脑桥中央髓鞘溶解症MRI表现(附4例报告)

目的:探讨脑桥中央髓鞘溶解症(central pontine myelinolysis,CPM)磁共振成像特点。方法:回顾分析我院经临床及影像学检查确诊的4例CPM患者的MRI表现,总结其诊断及鉴别要点。结果:CPM的MRI表现:①T1WI病灶呈低信号,T2WI为高信号影;②病灶多为蝴蝶形或环形;③病变位于脑桥中央,皮质脊髓束的轴索无损害。结论:脑桥中央髓鞘溶解症MRI表现有一定特征性,根据MRI可做出正确诊断。     

桥脑外髓鞘溶解症的MRI诊断

目的：分析桥脑外髓鞘溶解症（EPM）的MRI特点.方法：经临床及影像确诊的EPM患者10例,均行头颅MRI检查,其中2例仅行平扫,8例行平扫和增强扫描,回顾性分析其MRI表现,总结其诊断和鉴别诊断要点.结果：10例患者均出现双侧尾状核、豆状核对称性异常信号,T1WI病灶呈低信号,T2WI呈稍高信号,T2-FLAIR病灶呈更加明显的异常高信号,增强扫描无明显强化.其它病灶分布：双侧背侧丘脑2例,双侧岛叶1例,顶叶皮层下白质3例;3例患者伴发脑桥中央对称性异常信号.结论：EPM的MRI表现具有一定特征性,结合临床及实验室检查可作出正确诊断.     

桥脑中央髓鞘溶解症MRI表现分析

目的 :通过对21例桥脑中央髓鞘溶解症(central pontine myelinolysis,CPM)患者的MRI表现进行分析,探讨CPM的MRI特征性表现。方法 :回顾性分析21例CPM患者的MRI表现。结果 :21例均表现桥脑基底中央部对称性长T1、长T2信号,其中11例可见双侧半卵圆形中心及双侧额顶叶皮层下白质、双侧豆状核、尾状核、双侧桥小脑结合臂、小脑中脚、小脑齿状核对称性长T1、长T2信号;所有患者桥脑基底部病变在T1WI及T2WI上边界清晰。结论 :CPM具有较为特征性的MRI表现,MRI对其具有较大诊断和鉴别诊断价值。     

桥脑中央髓鞘溶解的MRI诊断(附2例分析)

目的:探讨桥脑中央髓鞘溶解症(central pontine Myelinolysis CPM)的MRI特征。方法:分析CPM患者的MRI表现,总结了CPM的最佳MR影像诊断与鉴别诊断要点。结果:MRI表现为:(1)病灶位于桥脑上部;(2)T1WI病灶呈低或略低信号强度,T2WI呈高信号或略高信号;(3)静脉注入GD-DTPA后,病灶中央呈明显均匀强化,及轻度强化,边缘清晰锐利。结论:MRI是CPM的最好检查方法,当有上述表现时高度提示CPM的可能。     

肝豆状核变性合并中央桥脑髓鞘溶解症的MRI表现

目的　探讨肝豆状核变性合并中央桥脑髓鞘溶解症 (CPM)的MRI表现及弥散加权成像(DWI)的应用价值。方法　采用 1 5TMR仪对 2例肝豆状核变性合并CPM患者进行T1WI、T2 WI、液体衰减反转恢复成像 (FLAIR)、DWI和增强扫描MR检查。结果　桥脑中央部、双侧豆状核、尾状核、丘脑等部位出现对称性长T1、T2 信号 ,增强MRI无明显强化反应。DWI显示桥脑病变呈明显高信号 ,表观弥散系数 (ADC)值在 10 0× 10 -6mm2 /s～ 30 0× 10 -6mm2 /s之间 ,FLAIR仅显示为略微高信号 ,表明病变伴有明显的细胞毒性水肿 ;同时 ,双侧肝豆状核亦表现出DWI高信号 ,ADC值在 30 0× 10 -6mm2 /s～ 6 0 0× 10 -6mm2 /s之间 ,FLAIR呈不均匀较高信号 ,其中 1例尚出现尾状核头对称性DWI略低信号 ,表明在缓慢的病程进展中同时伴有细胞毒性水肿和血管源性水肿等改变。结论　肝豆状核变性和CPM具有较为特征的MRI表现 ,DWI对其具有较大的诊断和鉴别诊断价值。     

