SWI在出血性弥漫性轴索损伤诊断中的应用

目的 :探讨SWI在诊断出血性弥漫性轴索损伤(DAI)中的影像学表现特点,以提高诊断准确率。方法 :回顾性分析70例经临床及影像学确诊的出血性DAI患者的MRI资料,将SWI与常规MRI(T1WI、T2WI和FLAIR)及DWI对比,评价SWI对出血性DAI检出的优越性。结果:70例SWI均得到明确显示。SWI发现病灶436个,明显多于T1WI显示的98个、T2WI显示的132个、FLAIR显示的236个、DWI显示的302个;SWI典型表现为:脑白质、皮髓质交界区、基底节、胼胝体、小脑上脚、脑干背外侧等易损区散在点状、串珠状、斑点状、团状、点片状显著低信号灶,边界清晰,大小不均呈多灶性。结论:SWI比常规MRI及DWI序列对出血性DAI的检出更敏感,能检出更多微出血灶,结合常规MRI及DWI序列能做出出血性DAI的定性及定量诊断,为出血性DAI的早期诊断及预后评估提供更多帮助。     

MR各成像序列对脑弥漫性轴索损伤的诊断价值

目的比较MR各序列成像诊断脑弥漫性轴索损伤(DAI)的价值。方法对21例临床诊断DAI的患者行常规自旋回波(SE)T1WI、快速自旋回波(TSE)T2WI、流动衰减反转恢复序列(FLAIR)、扩散加权成像(DWI)和小角度激发快速梯度回波序列(FLASH)扫描,比较各序列脑内病灶的显示率,分析其信号特征。结果FLASH为显示DAI病灶最敏感的序列,能显示常规序列所不能显示的DAI小针尖样大小的出血灶。21例各序列脑内各部位DAI病灶平均检出数依次为:T1WI(0.78±0.58)个、T2WI(1.96±1.30)个、FLAIR(2.98±2.39)个、DWI(3.67±2.75)个、FLASH(6.24±5.46)个。FLASH的DAI病灶检出数最高,与SE T1WI、TSE T2WI的差异有统计学意义(q值分别为3.14、2.47,P值均<0.05)。结论FLASH序列能提高DAI病灶的检出数及早期诊断率,应作为MR诊断DAI的首选序列。     

联合DWI和常规MRI对非出血性弥漫性轴索损伤的诊断价值

目的 探讨扩散加权成像(DWI)和常规MRI对非出血性弥漫性轴索损伤(DAI)的诊断价值以及推测非出血性DAI病灶表观扩散系数值(ADC)变化的病理基础.资料与方法 回顾性分析17例经临床和影像证实的非出血性DAI患者的常规MRI和DWI资料,比较两者对非出血性DAI病灶的检出数目,并测量DWI所发现病灶的ADC值.结果 DWI和液体衰减翻转恢复(FLAIR)序列共发现各期非出血性DAI病灶121个,17例患者中15例胼胝体受累;其中DWI显示病灶但FLAIR显示为阴性的各期病灶总数为47个,而FLAIR显示病灶但DWI显示为阴性的各期病灶总数为25个;非出血性DAI病灶的ADC值可以降低、升高或者无变化.结论 对于急性期和亚急性期非出血性DAI病灶的显示,DWI比FALIR序列敏感,差异有统计学意义(P＜0.05).联合DWI和FALIR可以提高非出血性DAI病灶的检出率,非出血性DAI病灶的ADC值的升高和降低反映了轴索损伤的程度不同,有助于临床准确评估病情.     

