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肾上腺肿瘤影像学诊断策略

2018-08-24 72页 ppt 9MB 47阅读

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肾上腺肿瘤影像学诊断策略肾上腺肿瘤影像学诊断策略*Goodmorning,mytopicisImagingalgorithmstowardincidentaladrenalmasses内容提要一、概述二、影像检查技术三、肾上腺CT、MRI正常表现四、肾上腺基本影像学概念五、肾上腺肿瘤诊断原则六、肾上腺肿块推荐诊断流程*一、概述肾上腺肿瘤是较常见的肿瘤,尸检肾上腺肿瘤发生率为1.4%-8.7%。腹部CT检查中肾上腺偶发瘤约占1%肾上腺肿瘤大多数为良性,甚至已知有恶性肿瘤的病人,可偶发无功能腺瘤肾上腺肿瘤良恶性鉴别非常重要二、影像检查技术肾上腺疾病的影像...
肾上腺肿瘤影像学诊断策略
肾上腺肿瘤影像学诊断策略*Goodmorning,mytopicisImagingalgorithmstowardincidentaladrenalmasses内容提要一、概述二、影像检查技术三、肾上腺CT、MRI正常表现四、肾上腺基本影像学概念五、肾上腺肿瘤诊断原则六、肾上腺肿块推荐诊断*一、概述肾上腺肿瘤是较常见的肿瘤,尸检肾上腺肿瘤发生率为1.4%-8.7%。腹部CT检查中肾上腺偶发瘤约占1%肾上腺肿瘤大多数为良性,甚至已知有恶性肿瘤的病人,可偶发无功能腺瘤肾上腺肿瘤良恶性鉴别非常重要二、影像检查技术肾上腺疾病的影像检查:1)超声检查是基础2)CT检查是最佳3)MRI检查是重要补充CT检查方法:1)平扫:层厚:3-5mm扫描前口服清水500-800m1价值:钙化、肿瘤2)增强:双期扫描(1min、3-5min)价值:病变定性CT优势:1.解剖关系明确,易于发现肾上腺肿块,肾上腺增生及肾上腺萎缩;2.密度分辨率高,能显示肾上腺病变的一些组织特征,如脂肪、液体、钙化等成分;3.肾上腺病变的类型虽然较多,但依据其对肾上腺功能的影响与否,结合临床症状、体征、实验室检查,多数病变能做出准确诊断。CT限度:1、对于肾上腺区较大肿块,特别右侧者,有时难于判断肿块的来源。2.对于肾上腺增生及萎缩的诊断,CT虽然优于其它检查,当组织学有改变而形态学无明显改变时不能做出诊断。3.某些非功能性肾上腺肿瘤,CT定性诊断仍有困难。肾上腺解剖肾上腺:是人体重要的内分泌腺;位于腹膜后,与肾脏共同包在肾筋膜内,有完整的被膜。左右各一。其实质分为皮质(占肾上腺的90%)和髓质;(平扫、增强或MR检查不能分辨。)皮质:产生和分泌醛固酮、皮质醇和雄激素髓质:由交感神经节细胞和嗜铬细胞组成。产生儿茶酚胺 三、肾上腺正常CT、MRI表现1)形态:形态各异:右侧:斜线状、倒“V”、倒“Y”形;左侧:倒“V”、倒“Y”形或三角形;三维重建呈叶状2)大小:侧支厚度<10mm; 侧支厚度小于同侧膈肌脚。面积小于150mm3)密度:均匀,边缘光滑,无外凸结节4)强化:均匀,边缘光滑(一)正常CT表现 正常肾上腺三维形态呈三叶草形,边缘光滑,密度均匀,强化一致肾上腺血供肾上腺上、中、下3支动脉肾上腺上动脉-------膈下动脉肾上腺中动脉-------腹主动脉(L1)肾上腺下动脉-------肾动脉* 平扫 正常肾上腺的信号强度:类似正常肝实质信号,明显低于周围脂肪信号;抑脂像上信号强度显著高于周围被抑制的脂肪组织,呈相对高信号(二)正常MRI表现* 增强扫描均匀强化,边缘光滑,短径小于10mm(三)肾上腺区假病变副脾胃底憩室静脉曲张肾囊肿,肝囊肿胰腺假囊肿部分容积效应*Firstofall,becausethecontourofbothadreanlglandaregeometriccomplex,false-positivefindingsfromtheadjacentstructureshouldbeexcluded.Theyaremorecommoninleftadrenalgland,includingaccessoryspleenGastricdiverticulumVaricoseRenalcyst,livercyst,PancreaticpseudocystandPartialvolumeeffect左膈下曲张静脉*ThisisahighlyvascularlednodulardemonstratedasLeftsubphrenicvarixwhichiscommonlyseenincirrhoticpatient.ThisisbecauseLeftsubphrenicveiniscoursingalongwiththelaterallimbofleftadrenalgland.