延髓肿瘤的外科临床表现（附68例临床报告）

目的：分析68例不同性质延髓肿瘤临床表现，有助于早期诊断，早期治疗。万法：全面分析68例延髓肿瘤临床症状与体征、神经放射学特征，评估术前呼吸循环功能，并结合术中所见和术后病理诊断，对不同性质肿瘤进行对比研究。结果：延髓肿瘤以后组预神经功能受累最为多见。良性肿瘤生长较缓慢，常见肿瘤巨大而临床症状轻微，很少发生明显呼吸循环功能改变。出血性肿瘤如海绵状血管瘤常突然发病，症状突然加重，表现出呼吸、循环改变，恶性度高的胶质瘤，病情进展迅速，临床症状较重。结论：延髓肿瘤早期症状元明显特异性，如果出现后组颅神经功能障碍及长束征或特发呼吸功能障碍者，宜进一步行MRI检查以明确诊断。     

MRI characteristics of acute and subacute brainstem and thalamic infarctions: value of T2- and diffusion-weighted sequences

MRI including diffusion-weighted sequences (DW-MRI) has demonstrated its high sensitivity for acute supratentorial ischemic lesions. In this study we examined the sensitivity of different MRI sequences for the detection of acute brainstem and isolated thalamic infarctions. Diffusion- and T2-weighted MRI of 45 consecutive patients with signs and symptoms of infratentorial and thalamic infarction between 6/1997 and 1/2000 were analysed. The time between the onset of symptoms and the first MRI varied between 2 hours to 7 days with a median of 2 days. MRI repeats were performed in 4 patients in whom the clinical brainstem infarction had not been detected initially. Lesion detectability and size were evaluated for different brainstem and thalamic localizations. An acute brainstem or thalamic infarction as defined by the clinical condition could be identified in all patients by comparison of DW-MRI and T2-weighted images. Pons infarctions were the largest, followed by midbrain and thalamic lesions. Medulla oblongata infarctions were small in comparison. Pons, midbrain and thalamic infarctions were reliably identified beginning 12 hours after the onset of symptoms. In contrast, detectability of medulla oblongata infarctions varied within the first 24 hours and their overall visibility was worse than that of other brainstem infarctions corresponding to their small size. However, regardless of location, none of the 3 infarctions examined within the first 5 hours after the onset of symptoms could be identified. These lesions were demonstrated in follow-up examinations. In conclusion, pontine, midbrain and thalamic infarctions can reliably be visualized by a combination of DW-MRI and T2-weighted images beginning 12 hours after the ischemic attack. However, sensitivity seems to be lower earlier than 12 hours after ischemia and for medulla oblongata lesions. Received: 16 March 2001, Received in revised form: 25 April 2001, Accepted: 26 April 2001     

Brainstem representation of vestibular evoked myogenic potentials

ObjectiveVestibular evoked myogenic potentials (VEMPs) are caused by a short-latency reflex recorded from averaged electromyography from the sternocleidomastoid muscle evoked by intense auditory clicks. Besides peripheral vestibulopathy, abnormal VEMPs can be caused by lesions of the brainstem. The aim of this study was to analyze the topology of ischemic brain lesions generating pathological VEMPs.MethodsTwenty-nine patients with brainstem infarcts were prospectively studied using VEMPs and MR imaging to evaluate the brainstem representation of the VEMP reflex. Individual brainstem lesions were projected to a standard MR-dataset for normalization. Probabilistic lesion maps were calculated. A digital brainstem atlas was fitted to the lesion maps.ResultsTwelve patients showed unilaterally abnormal VEMPs, 10 patients had normal VEMPs. Seven patients with bilaterally absent VEMPs were not analyzed. Most lesions were located in the lateral medulla oblongata involving the spinal accessory nerve. Most lesions in the pons were associated to anterolateral parts of pyramidal tract fibers. In a few cases, lesions were located in the tegmental area of the pons, including the vestibular nuclei.ConclusionsAbnormal VEMPs may be produced not only by peripheral vestibulopathy but also by brainstem lesions. VEMPs may be influenced by effects caused by lesions located above the level of the vestibular nuclei.SignificanceThis study adds to the knowledge of anatomical brainstem representation of VEMP.     

