Magnetic resonance imaging of medial medullary infarction

Medial medullary infarction is characterized by ipsilateral hypoglossal nerve palsy, contralateral hemiparesis sparing the face, and contralateral disturbance of deep sensation. Although it is possible to make a clinical diagnosis in typical patients, diagnosis is difficult if hypoglossal nerve palsy is absent. We describe a patient with medial medullary infarction without hypoglossal nerve palsy. The patient suffered from left hemiplegia and homolateral disturbance of deep sensation. Magnetic resonance imaging revealed the site of the lesion to be in the medial portion of the upper medulla oblongata. The result of somatosensory evoked potential testing was compatible with disturbance of the medullary medial lemniscus. In a review of the literature, we examined the relation between clinical features and lesion location in 16 patients with medial medullary infarction and compared these to the present patient. Motor paresis was present in every patient, while disturbance of deep sensation was recorded in nine of 13 patients and hypoglossal nerve palsy in six of 14 patients. In atypical patients with medial medullary infarction (such as the present patient), magnetic resonance imaging is necessary to detect the lesion and to make a clinical diagnosis.     

急性期脑梗死的磁共振化学位移成像研究

目的采用磁共振化学位移成像(CSI)研究急性期脑梗死不同部位代谢产物浓度变化 的差异及其与弥散加权成像(DWI)表现的相关性。方法28例发病3d内非腔隙性脑梗死患者完成 CSI和DWI检查。测算梗死区N-乙酰天门冬氨酸(NAA),肌酸(Cr),胆碱化合物(Cho)与对侧相应 正常脑区代谢产物比值(rNAA、rCr、rCho)及同侧乳酸／胆碱值(Lac／Cho),比较不同部位各代谢产物 相对浓度;比较:DWI上梗死区相对信号强度(rDWI)、表观弥散系数(rADC)值与代谢产物浓度的相 关性。结果(1)与对应脑区比较,急性期脑梗死灶内NAA明显降低,Lac明显增加(P<0.001),cr、Cho无显著变化(P=0.543,0.817)。(2)梗死核心区、内缘、外缘及正常组织间rNAA及Lac／Cho差异均有显著意义(均P<0.001),rCr及rCho各部位间差异无显著意义(P=0.266,0.737)。rNAA梗死外缘与正常区域间差异无显著意义(P=0.733);Lac／Cho外缘与正常区域差异有显著意义(P=0.003)。(3)急性期脑梗死rNAA与Lac／Cho(r=0.496)、rADC(r=0.405)成正相关,与rDWI成负相关(r=-0.432);Lac／Cho与rDWI成负相关(r=-0.587),与rADC成正相关(r=0.561)。结论(1)急性期梗死灶NAA降低局限于DWI高信号范围内,而Lac升高范围可超过NAA下降和DWI高信号区域,可能预示缺血半影区。(2)急性期梗死区La     

Magnetic resonance imaging in a case of paramedian mesencephalic infarction

A case of paramedian midbrain infarction was studied by magnetic resonance imaging. The clinical syndrome included a paralysis of the oculomotor nerve sparing the pupil and cerebellar disorders of the opposite side. MRI disclosed a cylindrical infarction in the paramedian midbrain tegmentum.     

Magnetic resonance imaging in horizontal oculomotor paralysis caused by infarction

Four patients with focal brainstem ischemic strokes and various types of horizontal oculomotor disturbances have been studied clinically and radiologically. One had a six nerve palsy, one a unilateral internuclear ophthalmoplegia, one a Fisher's one-and-a-half syndrome, and one a paramedian pontine reticular formation syndrome with a sixth nerve palsy. In all patients a C.T. Scan and a Magnetic Resonance Imaging (MRI) were obtained. The MRI study was performed on a CGR Magniscan 5000 with a superconducting magnet of 0.5 Tesla. In all patients a hypersignal in T2 weighted images was shown and corresponded to the brainstem infarct. MRI allowed accurate delineation of the lesion and clinico-radiologic correlations in three patients. But the low specificity of MRI does not permit to distinguish edema from necrosis, gliosis or demyelination in a region with a pathological MRI signal. In one patient this low specificity and perhaps partial volume effects decreased the accuracy of the clinico-topographic correlation.     

