神经白塞病的MRI价值探讨

目的通过对神经白塞病(Neuro-Behcet's disease NBD)磁共振(magnetic resonance image,MRI)的影像学表现分析,以提高对神经白塞病MRI诊断的认识。方法回顾性分析经临床证实的6例神经白塞病MRI表现,评估病灶的分布及形态学特点,分析总结不同序列MRI的信号特征。结果 6例患者均为实质型中枢神经系统损害,其中单纯脑干损害1例,混合型损害5例。6例脑干损害表现为长条形或不规则形,包括中脑大脑脚、桥脑、和延髓病变;5例为类圆形基底节区损害;2例颈髓损害为长条形。6例行头颅MRI检查,均显示颅内散在T2WI稍高信号,T1WI等或低信号影,FLAIR呈高信号,DWI(b值为1000s/mm2)显示为稍高信号,ADC图信号轻度升高且ADC值病灶处较对侧增高。3例行增强扫描均出现环形强化。2例颈髓MRI分别显示颈4、5水平颈髓长条形T2稍高信号影。1例行磁共振波谱(Magnetic resonance spectroscopy,MRS)检查显示病灶处各代谢产物的峰值均正常。结论 MRI检查对于神经白塞病的诊断非常敏感,且不同序列均具有其特征性的改变。     

Imaging findings in diffuse axonal injury after closed head trauma

Even in patients with closed head trauma, brain parenchyma can be severely injured due to disruption of axonal fibers by shearing forces during acceleration, deceleration, and rotation of the head. In this article we review the spectrum of imaging findings in patients with diffuse axonal injuries (DAI) after closed head trauma. Knowledge of the location and imaging characteristics of DAI is important to radiologists for detection and diagnosis. Common locations of DAI include: cerebral hemispheric gray-white matter interface and subcortical white matter, body and splenium of corpus callosum, basal ganglia, dorsolateral aspect of brainstem, and cerebellum. In the acute phase, CT may show punctate hemorrhages. The true extent of brain involvement is better appreciated with MR imaging, because both hemorrhagic and non-hemorrhagic lesions (gliotic scars) can be detected. The MR appearance of DAI lesions depends on several factors, including age of injury, presence of hemorrhage or blood-breakdown products (e. g., hemosiderin), and type of sequence used. Technical aspects in MR imaging of these patients are discussed. Non-hemorrhagic lesions can be detected with fluid attenuated inversion recovery (FLAIR), proton-density-, or T2-weighted images, whereas gradient echo sequences with long TE increase the visibility of old hemorrhagic lesions. Received 17 September 1997; Revision received 2 December 1997; Accepted 15 December 1997     

Serial MR observation of cortical laminar necrosis caused by brain infarction

To examine the chronological changes characteristic of cortical laminar necrosis caused by brain infarction, 16 patients were repeatedly examined using T1-, T2-weighted spin-echo, T2^*-weighted gradient echo, fluid attenuated inversion recovery (FLAIR) images, and contrast enhanced T1-weighted images at 1.0 or 1.5 T. High intensity cortical lesions were visible on the T1-weighted images from 2 weeks after ictus and became prominent at 1 to 3 months, then became less apparent, but occasionally remained at high intensity for 2 years. High intensity cortical lesions on FLAIR images became prominent from 1 month, and then became less prominent from 1 year, but occasionally remained at high intensity for 2 years. Subcortical lesions did not display high intensity on T1-weighted images at any stage. On FLAIR images, subcortical lesions initially showed slightly high intensity and then low intensity from 6 months due to encephalomalacia. Cortical lesions showed prominent contrast enhancement from 2 weeks to 3 months, but subcortical lesions were prominent from 2 weeks only up to 1 month. T2*-weighted images disclosed haemosiderin in 3 of 7 patients, but there was no correlation with cortical short T1 lesions. Cortical laminar necrosis showed characteristic chronological signal changes on T1-weighted images and FLAIR images. Cortical short T1 lesions were found not to be caused by haemorrhagic infarction. Received: 27 March 1998 Accepted: 23 July 1998     