误诊为肾上腺囊肿的胰腺假囊肿*AcysticmassinleftadrenalturnedouttobePancreaticpseudocyst多平面重组MPR对于显示肾上腺和肿物关系非常重要*Multiplanarreformatishelpfultodepicttherealshapewithadjacentorgan.AhypervascularmassisturnedouttobeanaccessoryspleeninserialMPRimages四、肾上腺基本异常CT影像学表现1、肾上腺增大(增生)1)弥漫性增大:侧肢厚度大于10mm或面积大于150mm^①肾上腺增生:肾上腺结构,形态及密度正常②肾上腺炎症或肿瘤:TB、转移性肿瘤、淋巴瘤。肾上腺增大,结构破坏2)局部增大①肾上腺增生结节:局部增大,可有小的结节外突,结构正常②肾上腺腺瘤:局部结节病灶,正常肾上腺组织压迫或破坏2、肾上腺肿块1)原发性和转移性肿瘤:①原发性肿瘤:单发、边缘清楚,邻近肾上腺正常或受压②转移性肿瘤:双侧多发,病变边缘不清,邻近肾上组织破坏肿块数目:双侧:常见于转移瘤、也可见于结核、皮质腺瘤和嗜铬细胞瘤肿块大小:小-----良性功能性腺瘤(2--3cm)大------非功能性腺瘤或恶性肿瘤密度(1)均匀水样低密度,均一强化,常为腺瘤;(2)均匀水样低密度,无强化,为囊肿;(3)混杂密度,内有脂肪性低密度,为肾上腺髓质瘤;(4)混杂密度,中心有不规则坏死、囊变,不均匀强化,见于多种肿瘤,包括肾上腺嗜铬细胞瘤、神经母细胞瘤、转移瘤、皮质癌、结核等。3、肾上腺萎缩(变小)代表肾上腺萎缩;常为垂体功能低下或特发性肾上腺萎缩所致;也可见于cushing腺瘤同侧肾上腺残部或对称肾上腺。4、肾上腺钙化:多见于肾上腺结核:肾上腺体积增大或缩小,伴沙粒样钙化。异常MR表现1、水样均匀长T1长T2信号,无强化,见于肾上腺囊肿;2、T1T2信号强度类似于肝实质,且化学位移反相位上,与同相位相比信号强度明显下降者为肾上腺腺瘤;3.混杂信号肿块,内有被抑制的脂肪高信号灶,提示肾上腺髓质瘤;4混杂信号肿块,呈不均强化,见于多种肿瘤,包括肾上腺嗜铬细胞瘤、神经母细胞瘤、转移瘤、皮质癌、结核等。分类肾上腺皮质肿瘤:良性:1、肾上腺皮质腺瘤功能性(皮质醇腺瘤;醛固酮腺瘤)非功能性2、肾上腺皮质增生3、肾上腺髓质瘤4、肾上腺囊肿恶性:1、转移瘤2、肾上腺皮质癌肾上腺髓质肿瘤1、嗜铬细胞瘤2神经母细胞瘤四、肾上腺肿瘤诊断原则良性皮质腺瘤 50%髓脂瘤 7%囊肿 2%出血 2%节细胞瘤 2%肉芽肿性病变 1%海绵状血管瘤 罕见恶性转移 30%嗜铬细胞瘤 4%皮质癌 1%原发性淋巴瘤罕见肉瘤 罕见成神经细胞瘤 罕见*TheCausesandPrevalenceofadreanlmasseslistedbelow.Corticaladenomatakes50%andmetastasestakesanother30%首先应区分腺瘤与非腺瘤诊断腺瘤的特异性应尽量接近100%其次鉴别肿瘤的良恶性*Besidesadenomasandmetastastes,otherbenignandmilitantsuchasMyelolipomacystHemorrhageTBallhavecharacteristicimagingfeatures,soTheprimarygoalistodifferentiateadenomasandnonadenomasExaminationsshouldbeascloseto100%specificityaspossible第一步:临床表现与肾上腺功能实验室检查原发性醛固酮增多症:高血压、低血钾血钾ALD和PRA,或ALD/PRA比值嗜铬细胞瘤和成神经细胞瘤:阵发性高血压儿茶酚胺,多巴胺,肾上腺素水平肾上腺性征异常性激素水平,染色体检查Cushing综合征:向心性肥胖:满月脸、水牛背血尿皮质醇水平ACTH水平功能性腺瘤需要影像来定位*ThefirststepistoperformcomperensiveBiochemicalAssaybylaboratorytesting,positiveresultsarehelpfultodiagnosehyperfunctioningadenomas,corticalcarcinomasandPheochromocytoma第二步:分析形态学特征CT,MRI,US主要根据肿块大小大于4cm时,70%恶性大于6cm时,85%恶性轮廓与质地不能可靠鉴别肿块良恶性与以往比较6个月内体积增大提示恶性肿瘤随诊6个月内体积无变化,当无恶性征象时可诊为良性正常肾上腺是否可见,肿块与肾上腺的关系*NextstepistoevaluatetheMorphologicfeature,malignantmassestendtobelarger,andadenomasissmaller,butitisalwaysthecase