Primary Study About The Value Of Energy Spectral CT Mutil-Parameter In Pathological Grade Of Renal Clear Cell Carcinoma

Background:Renal cell carcinoma is the most common renal malignancy,including more than 10 histological and molecular subtypes.Renal clear cell carcinoma（cc RCC）is the most common one and has the highest mortality.Nuclear grade of cc RCC has been proved to be an independent prognostic factor.Therefore,it is important to determine the pathological grade of cc RCC before operation for the selection of appropriate treatment and postoperative evaluation.Traditional imaging examination is difficult to distinguish high and low grade cc RCC,and spectral CT may provide quantitative parameters to distinguish them.Objective:To investigate whether spectral CT quantitative parameters can predict the pathological grade of cc RCC before operation.Methods:All of 38 patients who had underwent surgery in our hospital from June 2018to December 2020 and had pathologically confirmed cc RCC,including 28 cases of well differentiated group（Furhman I-II）and 10 cases of poorly differentiated group（Furhman III-IV）.All patients underwent conventional CT plain scan and spectral CT（GE Revolution energy spectral CT）cortical and parenchymal phase of enhanced scans before operation,the scanned images were sent to the post-processing workstation（Advanced Workstation4.7）,we reconstructed 70 kev monochromatic image,iodine based image,energy spectrum curve and effective atomic number histogram.The analysis of contents were:1.Analyze the conventional signs of tumor:The evaluation content includes signs of tumor morphology,calcification,necrosis,renal pelvis or perirenal fat invasion,and tumor thrombus formation,and the diameter of the tumor is measured.Including the patient’s age,gender and tumor site.2.Analyze the energy spectrum signs of the tumor:（1）70kev single energy CT value;（2）Measure the iodine content of lesion(IC_lesion)and the iodine content of abdominal aorta(IC_aorta)in the same layer,and calculate the standardized iodine concentration（Normolized iodine concentration,NIC）=IC_lesion/IC_aorta;（3）Observe the CT values corresponding to 40kev and 90kev,and calculate the energy spectrum curve slope（K）=（CT40kev-CT90kev）/50;（4）Effective atomic number.SPSS 25.0 and medcalc18.0 software were used to analyze the basic information of patients,conventional CT signs and spectral CT multi-parameters.The measurement data are expressed as mean±standard deviation（`X±S）and the statistical analysis uses independent sample t test,and count data are analyzed by Fisher’s exact probability method.Draw receiver operating characteristic curve（Receiver Operating Characteristic,ROC）to analyze the diagnostic performance of the energy spectrum CT parameters with statistically significant differences.Results:1.There was no significant difference in gender,age and tumor location between the two groups（P>0.01）.2.Comparing the conventional CT signs of high-grade and low-grade cc RCC,the differences of tumor diameter,renal pelvis or perirenal fat invasion between the two groups were statistically significant（P<0.01）,while the differences of morphology,calcification,necrosis,tumor thrombus formation between the two groups were not statistically significant（P>0.01）.3.The NIC value,K value,effective atomic number and 70kev single energy CT value of low-grade cc RCC are all greater than those of high-grade cc RCC,and the difference is statistically significant（P<0.01）.4.ROC curve analysis showed that NIC value had higher diagnostic value for the pathological grading of cc RCC,and the area under the curve was the largest（AUC=0.857）.The optimal threshold was 0.28,the specificity was 70%,and the sensitivity was85.71%.Conclusion:1.The size of the tumor and whether there is renal pelvis or perrenal fat invasion have certain value in the differentiation of high and low-grade cc RCC.2.The multi-parameter quantitative analysis can distinguish different pathological grades of cc RCC,especially NIC value.It has high specificity and sensitivity in diagnosing high-grade and low-grade cc RCC.It can provide help to clinicians in the personalized treatment and prognosis assessment of patients.