颅内原发性淋巴瘤DWI及PWI表现

目的 探讨颅内原发性淋巴瘤扩散加权成像(DWI)和灌注加权成像(PWI)特点.方法 回顾性分析10例颅内原发性淋巴瘤的DWI表现和9例颅内原发性淋巴瘤的PWI特征,所有病例均经病理证实,并结合其病理特征与高级别(Ⅲ、Ⅳ级)星形细胞瘤作对照.结果 颅内原发性淋巴瘤DWI多呈均匀高信号,肿瘤实质ADC值为(79.73±10.21)×10-5mm2/s,明显低于高级别星形细胞瘤ADC值(99.81±19.57)×10-5mm2/s(P=0.002).9例行PWI检查,颅内原发性淋巴瘤肿瘤实质最大rCBV比值为1.71±0.59,而14例高级别星形细胞瘤肿瘤实质最大rCBV比值为5.17±1.73,与高级别旱形细胞瘤比较,颅内原发性淋巴瘤呈低灌注趋势(P=0.001).结论 颅内原发性淋巴瘤DWI、PWI具有一定的特征,术前行DWI、PWI有助于提高MRI对颅内原发性淋巴瘤的诊断水平.     

Gamma knife radiosurgery for neuroepithelial tumors: Radiological and histological changes

Gamma knife radiosurgery (RS) has been introduced as a modern therapy for brain tumors. However, the effects of RS for neuroepithelial tumors are still obscure. The present study investigates the radiological and histological changes after RS to elucidate the biological effect. There were seven cases (two males and five females), ranging from 4 to 71 years with a mean age of 33 years. Two cases were located in the brainstem, another two in the cerebellum, and one each in the thalamus, the hypothalamus, and the frontal lobe. Histologically, two cases had gangliogliomas, four astrocytomas (1 pilocytic, 1 fibrillary, 2 anaplastic), and one glioblastoma. RS was performed after surgery with a central dose of 30–36 Gy. All cases were evaluated radiologically on MRI before and after RS. Four cases (3 astrocytomas and 1 glioblastoma) which neurologically deteriorated after RS were reoperated. These cases were examined using HE and immunohistochemical studies with antibodies of CD34, α‐smooth muscle actin (SMA), p53, p2l and MIB‐1 on the sections before and after RS. MRI demonstrated perifocal edema and intratumoral hypointensity on T₂ weighted imaging (T₂WI), suggesting radionecrosis in most of the cases within 6 months after RS. In the central part of the RS, destructive changes were observed in the tumor cells and endothelial cells: decrease in the tumor cell population, coagulation necrosis, and fibrinoid degeneration of vascular walls were revealed. In the peripheral part, however, some tumors contained viable tumor cells intermingled with blood vessels showing endothelial and pericytic proliferations. The increase of MIB‐1 staining index was found in only one case. The p2l immunoreactivity was increased in endothelial cells, although the p53 immunoreactivity was unchanged. These results suggested that radionecrosis occurred earlier and more frequently in neuroepithelial tumors after RS than after conventional radiation.     

Expression pattern of the water channel aquaporin-4 in human gliomas is associated with blood-brain barrier disturbance but not with patient survival