,itconfirmedbothbothtextureandmarginationisnothelpful.ButAnypriorimagingisusefulwithleastcostIncreasesinsize6monthsapartconsideredmalignant肺癌患者发现左肾上腺小结节,与6个月前片比较可资诊断SixmonthslaterSixmonthslater*Anypriorimagingisusefulwithleastcost.Increasesinsize6monthsapartconsideredmalignant双侧肾上腺转移瘤增大*ThisisaBilateraladrenalmetastases,theleftmassesisbig,withirregularcontourandnecroticcenter左侧非功能性肾上腺腺瘤*AndaNon-functioningadrenaladenomaisoftenlessthan3cmindiameter左肾上腺巨大非功能性皮质腺瘤*However,thisiscontroversial.Thisisalargedegeneratingnonfunctioningadenomagreaterthan12cm.良恶性鉴别:肾上腺表现①良性:肾上腺组织受压,无破坏;病变边缘清楚②恶性:肾上腺组织破坏,病变边缘不清良恶性鉴别:肾上腺形态密度积分:10%的平扫CT值+大小(cm)+分叶(2分)+不均匀(1分)。>7分为恶性,敏感性和特异性高(98%)第三步:区分腺瘤与非腺瘤探测肿块内脂质成分:腺瘤70%细胞内富含脂质CT密度测量T2WI信号强度化学位移同反相位成像 对比剂清除率:腺瘤对比剂快速廓清*Forthoseinditerminedmasses,lipid-sensitiveImagingshouldbeperformed.TheyCTdensitometryCThistologram,T2SICSIin/opposedphaseimaging.TheaimisdetectIntracellularlipidcontentinadenomasCT平扫密度测量法鉴别诊断腺瘤的阈值多选择10HU敏感性71%特异性98%30%乏脂性腺瘤,CT值大于10HU当测量标准差较大时,结果不准确*CTdensitometryischoice,ameanattenuationvalueof10-HUthresholdisusedasacutoffvalueforadenomastestsensitivity71%testspecificity98%30%adenomasarelipidpoorwithCTvaluegreaterthan10HUhowever,ifthestandarddeviationishigh,theaccuracyisdecrease.0HU以下像素比例27.0%CT平均值29.38HU例1左侧乏脂性腺瘤*HearwepresenttwocasewithsimilarCTvalue.CaseIisaadenomawithCTvalueofnear30HU,andwhenwecountthenegativepixelnumber,itis27inpercentage.0HU以下像素比例1.7%CT平均值29.28HU例2右侧肾上腺转移*Case2isametastaseswithsimilarCTvalue,andNegativepixelcount1.7%.Thisisenoughtodifferntiateanonadenomas.FromadenomasT2WI信号强度恶性肿瘤T2WI信号强度较高腺瘤信号强度与肝实质近似腺瘤与非腺瘤之间有10%~30%重叠右肾上腺转移右肾上腺腺瘤*IthasbeenknownforalongtimethatMalignantmasssoftenshowhighT2WISIwhileAdenomasisinmoderateSIbecauseofcholesterolcontent.However,there10%`30%percentoverlappingbetweenthem.