1H MR spectroscopy evidence for the varied nature of asymptomatic focal brain lesions in neurofibromatosis type 1

We present the MRI and ¹H MR spectroscopy findings in six patients with neurofibromatosis type 1 (NF1) and asymptomatic focal brain lesions. Variations in imaging appearances were seen, including regression of a previously identified lesion. MR spectra for the lesions and corresponding areas of normal brain show significant differences. The lesions could be separated into two groups, one demonstrating only slight metabolite ratio changes relative to normal brain and the other group showing significant increase in choline and decrease in N-acetyl aspartate. The lesion which regressed fell into the second group. These findings are not in agreement with those previously reported and provide evidence for the varied and possibly transient nature of these asymptomatic lesions. The spectroscopy findings suggest that metabolite changes may be present without visible changes on MRI. Received: 10 September 1999/Accepted: 26 June 2000     

Atypical focal non-neoplastic brain changes in neurofibromatosis type 1: mass effect and contrast enhancement

Abstract Children and young adults with neurofibromatosis type 1 often have small high-signal foci on T2-weighted images of the brain. We describe follow-up of two patients in whom one of the foci had atypical features, commonly regarded as signs of a neoplasm. In the first, one lesion showed temporary contrast enhancement and decreasing mass effect. The second developed an expanding lesion that increased minimally in size over 4.5 year's follow-up. The borderline between neoplastic and non-neoplastic lesions seems to be indistinct. Received: 12 September 2000 Accepted: 29 November 2000     

CT detection of basal ganglion lesions in neurofibromatosis type 1: correlation with MRI

Summary Prospective study of CT and MRI in 41 consecutive children with suspected type 1 neurofibromatosis revealed basal ganglion lesions on T2-weighted spin echo images in 22 cases (54%) and on CT in only 7 of those (32%). T2-weighted spin-echo MRI also revealed multiple signal changes in the supra- and infratentorial white matter and brain stem that went completely unnoticed on CT.     

Fibro-osseous lesions involving the brain: MRI

We present the MRI findings in two patients with “fibro-osseous lesions” involving the central nervous system. A left temporal lobe mass was present in one patient and an extra-axial mass at the skull base in the other. In both cases, calcification was present, with low signal intensity on T1- and T2-weighted images. Received: 30 December 1997 Accepted: 10 June 1998     

神经纤维瘤病I型的MRI研究

目的：回顾神经纤维瘤病I型（NF1）患者MRI表现，分析MR扫描序列及其诊断价值，以建立合适的MR成像方案，为NF1影像诊断提供有价值的依据。方法：对30例临床确诊为NF1患者采用本组MR成像方案进行扫描，主要包括：轴面SE序列T2WI；平扫矢状面SE脉冲序列T1WI；增强轴面或矢状面SE脉冲序列T1WI；轴面或冠状面液体衰减反转恢复（FLAIR）序列，同时分析病变的发病部位、数目、形态、信号的变化和病变的强化情况等。结果：MRI可见下列3种表现：（1）多发性脑内错构瘤：30例中25例在SE脉冲序列T2WI和FlAIR脉冲序列见高信号病灶，病灶主要位于苍白球、小脑和脑干。另外，25例中20例可见海马回、海马旁回等区晕状高信号改变。（2）视通道或下丘脑胶质瘤：视神经、视交叉增粗、扭曲；视交叉或下丘脑肿块，SE脉冲序列T2WI和FlAIR序列表现为不规则分叶状混杂信号肿块，在增强SE脉冲序列T1WI有明显不规则强化。（3）脊柱多发性神经纤维瘤：SE脉冲序列T2WI和脂肪抑制短时反转恢复（STIR）序列显示高信号沿脊神经分布的多发性肿瘤。结论：MRI能够作为1种 常规的影像检查方法对NF1患者进行诊断和追踪。本组MR成像方案能较好地显示NF1的多发性或多灶性病变。     

Malignant peripheral nerve sheath tumours in neurofibromatosis type 1: MRI supports the diagnosis of malignant plexiform neurofibroma

Plexiform neurofibroma (PNF) is a typical feature of neurofibromatosis 1 (NF1). About 10% of patients with NF1 develop malignant peripheral nerve-sheath tumours (MPNST), usually arising from PNF, and this is the major cause of poor survival. A better prognosis can be achieved if the tumours are diagnosed at an early stage. Our objective was to establish MRI criteria for MPNST and to test their usefulness in detecting early malignant change in PNF. MRI was performed on 50 patients with NF1 and nerve-sheath tumours, of whom seven had atypical pain, tumour growth or neurological deficits indicative of malignancy; the other 43 were asymptomatic. On MRI all seven symptomatic patients had inhomogeneous lesions, due to necrosis and haemorrhage and patchy contrast enhancement. In one patient, the multiplicity of confluent tumours with inhomogeneous areas in addition to central lesions did not allow exclusion of malignancy. Only three of the 43 asymptomatic patients had comparable changes; the other 40 patients had tumours being of relatively homogeneous structure on T1- and T2-weighted images before and after contrast enhancement. All three asymptomatic patients with inhomogeneous lesions were shown to have MPNST.     