Aquaporin-4 (AQP4), the most prominent CNS water channel, is restricted to the glia limitans and astrocytic endfeet. We previously showed the loss of spatial AQP4 expression in glioblastomas and a redistribution across the cell surface. However, opposing AQP4 functions have been described: protective in vasogenic but detrimental in cytotoxic brain edema. Thus, specific AQP4 induction to prevent or reduce vasogenic edema is suggested. To elucidate the AQP4 role in brain tumors, we investigated 189 WHO grade I-IV gliomas by immunohistochemistry and the prognostic significance for patients' survival. In gliomas, a remarkable de novo AQP4 redistribution was observed in comparison with normal CNS tissue. Surprisingly, the highest membraneous staining levels were seen in pilocytic astrocytomas WHO grade I and grade IV glioblastomas, both significantly higher than in WHO grade II astrocytomas. AQP4 up-regulation was associated with brain edema formation; however, no association between survival and WHO grade-dependent AQP4 expression was seen. Hence, AQP4 redistribution may go along with other tumor properties, such as vascular proliferation and resulting blood-brain barrier disturbance, features usually prominent in pilocytic astrocytomas WHO I and glioblastomas WHO grade IV. In summary, our findings question the protective role of AQP4 in vasogenic brain edema. Although AQP4 was associated with brain edema formation, one has to question the suitability of AQP4 induction as a promising approach in vasogenic brain edema prevention and treatment. In addition, our results provide unexpectedly high AQP4 levels in pilocytic astrocytomas and present AQP4 as tumor progression marker in WHO grade II-IV astrocytomas.     

AQP-1在星形细胞瘤及瘤周水肿组织中的表达及其意义

目的 探讨人星形细胞瘤及瘤周水肿组织中水通道蛋白-1（AQP—1）的表达及其对瘤周水肿和肿瘤浸润性生长的影响。方法 采用免疫组化SABC法，分析30例星形细胞瘤和瘤周水肿组织中AQP-1的表达。根据MRI结果，采用“多田公式”计算水肿指数（EI）。并以EI评价肿瘤性水肿的程度。结果 AQP—1在低（Ⅰ-Ⅱ级）、高级别（Ⅲ-Ⅳ级）星形细胞瘤中的表达积分光密度值分别为2．76±0．13和6．73±0．18。在对应瘤周水肿组织中分别为4．52±0．08和8．58±0．27，而在正常对照组中几乎无AQP—1表达，三组相较，差异显著（P〈0．05）。EI值在低、高级别组分别为1．59±0．40、3．96±0．85，两组相较，差异显著（P〈0．01）。星形细胞瘤、瘤周水肿组织中AQP-1的表达和肿瘤的EI值均呈正相关（P〈0．01）。结论 AQP—1在星形细胞瘤的侵袭性生长和肿瘤性水肿的发生中可能起重要作用。     

Cerebellar astrocytomas: a 24-year experience

INTRODUCTION: Cerebellar astrocytomas are the most benign tumors of the CNS. Seventy to eighty percent are found in children. METHODS AND RESULTS: We report on 38 children under 18 who had cerebellar astrocytoma in the posterior fossa and were treated by a multidisciplinary team in our Neurosurgical Department from January 1974 to December 1997. We included all patients in whom the histopathological diagnosis was astrocytoma, regardless of malignancy. The diagnostic methods used were pneumoventriculography, cranial X-rays, CT scan, and MRI. All patients were treated surgically. Neither radiotherapy nor chemotherapy was indicated in patients with pilocytic or fibrillary astrocytomas. A greater prevalence was observed in female (25/38; 66%) than in male (13/38; 34%) patients. Histopathological results revealed 27 (71%) pilocytic astrocytomas, 8 (21%) diffuse fibrillary astrocytomas, 1 (2%) anaplastic astrocytoma and 2 (6%) glioblastomas. These tumors were more frequently located in the right cerebellar hemisphere; increased intracranial pressure syndrome was the most frequent form of clinical presentation. Total tumor resection was obtained in 29 (83%) cases and subtotal resection in 9 (17%). In 6 (16%) cases, ventriculoperitoneal shunts were placed to control persistent hydrocephalus after tumor excision. CONCLUSION: The most frequent complication was increased ataxia. The mortality rate was 8.5%.     