粘液性(退变)肾上腺皮质腺瘤*ThisiscontroversialcaseofaMyxoidadrenalcorticaladenomashowinghighT2wiSI化学位移同反相位成像 SI指数=[(SIIP−SIOP)/SIIP]×100% 腺瘤信号强度下降诊断阈值10-15% 敏感性91-94%,特异性94-97% 目测观察与信号测量的诊断效能相当*ChemicalShiftImagingistomeasureSIlossinopposedphasecomparedtoinphaseimagesThecutoffvalueis10-15%Sensitivityof91%,specificityof94-%Qualitativediagnosisisasgoodasquantitativeassessment同相位反相位肾上腺腺瘤*ThisisaadnomasshowedobviousSIlossonopposedphaseimages肾上腺转移同相位反相位*AndAdrenalmetastastesdonotlossSI乏脂性腺瘤同相位反相位*Thereareexception,Lipid-pooradenomadonothaveSIloss,too第四步:功能成像测量动态强化CT/MRI廓清率CT灌注成像PET-CTDW-MRI*注:*诊断价值存在争议*SothefinalimagingmodelisFunctionalimaging,theyareWashoutratiobyDCECT/MRI,CTperfusion,PET-CT,MRspectrographyanddiffusionweightedisunderinvestigated动态增强CT/MR时间强度曲线增强检查,腺瘤比非腺瘤对比剂廓清(清楚)速度快清除率计算公式APW(绝对清除率)APW=(增强CT峰值-延迟期CT值)/(增强CT峰值-平扫CT值)×100%RPW(相对清除率)RPW=(增强CT峰值-延迟期CT值)/增强CT峰值×100%最常用扫描/诊断标准增强峰值时间在1分,延迟15分RPW大于40%或APW大于60%其他扫描方案延迟10分,RPW>50%延迟5分,RPW>50%接近100%敏感性与特异性!*IVcontrastmedium“washout”muchfasterforadenomasthannonadenomasPercentagewashoutratiosAPW(absolutepercentagewashout)(EnhancedCTvalue-DelayedCTvalue)/(EnhancedCTvalue-unenhancedCTvalue)×100%RPWrelativepercentagewashoutRPW=(EnhancedCTvalue-DelayedCTvalue)/EnhancedCT×100%Mostacceptedthreshold15-minutedelayedscan40%forRPWor60%forAPWAlsorecommended10-minutedelayscanRPW>50%Nearly100%sensitiveandspecific!肾上腺肿物TDCTypeI 延迟强化型 神经源性肿瘤TypeII快速廓清 腺瘤TypeIII中等廓清 可疑 TypeIV缓慢廓清 恶性肿瘤CT值结合对比剂清除率肾上腺肿块诊断*TypeI Delayedenhanced NeurogenictumorsTypeIIRapidwashout AdenomasTypeIIIModeratewashout Intimidate TypeIVSlowwashout Malignanttumors肾上腺CT灌注成像:良恶性肾上腺肿物间BV存在差异敏感性70%*BVcanbeuseddifferentiatingadenomasfromnonadenomasBVcanbeuseddifferentiatingadenomasfromnonadenomas肾上腺肿块六、肾上腺肿块推荐诊断流程US的价值在于肾上腺病变的筛查*七、常见肾上腺肿瘤的影像学特点(一)肾上腺腺瘤(二)髓样脂肪瘤(三)嗜铬细胞瘤(四)肾上腺皮质癌(五)肾上腺转移性肿瘤(六)其它肿瘤样病变 富含脂质腺瘤:平扫CT值小于10HU 乏脂腺瘤(一)肾上腺腺瘤髓样脂肪瘤是良性肿瘤,含骨髓成分,CT及MRI可检出含脂肪的区域,20%可见钙化髓样脂肪瘤(二)髓样脂肪瘤髓样脂肪瘤来源于肾上腺髓质的节旁细胞瘤,90%为功能性的CT及MRI:肿块较大,不均匀,明显强化,MRI呈长T1长T2信号嗜铬细胞瘤(三)嗜铬细胞瘤 嗜铬细胞瘤称为10%肿瘤:10%为恶性,10%肿瘤为双侧,10%为激素分泌不活跃,10%为肾上腺外;肿瘤常大于3cm,富血供,较大肿瘤易出血坏死肾上腺外的副节瘤 肾上腺嗜铬细胞瘤(adrenalpheochromocytoma)是发生于肾上腺髓质的肿瘤,多为良性,但也可为恶性。肾上腺是嗜铬细胞瘤的主要发生部位,约占90%。 肿瘤产生和分泌儿茶酚胺。临床表现:以20~40岁多见,典型表现为阵发性高血压、头痛、心悸、多汗,发作数分钟后症状缓解。实验室检查:24小时尿香草基扁桃酸(VMA)即儿茶酚胺代谢物显著高于正常值。病理:肿瘤一般较大,易发生出血、坏死和囊变。 [影像学表现] 超声、CT和MRI检查: 1)肾上腺肿块:单侧、偶为双侧性,呈圆形或椭圆形,常较大,直径多在3cm以上。 2)密度或信号:肿块密度类似肾脏、T1WI上为低信号而T2WI上呈非常高的信号;较大肿瘤易发生出血、坏死和囊变。 