大脑皮层DWI高信号病变的MRI诊断

目的探讨MRI对大脑皮层DWI高信号病变的诊断价值。方法回顾性地分析32例大脑皮层DWI高信号病变。结果经临床随访及相关检查诊断32例病例中克雅氏病(CJD)10例,均没有脑皮层肿胀,9例DWI大脑皮层及基底节同时存在高信号,均未见苍白球受累。3例线粒体脑肌病(ME),主要累及脑后部皮层,DWI为稍高信号。4例缺血缺氧性脑病(HIE),病变范围均符合血管分布区,2例大脑皮层肿胀,DWI为稍高信号。11例脑炎,4例大脑皮层肿胀,DWI高信号改变早于T2WI。2例脑桥外髓鞘溶解症(EPM),病变位于灰白质交界处,DWI为稍高信号。1例低血糖脑病(HE),病变以顶、枕叶为主,DWI为高信号。1例可逆性后部脑病(RPES),灰白质均受累,DWI高信号。结论结合患者发病部位及MRI表现有利于大脑皮层DWI高信号病变的诊断与鉴别诊断。     

常规MRI联合MR脑血管成像在围产期脑后部可逆性脑病综合征中的应用研究

目的：探讨常规磁共振成像（MRI）联合MR脑血管成像在围产期脑后部可逆性脑病综合征（PRES）诊断和鉴别诊断中的应用价值。方法：5例围产期PRES患者,平均年龄为26.5岁,且均于起病后2 d内行常规MRI和MR脑血管成像,MR脑血管成像包括MR脑动脉成像（MRA）和MR脑静脉成像（MRV）。结果：病变均累及双侧顶枕叶,另累及额叶2例,基底节区2例,桥脑1例,病变占位效应不明显。病变主要位于皮层下白质,其中1例累及皮质。病变T1WI呈低、等信号,T2WI及液体衰减反转恢复序列（FLAIR）呈高信号。3例磁共振扩散加权成像（DWI）呈等信号,表观扩散系数（ADC）图为高信号,另2例部分病变DWI为高或稍高信号。增强扫描以上病变未见明确强化,MRA、MRV未见明确异常。结论：围产期RPES的MRI表现较具特征性,常规MRI联合MR脑血管成像有助于本病的早期诊断和鉴别诊断。     

Balo同心圆硬化的MRI和功能MRI表现

目的:探讨常规MRI、扩散张量成像和MRS对Balo同心圆硬化(BCS)的诊断价值。方法:分析4例BCS的MRI表现,并与病理结果进行对照,其中行MR扩散张量成像和质子磁共振波谱(1H-MRS)检查各1例。结果:4例中MRI显示13个病灶,3例多发,1例单发。9个病灶呈典型同心圆或洋葱皮样改变,T1WI上呈等信号和低信号交替环,FLAIR序列T2WI上呈等信号和高信号相间,与病理显示的病灶严重脱髓鞘区和髓鞘保留区相间排列的特点一致。1例1H-MRS示病变区NAA降低、Cho升高。1例DWI显示病变不同信号区FA值均低于对侧正常白质,且病变中心区、T1WI和T2WI上显示的等信号带、T2WI上高信号带及病灶周围的FA值存在差异(P<0.05)。纤维束扩散张量成像显示纤维束在病变区部分中断。结论:MRI能反映BCS的病理改变,对BCS活体、无创诊断具有重要意义,DWI和MRS可以作为评价BCS进展、预后和判断疗效的一种成像方法。     

