单纯疱疹病毒性脑炎的CT及MRI表现

目的：探讨单纯疱疹病毒性脑炎的影像学表现。方法：回顾性分析9例经PCR（polymerasechainreaction）证实的单纯疱疹病毒性脑炎患者的影像及临床资料,9例患者均行颅脑MRI及增强检查,3例行头部CT扫描。结果：2例病灶位于单侧颞叶、岛叶和扣带回;2例位于双侧颞叶,岛叶、基底节、额叶内侧回及海马钩回;5例位于双侧额叶、颞叶、岛叶,一侧为重,病灶多累及皮层及皮层下白质;其中2例出现不同程度的占位效应。CT扫描病灶呈低密度;MRl扫描病灶呈长T,长T2信号,TIRM序列上病灶呈高信号,DWI显示病灶区扩散受限,增强扫描5例出现脑膜样强化,4例无强化。结论：单纯疱疹病毒性脑炎影像学表现具有一定特征性,常侵犯颞叶、额叶、基底节及岛叶,尤其一侧颞叶、岛叶和眶额区为重．MRI对病灶的显示优于CT．     

MRI of herpes simplex encephalitis

Summary The magnetic resonance imaging (MRI) findings in eight patients with herpes simplex meningoencephalitis were reviewed: 14 examinations were analysed. The most striking finding was high signal intensity in the temporal lobe(s) with the typical configuration known from CT. Meningeal enhancement after Gd-DTPA administration was clearly seen in four patients. Haemorrhagic changes are much better seen on MRI than on CT. When adequate motion control can be achieved, MRI becomes the examination of choice in the diagnosis and follow-up of herpes simplex encephalitis. Localized¹H MR spectroscopy also proved promising in the study of neuronal loss.     

A lesion simulating a cerebellar infarct on CT in a child with herpes simplex encephalitis

We describe an 8-year-old boy with fatal herpes simplex encephalitis in whom CT performed 2 days following the onset of symptoms apparently demonstrated an extensive infarct.     

Diffusion-weighted MRI in herpes simplex encephalitis: a report of three cases

Herpes simplex virus encephalitis (HSVE) is the most frequent fatal viral infection of the brain. Because antiviral treatment may improve the prognosis significantly, early diagnosis is mandatory. Imaging diagnosis rests on conventional MRI for the visualization of lesions in the limbic system, the hallmark of HSVE. Diffusion-weighted MRI (DW-MRI) has not been used for the evaluation of HSVE. We report on the DW-MRI findings in three patients with HSVE, who had cortical diffusion abnormalities in affected brain parenchyma, partially as the initial or most sensitive sign of encephalitis. Sequential imaging showed that the diffusion abnormality started to return to normal after 2 weeks in the presence of persistent contrast uptake. Thus, DW-MRI may be a valuable tool for early detection and diagnosis of HSVE whereas contrast-enhanced images are indispensable after the first week.     

MR findings in neonatal herpes simplex encephalitis type II

The CT findings in neonatal herpes simplex encephalitis (HSE) type II have been previously described, whereas magnetic resonance (MR) findings as yet have not. Early CT findings can be subtle and difficult to detect. However, as the abnormalities evolve, most notably the strikingly increased density of cortical gray matter, they appear highly characteristic of neonatal HSE type II. This case report with neuropathologic verification describes serial MR and CT findings in HSE type II that suggest an etiology of the increased density characteristically seen on CT scans; it does not appear to be hemorrhage or calcification.     

Sequential MR imaging and SPECT studies in herpes simplex encephalitis with crossed cerebellar hyperperfusion

We report a case of herpes simplex encephalitis in which sequential MR imaging and SPECT studies showed interesting findings. SPECT in the acute stage showed wide increased uptake in the left cerebral hemisphere, as well as increased uptake in the contralateral right cerebellar hemisphere. Tl-weighted images in the subacute stage showed hyperintense signals along the cerebral cortices, but T2*-weighted gradient-echo images did not show any signal decrease caused by the magnetic susceptibility effect of hemoglobin degradation. Sequential SPECT studies in addition to MR imaging facilitate precise understanding of the pathophysiology of herpes simplex encephalitis.     

