乙型脑炎脑电图特征及其与CT、MRI和预后的关系

 目的 探讨脑电图(electroencephalographic,EEG)对乙型脑炎的临床诊断价值。方法 收集62例确诊为乙型脑炎患者的EEG、CT和MRI检查结果,分别于入院后1个月、3个月进行随访,分析EEG特征及其与影像学、预后的关系。结果 62例EEG检查异常率为100%,发现2种类型的异常表现:弥散持续性δ波、棘波或尖波的癫样波。EEG与MRI、CT异常检出率比较,差异均有统计学意义(χ²=5.37,P=0.02;χ²=23.15,P<0.01)。62例中8例死于乙型脑炎急性期,10例失访。EEG异常类型与预后无相关性(P=0.75)。结论 乙型脑炎EEG与预后没有关联性,但作为一种辅助检查,在乙型脑炎的早期发现和提供诊断依据等方面有着重要的作用。     

Hyperacute infarction: a comparison of CT and MRI, including diffusion-weighted imaging

We compared CT and MRI obtained within the first 3 h of onset of a cerebral infarct. Echo-planar diffusion-weighted MRI delineated the infarcted areas most clearly, and subtle low-density areas on CT were consistent with those shown to be abnormal by diffusion-weighted MR. The signal changes of affected areas on fast spin-echo proton-density, T2-weighted and fast FLAIR images were subtler than the low density on CT. Received: 6 April 1998 Accepted: 29 June 1998     

粘多糖贮积症的颅脑CT及MRI表现

目的:探讨粘多糖贮积症的颅脑CT及MRI表现特征.方法:对经临床和实验室检查确诊为粘多糖贮积症的6例患者行颅脑CT及MRI扫描,分析其影像学表现.6例患者均行CT平扫,其中2例行CT增强扫描;6例患者中4例行MRI检查,其中1例行增强扫描.结果:CT平扫6例中4例显示两侧大脑半球白质内散在低密度灶,增强后病灶未见强化;1例仅见脑室扩大,1例未见异常.MRI检查4例中2例显示脑实质多发小囊状信号由脑室边缘向各脑叶呈放射状分布,脑白质病变呈斑片状长T1、长T2信号,增强后所有脑内病灶均未见强化;1例脑室扩大,白质减少;1例仅显示脑白质信号异常.MRI还显示3例齿状突发育不良伴周围软组织增厚,2例颅颈结合区硬脑脊膜增厚伴椎管狭窄.本组1例行脑组织活检,电镜显示神经元内有空泡状包涵体及斑马体.结论:粘多糖贮积症的颅脑CT及MRI表现有一定特征,可在一定程度上为临床诊断、估计病损程度、监察病变进程及选择治疗方案提供依据.     

Single-photon emission CT findings in acute Japanese encephalitis.

PURPOSETo determine the usefulness of single-photon emission CT (SPECT) in the diagnosis of acute Japanese encephalitis (JE).METHODSWe examined 10 patients (six men and four women; mean age, 69 years) with viral encephalitis. We divided the cases into two groups: the JE group (n = 4) and the non-JE group (n = 6; two with herpes simplex encephalitis and four with encephalitis of unknown origin). All cases were investigated with 99mTc-hexamethylpropyleneamine oxime (HMPAO) SPECT within 15 days after the onset of symptoms. Two patients in the JE group were also examinated by SPECT at a later stage. In all cases MR imaging was performed after the SPECT study.RESULTSIn the acute stage, all patients in the JE group showed a marked increase of HMPAO uptake that matched the hyperintense area observed on MR images in the thalami and putamina bilaterally. Follow-up SPECT studies of two patients with JE revealed a decrease of HMPAO deposition in the areas of high uptake. None of the patients in the non-JE group had an increased accumulation of HMPAO in the thalami or the putamina.CONCLUSIONSSPECT is helpful in differentiating JE from herpes simplex encephalitis and other types of encephalitis. SPECT may be useful as a diagnostic tool in the early stages of JE.     

