肿瘤样脑炎的MRI表现分析

目的:探讨肿瘤样脑炎的MRI表现。方法:回顾性分析本院10例肿瘤样脑炎患者的MRI资料,所有病例均行MRI平扫及增强检查。结果:肿瘤样脑炎平扫呈长T1、长T2不均匀信号,边界欠清晰,周围有水肿带,灰白质同时受累,占位征象较轻。增强扫描4例呈单发结节或环形伴核心样明显强化,6例为单发或多发偏心结节状明显强化,有5例(5/10)伴邻近脑膜线状强化、其中2例(2/10)同时有脑回状强化。结论:肿瘤样脑炎MRI平扫表现缺乏特征性,增强扫描表现有一定特征性,充分认识其MRI表现并结合临床对肿瘤样脑炎的诊断及鉴别诊断有重要意义。     

假瘤样炎性脱髓鞘病的 MRI 表现分析

目的：分析、总结假瘤样炎性脱髓鞘病（T IDD ）的M RI影像表现。方法回顾性分析10例经病理证实的 T IDD的M RI影像表现,10例均行M RI平扫及增强扫描。结果双侧额顶叶多发3例,单发7例,包括枕叶2例、基底节区2例、颈髓2例、左侧额顶叶1例。7例形态不规则,1例卵圆形,2例条带状。6例边界清楚,4例边缘模糊。单发病变直径1．7～5．6cm,平均（4．0±1．48） cm。8例瘤周轻度水肿,2例无水肿。长T1长T2信号8例,等T1长T2信号2例,FLAIR均呈高信号,3例DWI高信号,其中2例可见低信号区。3例可见出血。无囊变及钙化病例。增强扫描环形强化3例,不均匀明显强化2例,轻度强化及无强化各2例,1例半开环强化。结论 T IDD的M RI表现有一定特征,M RI具有较高的诊断价值。     

36例病毒性脑炎的临床与MR分析

目的 :提高对病毒性脑炎的MRI及临床的认识。方法 :回顾性分析 3 6例经临床治疗后好转的病毒性脑炎的临床及MRI表现。常规行矢状位T1WI、轴位T1WI、T2 WI、FLAIR序列检查 ,其中 3 0例行增强扫描。结果 :3 0例MR初诊为病毒性脑炎 ,MR表现为颅内多发、片状或团片状异常信号 ,累及额、顶、颞、枕叶、基底节 丘脑区、中脑、小脑半球。T1WI呈稍低或等信号 ,T2 WI呈稍高信号 ,FLAIR序列呈明显高信号。增强扫描有多种表现 ,包括无明显强化、小点状、线样、团片状及脑回状强化 ,脑膜亦可强化 ,其中单疱病毒性脑炎 12例。误诊为脑梗死 2例 ,胶质瘤 1例 ,胶质瘤病 1例 ,脱髓鞘性病变 2例。结论 :MR对病毒性脑炎显示清楚 ,部分病毒性脑炎MR表现复杂 ,应结合临床资料考虑。     

MRI in Japanese encephalitis

We document the MRI features in seven patients with Japanese encephalitis. MRI was carried out on a 1.5 T system within 10–60 days of onset. In all the patients MRI revealed bilateral thalamic lesions, haemorrhagic in five. Signal changes were present in the cerebrum in four patients, the midbrain and cerebellum in three each, the pons in two and the basal ganglia in one. The lesions were haemorrhagic in three of the four patients with lesions in the cortex, two of the three with lesions in the midbrain and cerebellum, but the pontine lesions were haemorrhagic in both patients. Spinal cord involvement was seen in one of the three patients who underwent MRI. In two patients MRI was repeated 3 years after the onset, showing marked reduction in abnormal signal; and all the lesions gave low signal on both T1- and T2-weighted images. Bilateral thalamic involvement, especially haemorrhagic, may be considered characteristic of Japanese encephalitis, especially in endemic areas. Received: 2 January 1996 Accepted: 2 February 1996     

MRI in carcinomatous encephalitis

We report a rare case of miliary brain metastases presenting with symptoms similar to encephalitis (“carcinomatous encephalitis”). Contrast-enhanced MRI demonstrated miliary metastases more distinctly than other imaging methods and reproduced the pathological features. Received: 28 March 1996 Accepted: 29 April 1996     