Spinal tumours in neurofibromatosis type 1: an MRI study of frequency, multiplicity and variety

In neurofibromatosis type 1 (NF1) spinal tumours cause neurological symptoms in about 2 % of patients. Among over 1400 patients with NF1 we saw symptomatic spinal tumours in 23 (1.6 %). MRI of the entire spinal canal was obtained in 54 patients aged 5–56 years with NF1. The number, site, morphology and signal characteristics of the spinal tumours were recorded and analysed. There were 24 patients with symptoms such as sensory impairment or paralysis; 30 patients had no neurological deficits. Of the 24 symptomatic patients, 23 (96 %) had spinal tumours, while we saw spinal tumours in 12 (40 %) of the 30 patients without neurological deficits. No spinal segment was preferred in symptomatic or asymptomatic patients. Most intraspinal extramedullary tumours were primarily extradural and intraforaminal. MRI showed intramedullary tumours in 3 patients (6 %), intraspinal extramedullary tumours in 18 (33 %) and intraforaminal tumours in 31 (57 %). Only neurological deficits in patients with NF1 should prompt further diagnostic clarification. In patients with neurological symptoms there may be a multiplicity of masses in the spinal canal, which can lead to difficulties in attaching symptoms to a certain tumour. In patients who do not satisfy the NIH criteria, it can be a helpful observation that spinal tumours in NF1 are primarily intraforaminal, extending into the spinal canal, while in NF2 they are mostly intraspinal intradural tumours. Received: 7 April 1998 Accepted: 15 December 1998     

脑内原发淋巴瘤的MRI诊断价值

目的 :探讨脑内原发淋巴瘤的MRI特征。方法 :回顾性分析 16例经手术和病理证实的脑内原发淋巴瘤的MRI表现。结果 :脑内原发淋巴瘤MRI表现为 :①肿瘤单发或多发 ,以幕上分布为主 ;②形态类圆形成不规则形 ,T1 WI呈低信号 ,T2 WI呈高或等信号 ,信号均匀 ,DWI呈高信号 ;③瘤周水肿及占位效应较轻 ;④增强扫描肿瘤明显均匀强化 ;⑤可侵及软脑膜和 /或室管膜并沿之播散 ;⑥肿瘤对放疗和化疗敏感 ;形态、大小变化显著。结论 :脑内原发淋巴瘤的MRI增强扫描形态、占位效应以及肿瘤的发生部位具有一定特征 ,在多数情况下可作出诊断并为临床治疗方法的选择提供依据。     

Spontaneous remission of chiasmatic/hypothalamic masses in neurofibromatosis type 1: report of two cases

We report two children with neurofibromatosis type 1 showing enhancing masses on MRI suggesting neoplasms in the chiasm and hypothalamic region. In both patients no visual or endocrinal dysfunction was present. On serial MRI spontaneous partial remission was found, implying that a cautious approach to therapeutic management of similar cases should be taken. Received: 10 June 1998 Accepted: 15 July 1998     

脑肿瘤MR弹性成像的初步临床研究

目的 探讨MR弹性成像(MRE)在脑肿瘤手术前评价其硬度的价值.方法 14例常规影像检查确定为实性脑肿瘤患者(男5例、女9例,年龄16～63岁),术前接受脑MRE检查,以脑白质为参照对肿瘤硬度进行评价.采用自行研制的用于脑MRE成像的激发装置,固定于头线圈上,并与患者头部固定,产生低频率振荡经颅骨传至颅内,引起剪切波在脑组织内传播;脉冲序列采用相位对比梯度回波序列,获得相位图像,从而显示脑组织内剪切波的传播.相位图像经局部频率估算法(LFE)处理后获得弹性图像;肿瘤的硬度在术中与正常脑白质对比,由术者判断分为偏软、中等和偏硬.将MRE的评价结果与手术结果作对照.结果 MRE检查结果显示,1例肿瘤的弹性模量低于正常脑白质、11例高于正常脑白质、2例与正常脑白质相似;术中检查1例肿瘤硬度偏软、11例偏硬,2例中等.14例由MRE评估的肿瘤弹性均与手术结果相符.结论 MRE可以无创地显示脑肿瘤的弹性,在术前对脑肿瘤的硬度进行评价.     

Cerebral ganglioglioma and neurofibromatosis type I

Summary We report the occurrence of a left frontal lobe ganglioglioma in a patient with neurofibromatosis type I (von Recklinghausen's disease) and conclude that the occurrence of a cerebral ganglioglioma in a patient with neurofibromatosis must probably be considered coincidental.     

