Computed tomography of germinomas in basal ganglia and thalamus

Summary CT findings of 6 cases with germinoma originating in the basal ganglia and thalamus are reported. The early finding of germinoma in this region on plain CT, was an irregularly defined, slightly high density area without mass effect. Repeated CT scanning showed enlarging iso-density lesion accompanied by mass effect to high. Intratumorous cysts and calcifications were frequently observed. The tumor showed mild to moderate and inhomogeneous enhancement by intravenous injection of contrast medium. A tendency to ipsilateral hemicerebral atrophy was found in one case. These findings were somewhat different from those of germinomas in the pineal and suprasellar regions. This phenomenon may be related to the anatomical difference of the brain where the tumor originated.     

High-signal basal ganglia on T1-weighted images in a patient with Sydenham's chorea

We report a 16-year-old girl with Sydenham's chorea. Choreiform movements involved both sides of her body. MRI 2 months after the onset revealed abnormal increased signal on T2-weighted images and enlargement of the caudate and putamen bilaterally. MRI 5 months later showed resolution of the swelling, but with increased signal on T1-weighted images in the putamen, globus pallidus and the head of the caudate nucleus bilaterally, with slightly increased signal intensity on T2-weighted images. Received: 19 January 1998 Accepted: 19 January 1998     

Effects of portal-systemic shunt embolization on the basal ganglia: MRI

We report MRI in a patient with portal-systemic encephalopathy, in which the high signal in the basal ganglia on T1-weighted images showed marked resolution after successful embolization of the intrahepatic portal-systemic venous shunt. Received: 21 June 1996 Accepted: 26 July 1996     

Acute bilateral basal ganglia lesions in diabetic uraemia: diffusion-weighted MRI

Methods We studied four patients with diabetes mellitus and chronic renal failure who developed sudden choreic movement disorders. The clinical manifestations, laboratory findings, MR imaging findings, and clinical outcome in each patient were evaluated. Results All four patients had long-term diabetes mellitus and severe azotaemia. Brain MR findings consisted of bilateral symmetric basal ganglia lesions, with decreased signal intensity on T1-weighted images and increased signal intensity on T2-weighted images. All three patients who underwent diffusion-weighted MR imaging (DWI) showed signal intensities similar to those of the surroundings in regions corresponding to increased signal intensity on T2-weighted images, with slightly increased apparent diffusion coefficient (ADC) values. Two of the patients showed small focal areas of restricted diffusion within the basal ganglia lesions. After haemodialysis, follow-up MR imaging in all patients demonstrated that the basal ganglia lesions had regressed markedly, with some residual changes. The movement disorders also improved in all patients. Conclusion A syndrome associated with acute bilateral basal ganglia lesions in diabetic uraemic patients is rare, with reversible changes demonstrated by clinical and imaging findings. DWI showed that the bilateral basal ganglia lesions in this syndrome were primarily vasogenic in origin, although there were small foci of cytotoxic oedema within the lesions.     

MRI of germinomas arising from the basal ganglia and thalamus

We reviewed the MRI findings of germinomas originating from the basal ganglia, thalamus or deep white matter in 13 patients with 14 germinomas, excluding those in the suprasellar or pineal regions. Ten cases were confirmed as germinomas by stereotaxic biopsy, three by partial and one by total removal of the tumour. Analysis was focussed on the location and the signal characteristic of the tumour, haemorrhage, cysts within the tumour and any other associated findings. Thirteen of the tumours were in the basal ganglia and one in the thalamus. Haemorrhage was observed in seven patients, while twelve showed multiple cysts. Associated ipsilateral cerebral hemiatrophy was seen in three patients. The signal intensity of the parenchymal germinomas was heterogeneous on T1- and T2-weighted images due to haemorrhage, cysts and solid portions. We also report the MRI findings of germinomas in an early stage in two patients. Received: 31 July 1997 Accepted: 6 January 1998     

Chronological changes in nonhaemorrhagic brain Infarcts with short T1 in the cerebellum and basal ganglia

