慢性胰腺炎及并發(fā)癥的MRI表現(xiàn)-課件

慢性胰腺炎及其并發(fā)癥的MRI表現(xiàn)1ppt課件Chronicpancreatitisisaninflammatorydiseasecharacterizedbyprogressiveandirreversiblestructuraldamagetothepancreasresultinginpermanentimpairmentofbothexocrineandendocrinefunctions.ERCPisthegoldstandardforearlychronicpancreatitis,butitisinvasive.MRImaybeanalternativeforpatientsinwhomCTorERCPiscontraindicatedornottolerated.MRIprovidesnoninvasivebiliaryandpancreaticductimagingandaccuratecharacterizationofpancreaticandperipancreaticpathology.

慢性胰腺炎是一種炎癥性疾病，其特征是對(duì)胰腺逐步和不可逆轉(zhuǎn)的結(jié)構(gòu)性損壞，導(dǎo)致外分泌和內(nèi)分泌功能的永久性受損。ERCP是診斷早期慢性胰腺炎的金標(biāo)準(zhǔn)，但它是侵入性檢查。在CT或ERCP為禁忌或不能耐受時(shí)，MRI可作為替代。MRI提供非侵入性膽胰管成像和胰腺及胰周病變的征象。

2ppt課件ThediagnosisofchronicpancreatitisonMRIisbasedonsignalintensityandenhancementchangesaswellasonmorphologicabnormalitiesinthepancreaticparenchyma,pancreaticduct,andbiliarytract.Theimagingfeaturesofchronicpancreatitiscanbedividedintoearlyandlatefindings.慢性胰腺炎MRI診斷是基于信號(hào)強(qiáng)度和增強(qiáng)的變化，以及胰腺實(shí)質(zhì)，胰管和膽道形態(tài)的異常。慢性胰腺炎的影像特征可分為早期表現(xiàn)和晚期表現(xiàn)。3ppt課件Earlyfindingsincludelow-signal-intensitypancreasonT1-weightedfat-suppressedimages,decreasedanddelayedenhancementafterIVcontrastadministration,anddilatedsidebranches.Latefindingsincludeparenchymalatrophyorenlargement,pseudocysts,anddilatationandbeadingofthepancreaticductoftenwithintraductalcalcifications.早期表現(xiàn)包括T1加權(quán)脂肪抑制圖像上呈低信號(hào)，延遲強(qiáng)化或強(qiáng)化程度減低，側(cè)支擴(kuò)張。晚期表現(xiàn)包括實(shí)質(zhì)萎縮或腫大，假性囊腫，胰管擴(kuò)張或呈串珠樣，導(dǎo)管內(nèi)常伴鈣化。4ppt課件MRIallowsearlyrecognitionofchronicpancreatitisbasedonchangesinpancreaticsignalintensity;thesechangesarebestvisualizedonunenhancedandgadolinium-enhancedT1-weightedfat-suppressedimages(Fig.1A,1B,1C,1D).MRI可以早期識(shí)別慢性胰腺炎胰腺信號(hào)強(qiáng)度的變化，平掃和增強(qiáng)T1加權(quán)脂肪抑制圖像顯示信號(hào)變化最佳（圖1A，1B，1C，1D）。5ppt課件Fig.1A.1B.Fig.1A.