肾上腺

肾上腺疾病肾上腺的解剖肾上腺的功能内部结构：包膜皮质球状带：醛固酮束状带：皮质醇网状带：性激素髓质儿茶酚胺adrenalmasseswillbeidentifiedin4%–5%ofabdominalCTstudiesBarzonetalreviewed26studiesof3868patientsandreportedthatamongincidentallyidentifiedmasses,71.2%werenonfunctioningadenomas,5.6%werepheochromocytomas,4.4%wereadrenocorticalcarcinomas,2.1%weremetastases,and1.2%werefunctioningadenomas.肾上腺病变的分类肿瘤性1.腺瘤（功能性、非功能性）2.转移瘤3.皮质癌4.嗜铬细胞瘤5.神经母细胞瘤6.髓脂瘤以及淋巴瘤、脂肪瘤、神经节瘤等非肿瘤性病变肾上腺增生/萎缩、囊肿、血肿、肉芽肿性病变等正常CT影像表现•位置右侧：右肾上极上方，下腔静脉后方，肝内缘与膈肌脚之间左侧：肾上极前方偏内侧，前方为胰腺体尾，内侧为膈肌脚和腹主动脉•形态右侧：逗号状、线条形或人字形左侧：倒Y字形、V字形、三角形边缘平直或稍有内凹•分布头部、分歧部、内侧枝、外侧枝•大小侧枝厚度小于10mm；面积小于150mm2•密度软组织密度，类似肾脏；+C均一强化，不能辨别皮髓质大小Wajchenbergetalreportedthat“lesions3cmareprobablybenign,whereaslesions5cmprobablyaremalignant.”密度Manyinvestigatorsuseacutoffoflessthan10HUtodiagnoseanadenoma,atechniquesupportedbytheAmericanCollegeofRadiologyappropriatenesscriteria.Despitevariablesensitivitywiththiscutoff,adenomaswithhigherprecontrastattenuationmaystillbeidentifiedassuchbyperformingdelayedcontrastmaterial–enhancedCTtomeasurewashoutcharacteristicsLipid-richadenomaina46-year-oldman.(a)AxialunenhancedCTimageshowsawell-defined,2-cm,low-attenuation,rightadrenalmass(arrow).(b)AxialunenhancedCTimageshowsthattheattenuationintheregionofinterest(ROI)is0HU,afindingindicativeofalipid-richadenoma.延迟10–15-minutedelaywasrecommendedbymostauthors门脉期腺瘤vs嗜铬细胞瘤Venousphasepostcontrastfindingsremainimportantbecausetheyareusedtocalculatewashoutandbecauseabsoluteenhancementlevelscanbeusedtodistinguishapheochromocytomafromanadenoma.Pheochromocytomasmaydisplayhighlevelsofenhancementandgenerallyenhancetoagreaterdegreethanadenomasdo,findingsthatweredescribedintwoinvestigationsthatcomparedadenomastopheochromocytomasduringthedynamicphase腺瘤vs非腺瘤Therearetwowaystomeasurepercentagewashout:absolutepercentagewashout(APW),whichincorporatesprecontrastattenuation,andrelativepercentagewashout(RPW),•绝对廓清率＝（峰值－延时强化值）/（峰值－平扫值）×100％•相对廓清率＝（峰值－延时强化值）/峰值×100％•相对廓清率的准确性为86％，特异性为100％•绝对廓清率的准确性为88％，特异性为90％•主要用于鉴别腺瘤和非腺瘤•TheRPWandAPWwerecalculatedasfollows:RPW=100·(EA−DA)/EAandAPW=100·([EA−DA]/[EA−PA]),whereEAisattenuationoncontrast-enhancedscans,DAisattenuationondelayedcontrast-enhancedscans,PAisprecontrastattenuation,andallattenuationmeasurementsareinHounsfieldunits.