Computed tomographic findings in acute viral encephalitis in adults with emphasis on herpes simplex encephalitis

Nine patients with acute viral encephalitis were diagnosed by CT. Seven had herpes simplex and two had nonherpetic acute viral encephalitis. All patients with herpes simplex encephalitis initially were febrile. They developed confusion and seizures. Five had focal neurological deficit and two had papilledema. The CT scan showed an abnormality on the initial CT in 6 of 7 cases. In one case initial CT study was normal; however follow-up scan (performed 5 days later) showed a definite abnormality. CT showed the characteristic pattern of herpes simplex encephalitis in all cases. This is a temporal lobe hypodense lesion (unilateral, 5 cases; bilateral, 2 cases) with a small interspersed hyperdense region. The hyperdense component represents hemorrhage. Mass elrect was seen in all cases. Two patients showed enhancement which was diffuse or patchy in one case and cisternnl-gyral in the other; however enhancement was absent in 5 cases. One patient showed progression of the size of the hypodense lesion despite antiviral treatment. Follow-up CT showed hypodense lesion(s) in the, temporal lobe region with enlargement of the temporal horns and contiguous basal cisterns in 4 cases. In 2 other cases of acute viral encephalitis the patients initially developed fever, confusion and seizures. CT showed basal ganglia calcification or hypodense lesions.     

36例病毒性脑炎的临床与MR分析

目的 :提高对病毒性脑炎的MRI及临床的认识。方法 :回顾性分析 3 6例经临床治疗后好转的病毒性脑炎的临床及MRI表现。常规行矢状位T1WI、轴位T1WI、T2 WI、FLAIR序列检查 ,其中 3 0例行增强扫描。结果 :3 0例MR初诊为病毒性脑炎 ,MR表现为颅内多发、片状或团片状异常信号 ,累及额、顶、颞、枕叶、基底节 丘脑区、中脑、小脑半球。T1WI呈稍低或等信号 ,T2 WI呈稍高信号 ,FLAIR序列呈明显高信号。增强扫描有多种表现 ,包括无明显强化、小点状、线样、团片状及脑回状强化 ,脑膜亦可强化 ,其中单疱病毒性脑炎 12例。误诊为脑梗死 2例 ,胶质瘤 1例 ,胶质瘤病 1例 ,脱髓鞘性病变 2例。结论 :MR对病毒性脑炎显示清楚 ,部分病毒性脑炎MR表现复杂 ,应结合临床资料考虑。     

Rasmussen脑炎的MRI诊断

目的 总结Rasmussen脑炎的MRI特点,提高对本病影像表现的认识.方法 回顾性分析10例Rasmussen脑炎患者的MR图像,男7例、女3例,平均年龄(11±4)岁.常规行横断面、矢状面及垂直于海马长轴的斜冠状面扫描,获得T1WI、T2WI及液体衰减反转恢复(FLAIR)序列图像.评估Rasmussen脑炎患者术前MR检查中脑萎缩和信号情况,以及上述改变在随访时MR的表现.结果 Rasmussen脑炎的影像特点为:(1)脑萎缩性改变:患侧侧脑室体部扩大(8/10),颞角扩大(9/10),外侧裂增宽(9/10),局部脑沟增宽和脑回变小(7/10),尾状核和壳核萎缩(6/10).病变晚期皮层萎缩多为半球性或累及2个以上脑叶.(2)信号改变:皮层或皮层下长T2信号(9/10),多累及2个以上脑叶.(3)病变进展性:8例接受随访MR的患者均可见病变侧半球的萎缩性改变加重,范围加大,由局部向半球性发展;皮层信号改变较大.结论 Rasmussen脑炎好发于儿童,表现为一侧大脑半球进展性萎缩改变,脑室扩大,外侧裂和脑沟增宽,脑回变小,伴有相应部位的皮层萎缩和皮层T2高信号,深部灰质核团也可受累.     

Surface enhanced Raman scattering of herpes simplex virus in tear film

Conjunctivitis is currently diagnosed using white light microscopy of corneal or conjunctival cells in culture. This takes time and is subjective. An ideal test would be sensitive, specific, near-patient and quick. Raman spectroscopy is the measurement of inelastic light scatter that produces unique molecular spectra. Infected human tear film can be analysed for viral and bacterial particles. However, the concentration of these and the constituents of the tear are very low. Surface enhanced Raman scattering can be used to amplify the Raman signal. For this experiment two different SERS substrates were used: silver mirror reaction glass and gold thin film. Heat denatured herpes simplex virus in transport medium culture and transport medium only were added to different ratios of a synthetic tear. The synthetic tear was modelled on the aqueous layer of the human tear film. Linear discriminant analysis was performed on each spectral dataset for each ratio of mixture on both substrates. From the classification tables, the sensitivity and specificity for silver mirror reaction glass were 75.5 ± 13.8%, 77.3 ± 8.3%, and for gold thin film 75.5 ± 5.9% and 78.3 ± 6.2% respectively. The results show proof of principle that SERS could potentially be used to detect the presence of herpes simplex viral particles in an aqueous solution such as the tear film.     

