Unilateral cerebral polymicrogyria with ipsilateral cerebral hemiatrophy

We evaluated six children in whom MR imaging showed unilateral cerebral polymicrogyria associated with ipsilateral cerebral atrophy and ipsilateral brain stem atrophy. The aim of this study was to clarify whether this disorder based on neuroimaging constitutes a new homogeneous clinical entity. The subjects were six children whose ages at the time of MR imaging ranged from 8 months to 11 years. Their clinical and MR features were analyzed. All of the children were born between 38 and 42 weeks gestation, without any significant perinatal events. Spastic hemiplegia and epilepsy were observed in all of the patients, and mental retardation was observed in four. The MR findings included unilateral cerebral polymicrogyria associated with ipsilateral cerebral hemiatrophy and ipsilateral brain stem atrophy in all patients. The ipsilateral sylvian fissure was hypoplastic in four patients. These patients showed relatively homogeneous clinical and neuroimaging features. Although the additional clinical features varied according to the site and the extent affected by the polymicrogyria, this disorder could constitute a new relatively homogeneous clinical entity.     

CT findings with cerebral hemiatrophy

Summary CT examination of 71 patients with cerebral hemiatrophy revealed dilatation of the ventricle and low density of the cortex of the involved side in all cases. Thickening of the calvarium and a shift of the midline were found in about half of the patients.     

Computed tomographic findings in cerebral hemiatrophy

Summary The clinical, plain skull radiographic, brain scan, and CT findings of four patients with cerebral hemiatrophy are described. CT scanning is the most innocuous and most sensitive diagnostic method available to confirm the clinical diagnosis when plain skull radiographic changes are not confirmatory.     

鼻咽潴留囊肿的 MRI诊断

目的：评价MRI对鼻咽潴留囊肿的诊断价值。方法：回顾性分析8例经手术穿刺及病理证实的鼻咽潴留囊肿的MRI表现。结果：MRI表现为：８例鼻咽潴留囊肿呈圆形,边界清晰,Ｔ１ＷＩ上６例呈低信号,２例呈稍低信号,Ｔ２ＷＩ均呈高信号。结论：ＭＲＩ对鼻咽潴留囊肿的诊断具有较高的敏感性和特异性。是诊断鼻咽潴留囊肿的重要方法。     

Intraspinal epidermoid cyst: diffusion-weighted MRI

We report a 7-year-old boy who presented with two-month history of worsening low back and right leg pain. Conventional MR images demonstrated a poorly outlined intradural mass recognized by the displacement of the conus medullaris and the nerve roots of the cauda equina at the L2–3 level. The signal intensity of the lesion was similar to CSF. There was no contrast enhancement of the lesion. Diffusion-weighted images and ADC values revealed restricted diffusion within the mass. Myelography confirmed the mass as an intradural filling defect with myelographic block at the L2–3 level. The patient underwent total surgical excision of the mass. Pathologic examination revealed the diagnosis of epidermoid cyst. Received: 11 July 2000 Accepted: 1 December 2000     

磁共振表观弥散系数图在脑梗死演变中的诊断价值

目的:探讨磁共振弥散加权成像(DWI)表观扩散系数图(ADC图)在脑梗死分期中的价值。方法:对75例脑梗死患者共作了81例次(超急性期15例次、急性期15例次、亚急性期31例次、稳定期12例次及慢性期8例次)DWI及常规MRI检查。测定各期梗死灶ADC值及对侧ADC值,计算相对ADC(rADC),分析判断rADC在各期脑梗死中的演变情况。结果:超急性期、急性期及亚急性期梗死灶ADC值为(4.96±0.98)×10-4mm2/s,低于对侧相应区域(8.18±1.07)×10-4mm2/s。(t=2.22,P<0.05);rADC以超急性期最低,随时间延长由低到高,于8~14天出现假性正常化,于慢性期高于正常水平,rADC与时间具有相关性(rs=1.00,P<0.05)。结论:各期脑梗死灶ADC值具有特征性演变规律,结合DWI、T2WI对早期脑梗死的检出和准确分期具重要价值。     

MRI of a dermoid cyst containing hair

A fourth ventricular dermoid cyst examined by CT, MRI and angiography is reported. The combination of CT density and MRI signal indicated the presence of hair within the cyst, which was confirmed at surgery.     

