磁敏感加权成像对弥漫性轴索损伤的诊断价值

目的 探讨磁敏感加权成像(SWI)对弥漫性轴索损伤(DAI)的诊断价值及与临床、预后的关系.方法 对20例临床确诊为DAI的脑外伤患者行3.0 T MR常规序列扫描[包括T1WI、T2WI、液体衰减反转恢复(FLAIR)序列]及SWI序列扫描,格拉斯哥评分(GCS)为3.0～5.0分者8例,6.0～8.0分者4例,9.0～12.0分者8例.分别为伤后3 h至20 d内行MR扫描并加扫SWI序列,分别测量所有患者在MR常规序列扫描和SWI的病灶数量及体积.常规扫描序列和SWI检出病灶数量的比较采用Mann-Whitney U检验,病灶体积比较采用配对t检验,观察有无差异;SWI检查与临床、预后采用Pearson相关分析.结果 DAI病灶在SWI表现为:脑内皮髓质交界区、脑白质、基底节、胼胝体、脑干、小脑等区域散在大小不等的点状、串珠状、斑片状、条索状显著低信号灶(病灶直径＜2.0 cm),病灶分布呈多灶性,大小不均,边界清晰.MRI常规序列扫描共发现78个病灶;SWI序列共发现424个病灶,SWI序列发现病灶数量明显多于常规MR扫描(U=-15.447,P<0.01);分别测量MRI常规序列扫描和SWI序列发现的病灶体积为19 340 mm3和38 042 mm3,两者比较差异有统计学意义(t=5.870,P<0.01).其中SWI序列显示的病灶数量和病灶体积与GCS评分之间呈明显的负相关,相关系数分别为-0.802、-0.767,P值均<0.01.结论 SWI序列可以在DAI患者中发现更多的出血病灶及较常规扫描明显扩大的病灶体积,并且病灶的体积和数量与GCS评分密切相关,对DAI的诊断及判断患者的预后有很高的价值.

Abstract：

Objective To study the diagnostic value of susceptibility weighted imaging (SWI) in diffuse axonal injury (DAI) and investigate the relationship between SWI and clinical prognosis. MethodsTwenty patients (15 males and 5 females) with DAI were included in this study. Routine sequences (T1WI, T2WI and FLAIR) and SWI were performed on a 3.0 T MRI scanner. There were 8 cases whose Glasgow score scale (GCS) ranged from 3.0 to 5.0, 4 cases from 6.0 to 8.0 and 8 from 9.0 to 12.0. The interval time between injury and examination were from 3 hours to 20 days. The number and volume of lesions observed on SWI and routine sequence were compared using Mann-Whitney U-test and paired t-test. Pearson correlation was used to analyze the relationship between the number and volume of all lesions and GCS. Results The lesions showed punctate, beaded, patchy and cord-like hypointense signal with various size on SWI (lesion diameter <2.0 cm). Distribution of lesions was multifocal with clear boundary. Routine MRI scan found a total of 78 lesions, while SWI sequence detected 424 lesions. The number of the lesions found on SWI was more than that on conventional MRI (U=-15.447,P＜0.01). The total volume of the lesions measured on routine MRI and SWI were 19 340 mm3 and 38 042 mm3, respectively. The total volume measured on SWI was more than that on routine MR (t=5.870,P＜0.01). The number and volume of all lesions were negatively correlated with GCS (r=-0.802, -0.767, P＜0.01). Conclusion SWI sequence could find more bleeding lesions than the routine MRI sequences. The number and the volume of the lesions were closely related to GCS. SWI showed high value in the diagnosis and prediction of the prognosis of DAI.     