Diffusion-weighted MRI and selection of patients for fibrinolytic therapy of acute cerebral ischaemia

Treatment of patients with acute cerebral ischaemic events remains controversial. We investigated the reversibility of high signal intensity on diffusion-weighted (DW) MRI after acute local intra-arterial fibrinolysis (LIF) and the feasibility of DW MRI for selecting patients for acute LIF. Nine patients with acute middle cerebral artery embolic occlusion underwent single-photon emission computed tomography (SPECT) and DW MRI followed by acute LIF using tissue plasminogen activator. Recanalisation was observed in all patients, and eight improved clinically. The area of high signal intensity on pretreatment DW MRI was smaller than the low-uptake area on SPECT in all patients, and went on to infarction, as detected by MRI or CT 3 days after onset in all patients. It appears to correlate, at least clinically, with irreversible brain damage. Therefore, acute LIF should not be performed in patients with areas of high signal intensity in the cortex responsible for the symptoms. SPECT remains important, because areas normal on DW MRI with low uptake on SPECT often contribute to functional prognosis. Received: 23 March 1999/Accepted: 30 August 1999     

Serial diffusion-weighted MRI of Creutzfeldt-Jakob disease

OBJECTIVE: The objective of our study was to evaluate the clinical usefulness of MRI findings, including diffusion-weighted imaging, in relation to the clinical signs and symptoms of Creutzfeldt-Jakob disease (CJD). MATERIALS AND METHODS: We reviewed nine cases of CJD in which MRI was performed from the early to terminal phase of the disease. MRI findings were correlated before (early phase) and after (intermediate phase) the onset of the characteristic clinical findings of myoclonus and periodic synchronous discharges on electroencephalograms. The chronologic changes in imaging findings were followed from the akinetic mutism to the terminal phase of the disease (terminal phase). T2-weighted images had been obtained in all the patients, and diffusion-weighted images and FLAIR images had been obtained in six patients. We evaluated the images for the presence and location of abnormal signal intensities. RESULTS: During the early phase, the T2-weighted images showed no abnormal findings. The diffusion-weighted images, however, revealed abnormal high signal intensities in the cortex in all patients and in the basal ganglia in five patients. In two cases, there were abnormal signals on FLAIR images that corresponded to diffusion-weighted imaging abnormalities. During the intermediate phase, the area of the high signal intensities on the diffusion-weighted images had expanded and progressive cerebral atrophy had become apparent. During the terminal phase, abnormal high signal intensities in the cerebral cortex and basal ganglia on the diffusion-weighted images in one patient disappeared. CONCLUSION: Diffusion-weighted imaging is extremely useful in detecting CJD during the very early phase-even before the onset of characteristic clinical findings.     

鼻腔原发性恶性黑色素瘤的影像学表现及鉴别诊断

目的:探讨鼻腔原发性恶性黑色素瘤的影像学表现及鉴别诊断.方法:回顾性分析经病理证实的9例鼻腔原发性恶性黑色素瘤的影像学表现.结果:9例患者主要CT表现为单侧(8例)或双侧(1例)鼻腔内密度均匀、形态不规则的软组织肿块,无钙化,8例(8/9)伴邻近结构的侵犯,2例增强后肿瘤不均匀明显强化,MRI表现:1例表现为典型的T1...     

CT perfusion parameter values in regions of diffusion abnormalities

BACKGROUND AND PURPOSE: Dynamic CT perfusion imaging is a rapid and widely available method for assessing cerebral hemodynamics in the setting of ischemia. Nevertheless, little is known about perfusion parameters within regions of diffusion abnormality. Since MR diffusion-weighted (DW) imaging is widely considered the most sensitive and specific technique to examine the ischemic core, new knowledge about CT perfusion findings in areas of abnormal diffusion would likely provide valuable information. The purpose of our study was to measure the CT-derived perfusion values within acute ischemic lesions characterized by 1) increased signal intensity on DW images and 2) decreased apparent diffusion coefficient (ADC) and compare these values with those measured in contralateral, normal brain tissue. METHODS: Analysis was performed in 10 patients with acute middle cerebral artery territory stroke of symptom onset less than 8 hours before imaging who had undergone both CT perfusion and DW imaging within 2 hours. After registration of CT perfusion and DW images, measurements were made on a pixel-by-pixel basis in regions of abnormal hyperintensity on DW images and in areas of decreased ADC. RESULTS: Significant decreases in cerebral blood flow and cerebral blood volume with elevated mean transit times were observed in regions of infarct as defined by increased signal intensity on DW images and decreased ADC. Comparison of perfusion parameters in regions of core infarct differed significantly from those measured in contralateral normal brain. CONCLUSION: CT perfusion findings of decreased cerebral blood flow, mean transit time, and cerebrovascular volume correlate with areas of abnormal hyperintensity on DW images and regions of decreased ADC. These findings provide important information about perfusion changes in acute ischemia in areas of diffusion abnormality.     

