病理证实的瘤样脱髓鞘病60例影像学特点

Imaging characteristics of 60 pathologically proven patients with tumor-like inflammatory demyelinating diseases

目的 探索瘤样炎性脱髓鞘病（TIDD）的影像学特点.方法 对60例病理证实的TIDD（最大病灶的最长直径≥2 cm）患者的头颅CT、MRI等影像学特点进行分析.结果 男性33例,女性27例;发病年龄6～56岁,平均（35.5±12.7）岁,随访3个月至8年.病灶累及单侧者26例（43.3％）、双侧34例（56.7％）、单发22例（36.7％）、多发38例（68.3％）;病灶直径2.1 ～8.5 cm,平均（4.5±2.2）cm;病灶形态：弥漫浸润样31例（51.7％）、环样24例（40.0％）、同心圆样11例（18.3％）、大囊样2例.60例TIDD患者头颅CT示病灶均呈低密度,MRI均呈长T1、长T2信号,呈云片状23例（38.3％）,4例（6.7％）病灶内可见密集排列的扩张静脉影.急性期（发病2周内）：17/18例头颅MRI呈不同程度强化,包括斑片状与结节样12例（70.6％）、闭合环形3例（16.7％）、开环形4例（23.5％）、“梳齿状”扩张静脉影3例（17.7％）;DWI均为高信号.亚急性期（发病3～6周）：52/54例头颅MRI不同程度强化,包括“开环样”18例（34.6％）、闭合环形14例（26.9％）、不规则边缘强化18例（34.6％）、结节样8例（15.4％）、“梳齿状”扩张静脉影25例（48.1％）,DWI均为高信号.慢性期（发病7周后）：13/28例头颅MRI仍可见增强病灶,包括斑片状8/13例（61.5％）、闭合环形或“开环样”强化6/13例（46.1％）,8/28例DWI仍呈高信号.21例行磁共振波谱成像（MRS）,均有不同程度胆碱峰升高、N-乙酰天冬氨酸峰降低,乳酸峰与脂质峰升高分别为15例、7例,β,γ-谷氨酸复合物峰升高10例（9.5％）.结论 TIDD病灶形态以弥漫浸润样、环形及同心圆样为主;且以T2 WI病灶长轴多垂直于侧脑室的“云片状”多见.MRI增强病灶形态随TIDD临床分期按一定规律演变：急性期以斑片状或结节状为主;亚急性期逐步演变为“开环样”、闭合环样或花环样;慢性期从开环或闭合环形增强信号逐渐变淡呈斑片状或消失;垂直于侧脑室的密集排列的扩张静脉影是TIDD影像特征.MRS的β,γ-谷氨酸复合物峰升高有助于TIDD诊断.不同影像学检查序列及动态观察对TIDD的诊断与鉴别有价值.

Objective To explore the imaging features of tumor-like inflammatory demyelinating diseases （TIDD） to facilitate the differential diagnosis of TIDD and neoplastic lesions.Methods The brain CT and MRI features in 60 patients with TIDD （〉20 mm in diameter） were studied and assessed.Results Among the 60 patients 27 are female,33 male,aged （35.5 ± 12.7） （6-56） years,headache being the most common initial symptoms,with follow-up for 3 months to 4 years.There were 34 cases involved in bilateral lesions （56.7%）,26 cases in unilateral lesions （43.3%）.Single intracranial lesion was found in 22 cases （36.7%）,and multiple lesions in 38 cases （68.3%） ; The diameter of lesions ranged from 2.1 to 8.5 cm.The lesions of 60 cases exhibited appearances which we termed diffusely infiltrating （n =31）,ringlike （n =24）,Balolike （n =11）,megacystic （n =2）.The brain unenhanced CT manifestations of 60 patients with TIDD were all showed with hypodense lesions.All the lesions appeared hypointense on T1 and hyperintense on T2 images,and the typical characteristics looked like cloud （n =23）,a dense array of dilated venular structures centrally located.On MRI,17/18 cases in acute phase （≤ 2 weeks） showed variable degrees of contrast enhancement with patchy or nodular （n =12）,complete ring （n =3）,open ring （n =4）,dilated venular （n =3） pattern of enhancement.All cases appeared hyperintense on diffusion weighted imaging （DWI） sequences.There were 52/54 cases in subacute phase （3-6 weeks） on MRI presented with marked contrast enhancement with open ring （n =18）,complete ring （n--14）,irregular round （n =18）,nodular （n =8）,a dense array of dilated venular structures （n =25） pattern of enhancement,52/54 cases presented with diffusion restriction.Totally 13/28 cases in chronic phase （≥ 7weeks） on MRI appeared milder contrast enhancement：mild patchy （n =8）,open or complete ring （n =6）,and 8/28 cases still appeared hyperintense on DWI squences.There were decreased N-acetylaspartate and increased choline on MR spectroscopy in all cases,besides,increased lactate,Lip,and β,γ-Glx in 15,7,and 10 cases respectively.Conclusions Multiple lesions are more common in TIDD,mainly presented with diffusely infiltrating,ring-like and Balo-like lesions.The cloud-like lesions on T2WI mostly perpendicular to ventricular are more specific for TIDD.The manifestation of the lesions on contrastenhanced MRI scan may develop according to the clinical stage of TIDD.In acute phase,patchy and nodular enhancement is mostly frequent.In subacute phase,the shape of enhanced lesions mostly evolve to open ring,complete ring and wreath like,but a few of them may still accompany with patchy enhancement.In chronic phase,the enhanced signal may become milder and milder,and eventually vanished.The dilated venular structure vertically densely arrayed along the lateral ventricle may be special for diagnosis of TIDD.The increased β,γ-Glx on MRS may be useful for diagnosis of TIDD.Dynamic observation of the imaging changes may be more important to facilitate the diagnosis of TIDD.