儿童后部可逆性脑病综合征的CT及MRI表现

目的 探讨儿童后部可逆性脑病综合征(PRES)的CT及MRI表现.资料与方法 搜集本院患儿资料8例,男7例,女1例,其中淋巴瘤化疗患儿、急性肾炎和肾病综合征各2例,紫癜肾和急性肾功能衰竭各1例.其中,5例肾病患儿血压升高.8例患儿行MRI扫描,包括T1WI、T2WI、液体衰减反转恢复序列(FLAIR)成像及扩散加权成像(DWI),其中1例间时行增强MR及MR血管威像(MRA),1例行MRA和MR静脉血管成像(MRV);其中4例行CT平扫.结果 MRI及CT显示双侧顶枕叶(8例)、额叶(2例)、颞叶(1例)、基底节区(1例)及左脑半球(1例)多发异常信号或低密度,主要位于双侧顶枕叶皮质及皮质下自质内,6例患儿皮质受累.在T1WI上病灶呈等或略低信号,T2WI及FLAIR上呈高信号,以FLAIR像显示皮质病变为佳.DWI显示大部分病灶呈等信号,表观扩散系数(ADC)图呈等或高信号.部分病灶DWI表现为高信号.1例行MR增强扫描患儿显示病灶部位沿脑膜斑片状及线样强化,皮层下脑组织内病变呈片状强化.2例MRA及1例MRV各大动脉血管及静脉窦未见明显狭窄、扩张或栓塞征象.随访MRI及CT显示所有患儿病灶范围逐渐缩小,数目减少.结论 FRES好发于顶枕叶皮层及皮层下白质,病变大部分为血管源性水肿,增强T1WI示病灶有强化.儿童与成人病变影像学表现及临床特点有所不同.MRI是PRES的主要检查方法.     

The Clinical Value of Combined MRI and Diffusion Weighted Imaging in Ankylosing Spondylitis

目的 探讨MRI联合DWI对强直性脊柱炎(AS)的诊断价值.资料与方法 搜集经修订纽约标准确诊的31例AS病例和25例正常对照组,两组均行两侧骶髂关节常规MRI横断位和冠状位抑脂T2WI、T1WI联合SE/EPI扩散加权成像(DWI)横断位扫描(b值0,600 s/mm2),观察两组骶髂关节的信号改变,测量表观扩散系数(ADC)值并作统计学检验.结果 31例病例组中的24例双侧或单侧骶髂关节面下骨质抑脂T2WI呈高信号,29例DWI呈高信号,25例对照组骶髂关节面下骨质T2WI、DWI均呈等信号,测量ADC值,病变组为(0.993±0.169)×10 -3mm2/s,对照组为(0.649±0 395)×10 -3 mm2/s,病变组ADC值明显高于对照组(t=4.14,P＜0.001),两者间差异有统计学意义.结论 MRI联合DWI对AS早期诊断有重要的临床价值.     

脑桥中央髓鞘溶解症的MR影像诊断(附三例分析)

目的研究脑桥中央髓鞘溶解症（ｃｅｎｔｒａｌｐｏｎｔｉｎｅｍｙｅｌｉｎｏｌｙｓｉｓ,ＣＰＭ）的ＭＲＩ特征。方法回顾性分析３例ＣＰＭ患者的ＭＲＩ表现,总结ＭＲＩ诊断与鉴别诊断要点。结果ＣＰＭ的ＭＲＩ特征表现为：（１）病变位于脑桥中央部位,主要累及桥横纤维的髓鞘,皮质脊髓束的轴索保持完好;（２）病灶多表现为环形或蝴蝶样,边缘模糊;（３）Ｔ１ＷＩ病灶呈低信号强度影,Ｔ２ＷＩ则为高信号影;（４）病变的早期阶段可见病灶内有斑点样高信号强度影;（５）静脉注入造影剂ＧｄＤＴＰＡ后,可见病灶边缘轻度增强。结论ＭＲＩ是ＣＰＭ的最好检查方法,当有上述表现时高度提示ＣＰＭ的可能     

Value of diffusion-weighted imaging in central pontine and extrapontine myelinolysis

Introduction

Central pontine myelinolysis (CPM) and extrapontine myelinolysis (EPM) are rare neurological disorders characterized by demyelination in and/or outside the pons. Whether diffusion-weighted imaging (DWI) might facilitate an earlier diagnosis has not yet been studied systematically.

