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1、肿瘤样脱髓鞘病变（Tumefactive demyelinating lesions，TDLs）影像特征以及鉴别诊断,MRI增强,中枢神经系统原发性炎性脱髓鞘病,特点：以神经纤维脱髓鞘及小血管周围炎性细胞浸润为主要病理表现的一组疾病典型表现为白质内多发、弥散的异常信号，病灶通常无明显占位效应包括多发性硬化视神经脊髓炎急性播散性脑脊髓炎等,肿瘤样脱髓鞘性病变(Tumefactive demyelinating lesions，TDLs）,但一些非典型病例，表现为占位性肿块的脱髓鞘性病变，从临床、影像学甚至病理学冰冻切片都很难与中枢神经系统肿瘤如胶质瘤、淋巴瘤等鉴别,Tumefactive dem
2、yelinating lesions,1979年，Van Dor Velden首次对该病进行了报告。关于这种临床综合症是否属于一种独立的疾病仍然存在争论，目前归类为多发性硬化和急性播散性脑脊髓炎之间的独立中间型。肿瘤样炎性脱髓鞘性病变(tumor-like inflammatory demyelinating diseases,TIDD）肿瘤样脱髓鞘病变(tumor-like masses of demyelination)脱髓鞘假瘤(demyelinating pseudotumor lesion)、假瘤样脱髓鞘病(pseudotumor formus of demyelinating di
3、sease,临床表现,该病多为单时相，对激素治疗敏感平均年龄33-36岁，可急性、亚急性或慢性起病，以急性起病多见，随病程延长，病情逐渐趋于稳定 与多发性硬化不同，其病情无缓解及复发交替的特点；不发生于感染或接种疫苗后,实验室检查,常规及脑脊液检查大多正常。少数低热患者可有白细胞升高和脑脊液蛋白含量升高；脑脊液白细胞可升高,病理表现,急性期或亚急性期的主要病理改变神经髓鞘的破坏,而神经轴索保留完好。光镜下可见大量淋巴细胞在血管周围呈袖套状浸润,而髓鞘破坏区则以大量单核细胞和泡沫状巨噬细胞浸润为主、同时伴有较多的肥胖型星形细胞增生。病变区内还可见出血或坏死。随着病程延长，巨噬细胞和肥胖型星形细胞
4、逐渐减少,纤维型星形细胞明显增生,病变开始趋于稳定，此时无论病理或影像学均易误诊为纤维型星形细胞瘤。,影像表现,一般为CNS白质内孤立病灶（大于2cm），少数多发；Kepes 统计孤立病灶占774(2431)，多发病例占226(731)病灶分布以脑室旁白质为主，单发肿块样病变,圆形或不规则形,灶周水肿程度轻至中度 肿块体积与占位效应不成比例,CT表现,急性或亚急性起病者多表现为低密度,少数呈等密度或高密度，密度均匀或不均；伴急性出血时低密度灶内可见片样高密度区；伴坏死、囊变时可见局灶性更低密度区；如病变区尚保留有正常脑组织或新旧病灶重叠,则可表现为低、等混杂密度。慢性起病者可表现为低、等或高密
5、度，水肿程度及占位效应比急性起病者更不明显。增强扫描病变多呈弥漫性强化或环形强化，少数不强化,MRI表现,多表现为均匀长 T1、长 T2信号,合并出血时呈短 T1、长 T1 混杂信号，有囊变时呈不均匀长 T1、长 T2 信号。急性起病者增强扫描多表现为弥漫性强化；随着病灶中心坏死和周围出现新病灶,则表现为环形强化非闭合性环行强化(openring sign）(77%)，口朝向皮质，灰质侧不强化。强化环代表脱髓鞘的前缘，因此通常面对白质。,NEUROLOGY,2007,A previously healthy 31-year-old woman presented with a 2-week h
6、istory of progressive left hemiparesis.,21-year-old woman presenting with new-onset seizure and biopsy-proven tumefactive demyelinating lesion.,垂直脱髓鞘征(Dowsons fingers）有垂直于侧脑室表面的倾向；在矢状位、冠状位脑室旁病灶可以观察到，病灶可以呈条索状、火焰状，长轴垂直于侧脑室也有闭合性增强,Multiple Sclerosis Dawsons,Fingers,Mechi等 认为具有强化效应的病灶是新的活动性病灶，而环形强化则提示病灶
7、病程小于1个月。同时有强化和非强化两种病灶时，表示病灶处于不同时期，或者脱髓鞘病灶在不断的发生,新鲜病灶在DWI上呈轻中度高信号，但低于急性脑梗死病灶，一般高于肿瘤T2序列或SW影像上病变中心可见扩张血管样结构走行，意味着向扩张室管膜下静脉引流 MRS可能对于诊断有帮助，MRS显示谷氨酸盐和谷氨酰胺峰，这在高等级的胶质瘤是看不到,小静脉，肿瘤样波谱，胼胝体累及,提示TDLs影像征象,相对特异性的征象肿块体积与占位效应不成比例非闭合性环状强化病灶中心扩张小静脉激素治疗有效非特异性征象胼胝体侵犯弥散增强类肿瘤样MRS,激素治疗后好转,50-year-old man presenting with
8、slurred speech and biopsy-proven tumefactive demyelinating lesion,2 months after corticosteroid therapy,鉴别诊断,单发多见，往往 80以上误诊为胶质瘤而行手术胶质瘤淋巴瘤脓肿多发性肿瘤样脱髓鞘病多发性硬化、急性播散性脑脊髓炎Balo病同心圆硬化转移瘤淋巴瘤鉴别,与肿瘤鉴别-胶质瘤 淋巴瘤,临床表现比肿瘤明显MRI强化的区域CT上呈低密度是区别淋巴瘤或胶质瘤鉴别诊断特征之一；胶质瘤等或低密度，淋巴瘤一般等或高密度；DWI均匀略高信号，CT等高密度，基本可以排除TDLs，,TDLs非闭合性增强是
9、鉴别诊断的依据之一；非脱鞘病(炎症、肿瘤等)只有7%出现非闭合性环形增强TDLs水肿程度及占位效应相对较轻 Distinguishing Tumefactive Demyelinating Lesions from Glioma or Central Nervous System Lymphoma:Added Value of Unenhanced CT Compared with Conventional Contrast-enhanced MR Imaging Radiology 2009,251（2）：467-484,TDLs,MR imaging and CT findings in