急性化脓性骨髓炎的MRI表现

目的：研究MRI在诊断急性化脓性骨髓炎早期病变的价值。方法：12例经临床证实的下肢骨急性骨髓炎患者分别于发病后2-14d在Philips0.5T超导型MR扫描仪下行横轴面、矢状面和冠状面扫描。结果：12例中11例骨髓内呈现异常MR信号，1例发病仅2d者骨髓内无异常信号。病变随时间的推移与正常骨髓间分界逐渐清晰，在T1WI骨髓内病变呈斑片状稍长T1、长T1低信号，在T2WI上病变呈斑片状长T2高信号，在短时反转恢复（STIR）序列上这种信号改变尤其明显。结论：MRI诊断急性化脓性骨髓炎优于其他影像学检查。     

MRI对椎体骨折的诊断价值

目的:探讨MRI对椎体压缩性(陈旧与新鲜)和隐匿性骨折的诊断价值。方法:对34例椎体骨折于初诊及伤后3,6,12个月行脊柱MRI检查,分析其信号改变与临床的关系。结果:37个骨折椎体急性期均表现为T1WI低信号、T2WI高信号,伤后3和6个月时分别有7个(18.9%)和22个骨折椎体(59.5%)恢复正常,12个月时全部恢复正常信号。伤后不同时期MRI检查结果相差十分显著。6个椎体陈旧骨折,与正常椎体信号无差别。8个隐匿性骨折椎体形态无异常,MRI T1WI、T2WI示椎体内横行条状低信号,3个月复查50%恢复正常,6个月复查基本恢复正常。结论:MRI能判断骨折修复的不同时期,鉴别椎体陈旧与新鲜骨折,尤其是存在多个椎体变形时则更具诊断价值;MRI检查对隐匿性骨折敏感。     

驱肠虫药相关脑病的MRI和CT研究

目的 描述驱肠虫药相关脑病的MRI和CT表现。方法 回顾性分析20例临床确诊的驱肠虫药相关脑病的影像特征,MRI检查10例,MRI及CT检查6例,CT检查4例;1例行脑穿刺活检。结果 MRT1WI病变呈低信号,T2WI呈高信号,6例增强扫描5例无强化,其表现可分4种类型：13例病变呈多发斑片状,多位于侧脑室周围中、后方区域白质;1例病变T1WI呈同心圆状改变,病理示神经细胞广泛空泡变性;1例病变呈斑片状螺及双侧海马区皮髓质;另1例T2WI示半球白质信号广泛增高并累及基底节核团。10例CT均示白质区多发斑片状低密度灶,4例增强扫描无强化。所有病变均无占位效应。结论 驱肠虫相关脑病的影像表现类似脱髓鞘病变或散发性脑炎,病理检查未发现脱髓鞘改变。     

MRI and MR angiography of vertebral artery dissection

A review of 4,500 angiograms yielded 11 patients with dissection of the vertebral arteries who had MRI and (in 4 patients) MR angiography (MRA) in the acute phase of stroke. One patient with incidental discovery at arteriography of asymptomatic vertebral artery dissection and two patients with acute strokes with MRI and MRA findings consistent with vertebral artery dissection were included. Dissection occurred after neck trauma or chiropractic manipulation in 4 patients and was spontaneous in 10. Dissection involved the extracranial vertebral artery in 9 patients, the extra-intracranial junction in 1, and the intracranial artery in 4. MRI demonstrated infarcts in the brain stem, cerebellum, thalamus or temporo-occipital regions in 7 patients with extra- or extra-intracranial dissections and a solitary lateral medullary infarct in 4 patients (3 with intracranial and 1 with extra-intracranial dissection). In 2 patients no brain abnormality related to vertebral artery dissection was found and in one MRI did not show subarachnoid haemorrhage revealed by CT. Intramural dissecting haematoma appeared as crescentic or rounded high signal on T1-weighted images in 10 patients examined 3–20 days after the onset of symptoms. The abnormal vessel stood out in the low signal cerebrospinal fluid in intracranial dissections, whereas it was more difficult to detect in extracranial dissections because of the intermediate-to-high signal of the normal perivascular structures and slow flow proximal and distal to the dissection. In two patients examined within 36 h of the onset, mural thickening was of intermediate signal intensity on T1-weighted images and high signal on spin-density and T2-weighted images. MRA showed abrupt stenosis in 2 patients and disappearance of flow signal at and distal to the dissection in 5. Follow-up arteriography, MRI or MRA showed findings consistent with occlusion of the dissected vessel in 6 of 8 patients. Received: 27 February 1996 Accepted: 4 June 1996     