Our purpose was to investigate nonhaemorrhagic infarcts with a short T1 in the cerebellum and basal ganglia. We carried out repeat MRI on 12 patients with infarcts in the cerebellum or basal ganglia with a short T1. Cerebellar cortical lesions showed high signal on T1-weighted spin-echo images beginning at 2 weeks, which became prominent from 3 weeks to 2 months, and persisted for as long as 14 months after the ictus. The basal ganglia lesions demonstrated slightly high signal from a week after the ictus, which became more intense thereafter. Signal intensity began to fade gradually after 2 months. High signal could be seen at the periphery until 5 months, and then disappeared, while low or isointense signal, seen in the central portion from day 20, persisted thereafter. Received: 1 February 1999 Accepted: 13 September 1999     

Basal ganglia lesions in children and adults

The term “basal ganglia” refers to caudate and lentiform nuclei, the latter composed of putamen and globus pallidus, substantia nigra and subthalamic nuclei and these deep gray matter structures belong to the extrapyramidal system. Many diseases may present as basal ganglia abnormalities. Magnetic resonance imaging (MRI) and computed tomography (CT) – to a lesser degree – allow for detection of basal ganglia injury. In many cases, MRI alone does not usually allow to establish diagnosis but together with the knowledge of age and circumstances of onset and clinical course of the disease is a powerful tool of differential diagnosis. The lesions may be unilateral: in Rassmussen encephalitis, diabetes with hemichorea/hemiballism and infarction or – more frequently – bilateral in many pathologic conditions. Restricted diffusion is attributable to infarction, acute hypoxic–ischemic injury, hypoglycemia, Leigh disease, encephalitis and CJD. Contrast enhancement may be seen in cases of infarction and encephalitis. T1-hyperintensity of the lesions is uncommon and may be observed unilaterally in case of hemichorea/hemiballism and bilaterally in acute asphyxia in term newborns, in hypoglycemia, NF1, Fahr disease and manganese intoxication. Decreased signal intensity on GRE/T2*-weighted images and/or SWI indicating iron, calcium or hemosiderin depositions is observed in panthotenate kinase-associated neurodegeneration, Parkinson variant of multiple system atrophy, Fahr disease (and other calcifications) as well as with the advancing age. There are a few papers in the literature reviewing basal ganglia lesions. The authors present a more detailed review with rich iconography from the own archive.     

青年抑郁症患者基底节和丘脑3D 1H-MRS研究

目的:探讨青年抑郁症患者基底节和丘脑可能存在的神经生化异常.方法:对44例青年抑郁症患者(抑郁症组)和40例年龄和性别匹配的健康志愿者(对照组)进行常规MRI扫描和三维氢质子MR波谱(3D 1H-MRS)检查,测量双侧基底节和丘脑的 N-乙酰天门冬氨酸(NAA)、胆碱复合物(Cho)、肌醇(mI)和肌酸(Cr)的绝对值,并计算它们与Cr的比值.对两组实验对象各代谢物及其比值进行统计学分析.结果:①抑郁症组双侧豆状核和尾状核头部Cho/Cr、mI/Cr明显高于对照组,差异有显著性意义(P＜0.05),而NAA/Cr在两组间差异无统计学意义(P＞0.05);②抑郁症组丘脑NAA/Cr、Cho/Cr和mI/Cr与对照组相比,差异无统计学意义(P＞0.05).结论:青年抑郁症患者基底节区豆状核和尾状核头部的Cho/Cr、mI/Cr增高,可能构成该病的神经生物学基础.     

青年抑郁症患者基底节和丘脑3D ^1H-MRS研究

目的：探讨青年抑郁症患者基底节和丘脑可能存在的神经生化异常。方法：对44例青年抑郁症患者（抑郁症组）和40例年龄和性别匹配的健康志愿者（对照组）进行常规MRI扫描和三维氢质子MR波谱（3D -1H-MRS）检查，测量双侧基底节和丘脑的N-乙酰天门冬氨酸（NAA）、胆碱复合物（Cho）、肌醇（mI）和肌酸（Cr）的绝对值，并计算它们与Cr的比值。对两组实验对象各代谢物及其比值进行统计学分析。结果：①抑郁症组双侧豆状核和尾状核头部Cho/Cr、mI/Cr明显高于对照组，差异有显著性意义（P〈0.05），而NAA/Cr在两组间差异无统计学意义（P〉0.05）；②抑郁症组丘脑NAA/Cr、Cho/Cr和mI/Cr与对照组相比，差异无统计学意义（P〉0.05）。结论：青年抑郁症患者基底节区豆状核和尾状核头部的Cho/Cr、mI/Cr增高，可能构成该病的神经生物学基础。     