3.0 T磁敏感加权成像在出血性弥漫性轴索损伤中的诊断价值

目的 探讨磁敏感加权成像(susceptibility weighted imaging,SWI)在出血性弥漫性轴索损伤(diffuse axonal injury,DAI)中的诊断价值. 方法 回顾性分析20例外伤后3d内行MRI检查的DAI患者的资料,扫描序列包括T1WI、T2WI、液体衰减反转恢复(fluid attenuated inversion recovery,FLAIR)序列和扩散加权成像(diffusion weighted imaging,DWI)及SWI扫描.GCS≤8分15例,9 ～12分3例,13 ～ 15分2例;统计病灶的发生部位、数量,测量各扫描序列发现的病灶面积,应用X2检验比较各序列病灶检出率的差异,并对患者DAI出血灶面积与GCS评分作相关分析. 结果 DAI出血灶在脑表浅部位较后颅窝和脑深部多,SWI序列对出血性病灶的检出率最高,与其他序列的差异有统计学意义(P＜0.05),出血灶的面积与GCS评分呈负相关(r=-0.921,P＜0.01). 结论 SWI能非常敏感地检出外伤后急性期DAI患者的脑内出血灶.     

磁敏感加权成像在弥漫性轴索损伤中的应用

目的：探讨磁敏感加权成像（SWI）技术在弥漫性轴索损伤（DAI）中的临床应用价值。方法收集临床诊断为DAI的患者25例,均行常规T1WI、T2WI、液体衰减反转恢复（FLAIR）、弥散加权磁共振成像（DWI）及SWI。结果25例患者中SWI较常规序列能清楚地显示脑内微小出血灶。结论在DAI患者中,SWI可提供更多的影像信息,在诊断DAI和治疗方案的制定中具有重要的临床应用价值。     

磁共振弥散张量成像在弥漫性轴索损伤中的研究价值

目的 探讨磁共振弥散张量成像(DTI)在弥漫性轴索损伤(DAI)中的研究价值.方法 DAI组急性期26例,其中9例为复查病例(慢性期),对照组20例,常规磁共振检查后,行DTI扫描,分别测量DAI急性期及慢性期和对照组各感兴趣区部分各向异性(FA)值,将2组间相应感兴趣区的FA值进行对比,并对急性期FA值与格拉斯哥昏迷计分表(GCS)评分进行相关性分析.结果 DAI急性期FA值(胼胝体压部0.560±0.004,胼胝体膝部0.467±0.004,内囊后 肢0.598±0.012,半卵圆中心0.434±0.002)与对照组(胼胝体压部0.756±0.006,胼胝体膝部0.542±0.007,内囊后肢0.639±0.009,半卵圆中心0.480±0.003)有差异,胼胝体压部FA值与GCS评分有较好的相关性(r=0.693,P=0.001).慢性期胼胝体压部(0.621±0.002),胼胝体膝部(0.502±0.003),内囊后肢(0.613±0.009),半卵圆中心(0.448±0.004)FA值较急性期升高,但仍低于对照组.DTT示受损部位神经纤维失去正常形态.结论 DTI可以较敏感地检测DAI病灶,FA值可用以协助评估患者的病情,预测患者的预后.     

MR高分辨磁敏感加权成像在颅脑弥漫性轴索损伤中的应用价值

目的 探讨高分辨磁敏感加权成像(susceptibility-weighted imaging,SWI)序列在颅脑弥漫性轴索损伤(diffuse axonal injury,DAI)诊断中的价值及SWI上病灶数目与患者临床预后的关系.方法 21例经临床及影像学确诊的DAI患者,分别在外伤后15 d内行3.0T MR常规序列(T1WI 、T2WI 和FLAIR)及高分辨SWI序列扫描,并观察患者病灶形态、分布、数目等,对比分析SWI和常规MR序列对DAI病灶显示的敏感性及信号特征,并与哥拉斯哥昏迷计分表(GCS)评分及预后进行相关性分析.结果 21例DAI患者中,MRI常规扫描共发现183个病灶,其中T1WI检出32个,T2WI检出65个,FLAIR检出86个;SWI序列共检出467个病灶.DAI出血灶的分布形态在SWI上表现多样,皮髓质交界区的病灶多呈斑点状或串珠状;脑白质和小脑病灶多呈团状或点片状;基底节、脑干病灶多呈斑片或点状.SWI序列发现病灶数量明显多于常规MR(t = -2.210,P＜ 0.05).SWI显示DAI的病灶数目与患者GCS评分呈负相关(r = -0.849,P＜0.05).结论 SWI对脑内微出血灶的检出明显优于常规MRI,并且病灶的数量与患者GCS评分密切相关,对DAI的诊断和预后判断有很高的价值.     