—24-year-oldwomanwithsmallpancreaticductstonecausingductobstructionandsegmentalpancreatitis.AxialT2-weightedHASTEimageshowsslightlyincreasedsignalintensityofpancreatictail(arrow)withmilddilatationofpancreaticduct.AxialT1-weightedfat-suppressedspoiledgradient-echoimageshowsabnormallowsignalintensityofpancreatictail(arrow)whileremainderofpancreashasnormalbrightsignalintensity.24歲，女。小胰管結(jié)石引起膽道梗阻和節(jié)段性胰腺炎。T2WI胰尾信號(hào)輕度升高，胰管輕度擴(kuò)張（箭頭）。T1WI顯示胰尾異常低信號(hào)（箭頭），胰腺其余部分信號(hào)強(qiáng)度正常，為高信號(hào)。6ppt課件AxialenhancedT1-weightedfat-suppressedspoiledgradient-echoimageobtainedduringarterialphaseshowsdelayedenhancementofpancreatictail(arrow)relativetonormalpancreasduetofibrosis.Patientlaterdevelopedatrophicchangesinthisareathatledtoresectionofpancreatictail.Contrast-enhancedCTscanshowspunctatehigh-densityfocus(arrow)inpancreaticductrepresentingsmallintraductalstone.ThisexampleillustratestheadvantageofCTinshowingtinyintraductalstonethatwasnotseenonMRI.It,however,alsoillustratestheadvantageofMRIinshowingchangesofsignalintensityassociatedwithchronicpancreatitisthatarenotvisibleonCT.動(dòng)脈期增強(qiáng)T1WI示因纖維化胰尾較正常胰腺?gòu)?qiáng)化延遲（箭頭），此處后來(lái)呈萎縮性改變，導(dǎo)致實(shí)行胰尾切除術(shù)。對(duì)比增強(qiáng)CT掃描顯示胰管內(nèi)小結(jié)石。這個(gè)例子說(shuō)明了CT的優(yōu)勢(shì)在于顯示微小的管內(nèi)結(jié)石，而在MRI未顯示。然而，它也顯示出磁共振成像的優(yōu)點(diǎn)：可顯示出慢性胰腺炎信號(hào)強(qiáng)度的變化與關(guān)系，此在CT上是不可見(jiàn)的。Fig.1C.1D.7ppt課件Chronicinflammationandfibrosisdiminishtheproteinaceousfluidcontentofthepancreas,resultinginthelossoftheusualhighsignalintensityonT1-weightedfat-suppressedimages.Thenormalpancreasenhancesuniformlyandintenselyonearlyarterialphasecontrast-enhancedT1-weightedimagesandexhibitsrapidwashoutofgadoliniumonsubsequentimages.慢性炎癥和纖維化減少胰腺的蛋白質(zhì)含量，使得在T1加權(quán)脂肪抑制圖像上高信號(hào)消失。正常胰腺動(dòng)脈期均勻明顯強(qiáng)化，并快速廓清。8ppt課件Incontrast,apancreaswithchronicfibrosisandglandularatrophyexhibitsdecreasedandheterogeneousenhancementonearlyarterialphaseimagesandincreasedrelativeenhancementondelayedimages(Fig.2A,2B,2C).相比之下，慢性纖維化并腺體萎縮的胰腺在早動(dòng)脈期強(qiáng)化程度減低并強(qiáng)化不均勻，延遲圖像上強(qiáng)化程度相對(duì)升高（圖2A，2B，2C）9ppt課件Fig.2A.2B.

Fig.2A.