多序列MRI评估脑外伤微出血及弥漫性轴索损伤

目的探讨MR常规序列(T1WI、T2WI、T2FLAIR)、扩散加权成像(diffusion-weighted imaging, DWI)及磁敏感序列(susceptibility weighted imaging, SWI)在脑外伤微出血及弥漫性轴索损伤(DAI)中的应用价值。方法对48例脑外伤患者,应用3.0T MR行常规MRI、DWI及SWI序列成像,比较各序列微出血灶及DAI病灶的检出率差异,并分析病灶在这些序列上的位置分布特点、信号特征。结果联合多种序列共检出547个剪切灶及微出血灶。T1WI检出205个病灶,T2WI检出358个病灶,T2FLAIR检出432个病灶,DWI检出396个病灶,SWI检出471个病灶,SWI病灶检出率高于常规T1WI(χ^2=273.94)、T2WI(χ^2=63.59)、T2FLAIR(χ^2=9.648)、DWI序列(χ^2=31.27),其检出率差异具有统计学意义(P<0.01)。DWI检出的大部分(80%)非出血性剪切灶表现为扩散受限、ADC值减低。SWI图像上微出血灶表现为条状、点状及类圆形低信号,病灶主要分布在皮髓质交界区及深部脑白质区域,位于皮髓交界区病灶排列呈甩鞭样或串珠状,具有特征性。结论 SWI序列对脑外伤微出血的敏感性高,多种序列联合应用对脑外伤微出血和DAI各期的诊断有重要的临床价值。     

脑弥漫性轴索损伤的MRI诊断价值与序列优化

目的比较MR各序列成像诊断脑弥漫性轴索损伤(DAI)的价值,优化MRI显示DAI的最佳序列组合.材料和方法对23例DAI患者行常规快速自旋回波(FSE)T1WI、T2WI 、液体衰减反转恢复序列(FLAIR)和场回波序列(FE)T2*WI、快速场回波-平面回波(FFE-EPI)T2*WI扫描,比较各种序列对DAI的显示率,分析其信号特征.结果82个病灶中47个为非出血性病灶,FLAIR显示47个,常规序列显示42个,FLAIR序列对非出血性DAI病灶显示多于常规序列.35个为出血性病灶,FE显示35个,常规序列显示21个,FE和FFE-EPI序列对出血性DAI的检出率、对比度明显高于常规序列.结论FLAIR FE或FFE-EPI序列组合可以准确诊断不同类型的DAI.     

MR磁敏感加权成像对脑弥漫性轴索损伤的诊断价值

目的 探讨磁敏感加权成像技术(SWI)在脑弥漫性轴索损伤(DAI)中的应用价值.方法 27例DAI患者行1.5 T MR检查,扫描方法为T1WI、T2WI、FLAIR及SWI序列扫描,比较不同序列对DAI脑内病灶的显示率并分析其信号特征,评价SWI在检查和诊断中的作用.结果 27例各序列脑内各部位DAI病灶平均检出数依次为:T1WI 0.35±0.27 、T2WI 1.74±0.81 、FLAIR 3.04±2.11 、SWI 7.25±4.86,SWI检出数最多,共检出DAI出血灶1175个,与T1WI、T2WI和FLAIR的差异有统计学意义(Z值分别为-6.324,-5.752,-4.357,P<0.01),SWI可以显示常规序列不能显示的针尖大小的出血灶,且病灶边界显示更加清晰.DAI出血病灶主要分布在皮髓交界区、基底节、胼胝体、脑干及小脑等区域,SWI图像上表现为大小不等的斑点状、结节状、条索状显著低信号.结论 SWI对DAI出血性病灶的检出具有极高的敏感性,能够检出更多、更小病灶,且病灶显示更加清晰,应作为MR诊断DAI常规序列.     

3.0T磁共振磁敏感加权成像对出血性脑梗死的诊断和鉴别诊断价值

目的探讨3.0T磁共振磁敏感加权成像(SWI)对出血性脑梗死的诊断和鉴别诊断价值。方法对430例脑梗死患者行MR的T1WI、T2WI、DWI与SWI扫描,分析T1WI、T2WI、DWI和SWI对出血性脑梗死检出率的差异和SWI对于出血性脑梗死的鉴别诊断价值。结果 SWI检出出血性脑梗死45例,T1WI检出20例,T2WI检出28例,DWI检出31例。结论 SWI较MR常规序列(T1WI和T2WI)和DWI序列可检出更多的出血性脑梗死病例;可早期发现脑梗死中的出血灶,明显优于MR常规序列(T1WI和T2WI)和DWI序列;具有一定的鉴别诊断价值;可作为出血性脑梗死检查的一线方法或常规序列。     