MR扩散加权成像对脑弥漫性轴索损伤的诊断价值

目的:探讨磁共振扩散加权成像在脑弥漫性轴索损伤诊断中的应用价值.方法:对13例临床诊断为弥漫性轴索损伤的脑外伤患者磁共振检查资料进行回顾性分析.结果:扩散加权成像对弥漫性轴索损伤出血性病灶和水肿性病灶检出均很敏感,尤其是对小出血灶和小水肿灶的检出能力显著超过自旋回波序列.扩散加权成像对小出血灶有独特优势,其特征性表现是斑点状低信号周围有水肿环,而且通过消除脑脊液信号,扩散加权成像能更好显示胼胝体水肿灶.讨论:与自旋回波序列比较,磁共振扩散加权成像能更加敏感地检出脑内小病灶,对脑弥漫性轴索损伤的诊断显示出更高的应用价值.     

磁敏感成像在脑弥漫性轴索损伤中的应用价值

目的:评价磁敏感成像(SWI)在脑弥漫性轴索损伤(DAI)中的价值。方法:回顾性分析45例DAI的SWI序列影像特点,并与常规MRI序列对照分析。结果:所有序列共检出病灶413个。SWI序列检出病灶402个,其中水肿灶56个,表现为片状高(稍高)信号;水肿伴出血灶346个,表现为片状高(稍高)信号区内分布斑点状低信号。常规MRI序列共检出病灶392个,表现为单纯水肿灶316个,水肿伴出血灶76个灶。SWI检出病灶以及病灶内合并出血的敏感性明显高于常规检查序列,差异有统计学意义。结论:SWI能高效检出DAI病灶,同时可明显提高出血性病灶的检出率,有助于准确评价病变的严重程度,为DAI最有价值的检查方法。     

磁敏感加权成像在弥漫性轴索损伤中的应用价值

目的通过比较磁敏感加权成像(susceptibility weighted imaging,SWI)与常规MRI序列对弥漫性轴索损伤(diffuse axonal injury,DAI)病灶的显示情况,探讨SWI对DAI的诊断价值;比较SWI及常规MRI序列在检测DAI病灶数目及体积方面的差别,探讨SWI显示DAI病灶数目、体积与患者格拉斯哥昏迷评分(glasgow coma score,GCS)之间的相关性。资料与方法对36例临床确诊为DAI的患者分别行常规MRI及SWI扫描;常规MRI与SWI在显示病灶数目及体积方面分别采用U检验及配对t检验。结果 SWI显示DAI病灶分布于皮髓质交界以及白质区域,呈"斑点"状、"串珠"状、"线条"状明显低信号病灶;常规MRI序列检出96个病灶,SWI检出511个病灶,两种方法在检测病灶数目方面差异具有统计学意义(Z=-6.801,P=0.000)。常规序列检测病灶总体积约29.09 cm3,SWI显示病灶总体积约为66.95 cm3,两种方法在检测病灶总体积方面差异具有统计学意义(t=-7.916,P=0.000)。SWI显示病灶数目与患者GCS之间存在负相关性(r=-0.796,P=0.000);SWI显示病灶体积与患者GCS之间存在负相关性(r=-0.652,P=0.000)。结论 SWI在显示DAI病灶及评价患者病情方面优于常规MRI序列。     

磁敏感成像在弥漫性轴索损伤诊断中的应用价值

目的:探讨磁敏感加权成像(SWI)对弥漫性轴索损伤(DAI)的诊断价值.方法:对25例临床可疑DAI病例行常规TSE、液体衰减反转恢复(FLAIR)序列和磁共振扩散加权成像(DWI)及SWI扫描.结果:SWI可清楚显示18例DAI的颅内异常小出血灶,表现为点状、条索状、类圆形或环形的低信号影,检出率为72%.常规TSE序列检出7例,检出率为28%,FLAIR序列检出12例,检出率为48%,DWI序列检出14例,检出率为56%.结论:SWI能非常敏感地检出外伤后弥漫性轴索损伤患者的脑内小出血灶.     

