脑内环形强化病变鉴别诊断.ppt

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1、InfectiousRingEnhancingLesionsoftheBrain“MRICluesforEtiologicalDiagnosis”脑内感染性环强化病变-病因诊断的MRI线索Introduction(前言)Centralnervoussystem(CNS)infectionsareanemerginghealthproblemwithpoorprognosisiftreatmentisnotadequate.Establishingacorrectdiagnosisisnecessarytoquicklystarttheappropriatetreatment.Thisis

2、arealchallengefortheradiologist,asitfrequentlyrequiresamultidisciplinaryapproach.RingenhancinglesionsonMRIhavealonglistofdifferentialsrangingfrominfectiousprocessestonecroticneoplasm.Althoughradiographicdifferentiationofthecauseoftheintracranialabnormalityisdifficultandoftennonspecific,certainclu

3、esmayhelpdifferentiatetheetiologyoftheinfection.概述中枢神经系统感染性疾病是一种新出现的健康问题，若治疗不充分将预后不良建立一个正确的诊断是必要的，以便迅速开展适当的治疗这对放射科医生来说是一个真正的挑战，由于其经常需要联合多学科知识在MRI上，环形强化病变有种类繁多，从感染性病变到坏死肿瘤虽然影像学鉴别颅内异常的病因是困难的，往往也是非特异性的，但某些线索可能有助于鉴别感染的病因CASE1Mostlikelydiagnosis？A)Pyogenicabscess（化脓性脓肿）B)Tuberculoma（结核瘤）C)Fungalabsces

4、s（真菌性脓肿）D)Toxoplasmosis（弓形虫）PYOGENICABSCESSCAVITY（化脓性脓肿腔）Markedandhomogeneousrestricteddiffusion（均匀弥散受限）–Highconcentrationofprotein,bacteriaandcellulardebris（高浓度蛋白、细菌、细胞碎片）DWIisregardedasthebestsequencefordifferentiationofring-enhancingpyogenicabscessfromnecrotictumor（DWI被认为是鉴别环化强化病变化脓性脓肿与坏死肿瘤的最佳

5、序列）However,restricteddiffusionisnotpathognomonic(metastases,subacutehematomas…)（弥散受限不具有特征性，如转移瘤，亚急性血肿…）PYOGENICABSCESSWALL化脓性脓肿壁HyperintensityonT1WIagainstthehypointensebackgroundofnecroticcavityandsurroundingedema.（T1WI在坏死脓腔和周围水肿低信号背景下表现为高信号）–Paramagneticeffectoffreeradicalsgeneratedbymacrophage

6、s.（巨噬细胞产生自由基的顺磁效应）HypointensityonT2WI（T2W低信号）–Freeradicalsandcollagenousfibrouscapsule.（自由基及胶原纤维囊）Usuallyacontinuoussmooththinrim.脓肿壁通常是薄而连续光滑的环Neoplasmsusuallyhaveamorenodularandirregularappearance.肿瘤通常伴有结节状和不规则的外观Butitisnotaspecificfindingandnotalwayssosmooth…但这点并不是特异征象，也不总是那么光滑……PYOGENICABSCES

7、SWALL化脓性脓肿壁Thickernearthecortexbecauseoftherichvascularizationofthegreymatter.由于灰质的血供丰富，病变邻近皮层侧变厚Thinnerneartheventriclesbecauseoftherelativelypoorvascularity.由于血供应较差，病变邻近脑室侧较薄PYOGENICABSCESSWALL化脓性脓肿壁“DAUGHTER”ABSCESS