MRI in tick-borne encephalitis

The tick-borne encephalitis (TBE) virus gives rise to epidemic encephalitis. Mild forms usually manifest as influenza-like episodes or are clinically silent. MRI is usually normal in TBE. We describe severe TBE in a patient who presented with fever and altered mental status after a tick bite and a specific antibody response to TBE. MRI revealed pronounced signal abnormalities in the basal ganglia and thalamus, without contrast enhancement. These findings coincide well with neuropathological studies of severe nerve cell degeneration with inflammatory cell infiltrates, neuronophagia and reactive astrocytosis in the deep grey matter. We review the literature and discuss the relevant differential diagnosis. Received: 10 November 1999/Accepted: 4 February 2000     

Rasmussen脑炎的MRI诊断

目的 总结Rasmussen脑炎的MRI特点,提高对本病影像表现的认识.方法 回顾性分析10例Rasmussen脑炎患者的MR图像,男7例、女3例,平均年龄(11±4)岁.常规行横断面、矢状面及垂直于海马长轴的斜冠状面扫描,获得T1WI、T2WI及液体衰减反转恢复(FLAIR)序列图像.评估Rasmussen脑炎患者术前MR检查中脑萎缩和信号情况,以及上述改变在随访时MR的表现.结果 Rasmussen脑炎的影像特点为:(1)脑萎缩性改变:患侧侧脑室体部扩大(8/10),颞角扩大(9/10),外侧裂增宽(9/10),局部脑沟增宽和脑回变小(7/10),尾状核和壳核萎缩(6/10).病变晚期皮层萎缩多为半球性或累及2个以上脑叶.(2)信号改变:皮层或皮层下长T2信号(9/10),多累及2个以上脑叶.(3)病变进展性:8例接受随访MR的患者均可见病变侧半球的萎缩性改变加重,范围加大,由局部向半球性发展;皮层信号改变较大.结论 Rasmussen脑炎好发于儿童,表现为一侧大脑半球进展性萎缩改变,脑室扩大,外侧裂和脑沟增宽,脑回变小,伴有相应部位的皮层萎缩和皮层T2高信号,深部灰质核团也可受累.     

MRI of herpes simplex encephalitis

Summary The magnetic resonance imaging (MRI) findings in eight patients with herpes simplex meningoencephalitis were reviewed: 14 examinations were analysed. The most striking finding was high signal intensity in the temporal lobe(s) with the typical configuration known from CT. Meningeal enhancement after Gd-DTPA administration was clearly seen in four patients. Haemorrhagic changes are much better seen on MRI than on CT. When adequate motion control can be achieved, MRI becomes the examination of choice in the diagnosis and follow-up of herpes simplex encephalitis. Localized¹H MR spectroscopy also proved promising in the study of neuronal loss.     

森林脑炎的MRI表现

目的 探讨森林脑炎的MRI表现,提高对本病的认识水平及诊断水平.方法 对近期临床确诊森林脑炎并且有MRI资料的38例患者进行回顾性分析.结果 森林脑炎MRI主要表现是单发(5例)或多发(26例)的片状、斑片状T2WI高信号、T1WI略低信号影,其中累及丘脑16例,基底节10例,放射冠8例,岛叶5例,胼胝体5例,脑干5例,颞叶3例,顶叶3例,额叶2例,齿状核2例,局部脑肿胀4例.结论 森林脑炎MRI表现有一定的特征性,是诊断和判断森林脑炎病情的必不可少的检查.     

Serial MRI of limbic encephalitis

Introduction: The aim of the study was to analyze serial magnetic resonance imaging (MRI) scans in patients with various forms of limbic encephalitis (LE) in order to evaluate whether, and at what time point, MRI findings support the diagnosis of LE. Methods: Serial MRI scans (1 day to 15 years after the onset of symptoms) of 20 patients with LE were retrospectively evaluated. Of these 20 patients, 16 had definite LE (histopathological limbic inflammation, n=6; onconeural antibodies, n=5; voltage-gated potassium channel antibodies, n=3; malignant tumors, n=5), and 4 possible LE because they met the clinical criteria but had no typical antibodies or tumors. Results: Of 13 patients who were studied with MRI within 3 months after the onset of symptoms, 11 had swollen temporomesial structures (unilateral, n=7; bilateral, n=4). After up to 9 months, the swelling had resolved in nine of ten re-evaluated patients. Of seven patients who were initially studied with MRI more than 3 months after disease onset, three had swollen temporomesial structures, one had a hyperintense, normal-sized hippocampus, and three had hyperintense and atrophic temporomesial structures. Conclusion: LE starts as an acute disease with uni- or bilateral swollen temporomesial structures that are hyperintense on fluid attenuation inversion recovery and T2-weighted sequences. Swelling and hyperintensity may persist over months to years, but in most cases progressive temporomesial atrophy develops.     

