乳腺磁共振成像 (史浩 )

乳腺磁共振成像

MRIOFBREAST史浩山东省医学影像学研究所1/13/20231PREFACE1/13/20232MAMMOGRAPHY1/13/20233PITFALLSThesensitivityisbetween69%and90%.Thespecificityrangesfrom10%to40%.Tumoursmaybemissedbecauseofpoormammographictechniqueorobservererror,orthesizeandnatureofthelesionsrelativetothesurroundingbreasttissue,whichmayobscurethem.1/13/20234ULTRASOUND1/13/20235PITFALLSUShaslimitationsasascreeningmodalitybecausemicrocalcificationinductalcarcinomainsitumaynotbeidentified.Thefalsenegativerateisrangingfrom0.3%to47%insomeseries.Itisdifficulttoensurethattheentirebreasthasbeenimaged.USistimeconsuming.1/13/20236MRI1/13/20237ADVANTAGESExcellentsofttissueresolutionTomographicimagingMultipleorientationsHighspatialresolutionLackofionizingradiationGradingthecancerofbreast1/13/20238DISADVANTAGESLowersensitivitytocalcificationExpensiveExaminationfeeLongerexaminationtimeInfectionofheartmovementandrespiration1/13/20239EXAMINATIONINDEX钼靶或超声不能确诊的病灶区分术后疤痕和肿瘤复发要保留乳腺的乳腺癌患者，查找其它隐藏肿瘤，明确肿瘤范围，确定手术区域评价隆胸术后硅树胶植体的完整性及乳腺病变情况1/13/202310MRITECHNIQUE1/13/202311COILSdedicatedbreastcoilsingleordoublebreastmode1/13/202312EXAMINATIONTIMEAftermenopauseNotimerequestBeforemenopauseSixthtoSixteendaysofthemenstrualcycleOravoidingsixdaysbeforeandaftermenses1/13/202313POSITIONThepronepositionwilldecreasetheamountofrespiratorymotionartifact.Minimalcompressionappliedwithinthecoilwilldecreasemotionartifact.1/13/202314PHASE-ENCODINGDIRECTIONThephaseencodingdirectionshouldnotpassanteriortoposterior,butfromlefttoright,toensurethatcardiacactivityisnotprojectedoverthebreast.1/13/202315SATURATION&GATINGSaturationzoneislocatedbehindthoracicwallCardiacandrespiratorygating1/13/202316SCANNINGPLANESTransverseplaneCoronalplaneSagittalplane1/13/202317CONVENTIONALSEQUENCEST1WIT2WISTIR(Fatsuppressionsequences)1/13/202318SPECIALSEQUENCES3DFLASH(fastlowangleshot)PWI(PerfusionWeightedImaging)CSI(Chemicalshiftimaging)1/13/202319SCANPARAMETERSThickness:2mm~5mmGap:0~3mmMatrix:256256FOV:30cm~40cmAcquisitiontime:1~3Scantime:3min~5min1/13/202320MRIENHANCEMENT1/13/202321SIGNIFICANCEThereareanobviousoverlapbetweenbenignandmalignantlesionsinplainMRscanning.Theenhancementcanincreasethedistinctionbetweenthelesionandsurroundingnormaltissue.Sensitivityandspecificityofthediagnosiswouldbemarkedlyincreased.1/13/202322PRINCIPLEIntravenousgadoliniumpassesintotheextravascularspaceandaccumulatesintissueswithrichvascularity.1/13/202323CONTRASTAGENTGadolinium(Gd-DTPA)IntravenousinjectionDose:0.1mmol/kg~0.2mmol/kgSpeed:2ml/s~3ml/s1/13/202324NORMALPATTERNSNormalglandularbreasttissueenhancesrelativelyslowlyover10minfollowingtheinjectionofivgadolinium.1/13/202325BENIGNLESIONS不强化边缘光滑或分叶状结节强化强化结节内呈分隔状弥漫点状强化1/13/202326MALIGNANTLESIONS不规则或毛刺状结节强化环状强化导管状强化1/13/202327NORMALSTUDY1/13/202328NORMALBREASTS1/13/202329FINDINGS乳腺内腺体、导管和脂肪结缔组织分布和比例决定乳腺的MR表现特点腺体型（腺体实质为主，多见于青年女性）T1WI和T2WI呈均匀等信号，周围可见高信号脂肪围绕T2压脂序列显示导管呈树枝状并向乳头汇集脂肪型（以脂肪为主，多见于老年女性）T1WI和T2WI以高信号为主，仅于乳头周围可见少量残存等信号腺体影T2压脂序列示导管分布稀疏中间型（多见于生育过的中年女性）表现间于上两型之间1/13/202330NORMALSTUDY腺体型脂肪型中间型1/13/202331CASES1/13/202332FIBROADENOMA单发或多发形状规则，呈圆形、类圆形、分叶状边界清晰，与周围组织分界清楚可见包膜T1WI呈低（或等）信号T2WI呈等或略高信号增强后以纤维成分为主时强化较弱，以腺样成分为主时呈较明显强化1/13/202333FIBROADENOMAPre-contrastPost-contrastmammogramFibroed