Diffuse bilateral thalamic astrocytomas as examined serially by MRI

We report the case of a 13-year-old girl with diffuse bilateral thalamic astrocytomas. Incoordination was observed at the onset. Cranial computed tomography (CT) showed enlarged thalami, and magnetic resonance imaging (MRI) revealed these lesions to be symmetrically enlarged with high intensity on the T2-weighted image. Owing to these atypical findings in the neuroimaging studies, we had difficulty in making the correct diagnosis of a brain tumor. After the diagnosis of diffuse bilateral thalamic astrocytomas was obtained, we performed hyperfractionated radiotherapy followed by chemotherapy. Radiation therapy was effective for a while, but the girl's condition deteriorated again and she died 8 months after admission. Although diffuse bilateral thalamic astrocytomas are difficult to diagnose because they do not resemble most other neoplasms on neuroimaging studies, pediatricians should keep this entity in mind in order to arrive at a precise and prompt diagnosis. Received: 27 February 1997 Revised: 6 August 1997     

脑内海绵状血管瘤的CT及MRI诊断

目的探讨CT及MRI对脑内海绵状血管瘤(cavernous angiomas,CA)的表现和诊断价值。方法收集资料完整经手术病理证实的36例脑内CA患者的CT及MRI资料,重点分析其影像表现特征。结果 CA可位于脑内任何部位,单发病灶多见,周围无或轻度水肿,无占位效应,CT平扫为稍高密度影,钙化占68.7%,增强扫描大都无强化;MRI表现为桑椹状混杂高信号,周围有云絮状低信号环,增强后病灶大都无强化。结论脑内海绵状血管瘤的MRI表现有特异性,MRI对脑实质内CA的检出率优于CT,特别是MRI的T2WI像有助于明确诊断。     

颅内海绵状血管瘤的CT和MRI诊断

目的探讨颅内海绵状血管瘤的CT和MRI表现及诊断价值。方法搜集60例颅内海绵状血管瘤的CT和MRI影像资料,CT检查37例,MRI检查53例,CT和MRI检查30例,其中脑内型海绵状血管瘤57例,经手术病理证实42例,影像资料典型15例,经伽玛刀治疗随访证实;脑外型海绵状血管瘤3例,均经手术病理治疗证实。结果脑内型海绵状血管瘤可位于脑内任何部位,单发病灶多见,无明显占位效应,周围无或轻度水肿。CT检查的全部病例呈稍高及混杂密度影32例,增强扫描大都无强化;MRI检查T2WI表现为"桑葚状"混杂高信号,周围有云絮状低信号环,增强后病灶仅少数轻度强化。脑外型病灶位于中颅窝、鞍旁,MRI呈类似哑铃形或类圆形较均匀的稍长T1、明显长T2信号,增强扫描呈明显均匀强化。结论脑内与脑外型海绵状血管瘤的CT和MRI表现具有一定特征,MRI优于CT像,特别是MRI的T2WI像有助于明确诊断。     

Exophytic juvenile pilocytic astrocytomas of the posterior fossa

In children, posterior fossa juvenile pilocytic astrocytomas are common tumors. Radiologically, primarily extra-axial brainstem pilocytic astrocytomas are uncommon and extra-axial cerebellar pilocytic tumors are exceptional. We report two cases of such exophytic tumors, contrasting their presentation, imaging appearance, and prognosis. We also report the radiographic features of posterior fossa juvenile pilocytic astrocytomas from a 5-year review of our institutional experience.     

P-糖蛋白在脑星形细胞瘤中的表达及意义

目的探讨脑星形瘤细胞P-糖蛋白(P-gp)的表达及临床价值。方法采用免疫组织化学法,对36例脑星形细胞瘤和3例来自颅脑损伤患者的脑组织及3例胎脑组织(作为对照)中P-gp的表达进行检测。对其中24例脑星形细胞瘤术后接受化疗患者的术后生存时间与P-gp表达的关系进行分析。结果P-gp在对照组6例脑组织中未见表达,而在36例星形细胞瘤中28例表达阳性,阳性表达率为77.8%,明显高于对照组(P<0.01)。在P-gp表达阳性的28例脑星形细胞瘤中,肿瘤细胞阳性表达9例,肿瘤间质血管内皮细胞阳性表达11例,二种细胞同时阳性表达8例。24例术后接受了化疗的患者中,6例P-gp表达阴性,18例表达阳性。在这24例病人中,P-gp表达阴性的病人术后5年生存率明显高于P-gp表达阳性者(P<0.05)。结论脑星形细胞瘤中P-gp不仅在肿瘤细胞表达,而且也在肿瘤间质血管内皮细胞表达,其对化疗药物的耐受性,存在肿瘤细胞和血脑屏障双重耐受机制,可能是脑星形细胞瘤产生多药耐受性的机理之一。P-gp的表达水平可能是影响病人术后化疗效果及术后生存时间的主要因素之一。     