Paraorbital tumors and tumor-like conditions: role of CT and MRI

Tumors and tumor-like conditions of the paraorbital tissues that affect the eye usually require CT or MR imaging for complete evaluation. This article provides an overview of the wide variety of pathologic conditions to be considered when a paraorbital tumor is discovered or suspected. Some of the CT and MR imaging features of these disorders that aid in the differential diagnosis are reviewed.     

MRI and diffusion MRI in nonparaneoplastic limbic encephalitis.

This paper reports an 65-year-old woman with nonparaneoplastic limbic encephalitis. On MRI and diffusion MRI, diffuse and symmetrical, bilateral high-signal lesions were evident in the medial temporal lobes. The affected areas were hyperintense on b= 1000 s/mm(2) (heavily diffusion-weighted or true diffusion) images, a pattern similar to cytotoxic edema. However, apparent diffusion coefficient (ADC) values read directly from corresponding ADC maps at each temporal lobe were within normal limits: 0.96 and 0.97 x 10 x (-3) mm(2)/s, respectively, excluding cytotoxic edema. The changes were shown to be resolved on a 9-month follow-up MRI.     

乙型脑炎脑电图特征及其与CT、MRI和预后的关系

 目的 探讨脑电图(electroencephalographic,EEG)对乙型脑炎的临床诊断价值。方法 收集62例确诊为乙型脑炎患者的EEG、CT和MRI检查结果,分别于入院后1个月、3个月进行随访,分析EEG特征及其与影像学、预后的关系。结果 62例EEG检查异常率为100%,发现2种类型的异常表现:弥散持续性δ波、棘波或尖波的癫样波。EEG与MRI、CT异常检出率比较,差异均有统计学意义(χ²=5.37,P=0.02;χ²=23.15,P<0.01)。62例中8例死于乙型脑炎急性期,10例失访。EEG异常类型与预后无相关性(P=0.75)。结论 乙型脑炎EEG与预后没有关联性,但作为一种辅助检查,在乙型脑炎的早期发现和提供诊断依据等方面有着重要的作用。     

Diffusion MRI and spectroscopy in Rasmussen's encephalitis

The purpose of this study was to evaluate the diffusion MRI and proton MR spectroscopy findings in a rare disorder, Rasmussen's encephalitis. Diffusion MRI studies of 3 cases of Rasmussen's encephalitis were performed using the echo-planar trace sequence (TR=5700 ms, TE=139.03 ms). The gradient-echo diffusion sequence, PSIF (TR=21.6 ms, TE=5 ms), which is a reverse FISP sequence, and proton MR spectroscopy (TR=1500 ms, TE=40 ms) were applied in two patients. The trace sequence revealed high apparent diffusion coefficient values at the diseased regions (1.21±0.13×10^–3 mm²/s), compared with normal parenchymal values in 12 control cases (0.84±0.09×10^–3 mm²/s), indicating increased motion of water molecules (disintegration of the tissue) in these regions. The PSIF sequence revealed pixel value differences between the two hemispheres. Proton MR spectroscopy revealed decreased N-acetyl aspartate peaks, compared with five control cases.     

自身免疫性脑炎的MRI研究进展

自身免疫性脑炎（AE）是一组由抗神经元抗体导致的炎性脑病,炎症进程可以发生在大脑边缘系统等多个脑区。在常规MRI上常表现为T₂WI及T₂-FLAIR高信号,并有扩散受限,但仍有部分AE常规MRI表现为阴性;而高级MRI技术包括结构和功能MRI,可以利用基于体素的形态学分析（VBM）、基于表面的形态学分析（SBM）、扩散张量成像（DTI）及静息态功能连接（FC）、低频振幅（ALFF）、脑网络和任务态功能MRI（fMRI）等方法从多角度研究AE脑结构及功能改变,有助于探索疾病潜在的神经病理机制。就AE的常规MRI表现及高级MRI研究进展予以综述。     

