Study Of The Value Susceptibility Weighted Imaging And T2~* Mapping In The Differential Diagnosis Of Renal Tumors

Objective:To explore the application value of magnetic Susceptibility Weighted Imaging(SWI)and T2~*mapping in differential diagnosis of renal tumors by differential analysis of Intratumoral Susceptibility Signal(ITSS)and T2~* value,and to evaluate the correlation between SWI and T2~* mapping in the diagnosis of renal cell carcinoma.To provide imaging basis for clinical treatment and prognosis.Materials and Methods:113 patients with renal tumor in our hospital from September 2019 to September 2020 were retrospectively analyzed.All patients underwent preoperative routine MRI、SWI and T2~* mapping examinations,including clear cell renal cell carcinoma(ccRCC)group 67 cases(low-grade ccRCC 44 cases,high-grade ccRCC 23 cases),non-clear cell renal cell carcinoma(non-ccRCC)group 24 cases(including papillary renal cell carcinoma(pRCC)11 cases,chromophobe renal cell carcinom(CRCC)8 cases,xp11.2 translocation/TFE3 gene fusion-related cancer 2 cases,mucinous tubular and spindle renal cell carcinoma 2 cases and unclassified renal cell carcinoma 1 case),benign renal tumors group 22 cases(fat-poorangiomyolipoma(fpAML)20 cases,renal oncocytoma(RO)2 cases).All images are imported into the United Imagging post-processing workstation,Two radiologists used double blind method to evaluate and measure the ITSS grade and T2~* mean.ITSS morphology was divided into dot,line or dot-line mixed type,and ITSS is graded and scored into four levels of 0-3.Using United Imagging workstation MAPs advanced analysis software to process T2~*mapping original image,T2~* maps and R2*maps were generated.The parenchyma of tumor was selected as the region of interest(ROI).Three different layers of tumor parenchyma were selected on T2~* maps to draw ROIs,and the means of T2~* was measured and calculated.Use intraclass correlation coefficient(ICC)to determine the inter-observer variation level of ITSS grades and T2~* values.According to the results of normality test,Kruskal Wallis H test or one-way ANOVA was used for inter group comparison,and least significant difference(LSD)or Mann Whitney U test was used for post multiple comparison.The correlation between ITSS score and T2~* value was analyzed by Spearman rank correlation.Receiver operating characteristic(ROC)curve evaluats SWI And T2~* value for the identification of renal tumors,and calculate the best diagnostic threshold and its corresponding area under the curve(AUC),sensitivity,and specificity.Results:1.There were differences in age,gender and tumor sizes in the three groups of ccRCC,non-ccRCC and benign renal tumors,P<0.05.2.The two observers evaluated the ITSS grade and the measured T2~* value with good agreement(ICC was 0.933,0.953,respectively).3.(1)there was no significant difference in ITSS grade between the three groups(H=2.060 P=0.357)and significant difference in T2~* value(F=4.248P=0.02).non-ccRCC group had the highest T2~* value(46.44±12.19ms),followed by the ccRCC group(42.20±12.48)ms,while the benign renal tumor group had the lowest(36.54±6.74ms).The T2~* value of ccRCC group and non-ccRCC group was significantly higher than that of benign renal tumor group,P<0.05.There was no significant difference in T2~* value between ccRCC group and non-ccRCC group,P>0.05.(2)Compared with several common renal tumors,ITSS grade and T2~* value from high to low were pRCC(2.00±0.92),ccRCC(1.66±0.98),fpAML(1.30±1.17),CRCC(0.69±0.46);CRCC(57.56±5.76ms),ccRCC(42.20±12.48ms),pRCC(39.56± 9.44ms),fpAML(36.52 ± 7.04ms).The ITSS grade of ccRCC and pRCC was significantly higher than that of CRCC,P<0.05.There was no significant difference in ITSS grade between other tumors,P >0.05;The T2~* value of CRCC was significantly higher than ccRCC,pRCC and fpAML,and the T2~* value of ccRCC was significantly higher than fpAML,P< 0.05,while the T2~* value of pRCC was not significantly different from that of ccRCC and fpAML,P> 0.05.(3)The ITSS grade and T2~* value of different pathological grades of ccRCC are significantly different,P<0.05.The ITSS grade of low-grade ccRCC(1.39±0.88)is significantly lower than that of high-grade ccRCC(2.17 ± 0.98),while low-grade ccRCC The T2~* value(30.63 ± 9.21ms)of(48.24±9.30ms)was significantly higher than that of high-level ccRCC,P<0.05.4.There is a slight negative correlation between ITSS grade and T2~* value(r=-4.32,P<0.05).ITSS grade had no significant differential efficacy between three groups of renal tumors,P>0.05;T2~* values have moderate differential efficacy between ccRCC and benign renal tumors,non-ccRCC and benign renal tumors,the diagnostic threshold,AUC,sensitivity and specificity were 45.10 ms,0.649,47.8% and 95.5%;47.08 ms,0.747,50.0% and 95.5%,respectively.ITSS grade and T2~* value distinguish high and low ccRCCs with good performance.Its threshold,AUC,sensitivity,and specificity are:1.25,0.741,82.6%,0.62.8%;40.06 ms,0.903,81.8%,87.0%.While ITSS and T2~* had the best performance in distinguishing CRCC and pRCC,The results are: 1.25,0.892,81.8%,100%;40.06 ms,0.943,100%,81.8%.Conclusion:The ITSS grade and T2~* value of different kinds of renal tumors are different.SWI has a good effect in evaluating the pathological grade of ccRCC and differentiating CRCC from pRCC,but its value in the differential diagnosis of other renal tumors is not clear.T2~* mapping has a good diagnostic effect in differentiating different renal tumors and evaluating the grade of ccRCC.T2~* mapping has a good diagnostic effect in differentiating different renal tumors and evaluating the grade of ccRCC.SWI and T2~*mapping can provide a strong basis for preoperative classification and grading diagnosis of renal tumors,thus contributing to the formulation of surgical protocols and prognosis judgment.