Cardiovascular and respiratory consequences of bilateral involvement of the medullary intermediate reticular formation in syringobulbia

We studied five patients with clinical and radiological evidence of syringobulbia (SB) to determine whether the distribution of lesions in relationship to the cardiorespiratory control networks in the medullary intermediate reticular zone (IRt) correlates with the presence of abnormalities in autonomic cardiovascular and respiratory control in these patients. All patients underwent high resolution MRI to characterize the size, volume and distribution of the SB lesions, cardiovascular autonomic function testing and polysomnography. One patient with bilateral IRt involvement at both the rostral and caudal medulla had orthostatic hypotension (OH), absent HR_DB, abnormal Valsalva ratio, exaggerated fall of BP during phase II and absent phase IV during VM, and a dramatic fall of BP during head up tilt; this patient also had severe obstructive sleep apnea (OSA) and exhibited BP drops during each respiratory effort. A second patient, with bilateral IRt involvement restricted to the caudal medulla, had less severe cardiovascular autonomic dysfunction but also exhibited severe OSA. The other three patients had small SB cavities sparing the IRt and had sleep apnea but no autonomic dysfunction. Autonomic dysfunction could not be related to the size of the syrinx or the degree of atrophy in the cervical spinal cord in any of the five patients. Bilateral involvement of the IRt by SB produces cardiovascular autonomic failure and sleep apnea. In patients with more restricted lesions, autonomic and respiratory dysfunction may be dissociated. Clinico-radiological correlations using high resolution MRI assessment of medullary lesions can provide insight into the central organization of cardiovascular and respiratory control in humans. Received: 6 August 2002, Accepted: 26 September 2002 Correspondence to Dr. Martín Nogués     

Blink reflex in meningomyelocele,with special reference to its usefulness in the evaluation of brainstem dysfunction

The electrically elicited blink reflex (BR) was studied in 30 patients with meningomyelocele (MMC), including 21 with Chiari type II malformation. The relationship between the BR and brainstem auditory evoked potentials (BAEPs) is discussed with regard to its use-fulness in the evaluation of MMC's brainstem dysfunction. The following results were obtained: (1) The R₂ component was abnormal in 90% of these patients. The BR disclosed subclinical lesions in the medulla oblongata which were not detected by BAEPs alone. (2) In all patients in whom the BAEPs suggested the presence of stretched cochlear nerves, the BR indicated the existence of some dysfunction of the medulla oblongata. (3) No close relationship was found between the dysfunction detected by the BR and the degree of hindbrain anomaly on the neuroimaging. (4) Combining results from assessment of the measurement of the BR and BAEPs permits evaluation of the function of the fifth, seventh, and eighth cranial nerves, as well as the brainstem including the medulla oblongata, which is more comprehensive than evaluation by neuroimaging alone.Presented at the XXI Annual Metting of the International Society for Pediatric Neurosurgery, Phoenix, Ariz., 1993     

Diffusion tensor imaging findings of the brainstem in subjects with tonsillar ectopia

We aimed to evaluate the differences between apparent diffusion coefficient (ADC), fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) values obtained from different cranial sites in subjects with Chiari I Malformation (CM-I) and borderline tonsillar ectopia (BTE), and to determine correlations between diffusion tensor imaging (DTI) metrics and the severity of tonsillar ectopia. A total of 73 subjects with CM-I and BTE and 35 control underwent MRI and DTI. In our study, ADC values measured from the level of medulla oblongata and the RD values measured in middle cerebellar peduncles, thalamus, and globus pallidus were higher in CM-I patients than in controls. FA values at the medulla oblongata level and AD values at the medulla oblongata and pons level higher in patients with CM-I. ADC and AD values measured at the pons level were higher in BTE subjects than in controls. Compared with BTE, the CM-I subjects’ ADC values at the medulla oblongata and AD values at the pons level were higher. In addition, FAs at the pons and medulla oblongata level were higher. At the medulla oblongata level, a positive correlation was observed between ADC and the size of tonsillar ectopia. AD and FA values measured at the level of medulla oblongata and pons were positively correlated with the size of tonsillar ectopia. These findings may be related to the severity of microstructural changes involving neuronal tracts at the brainstem level due to tonsillar ectopia. DTI may be useful in determining the extent of microstructural changes at the tissue level in subjects with tonsillar ectopia.     