Histopathological spectrum of paediatric diffuse intrinsic pontine glioma: diagnostic and therapeutic implications

Diffuse intrinsic pontine glioma (DIPG) is the main cause of brain tumour-related death in children. In the majority of cases diagnosis is based on clinical and MRI findings, resulting in the scarcity of pre-treatment specimens available to study. Our group has developed an autopsy-based protocol to investigate the histologic and biologic spectrum of DIPG. This has also allowed us to investigate the terminal pattern of disease and gain a better understanding of what challenges we are facing in treating DIPG. Here, we review 72 DIPG cases with well documented clinical history and molecular data and describe the pathological features of this disease in relation to clinical and genetic features. Fifty-three of the samples were autopsy material (7 pre-treatment) and 19 were pre-treatment biopsy/surgical specimens. Upon histological review, 62 patients had high-grade astrocytomas (18 WHO grade III and 44 WHO grade IV patients), 8 had WHO grade II astrocytomas, and 2 had features of primitive neuroectodermal tumour (PNET). K27M-H3 mutations were exclusively found in tumours with WHO grade II–IV astrocytoma histology. K27M-H3.1 and ACVR1 mutations as well as ALT phenotype were only found in WHO grade III–IV astrocytomas, while PIK3CA mutations and PDGFRA gains/amplifications were found in WHO grade II–IV astrocytomas. Approximately 1/3 of DIPG patients had leptomeningeal spread of their tumour. Further, diffuse invasion of the brainstem, spinal cord and thalamus was common with some cases showing spread as distant as the frontal lobes. These findings suggest that focal radiation may be inadequate for some of these patients. Importantly, we show that clinically classic DIPGs represent a diverse histologic spectrum, including multiple cases which would fit WHO criteria of grade II astrocytoma which nevertheless behave clinically as high-grade astrocytomas and harbour the histone K27M-H3.3 mutation. This suggests that the current WHO astrocytoma grading scheme may not appropriately predict outcome for paediatric brainstem gliomas.     

Brain MRI findings in acute hepatic encephalopathy in liver transplant recipients

Acute hepatic encephalopathy has significant morbidity and mortality in liver transplant recipients unless it is promptly treated. We evaluated the brain magnetic resonance (MR) imaging findings associated with acute hepatic encephalopathy in transplant recipients. We retrospectively reviewed the clinical and imaging data and outcomes of twenty-five liver transplant patients (16 male; mean age, 49.3 years) with clinically diagnosed acute hepatic encephalopathy and forty liver transplant patients (20 males; mean age, 45.5 years) without neurological symptoms suggestive of hepatic encephalopathy at our institution. Bilateral symmetric hyperintensities of the insular cortex and cingulate gyrus were observed in twenty-one patients (84.00%), bilateral symmetric extensive increased cortical signal intensity (involving two or more regions) was observed in 72.00% of the patients, leptomeningeal enhancement in 73.68%, and visualization of prominent venules in 52.00%. The most common symptom at diagnosis was rigidity (n = 14), and the plasma ammonia levels ranged from 68.63 to 192.16 μmol/L. After active treatment, 17 patients gradually recovered, four patients suffered from mild or moderate neurologic deficits, and four patients with widespread brain edema died. The specific brain MR imaging features were bilateral symmetric increased cortical signal intensity, especially in the insular cortex and cingulate gyrus, leptomeningeal enhancement, visualization of the prominent venules, and widespread brain edema. These features may indicate poor prognosis and should alert radiologists to the possibility of acute hepatic encephalopathy in liver transplant recipients and encourage clinicians to prepare appropriate treatment in advance.     