子宫内膜良、恶性息肉样病变的MR表现与临床病理对照分析

目的 探讨常规MR及动态增强扫描在子宫内膜息肉样病变中的诊断价值及病理基础.方法 回顾性分析经病理证实的子宫内膜息肉样病变48例,其中恶性肿瘤26例(23例I期子宫内膜癌和3例子宫内膜肉瘤),良性息肉样病变22例(子宫内膜息肉12例和子宫黏膜下肌瘤10例),分析其MR平扫及增强图像病灶特征,并与病理结果 进行对照.采用Fisher精确概率法对纤维核、囊变区及完整结合带在不同子宫内膜息肉样病变中的出现概率进行分析比较.结果 26例子宫内膜恶性息肉病变,其中23例子宫内膜癌在MR T2WI上均表现为子官内膜均匀等或稍高信号肿块(23/23),增强后相对于肌层均呈低信号(23/23),并伴结合带中断或模糊(20/23);子宫内膜含间质成分恶性肿瘤3例,2例为腺肉瘤,1例为癌肉瘤,MR T2WI均为混杂信号,早期局部明显强化,至后期仍明显持续强化;26例子宫内膜恶性息肉病变在MRI上子宫结合带中断或模糊征象出现的概率(23/26)均较子宫内膜息肉(1/11)及子宫黏膜下肌瘤(1/9)高,差异具有统计学意义(P值均<0.05).肿块内小囊变影及不定形纤维核影见于子宫内膜息肉(分别为8/12及5/12),2种征象在子宫内膜息肉中的出现概率均较子宫内膜恶性息肉样病变(3/26及2/26)及子宫黏膜下肌瘤(0及2/10)高,差异具有统计学意义(P值均<0.05);10例子宫黏膜下平滑肌瘤MRI均表现为境界清晰,T2WI呈等或稍低信号肿块,且出现子宫黏膜推移征象(10/10).MR平扫及增强扫描对所有48例子宫内膜息肉样病变的定性诊断敏感度为92.3%(24/26),特异度为83.3%(20/24),准确度为95.8%(46/48).结论 MRI平扫及增强扫描能反映子宫内膜良、恶性息肉样病变的特征,具有很高的诊断价值.     

MR扩散张量成像对脑肿瘤的初步应用研究

目的 :评价MR扩散张量成像在脑肿瘤中的应用价值。方法 :搜集经手术及病理证实的脑膜瘤和星形细胞瘤病例共 3 3例 ,行常规MRI、扩散张量成像 (DTI)检查。构建各向异性分数 (FA)图 ,并测量肿瘤及周围白质的FA值。结果 :正常白质纤维在FA图上表现为高信号。在肿瘤存在时 ,周围白质纤维可表现为受推压移位或浸润破坏 ,破坏后FA值降低 ,表现为低信号。这些表现在常规MRI上均未清楚显示。结论 :DTI可清楚显示肿瘤与周围白质纤维的解剖关系 ,指导临床制订手术方案。     

颅内恶性淋巴瘤的CT及MR诊断

颅内恶性淋巴瘤少见，容易误诊。作者总结了１８例手术后病理证实为恶性淋巴瘤的病例，其ＣＴ、ＭＲ表现有如下特点：（１）ＣＴ上平扫为类圆形、椭圆形或不规则形稍高密度影，不规则形多见，且边界不清楚，周围水肿较轻，占位征象相对小；（２）注药后病灶明显强化；（３）ＭＲ表现为长Ｔ１、长Ｔ２信号，注药后病灶也明显强化；（４）在ＭＲ Ｔ２ＷＩ上可发现沿室管膜的种植病灶，优于ＣＴ。作者根据ＣＴ、ＭＲ表现提出诊断与鉴别     

Epithelioid haemangioendothelioma of the brain: a case report

We report a rare epithelioid haemangioendothelioma in the frontal lobe. The CT and MRI findings are characteristic and correspond to histological features intermediate between those a cavernous haemangioma and an aggressive vascular tumour. Received: 20 November 2000/Accepted: 10 January 2001     