The correlation between dysphagia and involvement of the ambiguous nucleus on MRI in acute-phase lateral medullary syndrome]

In this study, the clinical features and MRI findings of 21 patients admitted for acute lateral medullary syndrome, including 10 patients with dysphagia, were examined. According to Cytoarchitecture of the Human Brain Stem (Olszewski, J & Baxter, D), MRI-identified lesions were classified into four groups based on their location (upper, middle-upper, middle-lower, and lower parts of the medulla oblongata). We also examined whether each lesion involved the ambiguous nucleus (AN). We then studied the correlation between dysphagia and involvement of the AN. Ten patients had dysphagia, which improved very quickly in all but one. In the horizontal plane, lesions of all patients with dysphagia exhibited AN involvement, suggesting that dysphagia is strongly correlated with AN involvement. Among the 8 patients with lesions in the upper part of the medulla oblongata, the lesions of 7 patients included the AN, and 6 of those 7 patients had dysphagia. Among the 5 patients with lesions in the middle-upper part of the medulla oblongata, the lesions of two contained the AN, and one of those two patients had dysphagia. Among the 6 patients with lesions in the middle-lower part of the medulla oblongata, all lesions contained the AN, but only 3 of the patients exhibited dysphagia. In both patients who had lesions in the lower part of the medulla oblongata, the lesions did not include the AN and neither patient had dysphagia. Patients who had lesions involving the AN in the rostral part of the medulla oblongata were more likely to have dysphagia than the other patients. On the other hand, half of the patients with lesions involving the AN in the middle-lower part of the medulla oblongata did not have dysphagia. This might suggest that the caudal part of the AN has little involvement in the mechanisms of dysphagia.     

Blink reflex in patients with an ischaemic lesion of the brain-stem verified by MRI

The electrically elicited blink reflex was investigated in 25 patients with ischaemic lesions of the pons or the medulla oblongata. Only patients with a lesion on MRI appropriate to the clinical syndrome were included. Twenty patients had an infarction of the pons, bilateral in 5. Additional 5 patients had an infarction of the dorsolateral medulla oblongata. Patients with hemispheric lesions were excluded. Four of the 5 patients with Wallenberg's syndrome showed delayed R2 components to stimulation ipsilateral to the lesion. Additional loss of the ipsilateral R1 component was observed in 1 patient. Fifteen of the 20 patients with pontine infarctions had pathological blink reflexes. All 6 patients with a unilateral pons lesion and an abnormality of R1 had this abnormality on the side contralateral to the lesion. In 3 cases with bilateral pontine infarction R1 was abnormal on one side or on either side. Of 11 patients with a normal R1, 6 had isolated abnormalities of R2 without consistent correlation to the side of the lesion. We conclude that abnormalities of the blink reflex are of minor localizing value in pontine infarction. This may be explained by the fact that a pontine infarction affects either the reflex arch itself or descending pathways that have a modulating influence on the reflex arch. Infarctions of the medulla oblongata, however, have characteristic abnormalities that have already been described.     

脑干梗塞急性期弥散MRI的探讨

目的:弥散加权MRI(DW1)因能够在早期、快速、敏感地反映出脑部缺血性病变而成为脑梗塞患者急性期诊断不可缺少的重要的检查方法,但是对于某些部位的某些小的病灶在急性期DW1有时亦不能查出。本研究以脑干梗塞的患者为对象,对急性期DW1的敏感度进一步探讨。方法:以发病24小时以内施行DWI检查的28例患者作为对象;DWI是在1.5Tesl的MR装置下,采用断层回波成像的,与此同时,还进行了T2加权MRI及水抑制成像FLAIR(fluidattenuated inversion recovery)的检查,最终梗塞灶根据平均127小时后的以上所述的MRI检查中的所见及临床症状来综合判断的,只把明确的高信号区域判断为病灶。结果:最终梗塞灶为中脑2例,桥脑9例,延髓17例。通过第一次DWI,检查出病灶的16例(敏感度57.1％),没有明确检查出病灶的12例,其中在这12例患者中有11例是在以后的MRI检查中发现为延髓病变,有1例确认为桥脑病变。从发病开始到施行DWI检查为止,时间越短,病变越不容易查出。结论:应该注意在急性期的DWI中即使没有明确的病灶,也不能否认脑干梗塞,特别是延髓梗塞。     