Tumours around the foramen of Monro: clinical and neuroimaging features and their differential diagnosis.

The clinical and neuroimaging features of 20 patients with lateral ventricular tumours located around the foramen of Monro were reviewed retrospectively with special emphasis on the differential diagnoses. Histologic types were: eight neurocytomas, four subependymal giant cell astrocytomas (SGCAs), three subependymomas, two fibrillary astrocytomas, and one each of pilocytic astrocytoma, malignant astrocytoma and malignant teratoma. The mean age of the patients with neurocytoma was 29.6 years, with SGCA 13.3 years and with subependymoma 55.3 years. All tumours appeared nodular in shape, and on computed tomography (CT) neurocytomas were either isodense or highdense with the brain, while all subependymomas and SGCAs were lowdense. Calcification was observed in two SGCAs, and one neurocytoma. Five neurocytomas and all four SGCAs showed mild to moderate contrast enhancement, while all three subependymomas showed either no, or scarce, enhancement. Magnetic resonance imaging (MRI) studies were available in 10 patients, with the signal characteristics of four neurocytomas and three SGCAs being nonspecific, while two subependymomas were both hypointense on T1-weighted images and hyperintense on T2-weighted images. Thus important features for differential diagnosis included age of the patient and density on precontrast CT. In this series, either an extensive excision of the tumour or a partial removal, thus relieving the obstruction of the foramina of Monro, usually provided long term survival, with 18 patients surviving a mean of 10.8 years.     

Survival rates of malignant gliomas in Burgundy from 1990 to 1995

The aim of this study was to provide current data on case-fatality rates of malignant gliomas in the area of Burgundy (1,300,000 inhabitants). The ascertainment was specific according to imaging and histologic criteria, and was exhaustive because of the existence of a single University Hospital allowing both imaging and histologic diagnosis from stereotaxic cerebral biopsy. During six full years we collected 161 cases of malignant gliomas grades II to IV, 93 men (57.76%) and 68 women (42.23%). The mean age was 61 years. In all the age groups, there were a male predominance. Headache, epilepsy and motor deficit were the most frequent symptoms at onset. In most cases, the gliomas were localized within the frontal area. The post-surgical Karnofsky score was up to 70 in 40% of the cases. There were 89 glioblastomas with grade IV, 37 anaplastic astrocytomas, 13 gliomatous tumors with grade II and IV and six anaplastic oligodendrogliomas. This grading explains the very low survival rates, with a negative effect induced by age. Among the most relevant contributions of this study to the clinical features of malignant gliomas is an analysis of case-fatality rates, evaluation of health care services and therapeutic trials.     

Molecular genetics of radiographically defined de novo glioblastoma multiforme

Glioblastoma multiforme (GBM) represents the final endpoint of anaplastic progression in astrocytomas. GBM which arise without clinical evidence of a prior low-grade astrocytoma (LGA) have been designated de novo GBM, and are thought to develop rapidly from initial tumour formation. However, a purely clinical definition of de novo GBM does not exclude a long-standing, asymptomatic low-grade tumour. This study therefore sought to determine the genetic features of a unique group of cases in which GBMs were documented to have arisen radiographically in defined period of time (radiographically defined de novo GBM). Clinical and genetic features were examined in a group of 11 patients with a histological diagnosis of high-grade astrocytoma at first biopsy and radiographically defined de novo GBM. The mean age of the patients at tumour diagnosis was 62 years (range 32-87). Six of 11 tumours arose in the temporal lobes. Eight of 11 tumours had epidermal growth factor receptor (EGFR) overexpression, and EGFR gene amplification was found in five of the six analysed cases. Overexpression of p53 was observed in only one tumour, and a TP53 mutation was present in this case. p16 immunostaining was undetectable in 10 cases, and homozygous deletion of CDKN2A was observed in four of the six studied tumours. pRb expression was lost in four tumours. Mutations in the PTEN gene were detected in two of six cases. The results in this unique group of cases confirms the prior hypothesis that the profile of genetic alterations in de novo GBM is distinct from that of GBM arising from a known LGA, and that these specific genetic pathways promote the rapid development of GBM.     