磁共振DWI、FLAIR序列和MRA在急性缺血性脑中风的临床应用

目的:探讨磁共振扩散加权成像(DWI)、FLAIR序列和磁共振血管成像(MRA)对急性缺血性脑中风的诊断价值。方法:选择97例急性脑中风患者,其中超急性期23例,急性期74例。全部患者均行脑MRI常规T1WI、T2WI序列、FLAIR序列、DWI和3D TOF MRA检查。结果:97例超急性及急性期脑中风的DWI阳性检出率为100%,FLAIR序列和3D TOFMRA的阳性检出率分别为75.3%和52.6%,常规T1WI、T2WI序列的阳性检出率分别为20.6%和34.0%。结论:对于早期脑梗死病灶,DWI比FLAIR序列敏感性高,更易于发现病灶,FLAIR序列对于脑白质变性以及脑室、脑池、脑沟周围病变观察满意,MRA在分析脑中风病因方面可提供更多的影像学信息,DWI、FLAIR序列和MRA是对常规序列的重要补充,值得临床推广应用。     

MRI findings in 6 cases of children by inadvertent ingestion of diphenoxylate-atropine

Purpose

Compound diphenoxylate (diphenoxylate-atropine) poisoning can cause toxic encephalopathy in children, and magnetic resonance imaging (MRI) of the brain in this condition has not been reported. This study is to analyze brain MRI findings and to investigate the relations between MRI features and possible pathophysiological changes in children.

Methods

Six children accidentally swallowed compound diphenoxylate, 4 males, 2 females, aged 20-46 months, average 33 months. Quantity of ingested diphenoxylate-atropine was from 6 to 30 tablets, each tablet contains diphenoxylate 2.5 mg and atropine 0.025 mg. These patients were referred to our hospital within 24 h after diphenoxylate-atropine ingestion, and underwent brain MRI scan within 24-72 h after emergency treatment. The characteristics of conventional MRI were analyzed.

Results

These pediatric patients had various symptoms of opioid intoxication and atropine toxicity. Brain MRI showed abnormal low signal intensity on T1-weighted images (T1WI) and abnormal high signal intensity on T2-weighted images (T2WI) and fluid-attenuated inversion recovery (FLAIR) imaging in bilateral in all cases; abnormal high signal intensity on T1WI, T2WI and FLAIR in 4 cases. Encephalomalacia was observed in 3 cases during follow-up.

Conclusion

In the early stage of compound diphenoxylate poisoning in children, multiple extensive edema-necrosis and hemorrhagic-necrosis focus were observed in basic nucleus, pallium and cerebellum, these resulted in the corresponding brain dysfunction with encephalomalacia. MRI scan in the early stage in this condition may provide evidences of brain impairment, and is beneficial for the early diagnosis, treatment and prognosis assessment.     

FLAIR序列与TSE序列在颅脑病变中的应用

目的：通过头颅快速液体衰减翻转恢复序列与快速自旋回波序列应用研究,了解其各自的特点及临床价值。材料与方法：６５例颅内病变均用两种序列检查。快速ＦＬＡＩＲ设置以脑脊液信号低于脑组织为准,即ＴＲ／ＴＩ／ＴＥ：９０００／２５００／１１０ｍｓ。快速ＳＥ：Ｔ１Ｗ：６５０／１４ｍｓ,Ｔ２Ｗ：５２１７／１１０ｍｓ。结果：快速ＦＬＡＩＲ检出病变１３０６个,敏感率９８％,快速ＳＥ检出１１６４个,敏感率８８％（Ｐ〈０     

Temporal lobe focal cortical dysplasia: MRI imaging using FLAIR shows lesions consistent with neoplasia

Focal cortical dysplasia (FCD), a form of neuronal migration disorder, is a malformative lesion of the neocortex that occurs during development of the brain. It can cause partial and generalized epilepsy. Seizures occur at an early age and are often resistant to medication. Surgical resection has been found to be beneficial in these patients. Dual pathology, in the form of mesial temporal sclerosis, has been associated with FCD. At the Children’s Hospital of Eastern Ontario, four patients with temporal lobe FCD have re-cently, been identified. This paper discusses how these children presented and how they were managed, with particular emphasis on their MRI findings and differential diagnoses. In three of the four patients neuroimaging studies showed lesions consistent with a neoplastic process because of the large volume and mass effect. Radiologically, FCD may mimic the MRI appearance of tumors, such as dysembryoplastic neuroepithelial tumors, primitive neuroectodermal tumors, gangliogliomas, oligodendrogliomas, and astrocytomas. These lesions are best visualized on fluid-attenuated inversion recovery (FLAIR) imaging, a technique that has recently become applicable in the clinical setting, as we help demonstrate in this series. With better MRI capability, milder forms of FCD and microdysplasia may be distinguished. Received: 7 September 1999     

Arterial spin labeling hyperperfusion in Rasmussen's encephalitis: Is it due to focal brain inflammation or a postictal phenomenon?

Background and purpose

The study evaluated the utility of arterial spin labeling (ASL) perfusion imaging in Rasmussen's encephalitis (RE).