Methods

We describe demographics, clinical presentation, and early magnetic resonance imaging (MRI) findings with special emphasis on the relevance for diagnosis of CPM and/or EPM in eight patients.

Results

Of the analysed eight patients (aged 37–70 years; two men, six women), CPM was diagnosed in three, EPM in one, and a combination of CPM and EPM in four patients. Aetiology was rapid correction of sodium in two patients; a combination of hyponatremia, alcoholism and alcohol withdrawal in five patients and unclear in one patient. Seven patients suffered from chronic alcoholism and four from malnutrition. Demyelinating lesions were found in the pons, thalamus, caudate nucleus, putamen and midbrain. While the lesions could be clearly delineated on T2- and T1-weighted images, DWI demonstrated a strong signal in only six patients. Furthermore, DWI demonstrated lesions only to some extent in two patients and was completely negative in two patients on initial MRI. In none of the patients did the demonstration of hyperintense lesions on DWI precede detection on conventional MRI sequences. Apparent diffusion coefficient (ADC) values were heterogenous with a decrease in two cases and an increase in the remainder.

Conclusions

We conclude that early DWI changes are a common finding in CPM/EPM but do not regularly precede tissue changes detectable on conventional MRI sequences. Heterogenous ADC values possibly represent different stages of disease.     

MRI findings in osmotic myelinolysis

OBJECTIVES: Osmotic myelinolysis is a distinctive clinical syndrome with characteristic CT and MR features. This study was undertaken to determine the MR appearance of these lesions on T1 and T2-weighted, and diffusion-weighted imaging (DWI) sequences with apparent diffusion coefficient (ADC) mapping. MATERIALS AND METHODS: We describe six patients who presented with deranged serum sodium levels and subsequently developed osmotic myelinolysis. CT and MRI scans were retrospectively reviewed, including the advanced functional MR sequence of DWI with ADC mapping. RESULTS: Both cerebral white matter and pontine lesions were typically hypo and hyper-intense on T1 and T2W sequences respectively. Lesions were mildly hyperintense on isotropic DWI images with elevation of the ADC. CONCLUSION: MRI is superior to CT in depicting lesions in osmotic myelinolysis. DWI with ADC mapping suggests that osmotic myelinolysis is not simply a demyelinating disorder but has similarities to multiple sclerosis.     

Evolution of apparent diffusion coefficient, diffusion-weighted, and T2-weighted signal intensity of acute stroke

BACKGROUND AND PURPOSE: Serial study of such MR parameters as diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC), ADC with fluid-attenuated inversion recovery (ADC(FLAIR)), and T2-weighted imaging may provide information on the pathophysiological mechanisms of acute ischemic stroke. Our goals were to establish the natural evolution of MR signal intensity characteristics of acute ischemic lesions and to assess the potential of using specific MR parameters to estimate lesion age. METHODS: Five serial echo-planar DWI studies with and without an inversion recovery pulse were performed in 27 patients with acute stroke. The following lesion characteristics were studied: 1) conventional ADC (ADC(CONV)); 2) ADC(FLAIR); 3) DWI signal intensity (SI(DWI)); 4) T2-weighted signal intensity (SI(T2)), and 5) FLAIR signal intensity (SI(FLAIR)). RESULTS: The lesion ADC(CONV) gradually increased from low values during the first week to pseudonormal during the second week to supranormal thereafter. The lesion ADC(FLAIR) showed the same pattern of evolution but with lower absolute values. A low ADC value indicated, with good sensitivity (88%) and specificity (90%), that a lesion was less than 10 days old. All signal intensities remained high throughout follow-up. SI(DWI) showed no significant change during the first week but decreased thereafter. SI(T2) initially increased, decreased slightly during week 2, and again increased after 14 days. SI(FLAIR) showed the same initial increase as the SI(T2) but remained relatively stable thereafter. CONCLUSION: Our findings further clarify the time course of stroke evolution on MR parameters and indicate that the ADC map may be useful for estimating lesion age. Application of an inversion recovery pulse results in lower, potentially more accurate, absolute ADC values.     