Isolated cranial nerve palsies in multiple sclerosis

During a 10 year period 24 patients with definite multiplesclerosis with isolated cranial nerve palsies were studied (third andfourth nerve: one patient each, sixth nerve: 12 patients, seventhnerve: three patients, eighth nerve: seven patients), in whom cranialnerve palsies were the presenting sign in 14 and the only clinical signof an exacerbation in 10 patients. MRI was carried out in 20 patientsand substantiated corresponding brainstem lesions in seven patients(third nerve: one patient, sixth nerve: four patients, eighth nerve:two patients). Additional abnormal findings of electro-oculography, ormasseter reflex, or blink reflex, or combinations of these were foundin 20 patients and interpreted in favour of a brainstem lesion at thelevel of the respective cranial nerve. In 11 of 14 patients withisolated cranial nerve palsies as the presenting sign of multiplesclerosis, dissemination in space was documented by MRI, and in theremaining three by evoked potentials. In patients with multiplesclerosis with isolated cranial nerve palsies, MRI is the mostsensitive method of documenting dissemination in space andelectrophysiological testing the most sensitive at disclosing brainstem lesions.

     

主要累及全脊髓和脑干的CLIPPERS一例

目的探讨类固醇激素反应性慢性淋巴细胞性炎性反应伴脑桥血管周围强化症(CLIPPERS)的临床表现、影像学及病理改变,探讨其可能的发病机制。方法对1例主要累及全脊髓及脑干的CLIPPERS患者临床资料及影像学进行分析,并结合文献复习此病的特征表现及鉴别诊断。结果本例男性29岁,进行性双下肢无力、共济失调2年、及伴腹部麻木1年余。头颅磁共振(MRI)增强扫描示脑干、全脊髓多发小斑片状异常强化信号,边界较清楚,呈"胡椒粉征"。病变分布较均匀,延髓及脊髓分布更密集。另外双侧丘脑、基底核、小脑半球见散在类似异常强化灶。软脑膜及软脊膜也可见多处轻度线样强化。经糖皮质激素治疗2个月后,患者临床症状明显减轻。复查MRI示上述异常强化灶大部分消失,残存病灶缩小且强化程度减轻,边界变模糊。影像学提示病变明显好转。结论在有些CLIPPERS患者,MRI的强化灶主要累及脑干、脊髓全长及软脑(脊)膜,不一定以脑桥为中心。CLIPPERS糖皮质激素治疗效果好。CLIPPERS的诊断应结合临床、影像学及实验室检查,必要时行脑组织活检。     

Fractional anisotropy of the corticospinal tract in normal adults Preliminary study using a diffusion tensor imaging technique

BACKGROUND: The corticospinal tract is an important tract for conducting motor function. The majority of studies focus on lesions of the corticospinal tract on appearance and function, whereas observation of normal corticospinal pathways can also improve understanding of lesion outcomes. OBJECTIVE: To observe the normal adult corticospinal tract using a diffusion tensor imaging technique to analyze fractional anisotropy (FA) in different levels of the brain. DESIGN, TIME AND SETTING: Neuroimaging observation was performed in the MRI Department, First Affiliated Hospital of Kunming Medical College in China, from October 2005 to October 2008. PARTICIPANTS: A total of 30 healthy adults were selected from the Department of MRI, First Affiliated Hospital of Kunming Medical College in China, from October 2005 to October 2008, and people with nervous system symptoms and signs were excluded. METHODS: Participants with normal conventional MRI results underwent diffusion tensor imaging examination in a 1.5 T GE MRI (slice thickness 4-5 mm, slice gap 0) for gradient data acquisition from 15 directions. The scanning involved the entire brain from the inferior medulla oblongata to the inferior cranial plate. Imaging post-processing was performed to obtain FA values; a paired Mest was applied for statistical analysis.MAIN OUTCOME MEASURES: FA values of the bilateral corticospinal tract in the medulla oblongata, pons, cerebral peduncle, basal ganglia, corona radiata, and centrum semiovale. RESULTS: FA values in the medulla oblongata and centrum semiovale were similar (P> 0.01). FA values of left corticospinal tract were significantly greater than the right side in the pons, cerebral peduncle, basal ganglia and corona radiata (P< 0.01). CONCLUSION: FA values vary by brain levels, including pons, cerebral peduncle, basal ganglia, and corona radiata. Moreover, FA values of the left corticospinal tract pathway were greater than the right side, which may relate to right handedness.     