3.0T磁共振全身神经根成像在神经纤维瘤病中的应用价值

目的：探讨3.0T磁共振三维容积采集水脂分离技术（CUBE-FLEX）序列全身神经根成像在神经纤维瘤病中的应用价值。方法：采用GE SIGNA HDxt 3.0T超导磁共振成像系统,对20例神经纤维瘤病患者行MRI全身神经根成像检查,利用一次定位,自动进床和水脂分离技术三维容积采集,分4段行冠状面扫描,即颈段、胸段、腰骶段、下肢段,将原始图像传至工作站行后处理,将4段扫描图像自动无缝拼接显示全身神经根图像,评估图像质量及病变的空间位置。结果：本组20例神经纤维瘤病患者中19例的CUBE-FLEX序列后处理图像能整体、直观、全面、清晰地显示周围神经根、神经纤维瘤以及两者的空间关系;1例因原始图像分段扫描过程中患者体位发生变动,致使脊髓正中层面发生错位导致拼接失败,从而影响全视野神经根的观察。神经纤维瘤病在全身神经根成像中表现为沿神经纤维走行分布的均匀或不均匀高信号影,病变多发、弥漫且大小不一,呈圆形或者椭圆形,边界清楚。结论：3.0T MRI CUBE-FLEX序列全身神经根成像能整体、全面、清楚地显示神经根、神经纤维瘤及两者的空间关系,且有利于发现小的神经纤维瘤病灶,具有较高的临床应用价值。     

MR灌注成像在鉴别单发脑转移瘤与高级别胶质瘤中的价值

目的探讨MR灌注成像在鉴别单发脑转移瘤与高级别胶质瘤中的作用及价值。方法对10例单发脑转移瘤和15例高级别胶质瘤患者行手术前MR灌注成像扫描。分析其MR灌注曲线及伪彩图像,测量肿瘤实质部分及瘤周水肿区最大相对脑血容积(rCBV)值及相应部位相对平均通过时间(rMTT)数值并将所测值进行t检验。结果单发脑转移瘤的MR灌注曲线形态和伪彩图像中的色彩特点与高级别胶质瘤有明显区别。单发脑转移瘤与高级别胶质瘤肿瘤实质部分的最大rCBV值分别为3.70±2.34、6.01±2.17,瘤周水肿区则分别为0.80±0.28、1.77±1.19。单发脑转移瘤与高级别胶质瘤肿瘤实质相应部位的rMTT值分别为1.17±0.39、1.11±0.18,瘤周水肿区则分别为1.17±0.38、1.02±0.20。两者肿瘤实质部分和瘤周水肿区的rCBV值均数之间差异有统计学意义(P<0.05),而相应的rMTT值均数之间差异没有统计学意义(P>0.05)。结论MR灌注成像对术前鉴别单发脑转移瘤与高级别胶质瘤有临床实用价值。     

Role of diffusion-weighted echo-planar MRI in distinguishing between brain abscess and tumour: a preliminary report

Our purpose was to evaluate diffusion-weighted (DW) echo-planar MRI in differentiating between brain abscess and tumour. We examined two patients with surgically confirmed pyogenic brain abscess and 18 with metastatic brain tumours or high-grade glioma, using a 1.5 T system. The apparent diffusion coefficient (ADC) of each necrotic or solid contrast-enhancing lesion was measured with two different b values (20 and 1200 s/mm²). All capsule-stage brain abscesses (4 lesions) and zones of cerebritis (2 lesions) were identified on high-b-value DWI as markedly high-signal areas of decreased ADC (range, 0.58–0.70 [(10–3 mm²/s; mean, 0.63)]). All cystic or necrotic portions of brain tumours (14 lesions) were identified on high-b-value DWI as low-signal areas of increased ADC (range, 2.20–3.20 [(10–3 mm²/s; mean, 2.70)]). Solid, contrast-enhancing portions of brain tumours (19 lesions) were identified on high-b-value DWI as high-signal areas of sightly decreased or increased ADC (range, 0.77–1.29 [(10–3 mm²/s; mean, 0.94)]). Our preliminary results indicate that DW echo-planar MRI be used for distinguishing between brain abscess and tumour. Received: 23 January 1998 Accepted: 5 June 1998     

Intraventricular ganglioglioma: case report

We report a case of ganglioglioma located in the body and frontal horn of the right lateral ventricle. The lesion was found in a 71-year-old man who suffered from recurrent episodes of right hemicranial headache. CT and MRI showed a heterogeneous intraventricular tumour with multiple microcysts that suggested a diagnosis of subependymoma or central neurocytoma, but the pathological findings were consistent with ganglioglioma. Although the most frequent intracranial location of ganglioglioma is the temporal lobe, any location in the central nervous system may be seen. Nevertheless an exclusively intraventricular location is exceptional. To our knowledge this is the first complete radiological report of a purely intraventricular ganglioglioma. Received: 18 April 1997 Accepted: 10 September 1997     

DWI和1H-MRS在儿童脑肿瘤中的诊断价值

目的:探讨DWI及单体素1H-MRS在儿童脑肿瘤影像诊断中的价值.方法:对21例脑肿瘤患儿行常规MRI、DWI及单体素1H-MRS成像,在DWI上测量病变实质区3个感兴趣区的ADC值,计算其平均值,单体素MRS感兴趣区选在肿瘤实质部分(强化者选在强化区域),计算感兴趣区的Cho/Cr、NAA/Cho、NAA/Cr比值,...