fibroadenoma1/13/202334FIBROADENOMAPre-contrastPost-contrastAdenomatous

fibroadenoma1/13/202335FIBROADENOMAT1WIT2WICONTRASTAdenomatous

fibroadenoma1/13/202336PROLIFERATIONT1WI呈低信号T2WI根据水分的多少而表现不同，水分多信号高，水分少信号低增强后呈较广泛轻度斑片状强化表现不具特征性1/13/202337PROLIFERATIONSE400/30SE2400/90MammogramFocalfibroticfibrocysticcondition1/13/202338PROLIFERATIONmammogram3DFE40/14/50enhancedimageNonproliferativefibrocysticchanges1/13/202339PROLIFERATION3DFE40/14/50enhanceddelayedmammogramProliferativechanges1/13/202340PROLIFERATIONPrecontrastT13DFLASHGd-DTPA-enhancedimagemammogramFocalproliferativechanges1/13/202341CYSTT1WI上单纯性囊肿呈低信号（取决于囊内蛋白含量）复杂性囊肿囊内常含有血液成分，可呈高信号表现T2WI一般呈高信号增强后病灶无强化，如伴发感染时可出现周边强化不规则或结节状周边强化提示为肿瘤坏死、囊肿内出现肿瘤病灶或乳头状瘤1/13/202342CYSTmammogramSE400/30SE2400/35SE2400/901/13/202343CARCINOMA病灶呈分叶状、星芒状、蟹足样、毛刺状边界不规则，与周围组织界限不清内部不均匀T1WI呈低或等信号，T2WI呈高或等信号不规则或毛刺状结节强化,环状强化,导管状强化1/13/202344CARCINOMAT1WI横轴位平扫横轴位增强扫描矢状位延迟1/13/202345CARCINOMAPre-contrastPost-contrast1/13/202346CARCINOMAPre-contrastPost-contrastsubtract1/13/202347CARCINOMAT1WI平扫1分钟增强扫描7分钟延迟病理1/13/202348FIBROADENOMA&CANCER平扫5分增强扫描A.纤维腺瘤B.乳腺癌平扫5分增强扫描减影像减影像1/13/202349DYNAMICENHANCEMENT1/13/202350TECHNIQUEIntravenousfleetbolusinjectionofGd-DTPAContinuousmulti-timesscanningwithfastsequenceonROI(lesion)immediatelyaftertheinjectionObservationonthelesiondynamicchangeandtime/intensitycurve1/13/202351PRINCIPLE对比剂首过（firstpass）组织增强与对比剂在血管结构内的分布有关反映病灶血管丰富程度和血液灌注情况与病变的微血管密度、管径和管壁渗透性等有关1/13/202352ANALYSINGINDEX病灶形态、大小、位置良性还是恶性单发或多发病灶强化模式(是从中心到周围还是从周围到中心)及早期化率绘制时间信号强度曲线1/13/202353PATHOLOGICALBASIS恶性病变由于其瘤内微血管密度大，微血管基底膜极不完整，病灶局部的灌注明显增大，因此早期即可显著强化，且迅速下降良性病变微血管密度较少且早期良性病灶常轻度或无明显强化，而随时间延长呈持续强化状态1/13/202354DIAGNOSTICVALUE增强速率（SIpost-SIpre/SIpre100%）<60%为良性60%～80%为性质待定病变>80%为恶性病变1/13/202355PATTERNSOFCURVE型（增长型）（increase/wash-in）信号强度迅速上升达到峰值后便呈平缓上升状态多见于良性病变型（平台型）（plateau）强化初期迅速上升，后期呈平台状多为可疑恶性病变型（下降型）（decrease/wash-out）强化信号强度在中后期呈下降趋势多为恶性病变1/13/202356PATTERNSOFCURVE1/13/202357PATTERNSOFLESIONS动态增强形式 乳腺癌 纤维腺瘤型(增长型) 6% 83%型(平台型) 64% 11.5%型(下降型) 78% 1%1/13/202358FIBROADENOMAT1WIT2WI1/13/202359CARCINOMA1/13/202360DIFFERENTIATIONPostcontrastMIPEarlypostcontrastsubtractedMRimagesEarlypostcontrastsubtractedMRimagesTime–signalintensitycurveTime–signalintensitycurvefibroadenomacarcinoma1/13/202361DIFFUSION