磁敏感加权成像对弥漫性轴索损伤的诊断价值

目的探讨磁敏感加权成像(SWI)对弥漫性轴索损伤(DAI)的诊断价值。方法对40例临床拟诊DAI病例常规T2WI,液体衰减反转恢复(FLAIR)序列和磁共振扩散加权(DWI)及磁敏感加权(SWI)扫描。结果 SWI可清楚显示29例DAI的颅内异常小出血灶,表现为点状、条索状、类圆形或串珠状的低信号影,检出率为72.5%,常规T2WI序列检出率为27.5%(11/40),FLAIR序列检出率为47.5%(19/40),DWI序列检出率为55.0%(22/40)。结论 SWI能非常敏感地检出外伤后弥漫性轴索损伤患者的脑内小出血灶。     

磁共振在诊断弥漫性轴索损伤中的应用进展

弥漫性轴索损伤是脑外伤的严重类型,也是影像学诊断的难点。随着软硬件的更新和新序列的研发应用,MRI在弥漫性轴索损伤的诊断中起着越来越重要的作用。本文将磁共振成像各个序列对弥漫性轴索损伤的应用情况综述如下。     

SWI在弥漫性轴索损伤诊断中的价值

目的:探讨磁敏感加权成像在急性期脑弥漫性轴索损伤(diffuse axonal injury,DAI)中的诊断价值。方法:回顾性分析23例经临床确诊DAI患者的影像学资料,所有患者均在常规MRI扫描基础上行液体衰减翻转恢复(FLAIR)序列及磁敏感加权成像(SWI)扫描,比较两者DAI病灶的检出率,分析信号特征。结果:联合常规序列和SWI共发现DAI病灶378个;其中SWI检出病灶341个,敏感度为90.2%,在磁敏感图(SWI image)表现为散在、大小不等且不规则形低信号影,边界清晰,在相位图(Phase image)测病灶较正常脑组织相位位移量明显大(P0.05);在FLAIR检出病灶197个,敏感度为52.1%,表现为边界模糊的大小不等点片状高或稍高信号影,SWI对于DAI的检出率显著高于FLAIR(P0.01)。结论:对于急性期DAI病灶的显示,SWI比常规序列敏感,具有更高的诊断价值。     

Diffusion-weighted MRI in diffuse axonal injury of the brain

The goal of this study was to identify and describe the different types and patterns of tissue injury which are encountered by diffusion-weighted imaging (DWI) in diffuse axonal injury (DAI) of the brain. The DWI data sets of 98 patients who suffered from a closed-head injury were retrospectively evaluated. Medical records were reviewed to rule out pre-existing neurological diseases. Lesions were studied for their DWI signal characteristics and lesion size or extension. Traumatic lesions were classified into three categories depending on their signal characteristica on DWI and apparent diffusion coefficient (ADC) maps: type 1, DWI- and ADC-hyperintense most likely representing lesions with vasogenic edema; type 2, DWI-hyperintense, ADC-hypointense indicating cytotoxic edema; type 3, central hemorrhagic lesion surrounded by an area of increased diffusion. According to the size and extent of lesions, injury was classified into three groups: group A, focal injury; group B, regional/confluent injury; and group C, extensive/diffuse injury. Our study showed that diffusion-weighted imaging differentiates between lesions with decreased and increased diffusion in patients with DAI. Different degrees of tissue injury extent were noticed. Future prospective studies should study if this additional information can be used as a predictor of injury reversibility, final outcome and prognosis.     

