Objective ToinvestigatetheMRIandCTimagingcharacteristicsofcerebralpleomorphicxanthoastrocytoma(PXA). Methods CTandMRImanifestationsof5cerebralPXAcasesconfirmedbypathologywereanalyzedandcomparedwiththosecases reportedindocumentation.Results The meanageof5caseswas (27±18)years,andallthecasesrespectivelyhadsinglelesion whichwaslocatedinthecortexorsubcortex.In5cases,3leionsoccurredinthetemporallobe,while1lesioninthefrontallobeand1 lesioninthecerebellarvermis.Solid-cystictumorsin3casesandsolidtumorsin2cases(including1casewithpartialpiamaterinfiltrated) wereidentifiedbyCTandMRI.ThecysticpartoflesionwasshownaslowdensitywhilethesolidpartasmixeddensityonplainCT scan,including1casewithscatteredpoint-stripecalcification.Thesolid-cysticcapsuleandthesolidpartoflesionweredemonstrated asuniform markedenhancementonenhancedCTscan.ThesolidareaoftumorwasshownasslightlyhypointenseonT1WI,slightly hyperintenseonT2WI,markedenhancement,andequisignalorhyperintenseonDWIimage.Thesolid-cysticcapsulewallwasenhanced in3cases,whilethecysticpartwasnotenhanced.ThemildtomoderateedemaaroundthetumorwasdetectedinalltumorsbyCT and MRI.Conclusion PXAoccursmostfrequentlyinthetemporallobeofadolescents.TypicalcharacteristicsofCTandMRIaresolid-cystic massandmarked-enhancementofwallnodule,withdifferentdegreeofedemaaroundthetumor.

Objective To investigate the predictive value of CT signs in the pathological Fuhrman grading of clear cell renal carcinoma (ccRCC).Methods The clinicopathological features and CT findings of 72 patients with ccRCC which confirmed by operation and pathology were analyzed retrospectively.According to the WHO Fuhrman grading,all patients were divided into low-grade(Fuhrman gradeⅠorⅡ)or high-grade (Fuhrman gradeⅢorⅣ).ChiG square test and t-test were used to compare the clinical data and CT findings between the two groups,including morphological features (site,whether the renal medulla invasion,morphology,growth pattern,border,pseudo-envelope,lobulation sign,interface,perirenal fascia and the same lateral adrenal invasion,renal sinus and perirenal fat invasion,venous invasion,lymphadenopathy, maximum diameter),density (bleeding,necrosis ratio,calcification,fat)and enhancement characteristics (the degree of enhancement, strengthening method).And the pathological Fuhrman grading was the gold standard.The ROC was used to analyze the diagnostic efficacy of CT signs on Fuhrman grading.The Delong test was used to compare the AUC of different CT signs.Results There were significant differences in tumor maximum diameter,the renal medulla invasion,and lobulation sign between the Fuhrman low-grade and high-grade group(χ2/t＝－4.31 7,9.794,7.325,P＜0.05).There were no differences in gender,age,location sign,morphology,growth pattern, border,pseudo-envelope,interface,perirenal fascia and ipsilateral adrenal invasion,renal sinus and perirenal fat invasion,necrosis ratio,degree of enhancement,strengthening method between two groups (P＞0.05). The largest diameter of the tumor,the renal medulla invasion and the lobulation sign were useful for Fuhrman diagnosis.The AUC was 0.778,0.647 and 0.644,respectively.And there were significant differences between the maximum diameter and the renal medulla invasion or lobulation sign (P＜0.05).Conclusion The maximum diameter,medulla and lobular sign can predict the Fuhrman grading of ccRCC,and the maximum diameter prediction is the most accurate.