双侧病变Thesizeofanadrenalmasscontributestothediagnosis,butbyitselfitisnotadefinitiveindicatorofmalignancy.Inpatientswithnohistoryofmalignancy,benign-appearingmassesthataresmallerthan3cmlikelyarebenign,whereasthoselargerthan5cmoftenareresected.Precontrastattenuationoflessthan10HUisusedbymanyauthorstoidentifylipid-richadenomas.Homogeneousmasseswithmorethan60%APWormorethan40%RPW,inconjunctionwithportalphaseabsoluteenhancementlevelsoflessthan100HU,likelyareadenomas.Amasswithwashoutofmorethan60%APWormorethan40%RPW,butwithabsoluteenhancementofmorethan110–120HU,issuggestiveofpheochromocytoma.Bilateralityismorecommoninmetastases,lymphoma,infection,hyperplasia,andhemorrhage,whereasadenomas,pheochromocytomas,adrenocorticalcarcinomas,andmyelolipomasarebilateralinlessthan30%ofcases.一.肾上腺腺瘤•最常见的肾上腺肿瘤（51%），好发于40-50岁女性•功能性腺瘤（cushing腺瘤、conn腺瘤）非功能性腺瘤•病理：有包膜，表面光滑，切面黄色或褐色，质软。较大肿瘤可有出血、坏死及囊变Figure4Drawingshowswashoutcharacteristicstypicalofanadrenaladenoma.Precontrastattenuationis4HU,venousphasepostcontrastattenuationis50HU,anddelayedattenuationis12.5HU.ThecorrespondingAPWandRPWare82%and75%,respectively.(CourtesyofFrankM.Corl,MS,theRussellH.MorganDepartmentofRadiologyandRadiologicalScience,JohnsHopkinsSchoolofMedicine,Baltimore,Md.)RadioGraphics,:PamelaT.Johnson;KarenM.Horton;ElliotK.Fishman;RadioGraphics2009,29,1319-1331.©RSNA,2009OnePowerPointslideofeachfiguremaybedownloadedandusedforeducationalnotpromotionalpurposesbyanauthorforslidepresentationsonly.TheATScitationlinemustappearinatleast10-pointtypeonallfiguresinallpresentations.PharmaceuticalandMedicalEducationcompaniesmustrequestpermissiontodownloadanduseslides,andauthorsand/orpublishingcompaniesusingtheslidesfornewarticlecreationsforbooksorjournalsmustapplyforpermission.Forpermissionrequests,pleasecontactthePublisherat.Drawingshowstheenhancementpatternofalipid-pooradenoma.Regardlessoflipidcontent,adenomastypicallywashoutmorethan60%(APW)or40%(RPW),whereasmetastases,adrenocorticalcarcinomas,andsomepheochromocytomasusuallywashouttoalesserdegree肾上腺腺瘤cushing腺瘤conn腺瘤无功能腺瘤大小2-3cm小于2cm3-5cm密度类似肾脏或稍低水样低密度10-17HU类似肾脏或稍低增强迅速增强，快速廓清3min后相对廓清率35%；5min后相对廓清率40%同侧肾上腺残部及对侧肾上腺萎缩无萎缩无萎缩临床表现库欣综合症conn综合症多无症状图a：平扫CT，左肾上腺较低密度椭圆形肿块图b：+C呈均匀强化；*左肾上腺其余部分及右侧肾上腺呈萎缩改变cushing腺瘤23Cushing腺瘤conn腺瘤左侧肾上腺肿块，平扫呈水样低密度，增强扫描轻度强化。25Conn腺瘤无功能腺瘤二.肾上腺转移瘤•较常见，仅次于肺、肝脏和骨转移•原发肿瘤以肺癌、乳腺癌和肾癌最常见•临床极少造成肾上腺功能改变（破坏90％出现）•双侧者占30－50％•肺癌患者：肾上腺结节及肿块，约1/3为良性肿瘤肾上腺转移瘤CT•单侧或双侧圆形、分叶状肿块•较小者边界清楚，密度均匀大者中心常发生出血、坏死，密度不均，较大的肿瘤边界可不清，累及周围结构•平扫90％CT值大于20HU增强扫描：平扫均匀者呈均匀性强化，不均者呈环形强化延迟扫描可见持续性强化肾上腺转移瘤图a：左侧肾上腺肿块图b：三个月后复查，肿块明显增大右肺癌合并双侧肾上腺转移肾上腺转移瘤(adrenalmetastasis)34肾上腺转移瘤小细胞型肺癌肾上腺转移左侧肾癌左侧肾上腺转移(a)Precontrast,(b)portalvenousphaseenhanced,and(c)10-minutedelayedenhancedtransverseCTimagesofleftadrenalmass(arro