyzation of soft tissue tumors.2.Extended Tofts Linear model have the highest diagnostic efficiency for identification of the nature of soft tissue tumors with DCE-MRI quantificative analyze.3.It is useful to the identification of benign soft tissue tumor and malignant soft tissue tumor with K^trans and Ve which calculated from Avg-AIF of Extended Tofts Linear model,and K^trans which calculated from Avg-AIF of Extended Tofts model,when K^trans which calculated from Avg-AIF of Extended Tofts Linear model greater than 0.009 min-1or Ve which calculated from Avg-AIF of Extended Tofts Linear model greater than 0.036 or K^trans which calculated from Avg-AIF of Extended Tofts model greater than 0.016.,malignant soft tissue tumor will be took into consideration.4.The pseudo color map of K^trans,Ve and Kep can show the blood supply condition of soft tissue tumor visually,red represents the area which have the most abundant blood supply,blue represents the area which have poor blood supply or without blood supply,yellow area's blood supply between the red and blue.