MRI in Japanese encephalitis

We document the MRI features in seven patients with Japanese encephalitis. MRI was carried out on a 1.5 T system within 10–60 days of onset. In all the patients MRI revealed bilateral thalamic lesions, haemorrhagic in five. Signal changes were present in the cerebrum in four patients, the midbrain and cerebellum in three each, the pons in two and the basal ganglia in one. The lesions were haemorrhagic in three of the four patients with lesions in the cortex, two of the three with lesions in the midbrain and cerebellum, but the pontine lesions were haemorrhagic in both patients. Spinal cord involvement was seen in one of the three patients who underwent MRI. In two patients MRI was repeated 3 years after the onset, showing marked reduction in abnormal signal; and all the lesions gave low signal on both T1- and T2-weighted images. Bilateral thalamic involvement, especially haemorrhagic, may be considered characteristic of Japanese encephalitis, especially in endemic areas. Received: 2 January 1996 Accepted: 2 February 1996     

Magnetic resonance imaging of limbic encephalitis

Summary In two patients with limbic encephalitis serial magnetic resonance (MR) imaging showed evolution of abnormal high-signal intensity in both hippocampal formations on T2-weighted images.     

病毒性脑炎扩散张量成像的初步研究

目的:比较病毒性脑炎脑内病灶和对照侧镜像区的扩散特性的差异,探讨扩散张量成像(DTI)在诊断病毒性脑炎中的应用价值。方法:分别对13例病毒性脑炎患者行常规MRI和DTI检查,经处理后分别获得每个层面的表观扩散系数(ADC)图、各向异性(FA)图、1-VR(VR)图和纤维束成像(DTT)图,并对DTI各输出参数ADC、FA、1-VR进行统计分析。结果:13例患者共计20个病灶,病灶区的FA值及1-VR值减低,病灶区与对照侧的FA值及1-VR值间的差异有统计学意义(P<0.01),病灶区与对照侧的ADC值间的差异无统计学意义(P=0.2026,P>0.05)。FA图显示病灶的范围比常规T2WI大。DTT图显示受累白质纤维束是浸润性改变,部分纤维中断。结论:DTI指标可以反映病毒性脑炎病变组织的微观结构变化信息,为常规MRI检查提供补充信息,对其临床诊疗和评估也有一定的价值。     

小儿流行性乙型脑炎的MR成像及其扩散加权成像特征

目的探讨小儿乙型脑炎的MRI表现及其扩散加权成像（DWI）的特征。方法16例临床诊断符合小儿乙型脑炎的患者，均行头颅常规MRI和轴面DWI，其中7例在发病10d内检查，9例在10d后检查。观察患者脑DWI、T2WI序列的表现；同时测量感兴趣区的表观扩散系数（ADC）值，并将病灶的ADC值与其对应的发病持续时间作相关分析。结果脑部病变区主要呈稍长T1、长T2信号，丘脑受累最常见。16例患者中，15例丘脑受累，其中6例病变仅累及丘脑。7例10d内行MR检查者，病灶在DWI较T2WI信号高，而且病变范围更清楚，其中2例在DWI还显示了T2WI未能显示的病灶；9例发病10d后行MR检查者，T2WI显示病变较DWI清晰。丘脑病灶的ADC值与其病程呈正相关（r=0．84，P〈0．01）。结论 小儿乙型脑炎在MRI上常表现为较特征的丘脑受累，结合临床，DWI对乙型脑炎的早期诊断有一定帮助。     

小儿重症手足口病并发脑炎的MRI表现

目的:探讨小儿重症手足口病(HFMD)并发脑炎的MRI表现.方法:回顾性分析24例小儿手足口病并发脑炎的MRI表现.结果:24例小儿脑部病变共69处病灶.病变多发13例,对称性分布10例,非对称性3例;多发病灶以脑白质病变为主,共37处病变;病变单发11例,其中累及丘脑2例,累及基底节区4例,累及脑干2例,累及颞叶1例...     