磁共振扩散加权成像对于颅内表皮样囊肿的诊断价值

目的:探讨磁共振扩散加权成像(DWI)对于颅内表皮样囊肿的诊断价值。方法:回顾性分析11例经手术病理证实的颅内表皮样囊肿术前常规MRI和DWI的信号特征。结果:11例均为单发;7例表现为囊状均匀性长T1长T2信号,4例病灶信号不均匀,以长T1长T2信号为主,其内混杂少许等T1等T2信号;5例行增强扫描均未见异常强化;所有病灶在DWI上均表现为明显高信号,边界清楚,ADC图表现为中等信号。结论:DWI对于颅内表皮样囊肿的诊断及鉴别诊断具有重要价值,应作为首选检查与常规扫描同时应用。     

桥脑中央髓鞘溶解症的临床与MRI表现分析

目的　探讨桥脑中央髓鞘溶解症的临床表现及磁共振成像特点。方法　对我院经临床及影像学检查确诊的 1 1例桥脑中央髓鞘溶解症的MRI表现进行了回顾性分析。结果　临床表现有长期饮酒史者 7例 ,营养不良者 4例 ,出现低血钠者 1 0例 ;MRI均表现桥脑中央长T1 及长T2 信号 ,4例伴有皮层下白质及基底节病灶 ,3例病灶周边强化 ,2例病灶中央显著强化 ,4例不强化。结论　桥脑中央髓鞘溶解症MRI表现有一定特征性 ,结合临床表现及激素试验性治疗 ,可早期做出正确诊断。     

Intraparenchymal epidermoid cysts in the brain: diagnostic value of MR diffusion-weighted imaging

AIM: To evaluate the value of magnetic resonance (MR) diffusion-weighted imaging (DWI) and apparent diffusion coefficients (ADC) maps in the diagnosis of intraparenchymal epidermoid cysts (ECs). MATERIALS AND METHODS: Six cases of histopathologically proven intraparenchymal ECs were studied. All patients were examined with conventional MR (T1WI, T2WI, contrast-enhanced T1WI) and DWI sequences. Along with the mean ADC values (mADC) of the ECs, the cerebrospinal fluid (CSF) and grey matter (GM) were measured. Qualitative and quantitative assessments, as well as MRI findings, were retrospectively analysed using a double blind method by three radiologists in consensus. RESULTS: Four lesions were located in the cerebellum, among them, one was accompanied by an arachnoid cyst; one huge lesion crossed the parenchyma of the frontal and temporal lobes; the other was located in the left temporal lobe. Two lesions had a homogeneous CSF-like intensity on both T1WI and T2WI. The other four were of mixed-intensity on both T1WI and T2WI. All lesions were strikingly hyperintense on DWI, and iso- or slightly hypointense on ADC (relative to the brain). The mADCs of the ECs were significantly higher than that of GM, but significantly lower than that of CSF. Three cases (3/6) were accurately diagnosed using conventional MR sequences without DWI, but in the remaining three cases, correct diagnosis could only be made with help of DWI. CONCLUSION: DWI sequences can facilitate the diagnosis of intraparenchymal ECs, thus alerting surgeons of the risk of chemical meningitis at surgery. The MR findings of intraparenchymal ECs are basically as the same as those of extracerebral ECs, but the former is likely to have a mixed signal. The hyperintense signal of ECs on DWI is probably caused by the T2 shine-through effect in tumour tissue.     