WEIGHTEDIMAGING1/13/202362FUNCTIONSToobservethemicrocosmicmovingofwatermoleculesTostudyADC(ApparentDiffusionCoefficient)oflesionarea1/13/202363PRINCIPLE利用MRI的特性序列观察活体中水分的微观运动的一种成像方法，是一种对水分子扩散运动的成像技术DWI使磁共振研究深入到更微观水平，反映组织空间组成信息及病理生理状态下各组织成分之间交换水分的功能状况1/13/202364PRINCIPLED值（DiffusionCoefficient）为弥散系数，反映水分子的弥散运动能力ADC值（ApparentDiffusionCoefficient）活体水分子的弥散受多种因素综合作用，所以D值不能完全代表其弥散程度1/13/202365PRINCIPLEDWI图反映弥散信号的强弱弥散快时呈低信号弥散慢时呈高信号ADC图直接反映组织弥散快慢的指标弥散快呈白色弥散慢呈黑色1/13/202366PRINCIPLE恶性肿瘤细胞生长旺盛，密度高生物膜对水分子的弥散具有明显限制作用ADC值小良性肿瘤细胞生长缓慢，细胞密度低生物膜对水分子的弥散限制作用小ADC值大1/13/202367METHODSConventionalMRIscanning(T1WI,T2WI)EPI-DWIbvalue:b1=0,b2=1000Scantime:40sADC=ln(Sb1-Sb2)/(b1-b2)1/13/202368FINDINGS恶性肿瘤DWI为高信号ADC值小，ADC图为低信号良性肿瘤DWI为高于或略高于腺体信号ADC值大，ADC图为高信号1/13/202369FIBROADENOMAT2WI-FST2WI-FSC+-SC+-Sb=0b=500b=1000ADCmap1/13/202370CARCINOMAb=0b=500b=1000T2WIFST1WIC+MIPSAGC+DC-CLC1/13/202371MRSPECTROSCOPY1/13/202372FUNCTION是检测活体内代谢和生化信息的一种无创性技术能在分子水平上反映病理情况提供的是定量化学信息，一般以数值或图谱来表达对这种代谢改变的潜在敏感性很高，故能提供信息以早期检测病变1/13/202373PRINCIPLE利用化学位移作用进行特定化合物的分析测量的MR信号通过傅里叶转换为MR波谱不同代谢产物化学位移产生不同的信号强度峰值谱的横坐标代表共振频率（单位:百万分率(ppm)）波峰信号的指标有共振频率、谱峰高、半峰高处线宽(表示谱峰的锐利度)以及波峰面积等各波峰面积与被测物中某化合物浓度的原子核数量成正比1/13/202374CATEGORY当前用于医学领域的波谱有1Ｈ、31Ｐ、13Ｃ、23Ｎａ和Ｋ等乳腺检查运用1H和31P谱，以前者效果更佳MRS在乳腺肿瘤的敏感性达100%,特异性为89%～100%1/13/202375METHODSThreedirectionplanesDecisionofvoxelarea(1cm3)Adjustingfield(<0.1ppm)WatersuppressionadjustmentInspectionofsignalAfter-procession1/13/202376FINDINGSH谱较P谱敏感性更高正常乳腺组织内不含胆碱乳腺癌组织胆碱峰明显增高，磷酸胆碱（Pcho）/磷酸甘油胆碱（GPcho）比值倒置P谱用于显示肿瘤和正常组织之间不同磷代谢、细胞能量和细胞间pH的变化信息肿瘤细胞膜可导致磷脂化合物成分的升高乳腺癌组织中磷酸单脂（