A Comparative Study Between DCE-MRI And Histopathology Grading Of Soft Tissue Sarcomas

Objective:To investigate the relationship between the characteristics of Dynamiccontrast enhanced-MRI(DCE-MRI) and histopathology grading of soft tissuesarcomas(STSs). To explore the value of DCE-MRI to assess the histopathologygrading of STSs.Materials and methods:1.Case data:We chose26cases of STSs for surgical treatment in March2012toMarch2013in first affiliated hospital of dalian medical university and the institute ofclinical oncology. Aged20-65, with an average age of35.4years. All cases wereconfirmed by surgical pathology. Among them,10cases of liposarcoma,6cases offibrosarcoma,3cases of Synovial sarcoma,1case of Malignant tumor of muscle fiber,1case of Malignant fibrous histiocytoma,2cases of angiosarcoma,2cases ofChondrosarcoma,1case of leiomyosarcoma.2. MR technology and image post-processing:26patients with STSs underwentconventional MR imaging and DCE-MRI,2D fast spoiled gradient echo sequence(2DFSPGR) was used in DCE-MRI and continuous scanning of16phases. Using Functoolautomatic analysis software of the GE ADW4.5workstation, we analysed theTime-intensity curve(TIC)of tumor, artery and normal muscle in different phases and aseries of quantitative parameters.3. The preparation of tissue section: Contrast of cross-section and coronal planeimages of DCE-MRI, pathology doctors made wax block and tissue sections withselection of tumor tissues which was significantly enhanced on the formalin fixed tumorspecimens after surgery. We try to ensure that the drawn parts were consistent with thedisplay portion of DCE-MRI.4. observational indexes:(1)TIC types of STSs: TIC were divided into four types for the26cases of STSs: type I(flat type), type II(slowly rising type), type III (speed up flat type), type IV(speed up falling type);(2)Parameters which can reflect the DCE-MRI characteristics of STSs: MaximumSlope of Increase(MSI), Signal Ehancement Ratio(SER), the signal intensity ofpeak(SIpeak), the relative Maximum Slope of Increase(rMSI), Time of peak(Tpeak) andSignal Enhanced Extent(SEE);(3)Histopathology grading:Using the French Federation of Cancer Centre gradingsystem(FNCLCC) and according to the tissue section, we classified the26cases ofSTSs into grade I~III based on the degree of tumor differentiation, mitotic count andtumor necrosis area.5.Statistical analysis:All the data were analyzed using SPSS statistical analysissoftware (version19.0).(1)We used Kruskal Wallis H and the Mann-Whitney U nonparametric tests toanalyze the diagnostic efficacy between I-IV TIC to assess the histopathologygrading of STSs;(2)We used single factor analysis of variance and Kruskal-Wallis H nonparametrictest to analyze the differences of DCE-MRI parameters in grade I-III STSs;(3)We used the Spearman correlation method to analyze the correlation betweenDCE-MRI parameters and histopathology grading of STSs.Results:1. Contrast of TIC types and histopathology grading of STSs: Within the26casesof STSs,7cases show type I,5cases show type II,9cases show type III and5casesshow type IV. For the histopathology grading,9cases of grade I,9cases of grade II and8cases of grade III.TIC types can reflect the histopathology grading of STSs(P＜0.05).STSs which show type I TIC are all for grade I(P＜0.05). STSs which show type II andIII TIC are all for grade II or III(P＜0.05). There was no significant difference betweentype I and type IV, between type II and type III, between type II and type IV andbetween type III and type IV(P＞0.05).2. Contrast of DCE-MRI parameters and histopathology grading of STSs:Dynamic parameters of rMSI, MSI, SEE, SIpeak have correlation with histopathologygrading of STSs(The correlation coefficients are0.635、0.539、0.592、0.586respectively,the value of P are all less than0.05). STSs which have higher value ofrMSI, MSI, SEE and SIpeak have higher histopathology gradings (P <0.05). Grade Iand grade III, grade II and grade III STSs can be identified according to MSI, SEE and SIpeak(P <0.05),but grade I and grade II can not be identified according to them(P＞0.05). Grade I and grade II, grade I and grade III can be identified according to rMSI(P<0.05), but grade II and grade III can not be identified according to it(P＞0.05).Therewas no clear correlation between SER, Tpeak and histopathology grading of STSs(P＞0.05). All the three grades of STSs can not be identified according to SER and Tpeak(P＞0.05).Conclusions：1. TIC types can reflect the histopathology grading of STSs. Type I is a indicationof grade I STSs on DCE-MRI, type II and III are indications of grade II or III STSs.2. DCE-MRI parameters of rMSI, MSI, SEE and SIpeak have correlation with thehistopathology grading of STSs,they can reflect the histopathology grading of STSs.Grade I and III,grade II and III can be identified according to MSI, SEE and SIpeak.Grade I and II,grade I and III can be identified according to rMSI.