1H MR spectroscopy of the basal ganglia in childhood: a semiquantitative analysis

Proton MR spectra of the basal ganglia were obtained from 28 patients, 24 male and 14 female, median age 16.3 months (5 weeks to 31 years). They included 17 patients with normal MRI of the basal ganglia without metabolic disturbance (control group) and 11 patients with various metabolic diseases: one case each of high serum sodium and high serum osmolarity, cobalamin C deficiency, Leigh disease, Galloway-Mowat syndrome, Pelizaeus-Merzbacher disease, hemolytic-uremic syndrome and Wilson disease and two cases of Alagille syndrome and methylmalonic acidemia with abnormal MRI of the basal ganglia or blood or urine analysis (abnormal group). The MR spectrum was measured by using STEAM. The MR-visible water content of the region of interest was obtained. Levels of myoinositol, choline, creatine and N -acetylaspartate were measured using a semiquantitative approach, with absolute reference calibration. In the control group, there was a gradual drop of water content over the first year of life; N -acetylaspartate, creatine and myoinositol levels showed no significant change with age, in contrast to the occipital, parietal and cerebellar regions. Choline showed a gradual decrease for the first 2 years of life and then remained fairly constant. In the abnormal group the water content was not significantly different. N -Acetylaspartate was decreased in patients with high serum sodium and high serum osmolarity, cobalamin C deficiency, Leigh disease and one case of methylmalonic acidemia. Decreased creatine was also found in Leigh disease, and decreased choline in Galloway-Mowat syndrome and Wilson disease. Myoinositol was elevated in the patient with abnormally high serum sodium, and decreased in the hemolytic-uremic syndrome. Received: 31 January 1997 Accepted: 31 January 1997     

丘脑肿瘤的MRI鉴别诊断

目的 探讨丘脑肿瘤的MRI表现,提高MRI对丘脑肿瘤诊断的准确性. 资料与方法 回顾性分析41例经手术病理证实的丘脑肿瘤患者的MRI资料. 结果 41例中,星形细胞瘤17例,生殖细胞瘤12例,室管膜瘤3例,畸胎瘤1例,淋巴瘤1例,转移瘤4例,动静脉畸形2例,海绵状血管瘤1例. 结论 MRI是诊断和鉴别诊断丘脑肿瘤的主要检查方法,它可更清楚、准确地显示病变侵犯范围,为治疗提供可靠依据.     

基底节区腔隙性脑梗死治疗前后MR表现分析

目的研究基底节区腔隙性脑梗死临床治疗前、后的生理及病理特征。方法收集28例基底节区腔隙性脑梗死患者病例资料,以入院治疗前患者的头颅核磁共振（MR）图像数据作为治疗前组,入院治疗一定时间后复查头颅MR所得数据作为治疗后组,对比治疗前后两组病灶范围大小及信号高低的变化。结果治疗后大部患者（男性87.5%,女性83.3%）原发病灶趋于稳定,少数患者病灶（男性12.5%,女性16.7%）扩大趋势。通过MR检查,发现急性期发病并及时诊断及治疗的患者,病情得到很好控制。结论 MR对腔隙性梗死诊断有很强的敏感性,对腔隙性脑梗死患者周边缺血半暗带也有很清晰的显示,急性期诊断符合率高,可作为诊断腔隙性脑梗死及是否治疗有效的重要指标之一。     

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     

The dorsal cyst in holoprosencephaly and the role of the thalamus in its formation