The various MRI patterns of pituitary apoplexy

The aim of this study was to describe the various MRI features, in correlation to surgical and pathological findings, in patients who presented with pituitary apoplexy (PA). Eleven patients presenting with PA, were evaluated with various MR protocols including spin-echo (SE) T1-weighted sequences in 9 of 11 patients, post gadolinium SE T1-weighted sequences in only 8 of 11 patients, and with T2-weighted SE sequences in 2 of 11 patients. All patients had transsphenoidal pituitary surgery after MR studies. The severity of presenting symptoms ranged from headaches to coma. Ten patients had pituitary macroadenoma; one had a non-hemorrhagic metastatic lesion into a non-adenomatous pituitary gland. Of the 11 patients, one was studied at the acute stage of PA (1 day after onset), 9 at the subacute period (3–15 days after onset), and one at the late stage (5 months after onset). Images compatible with intratumoral hemorrhage were found in all macroadenomas, whereas the metastatic pituitary lesion did not show evidence of bleeding. All gadolinium-enhanced studies showed partial tumoral enhancement. The SE T2-weighted studies demonstrated areas of low and high signal intensities in keeping with the presence of blood degradation contents. Pituitary apoplexy present with different MR features, including hemorrhagic and non-hemorrhagic characteristics on T1-weighted images. Gadolinium-enhanced images do not provide complementary diagnostic information when the presence of blood is assessed on plain images. Received: 20 May 1998; Revision received: 11 September 1998; Accepted: 14 September 1998     

Spinal subdural haematoma: a study of three cases.

AIMS: To define the clinical, computed tomography (CT) and magnetic resonance imaging (MRI) features and the role of MRI in the follow-up of spinal subdural haematoma (SSH), and to compare these findings with those of spinal epidural haematomas (SEH). METHODS: We report three cases of SSH (two women, one male, age: 50-74 years). Two patients were on anticoagulant therapy; in the other case the SSH was spontaneous. All the patients were examined 1-3 days after the onset of the symptoms. All of them had CT, two had MRI and one had angiography. Two patients underwent surgery. RESULTS: The haematoma was located in the thoracolumbar region (two) and in the thoracic region (one), extending from five (two) to 11 vertebral body levels (one). The haematomas were posteriorly located with lateral extension. The transverse shape differed with the level: biconvex, biloculated or circumferential. The haematomas were hyperdense on CT. On MRI, SSH yielded high signal on both T1 and T2. The integrity of the posterior fat pads, which was well shown on CT and MRI, and the visualization of the dura mater demonstrated the intradural location of these collections, making them easily distinguishable from spinal epidural haematoma. MRI provides better evaluation of the longitudinal extent. Our results are compared with those reported in the literature. CONCLUSION: MRI is superior to CT for diagnosis and follow-up of SSH. Our findings and those reported in the literature show that the MR features of SSH are quite specific and allow differentiation from SEH.     

Evaluation of 18F-FDG PET in acute ischemic stroke: assessment of hyper accumulation around the lesion

PURPOSE: Although pathophysiology of cerebrovascular disease has been reported previously, few clinical studies of glucose metabolism in acute stroke have been published. Purpose of this study is to evaluate glucose metabolism in acute stroke patients by 18F-FDG PET. SUBJECTS AND METHODS: Twenty-four patients with acute ischemic stroke were involved in this study. All subjects underwent MRI (conventional T1- and T2-weighted images, diffusion-weighted imaging, and MR angiography), CT and 18F-FDG PET. 18F-FDG PET was performed within 1 to 7 days after the first episode. 18F-FDG PET images were visually evaluated as well as MRI and CT images. RESULTS: Four patients out of 24 showed no abnormal 18F-FDG accumulation, while MRI demonstrated abnormal signal area and abnormal vascular findings that suggested acute stroke. Decreased 18F-FDG accumulation corresponding with abnormal signal area on MR images was noted in 20 cases. In 7 cases among these 20 with decreased 18F-FDG, hyper accumulation of 18F-FDG was recognized around the decreased accumulation area. CONCLUSION: Increased 18F-FDG accumulation (increased glucose metabolization) around the lesion may be due to: 1) acceleration of anaerobic glycolysis, 2) activated repair process of damaged brain tissue, i.e., phagocytosis and gliosis, and 3) neuronal excitation by excito-toxic amino acids which can be released after ischemia.     