脑灌注MRI与脑血管造影在评价脑缺血病变中的价值

目的 通过对脑缺血性疾病患者的脑动脉血管造影和脑灌注ＭＲＩ对照，评价脑缺血性疾病中侧支循环建立情况，并试图鉴别脑缺血性病变的性质。     

MRI of hemorrhagic choroid plexus cyst

An unusual case of hemorrhage within a cyst in the choroid plexus of the lateral ventricle is presented. choroid plexus cysts are commonly found incidentally on imaging studies, particularly MRI, where their characteristic appearance produces little diagnostic difficulty. In this case, high signal intensity of the cyst contents on T1-weighted images and apparent hemosiderin deposition in the cyst wall, not previously described, represented a dramatic change from a study 10 weeks previously and allowed a presumptive diagnosis of hemorrhage into the cyst, a presumption further supported by the changes in signal 20 weeks later.     

椎管内硬脊膜外蛛网膜囊肿的低场强MRI诊断

目的:探讨椎管内硬脊膜外蛛网膜囊肿的低场强MRI表现特征,提高对该病的认识。方法:回顾性分析12例经手术病理证实的硬脊膜外蛛网膜囊肿的临床及MRI表现特征,其中10例行Gd DTPA增强扫描,7例行X光平片或CT片检查。结果:本组病例发病于胸腰段8例,位于脊髓背侧9例,呈典型的椎管内硬脊膜外占位病变征象,囊肿的信号强度与脑脊液一致或相近,上、下缘与硬脊膜外脂肪毗邻,上或下方邻近硬脊膜的显示,可为硬脊膜外囊肿的定位诊断提供有力的佐证,囊肿与蛛网膜下腔相交通时,孔道区囊肿内可出现流空信号,可确定孔道的具体位置,为手术提供可靠可靠的依据。结论:MRI是目前评价椎管内硬脊膜外蛛网膜囊肿的定位和定性诊断最佳影像学方法和首选检查手段。     

弥散加权成像与MRI增强诊断表皮样囊肿的比较研究

目的:比较弥散加权成像(DWI)与MRI增强(CE-MRI)对表皮样囊肿的检出敏感性,评价DWI的临床应用价值.方法:对59例初次检查及66例术后复查疑似表皮样囊肿的患者行回顾性研究,所有病例均行常规序列[T1 WI、Tz WI、液体衰减反转恢复序列(FLAIR)]、弥散加权成像(DWI)和钆对比剂增强扫描(CE-MRI)检查.将所有图像分为DWI结合常规序列(Ⅰ组)、CE-MR1结合常规序列(Ⅱ组)及DWI联合CE-MRI并结合常规序列(Ⅲ组)三组进行判断,诊断结果与手术病理进行比较,判定三组检查方法的敏感性,组间比较采用配对资料的x2检验.另外选择32例经病理及随访观察证实的蛛网膜囊肿做对照,分析信号特征并测量ADC值,与表皮样囊肿ADC值的比较采用配对t检验.结果:Ⅰ组、Ⅱ组诊断表皮样囊肿的敏感性分别为90.5％、57.8％,二者具有明显统计学差异(x2=25.714,P＜0.01).Ⅲ组诊断表皮样囊肿的敏感性为91.8％,与11组具有明显统计学差异(x2=30.250,P＜0.01),与Ⅰ组没有统计学差异(x2=0.250,P＞0.05).病理证实的88例表皮样囊肿DWI均呈明显高信号,32例蛛网膜囊肿DW1均呈明显低信号,表皮样囊肿的ADC值(1.06士0.21×103)mm2/s明显低于蛛网膜囊肿的的ADC值(3.24±0.39×101)mm2/s,两者比较差异有统计学意义(t =-3.647,P＜0.01).结论:DWI较MRI增强检查对表皮样囊肿具有较高的检出率,在与蛛网膜囊肿的鉴别及判断表皮样囊肿复发上能提供有价值的诊断信息.     