Acute encephalitis associated with measles: MRI features

We document the MRI features in six patients aged 5-14 years with acute encephalitis following measles. The diagnosis was made on a characteristic morbiliform rash and detection of specific IgM and IgG antibodies. The symptoms of encephalitis occurred 1-11 days after the appearance of the rash. All patients underwent MRI within 1-4 days of the onset of neurological symptoms. Diffusion weighted images (DWI) were obtained in three patients. In all patients, T2-weighted images showed widely distributed, multifocal high signal in both cerebral hemispheres with swelling of the cortex, with bilateral, symmetrical involvement of the putamen and caudate nucleus. The lesions had showed low apparent diffusion coefficients. Three patients showed subacute gyriform haemorrhage, and asymmetrical gyriform contrast enhancement on follow-up MRI.     

The earliest manifestation of focal encephalitis on diffusion-weighted MRI

We report the case of an adult patient with a focus of meningioencephalitis in whom the earliest magnetic resonance imaging (MRI) manifestation was hyperintense signal on diffusion-weighted (DW) sequence only. To our knowledge, this is the first adult encephalitis case to be reported with the MRI diffusion-weighted pulse sequence being the only positive MRI finding. A brief review of the pertinent literature is included.     

Diffusion MRI in Rasmussen's encephalitis, herpes simplex encephalitis, and bacterial meningoencephalitis.

Three patients with Rasmussen's encephalitis, herpes simplex type 1 encephalitis, and bacterial meningoencephalitis are included in this study. Echo-planar diffusion MRI was acquired with the trace protocol at 1.5 T. b= 1000 s/mm(2) images, and apparent diffusion coefficient (ADC) maps were studied with respect to lesion identification. ADC values were also studied, and compared to those of 25 normals. In Rasmussen's encephalitis b= 1000 s/mm(2) images were uninformative while ADC maps had superior information. In herpes simplex type 1 encephalitis both b= 1000 s/mm(2) images, and ADC maps had diagnostic information. In meningoencephalitis b= 1000 s/mm(2) images had superior information, especially with respect to early cerebritis while ADC maps were negative. In conclusion, diffusion MRI provided useful imaging data on different types of encephalitis, either on b= 1000 s/mm(2) images or on ADC maps, or on both.     

MRI findings in a remitting-relapsing case of Bickerstaff encephalitis

A case of remitting-relapsing Bickerstaff encephalitis is reported. The article focuses on its imaging findings and their significance when a clinical differentiation between Bickerstaff encephalitis and Miller-Fisher syndrome is attempted. Signs and symptoms may occasionally overlap. However, because Miller-Fisher syndrome is related to the peripheral nervous system and Bickerstaff encephalitis is a central disease, the recognition of brain stem hypointense lesions on T1-weighted images, which are hyperintense on T2-weighted sequences, could be a reliable tool when the clinical diagnosis is unclear.     

MRI对下肢软组织肿瘤及肿瘤样病变的诊断价值

目的:探讨MRI对下肢软组织肿瘤及肿瘤样病变的诊断价值。方法:回顾性分析25例经病理证实的下肢软组织肿瘤及肿瘤样病变的MRI表现。结果:25例中,良性11例,其中脂肪瘤5例,骨化性肌炎1例,假性动脉瘤1例,血管瘤4例;恶性14例,其中滑膜肉瘤6例,转移瘤3例,恶性纤维组织细胞瘤1例,平滑肌肉瘤1例,纤维肉瘤1例,脂肪肉瘤2例。良性组肿块最大径平均(8.36±3.50)cm,恶性组(11.9±4.61)cm,2组差异有统计学意义(P0.05)。良性组病变内部信号T1WI、T2WI以均匀中等或中等偏高信号为主,1例伴瘤周水肿;恶性组病变内部信号T1WI、T2WI以不均匀低信号为主的混杂信号,4例伴瘤周水肿(P0.05)。良性组6例未强化,恶性组均不同程度强化;良性组5例STIR呈低信号,恶性组2例STIR呈低信号;良性组无周围组织侵犯,恶性组8例伴周围组织侵犯,以上征象2组差异均有统计学意义(均P0.05)。结论:MRI能清晰显示软组织肿瘤及肿瘤样病变的边界、范围、大小、内部成分及与周围组织的关系,对良恶性的鉴别诊断价值较高。