—46-year-oldmanwithhistoryofchronicpancreatitisduetoalcoholabuse.AxialT1-weightedfat-suppressedspoiledgradient-echoimageshowsatrophyofpancreaticparenchymaandirregulardilatationofmainpancreaticduct(arrows),changessuggestiveofchronicpancreatitis.CalcificationsarenotaswellseenonMRIasonCT.AxialenhancedT1-weightedfat-suppressedspoiledgradient-echoimageobtainedduringarterialphaseshowsdiffuselydecreasedpancreaticenhancementrelativetomarkedenhancementseennormally.Thisdecreasedenhancementrelatestofibrosisduetochronicpancreatitis.Dilatedpancreaticduct(arrows)isvisualizedmoreclearlyaftercontrastadministration.46歲，男，因酗酒致慢性胰腺炎。T1WI顯示胰腺實(shí)質(zhì)的萎縮和不規(guī)則擴(kuò)張的主胰管（箭頭），提示慢性胰腺炎的變化。鈣化在MRI和CT上都沒(méi)有看到。動(dòng)脈期增強(qiáng)T1WI顯示胰腺因慢性炎癥引起的纖維化而強(qiáng)化彌漫性降低，而非通?？吹降娘@著增強(qiáng)。胰管擴(kuò)張（箭頭）顯示更清。10ppt課件DuctAbnormalities胰管異常

MRCPishighlyaccurateforidentifyingpancreasdivisum(Fig.6).However,itsassociationwithpancreatitisremainscontroversial.Ductabnormalitiessuchasdilatation,irregularity,andstonesandcomplicationsofchronicpancreatitissuchaspseudocystsarebestdepictedbythin-sectionT2-weightedHASTEorsingle-shotfastspin-echoandthick-slabT2-weightedhalf-FourierRAREMRCPimages.MRCP發(fā)現(xiàn)胰腺分裂的準(zhǔn)確度很高（圖6）。然而，它與胰腺炎的關(guān)系仍存在爭(zhēng)議。胰管異常，如擴(kuò)張，不規(guī)則，結(jié)石和并發(fā)癥如假性囊腫，在薄層T2加權(quán)HASTE或MRCP顯示最佳。11ppt課件Fig.6.—53-year-oldwomanwithhistoryofcholecystectomywhopresentedwithjaundice,abnormalresultsonliverfunctiontests,andpancreasdivisum.AxialT2-weightedimageshowsnoncommunicatingmainpancreaticduct(straightarrow)andaccessoryduct(curvedarrow)drainingseparatelyintoduodenum.圖6，53，女。膽囊切除術(shù)后，黃疸，肝功能異常，胰腺分裂癥。軸位T2WI顯示軸向T2加權(quán)圖像顯示，互不溝通的主胰管（直箭頭）和配胰管（彎箭頭）分別進(jìn)入十二指腸引流。Fig.6.12ppt課件MRCPisaccurateindepictingstricturesofthepancreaticductorbiliarytract(Fig.7).Inequivocalcases,ductaldistentionbycontrastinjectionduringERCPmaybehelpful.Thebeadedmainpancreaticductwithitsdilatedsidebranchesmayhaveachain-of-lakesappearancewhenmoreextensive(Fig.8).MRCP可準(zhǔn)確的描繪胰管或膽管的狹窄（圖7）。在模棱兩可的情況下，在ERCP過(guò)程中導(dǎo)管注射造影劑擴(kuò)張胰膽管可能會(huì)有幫助。當(dāng)病變廣泛時(shí)，串珠樣主胰管和擴(kuò)張的側(cè)枝，可能有連鎖湖樣改變。13ppt課件Fig.7.—62-year-oldwomanwithhistoryofchronicpancreatitisandpseudocysts.CoronalT2-weightedthick-slabRAREimageshowsstricture(straightarrow)ofpancreaticductatlevelofpancreatichead.Upstreampancreaticductisdilatedandirregular,andthereismilddilatationofsidebranches.Notediverticulum(curvedarrow)arisingfromduodenum.圖7。62，女。慢性胰腺炎，假性囊腫。冠狀T2WI顯示胰頭水平胰管狹窄（直箭頭）。上游胰管不規(guī)則擴(kuò)張，側(cè)枝輕度擴(kuò)張。注意十二指腸憩室（彎箭頭）。Fig.7.14ppt課件Fig.8.