3)强化:强化明显,较大肿瘤多不均匀。 [诊断与鉴别诊断] 临床考虑为嗜铬细胞瘤时,若超声、CT或MRI检查发现肾上腺较大肿块并具有上述表现,可诊断为肾上腺嗜铬细胞瘤。   若肾上腺区未发现异常,则应检查其它部位,有可能查出异位嗜铬细胞瘤,后者常位于腹主动脉旁,表现类似肾上腺嗜铬细胞瘤。 肾上腺皮质癌罕见 临床表现:腹痛、腹部肿块、cushing综合征(50%) CT表现:常大于5cm;不均匀密度及强化肿块,中心坏死多见,20-30%可见钙化典型肾上腺皮质癌呈巨大不均匀肿块,中心钙化(四)原发性肾上腺皮质癌 恶性肿瘤病人尸检肾上腺转移发生率约为27%,以肺癌、乳腺癌最为常见 癌症病人检出肾上腺转移很重要转移性肿瘤致双侧肾上腺弥漫增大和不均匀强化,累及周围脂肪间隙(五)肾上腺转移性肿瘤 大多数肿瘤经血行(肺、肝和骨)及淋巴途径转移 转移至同侧肾上腺,双侧肾上腺同时转移亦可见右侧肾上腺小肾癌侵犯下腔静脉,形成癌栓结肠癌肝转移部分肝叶切除术后,左侧肾上腺转移 弥漫性肾上腺出血可发生于任何年龄,可发生于手术、化脓感染、烧伤、高血压等慢性肾上腺出血出血(六)其它肿瘤样病变 大多为单侧,可以任意大小 病理上包括上皮的、内皮的、寄生虫性、假性囊肿 大多数病灶薄壁,无强化肾上腺囊肿囊肿小结 1、肾上腺影像检查技术:超声、CT、MRI 2、肾上腺解剖特征:叶形,密度均匀,强化均匀,径线小于10mm 3、肾上腺增大、肾上腺破坏、肾上腺肿块:区分肾上腺组织的异质性是诊断的关键 4、肾上腺肿瘤的诊断,临床及实验室检查很重要,影像学的价值在于病变定位及良恶性的区分。Chestx-ray:washoutmeasurementThissiteprovidesacalculatortomeasurethewash-outofadrenalmassesfordifferentiationofbenignmasses(usuallyadenomas)frommalignantlesions(usuallymetastases).ImagingofAdrenalIncidentalomas:CurrentStatusN.ReedDunnickandMelvynKorobkinAm.J.Roentgenol.,Sep2002;179:559-568.AdrenalMasses:CharacterizationwithCombinedUnenhancedandDelayedEnhancedCTElaineM.Caoilietal.Radiology2002;222:629-633.ManagementoftheclinicallyinapparentAdrenalMass'Incidentaloma'NIHState-of-the-ScienceConferenceFeb4-6,2002.StateoftheScienceStatement(htmlandpdf)and3dayvideoconferenceDifferentiationofadrenaladenomasfrommetastaseswithunenhancedcomputedtomography.GuflerH,EichnerG,GrossmannA,KrentzH,SchulzeCG,SauerS,GrauG.JComputAssistTomogr.2004Nov-Dec;28(6):818-22.eMedicine-Pheochromocytoma:ArticlebyAnantKrishnan,MDAdrenalMassesintheCancerPatient:SurveillanceorExcisionIanC.Mitchell,FiemuE.NwariakuTheOncologist,Vol.12,No.2,168-174Evaluationofadrenalmassesinpatientswithbronchogeniccarcinomausing18F-fluorodeoxyglucosepositronemissiontomographyJJErasmus,EFPatzJr,HPMcAdams,JGMurray,JHerndon,REColemanandPCGoodmanAmericanJournalofRoentgenology,Vol168,1357-1360IntegratedPET-CTfortheCharacterizationofAdrenalGlandLesionsinCancerPatients:DiagnosticEfficacyandInterpretationPitfallsSeminChongetalRadioGraphics2006;26:1811-1824PearlsandPitfallsinInterpretationofAbdominalandPelvicPET-CTMichaelA.BlakeetalRadioGraphics2006;26:1335-1353TheClinicallyInapparentAdrenalMass:UpdateinDiagnosisandManagementGeorgMansmann,JosephLau,EthanBalk,MichaelRothberg,YukitakaMiyachiandStefanR.BornsteinEndocrineReviews25(2):309-340*Thankyouforyourattention!!!