Breathing control in neurological diseases

Control of ventilation depends on a brainstem neuronal network that controls activity of the motor neurons innervating the respiratory muscles. This network includes the pontine respiratory group and the dorsal and ventral respiratory groups in the medulla, which contain neurons that fire primarily during inspiration, post-inspiration, or expiration. The ventral respiratory group includes the pre-B?tzinger complex, which contains neurokinin-1 receptor immunoreactive neurons critical for respiratory rhythmogenesis. Structural and degenerative disorders affecting this network produce abnormalities of respiration, including sleep apnea and various patterns of dysrhythmic breathing, not infrequently associated with disturbances of cardiovagal and sympathetic vasomotor control. This emphasizes the important interactions between the respiratory and cardiovascular control networks in the medulla. Common disorders associated with impaired cardiorespiratory control include brainstem stroke or compression, syringobulbia, Chiari malformation, high cervical spinal cord injuries, and multiple system atrophy. This review focuses on the functional organization of the respiratory control network and common causes of impaired control of respiration. Received: 23 April 2002, Accepted: 5 September 2002 Correspondence to Dr. Martín A. Nogués     

Dysphagia-gastroesophageal reflux complex: complications due to dysfunction of solitary tract nucleus-mediated vago-vagal reflex

We report on the complication of gastroesophageal reflux (GER) in four patients with lower brainstem dysfunction. These patients suffered from perinatal asphyxia, cerebellar hemorrhage, or congenital dysphagia of unknown origin and showed facial nerve palsy, inspiratory stridor due to vocal cord paralysis, central sleep apnea, and dysphagia, in various combinations. Naso-intestinal tube feeding was introduced in all of the patients due to recurrent vomiting and aspiration pneumonia resulting from GER. T2-weighted magnetic resonance (MR) imaging revealed symmetrical high intensity lesions in the tegmentum of the lower pons and the medulla oblongata in two of the patients, and pontomedullary atrophy in another patient. In normal subjects, lower esophageal sphincter contraction is provoked by distension of the gastric wall, through a vago-vagal reflex. Since this reflex arc involves the solitary tract nucleus, where the swallowing center is located, the association of dysphagia and GER in the present patients is thought to result from the lesions in the tegmentum of medulla oblongata. We propose the term "dysphagia-GER complex" to describe the disturbed motility of the upper digestive tract due to lower brainstem involvement. In children with brainstem lesions, neurological assessment of GER is warranted, in addition to the examination of other signs of brainstem dysfunction, including dysphagia and respiratory disturbance.     

An autopsied case of medullary glioma with an abrupt onset of headache and hemiparesis]

We describe an 89-year-old woman who presented with an abrupt onset of headache and right hemiparesis. With the initial diagnosis of cerebral infarction, we started therapy using sodium ozagrel. The right hemiparesis worsened, however, and a continuous intravenous heparin injection showed no effect. Furthermore, nystagmus in the bilateral eyes, dysphagia, left hemiparesis, and central ventilation disorder appeared one after another in three weeks. A magnetic resonance images (MRI) of the head, performed on the fifth hospital day with regular intervals of axial sections, disclosed no lesion responsible for right hemiparesis. MRI of the brainstem and upper cervical cord, performed after two weeks with smaller intervals of axial sections, revealed a T2 high signal lesion in the left side of the medulla oblongata and upper cervical cord. After about five weeks from the onset of the disease, she died of pneumonia. With the pathological examination, we diagnosed as glioma originated in the left ventral part of medulla oblongata. Five similar cases of brainstem glioma have been reported so far. Our patient, the oldest one, showed an exceptionally rapid clinical course, instructing us to consider the possibility of medullary glioma even in the elderly patients presenting with acute onset hemiparesis followed by rapid and progressive appearance of brainstem signs.     