—69-year-oldmanwithchronicpancreatitis.AxialT2-weightedHASTEimageshowsirregulardilatedmainpancreaticductandsidebranchesgivingchain-of-lakesappearance.Noteatrophicchangesinpancreasandsignal-voidareas(arrows)relatedtocalcificationsfromchronicpancreatitis.圖8。69歲，男。慢性胰腺炎。軸向T2WI顯示不規(guī)則擴(kuò)張的主胰管和側(cè)枝，連鎖湖外觀?？梢?jiàn)胰腺萎縮及無(wú)信號(hào)鈣化區(qū)（箭頭）。Fig.8.15ppt課件CTismoresensitivethanMRIforthedetectionofcalcificationsassociatedwithchronicpancreatitis;however,MRIbestdepictsintraductalstonesandductobstruction(Figs.9A,9Band10).UnlikeERCP,MRCPcanshowthedilatedductupstreamfromanobstructingstone.Nevertheless,visualizingintraductalstonesnotsurroundedbyfluidmaybedifficultonMRI(Fig.1A,1B,1C,1D).對(duì)慢性胰腺炎的鈣化檢測(cè)，CT比MRI敏感，然而，MRI顯示管內(nèi)結(jié)石和胰膽管阻塞最佳（圖9A，9B和10）。不同于ERCP，MRCP能顯示上游擴(kuò)張導(dǎo)管。然而，MRI診斷不被液體包圍的導(dǎo)管內(nèi)結(jié)石困難（圖1A，1B，1C，1D）。16ppt課件Fig.9A.—46-year-oldmanwithhistoryofchronicpancreatitisduetoalcoholabuse.Axialcontrast-enhancedCTscanshowsmultiplecalcificationsinpancreatichead.Itisdifficulttodeterminethatastoneisinpancreaticduct.Calcificationsareseencommonlyinchronicalcohol-relatedpancreatitis,asinthispatient.AxialT2-weightedHASTEimageshowsstone(arrow)inmainpancreaticductdelineatedbyhigh-signal-intensityfluid.圖9A。男，46歲。酗酒史，慢性胰腺炎。軸向增強(qiáng)CT掃描顯示胰頭多發(fā)鈣化。從CT很難確定胰管內(nèi)有無(wú)結(jié)石。鈣化在慢性酒精相關(guān)性胰腺炎中很常見(jiàn)，此例即如此。軸向T2WI的顯示主胰管內(nèi)結(jié)石（箭頭）被高信號(hào)液體包繞。Fig.9A.9B.17ppt課件Fig.10.—45-year-oldwomanwithhistoryofabdominalpain.CoronalT2-weightedHASTEimageshowspancreaticductstone(straightarrow)andgallstone(curvedarrow).GB=gallbladder,CBD=commonbileduct,PD=pancreaticduct,DUOD=duodenum.圖10。45歲，女，腹痛。冠狀T2WI的顯示胰管內(nèi)結(jié)石（直箭頭）和膽結(jié)石（彎箭頭）。GB=膽囊，CBD=膽總管，PD=的胰管，DUOD=十二指腸。Fig.10.18ppt課件Complications1.Pseudocysts假性囊腫2.Vascular血管相關(guān)并發(fā)癥3.Biliary膽管相關(guān)并發(fā)癥19ppt課件1.PseudocystsPseudocystsareencapsulatedcollectionsofpancreaticsecretionsthatoccurinoraroundthepancreas.Althoughmostresolvespontaneously,complicationssuchasinfection,hemorrhage,andgastricorbiliaryobstructionmayoccur(Fig.11A,11B).Pseudocystscanbecommunicatingwiththemainpancreaticduct(Fig.12)ornoncommunicating.MRIcandepictpseudocystsandcanbeusedtocharacterizetheircontentandthustoguidedrainage.假性囊腫是發(fā)生在胰腺內(nèi)或胰腺周圍被包裹的胰腺分泌物。雖然大多數(shù)可自發(fā)吸收，但也可發(fā)生并發(fā)癥，如感染，出血，胃或膽道梗阻（圖11A，11B）。假性囊腫與主胰管可連通（圖12）或不連通（圖13）。MRI可以描繪假性囊腫并檢測(cè)內(nèi)容物成分以指導(dǎo)引流。