Three-dimensional chemical shift-selective MRI of a ruptured intracranial dermoid cyst

We report a man with a ruptured intracranial dermoid cyst, suffering from headache, nausea, vomiting and a generalised seizure. MRI was performed before and 2 weeks after surgical resection. On T1-weighted images the tumour gave high signal, as did fatty material in the frontal and parietal brain sulci. Identification of this hyperintense material as lipids was possible by chemical-shift-selective 3 D gradient-echo imaging, which provided excellent contrast between the subarachnoid lipids and the adjacent normal brain, with a good spatial resolution. Possible complications of subarachnoid and intraventricular lipid particles after dermoid cyst rupture are discussed and the diagnostic value of 3 D chemical-shift-selective additional to conventional T1-weighted spin-echo images in identification of even small amounts of fat is emphasised.     

卒中患者脑微出血的MRI特点及其临床意义

目的 探讨卒中患者脑微出血（CMBs）的MRI特点及其临床意义，并比较MRI不同扫描序列检出CMBs的能力。方法 卒中患者60例，分为脑缺血组（34例）和脑出血组（26例），以同期查体的60岁以上健康老年人为对照组（30例）。采用常规MRI（包括SE T1WI和FSE T2WI）、扩散加权成像（DWI）、梯度回波T2加权成像（GRE-T2WI）和平面回波成像（EPI）检查，分别统计各组CMBs、腔隙性梗死、脑白质稀疏情况，同时记录卒中患者的高血压、糖尿病、卒中病史，比较不同扫描序列检出CMBs的差异。结果 CMBs在缺血组、出血组和对照组的发生率分别为29．4％，61．5％和6．7％。CMBs最常见于基底节／丘脑区。CMBs与高血压、卒中病史相关（P〈0．01），而与糖尿病无关（P〉0．05）。CMBs的数目与腔隙性脑梗死的数目和脑白质的改变程度成正相关（P〈0．01）。常规MRI和DWI均不能显示CMBs，EPI与GRE-T2WI检出CMBs的差异无统计学意义（P〉0．05）。结论 脑卒中患者多发性CMBs的存在提示微血管病变的严重程度和出血倾向，对于临床治疗决策具有重要的指导意义。GRE-T2WI是检测CMBs的首选方法，EPI可作为GRE-T2WI的补充手段。     

Epidermoid cyst of the conus medullaris: atypical MRI and angiographic features

We report a 50-year-old man with an epidermoid cyst of the conus medullaris which showed a nodular gadolinium enhancement on MRI and a blush on angiography. These radiological features are compared with pathological examination.     

Gadolinium-enhanced MRI in cerebral Whipple's disease

Confusion developed in a 44-year-old man, who had diarrhoea and weight loss for three months. Jejunal biopsy showed infiltration by PAS-positive macrophages, indicating Whipple's disease. Cranial MRI disclosed multiple lesions mainly in the white matter and grey-white matter junction better demonstrated after gadolinium injection.     

磁共振扩散加权和灌注成像对超急性期脑梗死影像半暗带的研究

目的　应用扩散加权成像 (diffusionweightedimaging ,DWI)和灌注成像 (perfusionimaging,PI)观察超急性期脑梗死影像半暗带的转归。方法　对 41例发病 2～ 72h(其中 3 1例发病 <6h ,为超急性期脑梗死 ;10例发病 7～ 72h ,为急性期脑梗死 )的脑梗死患者行MR扫描 ,并使用平面回波技术(echoplanarimaging ,EPI)进行DWI检查。全部病例在治疗后 1～ 2个月行MRI复查。将发病时DWI呈异常高信号 ,而于复查时T2 WI呈正常信号的脑组织定义为影像半暗带 ;将发病时DWI呈高信号而复查时T2 WI亦为高信号的组织定义为病灶中心区。以年轮状方式由外向内测定上述 2个区域的表观扩散系数 (apparentdiffusioncoefficient,ADC)值。同时 ,对发病 <6h的患者中的 17例行表观扩散系数比率 (apparentdiffusioncoefficientratio,ADCR)测定 ,并对 10例行动态对比剂增强血流灌注成像。结果　 3 1例超急性期脑梗死在首次发病时T2 WI未能提示梗死灶 ,19例仅提示病变处血管流空信号消失 ;10例急性期脑梗死T2 WI均可见局部异常高信号 ;同一时期DWI于全部 41例明确显示梗死灶。超急性期脑梗死经治疗后 ,最终梗死灶的面积较首次DWI上异常高信号区域的面积减小 (t =17,P <0 0 1)。病灶中心区周边的影像半暗带呈可逆性转归。起病初期DWI上     

