Characterization And Quantitative Analysis Of Renal Invasive Urothelial Carcinoma And Acute Pyelonephritis: Differentiation With Multiphasic Multislice Spiral Computed Tomography

ObjectiveTo diagnose and discriminate renal invasive urothelial carcinoma(RIUC)and acute pyelonephritis(APN),retrospective analyses of clinical features and multiphase multislice spiral computed tomography(MSCT)imaging features and quantitative analyses of their enhancement patterns were carried out.Materials and MethodsThe institutional review board approved this retrospective study and waived the requirement for patient informed consent.Clinical data and complete standard renal quadriphasic enhancement MSCT images of 22 cases of RIUC(22 lesions,including 17 focal and 5 diffused lesions)and 39 cases of APN(62 lesions,including 50 focal and 12 diffused lesions)between January 2013 and June 2018 were included in this study.RIUCs were confirmed by surgery and pathology,APNs were confirmed by clinical data and laboratory findings.Clinical data,CT imaging characterizations and quantitative enhancement analyses of attenuations of lesions and relative normal renal cortexes were reviewed by two abdominal radiologists who were all blind to the final diagnoses.The enhancement patterns of RIUC,APN,relative normal renal cortexes of focal lesions were demonstrated by using time-attenuation curves.Clinical data and imaging characterizations were compared by Pearson chi-square test and Fisher exact test;the difference of ages,sizes and quadriphasic CT values of lesions between the two groups were analyzed by independent t-test and non parameter Mann-Whitney U test.Differences with P value less than 0.05 were considered statistically significant.To evaluate the threshold levels,accuracy,specificity,positive predictive value and negative predictive value of absolute enhanced values(relative to the lesion itself)and relative values(relative to the relative normal renal cortexes in the same phase)and determine the threshold levels of the two diseases,receiver operating characteristic(ROC)curves and Youden index were utilised.Inter and intra-observer reliability were evaluated with the intraclass correlation coefficient(ICC).ResultsIn clinical characterizations,the majority of RIUC group was male,the ratio of male to female was 13:9,the average age was about 59.361 8.86 years old.In APN group,female was the majority,the ratio of male and female was 14:25,the average onset age was about 44.93±23.76 years old,there was statistical difference between the two groups in the age of onset(P=0.008),but without statistical difference in gender(P=0,080),Typical clinical characterizations of APN were fever and urinary tract infection(P=0.038,P<0.001),while haematuria was the typical clinical characterization of RIUC(P<0.001).There was no significant difference in flank pain between the two groups.In imaging features,reniform contours remained in two groups.About 81.82%RIUCs and 70:97%APNs showed unclear boundary,and the difference was not statistically significant(P=0.320);all RIUCs and about 58.97%APNs occurred to be solitary,and the difference was statistically significant(P<0.001);RIUC and APN were not statistically significant in left,right,unilateral and bilateral distribution(P=0.580,P=0.090).Necrosis and calcification could occur in RIUC more often(P<0.001,P=0.004).Maximal diameter of RIUC was larger than APN(5.35±1.98cm vs 3.27±2.10cm,P<0.001).In quantitative analysis of CT values,average CT values of RIUCs and APNs were with significant difference in corticomedullary,nephrographic and excretory phases(P<0.001,P<0.001,P<0.001).Peak of absolute enhanced values of RIUC and APN were 39.16±11.52HU and 80.19±18.98HU respectively,the difference was statistically significant(P<0.001).Area under the curve(AUC)was 0.957,the threshold value was 57.03HU,the accuracy was 90.48%.Compared with normal renal cortex,the relative values of RIUC and APN were all significantly different in unenhanced,corticomedullary,nephrographic and excretory phases(P<0.001,P<0.001,P<0.001,P<0.001).Nephrographic phase was with the largest AUC,the diagnostic accuracy was about 83.58%,and the threshold value was about 46.27HU.Excretory phase was with the highest diagnostic accuracy of 85.07%,the threshold value was 38.31 HU.ConclusionQuantitative analysis of enhancement at multiphasic MSCT,combined with clinical and imaging features,could assist the diagnoses and discrimination of RIUC and APN.