10、30-year-old woman with TDL.A,Axial T2-weighted and,B,con-trast-enhanced axial T1-weighted MR images show a round mass with complete rim enhancement and perilesional edema in left frontal white matter.The signal intensity of the rim is isointense to gray matter on the T2-weighted image(arrow).C,Unenh
11、anced axial CT image shows hypoattenuation(grade 1)of the rim;the margin of the enhanced rim on the MR image is not discernible on unenhanced CT image.,胶母,MR imaging and CT findings in 54-year-old woman with glioblastoma.A,Axial T2-weighted and,B,contrast-enhanced axial T1-weighted MR images show a
12、round cystic mass with complete rim enhancement and peritumoral edema in the subcortical white matter of the right frontal lobe.The signal intensity of the rim is isointense to gray matter on the T2-weighted image(arrow).C,Unenhanced axial CT image demonstrates isoattenuation(grade 2)of the rim(arro
13、whead).,TDLs,胶母,Glioblastoma Multiforme:no dark line of advancing demyelination,胶母,TDL,MR imaging and CT findings in 32-year-old man with TDL.A,Axial T2-weighted and,B,contrast-enhanced axial T1-weighted MR images demonstrate white matter lesions with heterogeneous enhancement in the parietal lobe a
14、nd corpus callosum.The signal intensity of the enhancing components of the right parietal lobe is mixed(isointense plus hyperintense)on the T2-weighted image.C,Unenhanced axial CT image shows hypoattenuation(grade 1)of both the enhanced and unenhanced components of the lesions(arrows).,与淋巴瘤鉴别,MR ima
15、ging and CT findings in 65-year-old woman with lymphoma.A,Axial T2-weighted and,B,contrast-enhanced axial T1-weighted MR images demonstrate bilateral lesions with diffuse enhancement in the white matter of both parieto-occipital lobes.Signal intensities of the enhancing lesions are hyperintense on t
16、he T2-weighted image.C,Unenhanced axial CT image demonstrates isoattenuation(grade 2)of the lesion in the left parietal lobe(arrowhead).,淋巴瘤,T1WI C+,肿瘤位于侧脑室旁，形状和轮廓均不规则，明显增强。,（例）,脓肿,女性，47岁，出现持续数个月的虚弱,The mass has well defined borders and partially effaces the atrium(trigone)of the left lateral ventri
17、cle.There is mild patchy enhancement.DWI images demonstrate increased signal throughout,but only the even more hyperintense rim demonstrates true restricted diffusion on ADC images.The remainder of the mass is increased signal on ADC images,indicating increased diffusivitiy.,脓肿,多发性硬化,多发病灶与MS难鉴别，占位效应
18、明显肿瘤样脱髓鞘病变长期随访复发少见（Kepes等随访31例9-12年，28例未复发）,F 28Y，病灶呈类圆形，病灶位于两侧脑室旁、右侧颞叶及胼胝体。,MS 多发病灶,“黑洞”、“核心”+“晕环”现象,转移瘤皮髓交界处多见，水肿广泛，而肿瘤样脱髓鞘病变分布在深部脑白质年龄,1，病灶多发2，两侧脑室旁及额顶叶深部白质3，病灶较大，部分病灶呈融合状4，信号：与急性MS病灶相似5，强化：结节状急性或亚急性起病，多见于儿童及青少年。病前多有病毒感染或疫苗接种史，病变以静脉性脱髓鞘主 累及范围广泛常同时累及脑和脊髓病程急,急性播散性脑脊髓炎,播散性脑脊髓炎,Balos concentric sclerosis（BCS）同心圆硬化,一种少见的脱髓鞘病变，被认为是多发性硬化的一种变异病理学上表现为环状正常髓磷脂或髓鞘再生与脱髓鞘病变相交替，累及大脑半球、脑干、脊髓和视交叉。病变位于脑室周，类似于其他的多发性硬化，常多发以顶叶半卵圆中心多见层状（洋葱皮样、“年轮状”-提供诊断线索，是所谓的“Aunt Minnie”,以下临床特点时应考虑脱髓鞘假瘤,年轻病人急性或亚急性起病；影像学检查显示脑内有孤立的、以白质为主的病灶，其水肿及占位效应较轻；病灶的强化呈非闭合性或垂直于脑室；试行激素治疗后病灶水肿或强化明显减轻以至消失。,M,10岁，病理血肿？,谢谢！,