Magnetic resonance imaging in young adults with cerebral infarction due to moyamoya

The number, size, and location of cerebral infarctions, and blood flow in the middle cerebral artery as seen on proton magnetic resonance imaging were assessed in six white adults with angiographically documented moyamoya. Findings were correlated with clinical presentation, computed tomography, and angiography. Large hemispheric infarctions were found in five hemispheres, predominantly in watershed regions. Subcortical infarctions (n = 56) were found in all hemispheres. They were predominantly located in the centrum semiovale, in the distal beds of supply of the penetrating branches of the anterior and middle cerebral arteries. Infarction of the putamen was found in three hemispheres, caudate nucleus in four, globus pallidus in two, and anterior limb of the internal capsule in two. There were none in the posterior limb of the internal capsule, thalamus, brain stem, or cerebellum. Middle cerebral artery flow was visualized as a signal-void flow sign in only three hemispheres. Cerebral infarctions due to moyamoya are bilateral, multiple, often small, and asymptomatic, affecting predominantly the carotid circulation in watershed regions. Subcortical infarctions in the centrum semiovale and large hemispheric infarctions in hemodynamically compromised areas are the predominant findings.     

Magnetic resonance imaging and Cogan's syndrome

We report the case of a 25-year old man with vestibulocochlear and ocular impairment compatible with Cogan's syndrome. Later on, severe headache developed. CT scan showed an ischaemic lesion in the right frontal lobe. Magnetic resonance imaging demonstrated multiple bilateral nodular lesions on T2-weighted sequences. These were unmodified at a second MRI examination performed six months later. Under corticosteroids, the neurological and ophthalmic symptoms disappeared, but the patient remained deaf. We believe that this patient had vasculitis involving the brain, with infarcts. To our knowledge, no case of Cogan's syndrome with cerebral magnetic resonance imaging has yet been reported.     

Magnetic resonance imaging and herpetic encephalitis

Cerebral lesions in two cases of herpetic encephalitis were detected by MRI using a spin-echo sequence and delayed echo signal recordings, whereas CT scans were normal. In one case pathology showed lesions to be more extensive than MRI anomalies. This suggests that even in the absence of EEG and CT anomalies, an encephalitis can be suggested by MRI.     

高血糖并脑干梗死的磁共振特点、分型及发病机制的探讨

目的 比较高血糖脑梗死患者与血糖正常脑梗死患者危险因素及核磁共振(MR)影像学特点,并根据MR影像学特点进行分型,分析分型与预后的关系、高血糖对脑干梗死的影响,并探讨脑干梗死的发病机制. 方法 应用1;1配比的病例对照研究方法 ,对比高血糖组与正常血糖组脑梗死患者的危险因素、MRI影像学特征;采用mRS评分对脑干梗死患者预后进行比较. 结果 根据MR影像学特点将脑干梗死分为5型;中脑型、桥脑型、延髓型、全脑干型、脑干腔梗型,其中中脑型再分3个亚型、桥脑5个亚型、延髓型3个亚型.高血糖组脑干梗死发生率比正常血糖组高,差异有统计学意义(P<0.05);高血糖组收缩压、纤维蛋白原、甘油三酯、总胆同醇、低密度脂蛋白水平、合并高血压发生率较正常血糖组高,差异均有统计学意义(P<0.05),而舒张压及高密度脂蛋白水平两组差异无统计学意义(P0.05);脑干梗死人群高血糖组与正常血糖组相比,甘油三酯、纤维蛋白原、总胆固醇、高密度脂蛋白、低密度脂蛋白、高血压例数、高血压病程、收缩压、舒张压均无统计学意义(P0.05);高血糖脑梗死组脑干梗死人群与非脑干梗死人群相比,空腹血糖、餐后2h血糖、糖化血红蛋白均无统计学意义(P0.05).脑干梗死mRS评分2～5的占50.4%,0～1分占49.6%. 结论 高血糖与脑干梗死关系密切,提示高血糖对后循环穿支血管的影响更大,更易导致脑干梗死的发生;脑干梗死致残率较高.     