磁敏感加权成像在弥漫性轴索损伤诊断和分级中的临床应用

目的探讨磁敏感加权成像(susceptibility-weighted imaging,SWI)在弥漫性轴索损伤(diffuse axonal injury,DAI)的临床诊断和分级中的应用价值。资料与方法 26例DAI患者均行3.0 T MR检查,扫描序列包括T1WI、T2WI、液体衰减反转恢复(FLAIR)、扩散加权成像(DWI)及SWI,比较不同序列对DAI脑内病灶的显示率并分析其信号特征,评价SWI在DAI检查、诊断和分级中的作用。结果各序列显示脑内各部位DAI病灶平均检出数依次为:T1WI(0.327±0.910)、T2WI(0.523±1.332)、FLAIR(1.179±2.832)、DWI(1.417±3.579)、SWI(5.340±10.483),其中SWI序列检出DAI病灶的数目最多,共检出DAI出血灶833个,与T1WI、T2WI、FLAIR和DWI的差异有统计学意义(F值分别为12.42、14.29、15.34、20.36,P<0.001)。在SWI表现为斑点状或小结节低信号改变,位于白质及皮髓交界区病灶排列呈甩鞭样或串珠状,具有特征性。在SWI上,38.46%(10/26例)患者为DAI分级Ⅰ级,26.92%(7/26例)患者为DAI分级Ⅱ级,34.62%(9/26例)患者为DAI分级Ⅲ级,DAI分级与格拉斯哥昏迷评分(GCS)之间具有相关性(r=-0.759,P=0.00026),DAI的SWI分级能较好地反映DAI的损伤程度。结论SWI对DAI出血性病灶的检出具有较高的敏感性,能较常规MRI其他序列检出更多、更小病灶,其呈甩鞭样或串珠状排列更能体现DAI的损伤特点,较常规MRI序列更好地对DAI进行分级诊断,为临床预后提供重要依据。     

The Application of Susceptibility Weighted Imaging in Diagnosis and Classification of Diffuse Axonal Injury

目的 探讨磁敏感加权成像( susceptibility-weighted imaging,SWI)在弥漫性轴索损伤(diffuse axonal injury,DAI)的临床诊断和分级中的应用价值.资料与方法 26例DAI患者均行3.0 T MR检查,扫描序列包括T1WI、T2WI、液体衰减反转恢复(FLAIR)、扩散加权成像(DWI)及SWI,比较不同序列对DAI腩内病灶的显示率并分析其信号特征,评价SWI在DAI检查、诊断和分级中的作用.结果 各序列显示脑内各部位DAI病灶平均检出数依次为:T1WI (0.327 +0.910)、T2 WI (0.523±1.332)、FLAIR(1.179±2.832)、DWI(1.417±3.579)、SWI (5.340±10.483),其中SWI序列检出DAI病灶的数目最多,共检出DAI出血灶833个,与T1WI、T2WI、FLAIR和DWI的差异有统计学意义(F值分别为12.42、14.29、15.34、20.36,P＜0.001).在SWI表现为斑点状或小结节低信号改变,位于白质及皮髓交界区病灶排列呈甩鞭样或串珠状,具有特征性.在SWI上,38.46％(10/26例)患者为DAI分级Ⅰ级,26.92％(7/26例)患者为DAI分级Ⅱ级,34.62％(9/26例)患者为DAI分级Ⅲ级,DAI分级与格拉斯哥昏迷评分(GCS)之间具有相关性(r=-0.759,P=0.00026),DAI的SWI分级能较好地反映DAI的损伤程度.结论 SWI对DAI出血性病灶的检出具有较高的敏感性,能较常规MRI其他序列检出更多、更小病灶,其呈甩鞭样或串珠状排列更能体现DAI的损伤特点,较常规MRI序列更好地对DAI进行分级诊断,为临床预后提供重要依据.     

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.     