DWI及ADC图对脑梗死病情进展的评估作用研究

目的:研究核磁共振弥散加权成像及表观弥散系数图像对脑梗死的病情进展和恢复状态的评估作用。方法:对一组超急性期(8例)和急性期(10例)脑梗死患者连续追踪行T_1-FLAIR、FSE-T_2WI、T_2-FLAIR、DWI序列扫描检查,及ADC图像重建,观察不同期相脑梗死灶的图像特征,计算其固定层面病灶区域残余弥散积(MSAFSS):面积×(3.0-1 000×ADC),并使其与相应的脑功能损害评分相对应,进行相关性分析。结果:①超急性期病灶,T_1-FLAIR、T_2WI均无明显信号改变,T_2-FLAIR偶可见等或稍高信号,DWI则可见明显的高信号,ADC图为低信号;急性期梗死灶,T_1-FLAIR基本都呈低信号改变,T_2WI表现为高信号,T_2-FLAIR为高信号,DWI仍为高信号,ADC图为低信号;亚急性期病灶,T_1-FLAIR信号较前都明显降低,T_2WI、T_2-FLAIR、DWI均为高信号表现,ADC图为稍低或等信号表现;慢性期病灶,T_1-FLAIR为低信号,T_2WI为高信号,T_2-FLAIR、DWI呈低或等信号,而ADC图为高信号。②对12例全程追踪的观察结果显示,病灶全过程的MSAFSS与评分分值之间无相关(P0.05);而亚急性早期前10例的MSAFSS与分值间具有正相关性(P0.05)。结论:各期脑梗死在DWI及ADC图上都有其不同的图像特征,并可据此大体判断脑梗死所处期相;通过计算MSAFSS可以对亚急性早期以前的脑梗死病情进展与功能恢复状态给予一定程度的评估。     

MR imaging of central pontine myelinolysis

Central pontine myelinolysis is a demyelinating disorder with characteristic magnetic resonance features. Findings on T1-weighted scans include a symmetric region of low signal involving the basilar pons with sparing of the descending corticospinal tracts as well as the peripheral pontine tissues. The T2-weighted images show an area of high signal corresponding to the abnormal region identified on T1-weighted scans. Associated extrapontine demyelinating lesions are also demonstrated.     

3.0 T MR扩散加权成像评价兔肝VX2瘤射频消融治疗的实验研究

目的 探讨3.0 T MR DWI评价兔肝VX2瘤射频消融治疗疗效的价值.方法 新西兰大白兔22只.20只用于建立VX2瘤模型,2只健康正常兔用于行正常肝射频消融术对照.于VX2瘤种植后14～21 d(平均17 d),对符合实验条件瘤兔(病灶位于肝实质内,最大直径≤3 cm,坏死病灶直径≤整个病灶直径的1/2)行3.0 T常规MRI和功能DWI.对瘤兔及对照组正常兔行射频消融治疗,射频消融术后7～10 d(平均8 d)行3.0 T常规MRI及DWI.所有射频消融治疗兔行MR检查后均行病理检查.测量兔肝VX2瘤、正常兔肝射频消融治疗前后ADC值,分析兔肝VX2瘤射频消融治疗前后3.0 T MR常规成像、ADC值特征,并与病理对照.同一b值射频消融治疗后不同组织间ADC值比较采用重复测量资料方差分析.结果 20只实验组兔肝VX2瘤模型均建立成功,1例肿瘤突出于肝表面、1例肿瘤病灶出现明显坏死未纳入实验.所有18个瘤灶及2例正常兔肝射频消融均成功.兔VX2瘤T1WI序列表现为低或等信号,T2WI为高信号.肝VX2瘤兔射频消融治疗后7～10 d,射频消融病灶T1WI序列表现为低或稍高信号,T2WI为混杂信号.T2WI序列周边环形稍高信号为肉芽组织,增强扫描明显强化,T2WI序列低、中等信号为凝固性坏死.坏死组织在DWI图上为低信号,活性肿瘤组织位于病灶周边,呈结节状,在T2WI、DWI图上为等或稍高信号.肿瘤标本为灰白色,部分肿瘤组织间夹杂增生血管、少许肉芽组织.b值为600 s/mm2时,射频消融治疗后活性肿瘤组织(9只)、坏死组织(18只)、肉芽组织(18只)、正常组织(18只)ADC值分别为:(1.227±0.140)×10-3、(0.702±0.050)×10-3、(1.918±0.124)×10-3、(1.739±0.044)×10-3mm2/s,各组间ADC值差异具有统计学意义(P＜0.01).b值分别为200、400、600、800、1000 s/mm2时治疗后坏死组织、活性残留或复发肿瘤组织、肉芽组织、正常肝组织间ADC值差异具有统计学意义(P＜0.01).结论 兔VX2瘤模型适合3.0 T MR评价射频消融治疗疗效的动物实验研究,对射频消融治疗基础及临床应用研究具有重要价值.