The dorsal cyst is poorly understood, although it is commonly encountered in holoprosencephaly. We endeavor to establish the role of diencephalic malformations in the formation of the dorsal cyst and speculate on the developmental factors responsible. We reviewed the imaging of 70 patients with holoprosencephaly (MRI of 50 and high-quality CT of 20). The presence or absence of a dorsal cyst, thalamic noncleavage and abnormal thalamic orientation were assessed for statistical association, using Fisher's Exact Test and logistical regression. The presence of a dorsal cyst correlated strongly with the presence of noncleavage of the thalamus (P = 0.0007) and with its degree (P < 0.00005). There was a trend toward an association between abnormalities in the orientation of the thalamus and the dorsal cyst, but this was not statistically significant (P = 0.07). We speculate that the unseparated thalamus physically blocks egress of cerebrospinal fluid from the third ventricle, resulting in expansion of the posterodorsal portion of the ventricle to form the cyst. Received: 13 July 2000/Accepted: 19 December 2000     

单侧颞叶癫痫病人双侧基底节区多体素MRS研究

目的 采用多体素MRS探讨单侧颞叶癫痫（TLE）病人双侧基底节区代谢物改变。方法 选取根据临床发作症状和脑电图综合诊断的左侧TLE病人10例,右侧TLE病人10例,正常志愿者10例纳入研究。所有TLE病人均进行利物浦痫性发作严重程度量表2.0（LSSS 2.0）评估,采用Simens 3.0 T超导MR设备进行多体素1H-MRS数据采集,对称性测量双侧尾状核头、豆状核和丘脑的N-乙酰天门冬氨酸（NAA）、乙酰胆碱（Cho）、肌酸（Cr）含量,计算各兴趣区NAA/Cr和Cho/Cr比值并进行统计学分析,将代谢物比值与LSSS 2.0评分进行Pearson相关分析。结果 左侧TLE组双侧丘脑NAA/Cr比值分别为1.92±0.15（左）和2.02±0.26（右）,右侧TLE组双侧丘脑NAA/Cr比值分别为2.19±0.16（左）和1.79±0.16（右）,均明显低于对照组[2.37±0.14（左）和2.36±0.10（右）,P＜0.05]。右侧TLE组,其致痫灶同侧丘脑的NAA/Cr比值较对侧丘脑要低（P＜0.05）。TLE组致痫灶同侧丘脑NAA/Cr比值与LSSS 2.0评分呈负相关（左侧 r=-0.667;右侧r=-0.643,均P＜0.05）。结论 单侧TLE病人存在双侧丘脑神经元丢失和/或功能障碍,且致痫灶同侧丘脑NAA/Cr比值与LSSS 2.0评分可以一致性反映近期痫性发作严重程度。     

Calcification of the basal ganglia following carbon monoxide poisoning

Summary Minor calcification of the basal ganglia was demonstrated by computed tomography in a woman, aged 66, who had survived carbon monoxide poisoning 48 years earlier. Extensive neuropathological investigations have demonstrated calcified lesions of the basal ganglia in a number of conditions, but their frequency and topographic distribution in vivo remain to be elucidated, by means of CT.     

正常人丘脑及岛盖功能连接的MRI研究

目的:探讨正常人在静息和认知任务状态下丘脑及岛盖功能连接的变化情况。方法:采用BOLD-fMRI方法,检测16例健康志愿者在静息和2-back任务状态下的脑功能连接,将前额叶内侧皮层作为种子点,应用SPM2、AFNI及Matlab软件进行图像数据处理,对2-back任务和静息状态行组内和组间2个水平的统计分析,统计阈值概率设定为P=0.005(未校正)。结果:与左侧丘脑前核相关的网络系统与默认网络一致,而丘脑背侧部属"任务正激活网络",且受试者反应正确率与左侧丘脑背侧的相关性差异有统计学意义(r=-0.52,P=0.04)。"岛盖相关网络"与"默认网络"呈负相关,前者在静息状态相关性高于任务状态,其主要脑区包括双岛叶、双顶下小叶、双中央旁小叶、双颞上回、双海马旁回等。结论:人脑在静息和任务状态下脑区间的功能连接不同,表现为丘脑前核和丘脑背侧部的功能分化,及"岛盖相关网络"与"默认网络"在静息状态的功能拮抗。     