A case of medial medullary syndrome detected by diffusion-weighted magnetic resonance imaging]

We report an 84-year-old woman with medial medullary syndrome diagnosed by diffusion-weighted magnetic resonance imaging (MRI). She was admitted because of left hemiparesis and hypesthesia. T2-weighted and diffusion-weighted MRI showed a high signal lesion at the right medial medulla oblongata 10 days after the onset. It is well known that diffusion-weighted MRI is useful for detecting supratentrial cerebral ischemic lesions in the extremely acute stage. However, to our knowledge, there have been only a few reports of diffusion-weighted MRI in patients with ischemic stroke of the medulla oblongata. Normal nerve fibers in the direction perpendicular to the motion-probing gradient (MPG) shows a high signal by diffusion-weighted MRI (anisotropy of apparent diffusion cofficient [ADC]). Normal nerve fibers in the pyramidal tract of medulla oblongata also shows a high signal when the MPG pulse is applied in the x and y directions. We solved this problem by using isotropic diffusion-weighted imaging and were able to detect ischemic lesion of medial medullary infarction in the acute phase.     

脑干海绵状血管瘤影像学

目的：结合临床表现特点，对４８例有组织学结果的脑干海绵状血管瘤的影像学表现进行分析。方法：４８例依发作方式分为两种类型。一类表现为突然发作的颅神经及传导束症状，部分为反复类似发作；另一种为静止性发作。所有病人均进行了ＣＴ及ＭＲＩ检查。并通过手术得到病理证实。结果：所有病例ＣＴ及ＭＲＩ均表现出海绵状血管瘤的特点。在非增强ＣＴ扫描表现为等或稍高密度，在增强ＣＴ扫描，病灶表现为轻至中度强化，水肿及占位效应均不明显。ＭＲＩ扫描表现为高信号或混杂信号，代表不同时相的出血及胶质样变。部分病例可见典型的桑椹样或网络样结构。除１８例病灶位于延髓或中脑外，大多病灶位于桥脑。３例在梯度回波扫描可见多发病灶。有１例组织学可见海绵状血管瘤的血管腔内存在弹性纤维；４例可见引流静脉及供血动脉。结论：桥脑是脑干海绵状血管瘤最常见部位；影像学特别是ＭＲＩ表现与病程及病变构成有关；部分组织病理学具有与其它血管畸形重叠的特点。手术彻底切除病灶对防止复发非常重要。     

延髓占位性病变的手术治疗对呼吸功能的影响(附68例临床总结)

目的　总结６８ 例延髓占位性病变手术治疗后呼吸功能障碍的发生与处理经验。方法　对６８ 例延髓占位性病变进行了显微手术治疗, 术中采用了保留自主呼吸的麻醉方法, 应用 Ｌ Ｅ Ｏ Ｎ Ａ Ｒ Ｄ Ｏ 呼吸监测系统持续观察呼吸变化。对不同性质、不同部位的肿瘤术中术后呼吸功能的变化进行对比分析。结果　７ 例良性肿瘤在术后３ 天内表现出轻微的中枢性低通气, 但预后良好。１２ 例有明显边界的恶性胶质瘤（ 星形细胞瘤, 室管膜瘤） 在术后表现出明显的中枢性低通气和吞咽困难,在术后４８ 小时内行气管切开术, 予间断呼吸机辅助通气, 预后良好。结论　良性或有明显边界的恶性肿瘤, 术后早期可有低通气, 但呼吸功能恢复较好; 对位于延髓闩部的恶性胶质瘤, 术后可发生呼吸功能障碍, 手术治疗应慎重