20ppt課件52-year-oldmanwithhistoryofrecurrentpancreatitis.AxialT2-weightedHASTEimageshowslargethick-walledmultiloculatedcysticcollectionlocatedprimarilyinlessersac,representingpseudocyst(P).Itdoesnotcommunicatewithpancreaticduct.AxialT1-weightedfat-suppressedspoiledgradient-echoimageshowshigh-signal-intensityfluidwithinpseudocyst,suggestiveofcomplicatedpseudocyst(P).Internalconsistencyofpseudocystsmaybealteredbecauseofpresenceofproteinaceousmaterial,hemorrhage,orinfection,anditmayrequirepromptdrainage.52歲，男，復(fù)發(fā)性胰腺炎。軸向T2WI的顯示主要位于小網(wǎng)膜囊的巨大厚壁多房假性囊腫(P)。不與胰管溝通。軸位T1WI顯示囊腫內(nèi)為高信號(hào)，提示其為復(fù)雜性假性囊腫（P）。因存在蛋白性物質(zhì)，出血，或感染，假性囊腫內(nèi)部一致性可被改變，提示需要盡快引流。Fig.11A.11B.21ppt課件Fig.12.—55-year-oldwomanwithabdominalpain,weightloss,andhistoryofpancreatitis.AxialT2-weightedHASTEimageshowshigh-signal-intensitypseudocyst(P)inpancreaticheadwithdilatedandirregularpancreaticduct.Pseudocystcanbeseencommunicatingwithmainpancreaticduct(arrow).圖12。55歲，女。腹痛，體重減輕，胰腺炎。軸位T2WI顯示胰頭部高信號(hào)假性囊腫（P）及不規(guī)則擴(kuò)張的胰管?？梢钥闯黾傩阅夷[與主胰管（箭頭所示）連通。Fig.1222ppt課件2.VascularArterialpseudoaneurysms,hemorrhageintopseudocysts,arterialbleeding,andsplenicorportalveinthrombosisarevascularcomplicationsofchronicpancreatitisthatmaybeseenonMRI.Inpatientswithchronicsplenicveinthrombosis,theveinmaynotbevisualized.(Fig.14A,14B).假性動(dòng)脈瘤，假性囊腫內(nèi)出血，出血，脾靜脈或門靜脈血栓為慢性胰腺炎的血管相關(guān)并發(fā)癥，MRI可檢測(cè)出。但當(dāng)有慢性脾靜脈血栓時(shí)，靜脈可能無(wú)法顯示（圖14A，14B）23ppt課件Fig.14A.—46-year-oldmanwithhistoryofchronicpancreatitisduetoalcoholabuse.AxialenhancedT1-weightedfat-suppressedspoiledgradient-echoimageobtainedduringvenousphaseshowschronicocclusionofportalveinwithcollaterals(arrow):cavernoustransformationofportalvein.Fig.Bshowscollateralvessels(arrows),whichissuggestiveofsplenicveinocclusion.46歲，男，慢性胰腺炎，酗酒史。靜脈期軸向增強(qiáng)T1WI示門靜脈慢性閉塞（箭頭）呈海綿樣變。圖B顯示側(cè)支循環(huán)形成（箭頭），提示脾靜脈阻塞。Fig.14A.B.24ppt課件3.BiliaryThebiliarycomplicationsofchronicpancreatitisincludecholedocholithiasis,fistulas,anddilatationofthecommonbileductduetoinflammatorystrictures.ThetypicalappearanceofbenignstricturesonMRCPisgradualtaperingwithafunnellikenarrowedsegment(Fig.15).慢性胰腺炎的膽道并發(fā)癥，包括膽總管結(jié)石，瘺管，由于炎性狹窄而致的膽總管擴(kuò)張。良性狹窄的典型MRCP表現(xiàn)為逐漸變細(xì)的漏斗樣狹窄（圖15）。25ppt課件Fig.15.—59-year-oldmanwithhistoryofchronicpancreatitis.MRimagewasobtainedtoevaluatebiliarytractandcomplexpseudocystsseenonpriorCTscan(notshown).CoronalT2-weightedthick-slabRAREimageshowsdilatedcommonbileductwithfunnel-shapednarrowing(arrowhead).Pancreaticductisdilatedandcontainscalculus(arrow)atpancreaticheadlevel.Alsoseenaremultiplepseudocysts(P)extendingbothsuperiorandinferiortopancreas.GB=gallbladder.男，59歲，明顯胰腺炎。行MRI檢測(cè)以明確CT所示復(fù)雜假性囊腫并評(píng)價(jià)膽道情況。冠狀T2WI顯示擴(kuò)張的膽總管、漏斗樣狹窄（箭頭）。胰管擴(kuò)張、胰頭處可見(jiàn)結(jié)石。并可見(jiàn)多發(fā)假性囊腫（P）延伸至胰腺前后方。GB=膽囊。Fig.1526ppt課件ChronicPancreatitis

VS.