**Goodmorning,mytopicisImagingalgorithmstowardincidentaladrenalmasses**Firstofall,becausethecontourofbothadreanlglandaregeometriccomplex,false-positivefindingsfromtheadjacentstructureshouldbeexcluded.Theyaremorecommoninleftadrenalgland,includingaccessoryspleenGastricdiverticulumVaricoseRenalcyst,livercyst,PancreaticpseudocystandPartialvolumeeffect*ThisisahighlyvascularlednodulardemonstratedasLeftsubphrenicvarixwhichiscommonlyseenincirrhoticpatient.ThisisbecauseLeftsubphrenicveiniscoursingalongwiththelaterallimbofleftadrenalgland.*AcysticmassinleftadrenalturnedouttobePancreaticpseudocyst*Multiplanarreformatishelpfultodepicttherealshapewithadjacentorgan.AhypervascularmassisturnedouttobeanaccessoryspleeninserialMPRimages*TheCausesandPrevalenceofadreanlmasseslistedbelow.Corticaladenomatakes50%andmetastasestakesanother30%*Besidesadenomasandmetastastes,otherbenignandmilitantsuchasMyelolipomacystHemorrhageTBallhavecharacteristicimagingfeatures,soTheprimarygoalistodifferentiateadenomasandnonadenomasExaminationsshouldbeascloseto100%specificityaspossible*ThefirststepistoperformcomperensiveBiochemicalAssaybylaboratorytesting,positiveresultsarehelpfultodiagnosehyperfunctioningadenomas,corticalcarcinomasandPheochromocytoma*NextstepistoevaluatetheMorphologicfeature,malignantmassestendtobelarger,andadenomasissmaller,butitisalwaysthecase,itconfirmedbothbothtextureandmarginationisnothelpful.ButAnypriorimagingisusefulwithleastcostIncreasesinsize6monthsapartconsideredmalignant*Anypriorimagingisusefulwithleastcost.Increasesinsize6monthsapartconsideredmalignant*ThisisaBilateraladrenalmetastases,theleftmassesisbig,withirregularcontourandnecroticcenter*AndaNon-functioningadrenaladenomaisoftenlessthan3cmindiameter*However,thisiscontroversial.Thisisalargedegeneratingnonfunctioningadenomagreaterthan12cm.