Angiographic changes in a case of herpes simplex encephalitis

Summary A case of herpes encephalitis predominating in the right temporal lobe with unusual angiographic changes is reported. Carotid angiography revealed a right temporal mass with vascular blush and early venous filling through irregular veins. Early venous filling and vascular blush have been known for a long time with cerebral inflammatory disease, but venous drainage through irregular veins is unusual.     

肿瘤样脑炎的MRI表现分析

目的:探讨肿瘤样脑炎的MRI表现。方法:回顾性分析本院10例肿瘤样脑炎患者的MRI资料,所有病例均行MRI平扫及增强检查。结果:肿瘤样脑炎平扫呈长T1、长T2不均匀信号,边界欠清晰,周围有水肿带,灰白质同时受累,占位征象较轻。增强扫描4例呈单发结节或环形伴核心样明显强化,6例为单发或多发偏心结节状明显强化,有5例(5/10)伴邻近脑膜线状强化、其中2例(2/10)同时有脑回状强化。结论:肿瘤样脑炎MRI平扫表现缺乏特征性,增强扫描表现有一定特征性,充分认识其MRI表现并结合临床对肿瘤样脑炎的诊断及鉴别诊断有重要意义。     

MRI and proton spectroscopy in a child with Rasmussen's encephalitis. Case report

The greater sensitivity of magnetic resonance spectroscopy (MRS) compared with MRI to brain abnormalities in Rasmussen's encephalitis was demonstrated in a 3-year-old boy. The patient, with symptoms, signs and morphological findings consistent with Rasmussen's encephalitis, was followed with MRI and MRS over 30 months. That metabolic changes can be disclosed by MRS before the development of symptoms or signs was demonstrated as pathological spectra were found not only in the diseased left hemisphere but also in the morphologically normal right hemisphere before any neurological disturbance of that side. Received: 21 December 1998 Accepted: 16 April 1999     

支原体脑炎的磁共振诊断价值

目的:探讨磁共振成像对支原体脑炎的影像学特点及临床诊断价值。方法:对21例支原体脑炎患者行颅脑MRI检查,12例增强扫描。结果:MRI表现异常16例,正常5例。①病变形态及分布:脑白质多发、散在的点状或/及斑片状异常信号8例;两侧大脑半球弥漫性异常信号3例;脑室扩大,侧脑室后角周围异常信号3例;皮层灰质内脑回状异常信号2例;②病变信号:所有病例T2WI及FLAIR序列呈略高或高信号,T1WI呈等或低信号,在DWI(b=1000)像上均呈异常高信号;③增强扫描:12例行增强扫描中,4例呈点状或/及斑片状强化,8例无异常强化。结论:MRI表现具有一定特征性,且有助于诊断支原体脑炎,并可显示支原体脑炎脑实质受累范围和程度,为临床治疗及判定预后提供可靠依据。     

眼眶肿块的MR扩散加权成像研究

目的 评价表现扩散系数(ADC)值对眼眶不同类型肿块的诊断与鉴别诊断价值. 资料与方法 65例眶内肿块病例行常规MRI及扩散加权成像(DWI)扫描.分别测量病变兴趣区及对侧颞叶脑白质ADC值,比较不同类型眼眶病变ADC差别. 结果 65例眶内肿块的ADCM为(1.38±0.55) ×10-3 mm2/ s,ADCw为(0.85±0.07) ×10-3 mm2/ s.其中淋巴造血系肿瘤ADCM为(0.76±0.12)×10-3 mm2/ s;癌ADCM为(1.36±0.39)×10-3 mm2/ s;良性实性肿块ADCM为(1.35±0.54)×10-3 mm2/ s;脉管性肿块ADCM为(1.50±0.30)×10-3 mm2/ s;囊性肿块ADCM为(1.92±0.99)×10-3 mm2/ s.不同组间眼眶肿块ADCM差异有统计学意义(P＜0.05),其中淋巴造血系肿瘤ADCM显著低于癌、良性实性肿块、脉管性肿块、囊性肿块(P＜0.01);癌、良性实性肿块ADCM显著低于囊性肿块(P＜0.05);癌、良性实性肿块与脉管性肿块之间ADCM差异无统计学意义(P＞0.05),脉管性肿块与囊性肿块ADCM差异无统计学意义(P＞0.05). 结论 DWI可反映眼眶肿块的扩散特征,不同类型眶内肿块ADC值之间具有差异,有助于病变的鉴别诊断.