多回波采集T*2加权三维梯度回波序列在弥漫性轴索损伤出血性剪切灶检出中的应用

目的 比较多回波采集的T2*WI三维梯度回波(ESWAN)序列和常规T2*WI梯度回波序列(GRE T2*WI)对弥漫性轴索损伤(DAI)出血性剪切灶的检出效能,并结合成像参数进一步探讨ESWAN序列的原理及优势.方法 回顾性分析17例DAI患者行MR检查的影像资料,比较ESWAN序列经多回波幅度平均技术后处理后的图像与常规GRE T2*WI序列对大脑总体及分区(大脑表浅区、深部区及后颅窝区)出血灶显示数量的差异,统计学分析采用配对比较秩和检验.结果 GRE T2*WI显示的出血灶在ESWAN图像上信号更低而更明显;ESWAN序列检出出血灶的中位数(范围)分别为全脑27(1～239)个、脑表浅区13(1～89)个、脑深部区5(0～111)个及后颅窝区1(0～39)个;GRE T2*WI序列检出出血灶的中位数(范围)分别为全脑7(1～34)个、脑表浅区5(1～27)个、脑深部区2(0～25)个及后颅窝区0(0～4)个.配对比较秩和检验显示两种序列在全脑及各分区的检出数量上差异均有统计学意义(Z值分别为-3.519、-3.182、-3.185、-2.677,P值均＜0.05).结论 ESWAN序列的多回波采集优势保障了足够的磁敏感效应,较GRE T2*WI序列检出小出血灶更敏感,为DAI的诊断及病情的评估提供了更多有价值的影像信息.

Abstract：

Objective To compare the efficiency of enhanced T2* weighted angiography (ESWAN) sequence with that of a conventional T2*-weighted gradient-recalled-echo (GRE T2*WI) sequence for the detection of hemorrhagic shearing lesions in patients with diffuse axonal injury (DAI). And combined with MRI parameters, to further discuss the principles and virtues of ESWAN sequence. Methods Seventeen patients with DAI were enrolled in this study. The raw data acquired from ESWAN scan were postprocessed by using the mean square root of multi-echoes. Then, the postprocessed images were compared with the conventional GRE T2* weighted images. The global and regional (superficial, deep and posterior fossa) lesion numbers determined by both sequences were compared by using Wilcoxon signed ranks test (two-tailed). Differences were considered to be significant at P≤0.05. Results Hemorrhagic lesions were more obvious on ESWAN images than those on conventional GRE T2* weighted images. The median and range value of the detected lesion numbers on ESWAN images were 27 and (1-239) in whole brain, 13 and (1-89) in cerebral superficial region, 5 and (0-111) in cerebral deep region and 1 and (0-39) in posterior fossa region, respectively; whereas, on GRE T2* weighted images, they were 7 and (1-34) in whole brain, 5 and (1-27) in cerebral superficial region, 2 and (0-25) in cerebral deep region and 0 and (0-4) in posterior fossa region, respectively. There were significant statistical differences between the two sequences in revealing the lesions in all the four regions (Z=-3.519,-3.182,-3.185,-2.677,P＜0.05). Conclusion In ESWAN sequence, multi-echo acquisition ensured sufficient magnetic susceptibility for detecting small hemorrhagic lesions. So, ESWAN is more sensitive to small hemorrhage, which revealed more hemorrhagic lesions than conventional GRE T2*WI and presented more valuable information for the diagnosis of DAI.     

联合SWI与DWI在急性脑弥漫性轴索损伤中的应用价值

目的：评价联合磁敏感成像（SWI）与扩散加权成像（DWI）在急性期脑弥漫性轴索损伤中的应用价值。方法：32例脑弥漫性轴索损伤急性期患者,所有患者行常规MRI序列、DWI及SWI序列全脑扫描。结果：共检出病灶313个,T1WI 78个,T2WI 207个,FLAIR 292个,DWI 286个,SWI 297个。SWI显示245个病灶内分布斑片状、点状出血灶,其它序列共显示43个内分布出血灶。SWI、DWI病灶检出率高于常规T2WI（χ2=82.465,χ2=59.584;P〈0.01）,SWI、FLAIR及DWI病灶检出率无明显差异（χ2=3.052;P〉0.05）。结论：联合SWI与DWI有利于提高急性脑弥漫性轴索损伤的检出率,有助于准确评价病变的严重程度,SWI与DWI应作为急性脑弥漫性轴索损伤的常规扫描序列组合。