Magnetic resonance imaging of parkinsonism

We have analyzed magnetic resonance images in 33 patients; 18 patients with Parkinson's disease, 1 patient with diurnally fluctuating progressive dystonia, 1 patient with pure akinesia, 6 patients with multiple system atrophy, 1 patient with flunarizine induced parkinsonism, and 4 patients with unclassified parkinsonism. The MR images were obtained using a 1.5-T GE MR System. A spin-echo pulse sequence was used with a TE of 30 msec and 80 msec and a TR of 2000 msec. No signal abnormalities were seen in any patient with Parkinson's disease but 3 showed slightly decreased signal intensity of the putamen on T2-weighted sequences. Patients with diurnally fluctuating progressive dystonia and pure akinesia evidenced no abnormal findings. All six patients with multiple system atrophy demonstrated decreased signal intensity of the putamen, particularly along their lateral and posterior portions, and an enlarged substantia nigra. Atrophy of the pons and cerebellum was detected in all cases with multiple system atrophy. One case of flunarizine induced parkinsonism showed slightly decreased signal intensity of the putamen. Four cases of unclassified parkinsonism showed decreased signal in the putamen on T2-weighted sequences. Magnetic resonance imaging has the potential to become a useful diagnostic tool in the management of parkinsonism.     

Magnetic resonance imaging in psychiatry

Recent technical advances in MR imaging have led to several new applications in psychiatric imaging. There is a renewed interest in the further elucidation of the etiopathogenesis of some psychiatric disorders and clinical-radiological correlations are increasingly reported. Volume measurements are frequently used and in the near future, functional MR imaging carries high expectations. A brief survey is given of the recent applications of these new techniques in schizophrenia, affective disorders, dementia, anorexia nervosa, and other less common disorders.     

Magnetic resonance imaging of myelin

The ability to measure myelin in vivo has great consequences for furthering our knowledge of normal development, as well as for understanding a wide range of neurological disorders. The following review summarizes the current state of myelin imaging using MR. We consider five MR techniques that have been used to study myelin: 1) conventional MR, 2) MR spectroscopy, 3) diffusion, 4) magnetization transfer, and 5) T₂ relaxation. Fundamental studies involving peripheral nerve and MR/histology comparisons have aided in the interpretation and validation of MR data. We highlight a number of important findings related to myelin development, damage, and repair, and we conclude with a critical summary of the current techniques available and their potential to image myelin in vivo.     

Magnetic resonance imaging of meningio-angiomatosis

We report the case of a patient with meningio-angiomatosis, a rare disorder of the cerebral cortex often associated with Von Recklinghausen's neurofibromatosis. Previous reports have described a variety of radiological findings but in general they have been of little value in the diagnosis of this disorder. We describe the magnetic resonance image, which identified a well-defined lesion. The imaging techniques are reviewed.     

Magnetic resonance imaging in psychiatry

Magnetic resonance imaging (MRI) is a relatively new radiological technique that may be useful in the study of psychiatric illness. MRI gives detailed structural information about the brain and also allows quantification of functional change. Current areas of study relevant to psychiatry include: schizophrenia, dementia, epilepsy and, to a lesser extent, alcohol and affective disorders. The authors review the basic principles of MRI, discuss the recent application to psychiatry, indicate its potential advantages and comment on the current limitations of this imaging modality.     

Magnetic resonance imaging and magnetic resonance spectroscopy in dementias

This article reviews recent studies of magnetic resonance imaging and magnetic resonance spectroscopy in dementia, including Alzheimer's disease, frontotemporal dementia, dementia with Lewy bodies, idiopathic Parkinson's disease, Huntington's disease, and vascular dementia. Magnetic resonance imaging and magnetic resonance spectroscopy can detect structural alteration and biochemical abnormalities in the brain of demented subjects and may help in the differential diagnosis and early detection of affected individuals, monitoring disease progression, and evaluation of therapeutic effect.