PancreaticCarcinoma

慢性胰腺炎VS.胰腺腫瘤27ppt課件ChronicPancreatitisVS.PancreaticCarcinomaDifferentiatingbetweenaninflammatorymassduetochronicpancreatitisandpancreaticcarcinomaonthebasisofimagingcriteriaremainsdifficult.DecreasedT1signalintensitywithdelayedenhancementaftergadoliniumadministrationaswellasdilatationandobstructionofthepancreaticobiliaryductscanbeseeninbothdiseases.Irregularityofthepancreaticduct,intraductalorparenchymalcalcifications,diffusepancreaticinvolvement,andnormalorsmoothlystenoticpancreaticductpenetratingthroughthemass(“ductpenetratingsign”)favorthediagnosisofchronicpancreatitisovercancer(Fig.16A,16B,16C).Indistinction,asmoothlydilatedpancreaticductwithanabruptinterruption,dilatationofbothbiliaryandpancreaticducts(“double-ductsign”),andobliterationoftheperivascularfatplanesfavorthediagnosisofcancer.鑒別慢性胰腺炎引發(fā)的炎性包塊和胰腺腫瘤，從影像學(xué)上尚屬困難。兩者均可出現(xiàn)延遲強(qiáng)化和胰膽管的阻塞擴(kuò)張。不規(guī)則的胰管，胰管內(nèi)或?qū)嵸|(zhì)內(nèi)鈣化，彌漫性胰腺受累，光滑狹窄的胰管從腫塊內(nèi)穿過(guò)（“穿透癥”）更支持慢性胰腺炎的診斷（圖16A，16B，16C）。相反的，平滑擴(kuò)張的胰管突然中斷，膽管和胰管同時(shí)擴(kuò)張（“雙管征”），以及血管周圍脂肪間隙消失則支持腫瘤的診斷。28ppt課件Fig.16A.—58-year-oldwomanwithbreastcancerandchronicpancreatitisrelatedtoalcoholabuse.Patienthad50-lb(23-kg)weightloss.ERCPimage(notshown)revealedstoneinpancreaticduct,whichwasremoved.Fine-needleaspirationwassuggestiveofadenocarcinoma.Whippleprocedureindicatedchronicpancreatitiswithoutcancer.AxialT1fat-suppressedspoiledgradient-echoimageshowslow-signal-intensitypancreasduetochronicpancreatitis.AxialenhancedT1-weightedfat-suppressedspoiledgradient-echoimageobtainedduringarterialphaseshowsdiffuselydecreasedenhancementofpancreasduetochronicpancreatitis.Notedilatedpancreaticduct.圖16A。58歲，女，乳腺癌、酗酒相關(guān)的慢性胰腺炎。發(fā)病以來(lái)體重下降23kg。ERCP圖像（圖中未示出）顯示胰管石并去除。細(xì)針穿刺提示腺癌。胰十二指腸切除術(shù)提示慢性胰腺炎無(wú)癌變。軸向T1WI顯示因慢性胰腺炎而呈低信號(hào)的胰腺。動(dòng)脈期增強(qiáng)T1WI示胰腺?gòu)浡詮?qiáng)化減低。注意胰管擴(kuò)張。Fig.16A.B.29ppt課件Fig.16C.AxialT2-weightedHASTEimageshowsmarkedlydilatedmainpancreaticduct(arrow)penetratingthroughpancreaswithchronicinflammatoryandfibroticchanges:“ductpenetratingsign.”Thisfindingsuggestschronicpancreatitisoveradenocarcinoma.