*Forthoseinditerminedmasses,lipid-sensitiveImagingshouldbeperformed.TheyCTdensitometryCThistologram,T2SICSIin/opposedphaseimaging.TheaimisdetectIntracellularlipidcontentinadenomas*CTdensitometryischoice,ameanattenuationvalueof10-HUthresholdisusedasacutoffvalueforadenomastestsensitivity71%testspecificity98%30%adenomasarelipidpoorwithCTvaluegreaterthan10HUhowever,ifthestandarddeviationishigh,theaccuracyisdecrease.*HearwepresenttwocasewithsimilarCTvalue.CaseIisaadenomawithCTvalueofnear30HU,andwhenwecountthenegativepixelnumber,itis27inpercentage.*Case2isametastaseswithsimilarCTvalue,andNegativepixelcount1.7%.Thisisenoughtodifferntiateanonadenomas.Fromadenomas*IthasbeenknownforalongtimethatMalignantmasssoftenshowhighT2WISIwhileAdenomasisinmoderateSIbecauseofcholesterolcontent.However,there10%`30%percentoverlappingbetweenthem.*ThisiscontroversialcaseofaMyxoidadrenalcorticaladenomashowinghighT2wiSI*ChemicalShiftImagingistomeasureSIlossinopposedphasecomparedtoinphaseimagesThecutoffvalueis10-15%Sensitivityof91%,specificityof94-%Qualitativediagnosisisasgoodasquantitativeassessment*ThisisaadnomasshowedobviousSIlossonopposedphaseimages*AndAdrenalmetastastesdonotlossSI*Thereareexception,Lipid-pooradenomadonothaveSIloss,too*SothefinalimagingmodelisFunctionalimaging,theyareWashoutratiobyDCECT/MRI,CTperfusion,PET-CT,MRspectrographyanddiffusionweightedisunderinvestigated*IVcontrastmedium“washout”muchfasterforadenomasthannonadenomasPercentagewashoutratiosAPW(absolutepercentagewashout)(EnhancedCTvalue-DelayedCTvalue)/(EnhancedCTvalue-unenhancedCTvalue)×100%RPWrelativepercentagewashoutRPW=(EnhancedCTvalue-DelayedCTvalue)/EnhancedCT×100%Mostacceptedthreshold15-minutedelayedscan40%forRPWor60%forAPWAlsorecommended10-minutedelayscanRPW>50%Nearly100%sensitiveandspecific!*TypeI Delayedenhanced NeurogenictumorsTypeIIRapidwashout AdenomasTypeIIIModeratewashout Intimidate TypeIVSlowwashout Malignanttumors*BVcanbeuseddifferentiatingadenomasfromnonadenomasBVcanbeuseddifferentiatingadenomasfromnonadenomas**
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