Redistribution of the water channel protein aquaporin-4 and the K+ channel protein Kir4.1 differs in low- and high-grade human brain tumors

The blood-brain barrier (BBB) regulation is characterized by an interplay between endothelial cells, subendothelial basal laminae and astrocytic cells. Astroglial cells are highly polarized by the differentiation of perivascular membrane domains. These domains are characterized by the aggregation of, among other molecules, the water channel protein aquaporin-4 (AQP4), the dystrophin-dystroglycan complex, and the inwardly rectifying potassium channel protein Kir4.1. Normally, this ion channel plays an important role in spatial buffering of extracellular K⁺ in the central nervous system, which only can be performed due to the non-uniform distribution of Kir4.1 across the surface of the glial cell. In this study, we observed a mislocalization of Kir4.1 in various human brain tumors (low- and high-grade astrocytomas and oligodendrogliomas), suggesting that buffering capacity of glial cells may be compromised, leading to water influx (cytotoxic edema). Interestingly, whereas dystrophin remained regularly restricted at the endfeet membranes in all cases investigated, AQP4 was found to be redistributed only in high-grade astrocytomas, not in low-grade astrocytomas. If the mechanisms of redistribution of AQP4 and Kir4.1 are different in low- and high-grade gliomas, this may suggest that the mechanisms of clustering of AQP4 and Kir4.1 at the glial endfeet membrane domains are also different. The redistribution of AQP4 in glioblastoma cells is discussed as a reaction to the vasogenic edema, as induced by the breakdown of the BBB, to facilitate reabsorption of excess fluid.     

Dysembryoplastic neuroepithelial tumors: CT, MR findings and imaging follow-up: a study of 53 cases

PURPOSE: To evaluate CT and MRI features and long term imaging follow-up of a large series of dysembryoplastic neuroepithelial tumors (DNTS). PATIENTS AND METHODS: We retrospectively analyzed CT (100%) and MR imaging (83%) findings of 53 patients with complex (n = 14), simple (n = 6) or non specific histological forms (n = 33) of DNTS. All patients underwent epilepsy surgery for the treatment of drug resistant partial seizures. Preoperative radiological follow-up from two to 10 years (81%) and a post-operative follow-up from one to 13 years (92%) were available. RESULTS: DNTs are intracortical tumors with no mass effect and no peritumoral edema. An associated deformity of the overlying skull was observed in 44% of the 34 patients with a cortical lesion of the convexity. We found a contrast enhancement of the lesion in 21% of cases, a calcic hyperdensity in 36% of cases and a cystic part in 7.5% of cases. DNTs were hypodense (82%) on CT examinations and had a decreased signal on the T1 Weighted Images (95%) and a hypersignal in T2 Weighted Images (100%) on MR imaging. Eighty-one percent of patients had a mean preoperative radiological follow-up of four years and the tumor was stable in size in all cases; 92% of patients had a mean post-operative radiological follow-up of 4.5 years and no recurrence was seen. CONCLUSION: Three radiological features of DNTs are helpful for the diagnosis: cortical location, absence of mass effect and no surrounding edema. Clinical, radiological and histopathological findings have to be considered together in order to assess the diagnosis and to differentiate DNTs, which are stable lesions from gliomas.     