圖16C。同一病例。軸向T2WI示明顯擴(kuò)張的主胰管（箭頭），穿過(guò)具有慢性炎癥和纖維化的胰腺：“穿透征”。這一征象提示慢性胰腺炎可能性大。Fig.16C.30ppt課件MRImaybesuperiortoMDCTfortheevaluationofpancreaticadenocarcinoma,especiallyifthelesionissmallandnon-contour-deforming.ThetumorisbestdelineatedonunenhancedT1-weightedfat-suppressedimagesandmultiphasicenhancedsequences(Fig.17A,17B,17C,17D).MRI在對(duì)胰腺腺癌的診斷上優(yōu)于MDCT，特別是病變較小且胰腺外形沒(méi)有異常時(shí)。平掃T1WI及多期增強(qiáng)序列上圖17A，17B，17C，17D）顯示最佳。31ppt課件—71-year-oldwomanwithweightlossduetoadenocarcinomaofpancreaswithassociatedchronicpancreatitis.Axialcontrast-enhancedCTscanshowsatrophyofpancreatictailandductdilatation(arrow)tolevelofsuspectedmass,whichisdifficulttosee.AxialT2-weightedHASTEimageshowsdilatationofpancreaticductwithabrupttermination(arrow)duetotumor.71歲，女。慢性胰腺炎并腺癌。軸向增強(qiáng)CT示胰尾萎縮和胰管擴(kuò)張（箭頭），無(wú)法判斷是否有腫塊。軸向T2WI示由于腫瘤擴(kuò)張的胰管突然終止（箭頭）。Fig.17A.B.32ppt課件Fig.17C.AxialT1-weightedfat-suppressedspoiledgradient-echoimageshowslow-signal-intensitymass(arrowhead),measuringlessthan1cm.Noteatrophyanddecreasedsignalintensityofpancreatictail(curvedarrow)relatedtoassociatedchronicpancreatitis.Normallyhighsignalintensityofpancreatichead(straightarrow)ispreserved.AxialenhancedT1-weightedfat-suppressedspoiledgradient-echoimageobtainedduringlatevenousphaseshowsdelayedenhancementoftumor(arrowhead).ThisexampleshowsvalueofMRItodepictnondeformingpancreaticmass.同一病例，軸向T1WI示低信號(hào)腫塊（箭頭），小于1厘米。注意慢性胰腺炎引起的胰尾信號(hào)減低并萎縮（彎箭頭）。胰頭仍為正常高信號(hào)（直箭頭）。靜脈期軸向增強(qiáng)T1WI示延遲強(qiáng)化的腫瘤（箭頭）。這個(gè)例子顯示MRI在診斷不伴有胰腺外形失常的胰腺腫瘤中的價(jià)值。Fig.17C.D.33ppt課件GroovePancreatitis溝部胰腺炎Groovepancreatitisisatypeoffocalchronicpancreatitisaffectingthegroovebetweentheheadofthepancreas,duodenum,andcommonbileduct.ThepredominantMRIfindingofgroovepancreatitisisasheetlikefibroticmassbetweenthepancreaticheadandthickenedduodenalwallassociatedwithduodenalstenosisandcysticchangesintheduodenalwall(Fig.18A,18B,18C,18D).Therecognitionofgroovepancreatitisisimportantfordifferentiationfrompancre