Importance of MRI in the diagnosis of vertebral involvement in generalized cystic lymphangiomatosis

A 9-year-old boy presented with the sudden onset of pleuritic chest pain and on CT was found to have a large pleural effusion, mediastinal fluid, splenic lesions and multiple apparently sclerotic vertebral bodies. Subsequent MRI showed that those vertebral bodies that appeared sclerotic were in fact normal, and the vertebral bodies initially interpreted as normal had an abnormal T1 and T2 hyperintense signal on MRI and were relatively lucent on CT. MRI also demonstrated abnormal heterogeneous T2 hyperintense paraspinal tissue and several multicystic soft tissue masses. Biopsy of two adjacent vertebral bodies, one relatively sclerotic and one lucent, demonstrated findings of bony remodeling without a specific diagnosis. Biopsy of an infiltrative mediastinal mass confirmed the diagnosis of generalized cystic lymphangiomatosis. MRI should be included in the assessment of vertebral involvement in this condition because CT and biopsy findings may be nonspecific.     

儿童危重症甲型H1N1流感中枢神经系统并发症的影像学表现

目的：探讨儿童危重症甲型H1N1流感中枢神经系统（CNS）并发症的影像学特点。方法：回顾性分析8例危重症甲型H1N1流感伴CNS并发症的临床及影像学资料,所有患儿住院期间均行MRI平扫及增强扫描,其中3例行CT扫描。结果：4例为流感相关脑病,影像学检查未见明显异常,痊愈出院。死亡4例,其中3例并发急性坏死性脑炎（ANE）,影像表现为多灶性、对称性脑部损害,以双侧丘脑受累为特征,内囊、豆状核、脑干及大小脑髓质均可受累,病变区CT呈低密度,MRI呈长T1、长T2信号,DWI示双丘脑中心区呈低信号,周边呈高信号;ADC图示中央呈稍高信号,环状略低信号环绕。另1死亡病例并发颅内真菌感染,真菌性脑膜炎MRI见脑膜明显强化,真菌性肉芽肿MRI呈类圆形稍长T1、长T2信号,增强边缘强化。结论：儿童危重症甲型H1N1流感CNS并发症有：流感相关脑病、ANE和机会性真菌感染。ANE病死率高,但其影像表现有相对特征性。     

MR imaging of brainstem tumors

Eighteen patients aged 4-72 years old with brainstem tumors were studied using a 0.5 T magnetic resonance (MR) imager and a third- or fourth-generation computed tomographic (CT) scanner. MR imaging showed the brainstem to be enlarged on sagittal views in all cases; exophytic growth was seen in eight. Alterations of signal intensities were shown in most cases on spin-echo sequences using 30 and 90 msec echo times and inversion recovery techniques. It was not possible to distinguish primary from metastatic tumors. The configurations and margins of the areas with abnormal signal did not appear to correlate with the clinical behavior of the tumors. CT was able to recognize brainstem tumor in only 13 of 16 cases. In the two cases of metastases, plain CT scans were normal, but enhancement was seen after administration of contrast material in one. It appears that MR imaging is sensitive in detecting tumor enlargement and abnormal signals and is superior to CT in evaluating brainstem tumors.     

眼球脉络膜转移癌的影像学

描述脉络膜转移癌的CT和MRI表现，对两种检查方法进行评估。材料和方法：回顾性分析经手术病理证实的9例脉络膜转移癌病例，其中7例经CT扫描检查，3例作MRI检查。结果：CT扫描显示眼球后部呈扁平状，均质中高密度肿块，有中度增强。MRI检查为扁平或半月状肿块，T1W呈高于玻璃体中等信号，PDW为高信号，T2W呈低信号。瘤体表面渗出性视网膜脱离在T1W和T2W均呈高信号。结论：CT和MRI对脉络膜转移癌等眼球内病变均可作出定位的影像学诊断。MRI对脉络膜转移癌与脉络膜黑色毒瘤的鉴别、瘤体内结构、与渗出性机网膜脱离的区分以及癌肿侵犯巩膜的情况较CT为优。     

A comparative study of magnetic resonance imaging and computed tomography in the evaluation of migraine

Seventy-four patients with classic migraine were examined by magnetic resonance imaging (MRI) and contrast enhanced head CT scanning. Patients chosen for the study ranged in age from 9 to 39 years with a mean age of 28 years. All had documented symptoms of classic migraine for over two years. Nineteen of the seventy-four patients (26%) had multiple foci of bright signal in the brain on T2 weighted MRI. None of these parenchymal abnormalities were detected on CT scans. Twenty-six patients (35%) had both MRI and CT demonstration of focal or generalized ventricular enlargement or sulcal prominence. These atrophic findings were shown equally well by both modalities. Ten patients (14%) with atrophic changes showed concomitant small bright foci of T2 signal abnormality. An additional migraine patient with homonymous hemianopsia had a large occipital lobe infarct which was seen as a region of bright T2 signal abnormality on MRI. Typical CT characteristics of an acute infarct were demonstrated.