肝硬化患者脑代谢的磁共振波谱成像研究

目的 利用磁共振波谱成像(MRS)评价肝硬化患者脑内代谢物的异常改变及其与临床静脉血氨值和神经心理学测试结果 之间的相关性. 资料与方法 52例经病理学和/或临床检查证实的肝硬化患者和30例健康志愿者纳入本研究.所有研究对象在MRI检查前进行数字连接试验-A(NCT-A)、数字符号试验(DST)以及符号数字试验(SDT).均行扣带回和右侧基底节的单体素氢质子波谱扫描,给出各代谢物曲线下面积与Cr的比值.记录肝硬化患者的静脉血氨值. 结果 患者组扣带回和基底节出现Cho/Cr降低、(Cho mIns)/NAA降低、Glx/Cr升高、mIns/Cr降低.扣带回的mIns/Cr与Child分级(r＝-0.496,P<0.001)及HE分级(r＝-0.313,P<0.05)之间均存在相关性;而基底节的Cho/Cr(r＝-0.497,P<0.001)、mIns/Cr(r＝-0.341,P<0.05)和(Cho mIns)/NAA(r＝-0.276,P<0.05)与Child分级之间有显著负相关,Glx/Cr与HE分级之间有正相关性(r＝0.385,P<0.05).扣带回与右侧基底节的MRS指标与血氨之间存在负相关关系.扣带回的Glx/Cr与NCT-A有正相关关系(r＝0.366,P＝0.028). 结论 肝硬化患者扣带回和基底节存在生化代谢的异常改变,扣带回可作为检测肝硬化患者脑改变的一个敏感部位.     

Age distribution and iron dependency of the T2 relaxation time in the globus pallidus and putamen

Summary Heavily T2-weighted spin echo sequences of the brain show age-dependent low signal intensity in many extrapyramidal nuclei. Although it has been suggested that this low intensity results from non-haem iron, the specific influence of non-haem iron on the T2 relaxation time has not been quantified and remains controversial. The T2 relaxation times of the globus pallidus and putamen were measured from MRI at 1.5T in 27 healthy patients, by using a mathematical model. They were then plotted as a function of age and compared to the curve of age-dependent iron concentration determined post mortem. The curves of T2 relaxation time in the basal ganglia are congruent with published curves of iron concentration, indicating a high probability that the changes in T2 relaxation times and the low signal in the basal ganglia result from the local, age-dependent iron deposition. Individual measurements of T2 relaxation time show less variation before than after 45 years of age, indicating the influence of a second, more individual factor.     

Atrophy of the corpus callosum correlates with white matter lesions in patients with cerebral ischaemia

Many studies of white matter high signal (WMHS) on T2-weighted MRI have disclosed that it is related to cerebral ischaemia and to brain atrophy. Atrophy of the corpus callosum (CC) has also been studied in relation to ischaemia. Our objective was to test the hypothesis that CC atrophy could be due to ischaemia. We therefore assessed CC, WMHS and brain atrophy in patients with risk factors without strokes (the risk factor group) and in those with infarcts (the infarct group), to investigate the relationships between these factors. We studied 30 patients in the infarct group, 14 in the risk factor group, and 29 normal subjects. Using axial T1-weighted MRI, cortical atrophy and ventricular enlargement (brain atrophy) were visually rated. Using axial T2-weighted MRI, WMHS was assessed in three categories: periventricular symmetrical, periventricular asymmetrical and subcortical. Using the mid-sagittal T1-weighted image, the CC was measured in its anterior, posterior, midanterior and midposterior portions. In the normal group, no correlations were noted between parameters. In the infarct group, there were significant correlations between CC and brain atrophy, and between CC atrophy and WMHS. After removing the effects of age, gender and brain atrophy, significant correlations were noted between some CC measures and subcortical WMHS. In the risk factor group, there were significant correlations between CC and brain atrophy and between CC atrophy and WMHS. After allowance for age, gender and brain atrophy, significant correlations between some CC measures and periventricular WMHS remained. The hypothesis that CC atrophy could be due to cerebral ischaemia was supported by other analyses. Namely, for correlations between the extent of infarcts and partial CC atrophy in patients with anterior middle cerebral artery (MCA) and with posterior MCA infarcts, there were significant correlations between the extent of infarct and midanterior CC atrophy in the former, and posterior CC atrophy in the latter. Our findings could indicate that CC atrophy is associated with cerebral ischaemia. Received: 5 December 1998/Accepted: 6 November 1999