脑动脉瘤的MRI、MRA诊断

目的：探讨常规MR／、MRA以及不同后处理方法对脑动脉瘤的显示能力及诊断价值。方法：应用磁共振T1、T2WI以及3D-TOF-MRA对44例患者进行检查，并使用最大信号强度投影(MIP)、表面遮盖成像(SSD)、多平面重建(MRR)、容积重建(VR)等方法进行后处理。结果：44例患者MR／均发现单发病灶，呈类圆形、梭形、不规则形、葫芦状等，边界清楚。病灶较特异的信号表现为，流空低信号、涡流信号(混杂信号)及部分病灶周围的血流伪影。MRA可清晰显示动脉瘤部位、形态、大小，选择适当后处理方法显示瘤体生长方向、瘤颈形态以及与载瘤血管的关系，为外科手术治疗提供依据。结论：MPI、MRA为无创性显示脑血管的有效方法，提高对脑动脉瘤常规MRI、MRA典型征象的认识，熟练掌握并灵活运用MRA后处理方法可以有效提高磁共振对脑动脉瘤的诊断率。     

3.0T MR扩散张量成像在脑梗死诊断中的应用

目的：探讨3.0T磁共振扩散张量成像（DTI）对脑梗死的诊断价值。方法：对75例不同时期脑梗死患者进行MRI常规检查、扩散加权成像（DWI）及DTI检查,重建平均扩散系数（DCavg）图及部分各向异性（FA）图。以T2WI与DWI图像为参照,测定各期脑梗死灶及对侧正常脑组织的平均DCavg值、平均FA值,并进行统计学处理。结果：与对侧正常脑组织相比,脑梗死平均DCavg值在超急性期及急性期显著减低（P〈0.01）,随着时间延长呈逐渐恢复升高的变化趋势;脑梗死平均FA值在超急性期无一致性变化,与对侧正常脑组织相比差异无统计学意义（P〉0.05）,可轻度升高或轻度降低,随着病程进展呈不可恢复持续减低规律。结论：联合DCavg值与FA值可对脑梗死进行更精确的临床分期,有助于及时准确了解脑梗死的病理生理改变,为临床治疗及预后判断提供依据。     

MRI of acute cerebral infarcts: increased contrast enhancement with continuous infusion of gadolinium

We compared contrast enhancement on T1-weighted MRI of acute cerebral infarcts after conventional bolus administration and continuous infusion of gadolinium. We examined 12 patients with a history of acute stroke with contrast-enhanced MRI once a week for a 1 month. Only ischaemic lesions were investigated after cerebral haemorrhage had been excluded by CT. Each MRI study included T2- and proton density-weighted sequences for determination of the size and site of the infarct, immediate postinjection T1-weighted imaging after bolus administration of 0.1 mmol/kg gadolinium-DPTA and delayed T1-weighted imaging after additional continuous infusion of 0.1 mmol/kg over 2 h. A total of 42 MRI studies was performed. In the first week after the onset of stroke, most infarcts (8 of 10) did not enhance after bolus administration, whereas all showed distinct contrast enhancement after the infusion. In the following weeks all but two infarcts showed contrast enhancement after bolus administration; after continuous infusion contrast enhancement could be seen in all cases. While contrast enhancement after bolus administration showed the typical gyriform pattern, enhanced areas were more extensive after the infusion and usually covered the entire infarcted area shown on T2- and proton density-weighted images. We presume that the disturbed blood-brain barrier in ischaemic areas favours delivery of contrast medium to the infarcted tissue if it is offered continuously so that a steady state can develop. Received: 8 April 1998 Accepted: 1 September 1998