急性氧化乐果中毒后脑水肿的MRI表现和病理改变对比研究

目的:建立40％氧化乐果皮下染毒急性猫中毒模型,观察急性有机磷中毒脑损害的MRI影像学表现的发生发展规律,分析影像学表现与脑组织光镜、电镜病理改变的关系。方法将健康家猫25只,分为三组,对照组、染毒治疗组、染毒未治疗组。对照组(5只):即未染毒动物。染毒治疗组(简称染毒组)(15只):腹部皮下四点等量注射40％氧化乐果0.3ml/kg。染毒后2min肌肉注射0.5mg/kg硫酸阿托品,然后视动物流涎、流泪情况酌情肌注阿托品。染毒未治疗组( 5只):腹部皮下四点等量注射40％氧化乐果0.3ml/kg。对染毒后3小时,6小时、24小时脑MRI。表现与相应时间点脑组织光镜、电镜检查结果进行对照研究。结果:40％氧化乐果皮下染毒制作猫急性中毒模型,染毒后6小时、24小时MRI图像出现脑水肿。HE染色光镜和透射电子显微镜观察,3小时开始即出现广泛水肿表现,同时存在细胞毒性水肿和血管源性水肿,三者形态学表现相符。电镜示血脑屏障出现形态学变化,延髓24小时、6小时电镜切片中观察到神经元细胞质近三角形类晶体样物质。结论:氧化乐果染毒急性脑水肿的模型成功建立,中毒后脑水肿为混合性水肿,MRI出现异常表现稍晚于病理改变。     

Alpha-synuclein-positive structures in cases with sporadic Alzheimer's disease: morphology and its relationship to tau aggregation

Alzheimer's disease (AD) and Parkinson's disease share common clinical and pathological features. In this study, we examined the relationship between AD pathology and alpha-synuclein aggregation. The frequency and distribution of alpha-synuclein-positive structures were systematically investigated in 27 cases with sporadic AD by alpha-synuclein immuno-histochemistry. Thirteen (48.2%) of 27 cases had various alpha-synuclein-positive structures as well as Lewy bodies. The frequency and density of senile plaques and neurofibrillary tangles were not significantly different between cases with alpha-synuclein structures and those without. alpha-Synuclein-positive structures were found most frequently in the amygdala. The alpha-synuclein-positive inclusions that are different from Lewy bodies were observed at the highest rate in the hippocampus. The discovery of alpha-synuclein as the constituent of Lewy bodies facilitated the detection of Lewy-related structures even in AD cases with widespread and numerous neurofibrillary tangles. alpha-Synuclein-positive inclusions except for Lewy bodies are exposed, and the distribution of them indicates that Lewy body formation may be influenced by the degree of tau aggregation. This study also supports the suggestion that cases with AD pathology can be classified into two groups according to the existence or absence of alpha-synuclein aggregation.     

可逆性后部白质脑病综合征的临床及影像学特点

目的 探讨可逆性后部白质脑病综合征(RPLES)的临床和影像学特点.方法 回顾性分析5例RPLES患者的临床资料.结果 本组患者的原发病为:高血压1例,尿毒症3例,红斑狼疮1例.5例均为突然发作的血压增高、头痛伴呕吐、意识障碍及癫疒间等,3例有视觉障碍,肢体运动功能均正常.实验室检查5例均有肾功能不全.头颅CT或MRI检查5例均显示双侧顶枕叶白质为主的较大范围的异常,其中CT为低密度、MRI为长T1、长T2信号.经过积极的降压、脱水等治疗,4例患者临床症状及体征在短时间内即恢复良好,影像学复查也显示病变明显减轻或消失;1例死于脑疝.结论 RPLES的临床特点为在血压突然升高或使用某些药物的情况下急性出现的脑损害症状.发病机制可能与脑血管自动调节功能障碍有关.影像学特点为双侧、对称性后部脑白质较大范围的病变.大多数患者经治疗可很快恢复,极少数病情严重者也可导致死亡.