Diffusion-weighted imaging for the evaluation of diffuse axonal injury in closed head injury

PURPOSE: The purpose of this work was to compare diffusion-weighted imaging (DWI) with conventional MRI in the detection of shearing injuries in acute closed head injuries. METHOD: Twenty-five patients (19 male, 6 female) were examined within 48 h of trauma. Conventional MRI included T2-weighted fast spin echo, fluid-attenuated inversion recovery (FLAIR), and T2*-weighted gradient echo sequences. Full tensor DWI with calculation of apparent diffusion coefficient (ADC) maps was also performed. Lesions were identified and compared on all sequences. RESULTS: Four hundred twenty-seven lesions were counted by the combined use of all sequences. DWI identified 70 lesions not seen on conventional MRI. DWI identified 310 shearing injuries, followed by T2/FLAIR (n = 248) and T2* (n = 202). The majority of DWI-positive lesions showed decreased diffusion (65%). CONCLUSION: DWI is valuable in closed head injury because it identifies additional shearing injuries not visible on T2/FLAIR or T2* sequences. Furthermore, DWI/ADC maps differentiate between lesions with decreased or increased diffusion. DWI is less sensitive than T2* imaging for detecting hemorrhagic lesions.     

联合多种MRI序列评估弥漫性轴索损伤

目的:探讨弥漫性轴索损伤(DAD在MR扩散加权成像,T2加权液体衰减翻转恢复序列(T2- FLAIR)及增强梯度回波T2*加权血管成像序列(ESWAN)上的影像学特征及各序列的诊断价值,合理规划DAI患者的MRI检查方案.方法:10例DAI患者在伤后两周内行DWI、T2-FLAIR及ESWAN检查,DWI为3个垂直方向...     

Role of diffusion-weighted magnetic resonance imaging in diffuse axonal injury

PURPOSE: To determine whether the signal changes on magnetic resonance imaging (MRI), including fluid attenuated inversion recovery (FLAIR), T2*-weighted gradient echo (GE) imaging, and diffusion-weighted imaging (DWI) in diffuse axonal injury (DAI) patients correlate with the clinical outcome. MATERIAL AND METHODS: We diagnosed patients with DAI based on the following criteria: 1) a loss of consciousness from the time of injury that persisted beyond 6 h; 2) no apparent hemorrhagic contusion on computed tomography (CT); 3) the presence of white matter injury on MRI. Twenty-one DAI patients were analyzed (19 M, 2 F, mean age 34 years) with MRI (FLAIR, T2*-weighted GE imaging, and DWI). RESULTS: 325 abnormalities were detected by MRI within a week after injury. The T2*-weighted GE imaging was significantly more sensitive than FLAIR and DWI in diagnosing DAI. DWI detected only 32% of all lesions, but could depict additional shearing injuries not visible on either T2*-weighted GE imaging or FLAIR. The mean number of lesions in brainstem detected by DWI in the favorable group (good recovery/moderately disabled) was significantly smaller than in the unfavorable group (severely disabled/vegetative survival/death). This trend was not observed on the T2*-weighted GE imaging and FLAIR findings. CONCLUSION: DWI cannot detect all DAI-related lesions, but is a potentially useful imaging modality for both diagnosing and assessing patients with 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。     

弥散加权MRI在脑梗塞诊断中的初步应用

目的：探讨弥散加权ＭＲＩ（ＤＷＩ）对早期脑梗塞诊断的敏感性和对急性与非急性脑梗塞的鉴别诊断价值。材料和方法：３１例脑梗塞（４例超急性,７例急性,１２例亚急性,８例慢性）患者行头颅单次激发回波平面弥散加权ＭＲＩ和常规ＭＲＩ扫描。结果：超急性、急性和亚急性脑梗塞在ＤＷＩ上均表现为高信号,其中４例超急性脑梗塞常规ＭＲＩ阴性。慢性脑梗塞除１例（发病１５天）ＤＷＩ表现为高信号,其余表现为混杂信号、等信号或低信号。６例患者常规ＭＲＩ显示多发脑梗塞灶,但ＤＷＩ显示１个急性高信号病灶。结论：ＤＷＩ对急性脑梗塞,尤其是超急性脑梗塞较常规ＭＲＩ具有更高的敏感性;ＤＷＩ还可以鉴别急性和非急性脑梗塞。     

MR imaging of corpus callosal injuries]

The MR imaging and CT findings of corpus callosal injury were analyzed in 32 of 224 patients with acute head injuries. MR imaging was more sensitive than CT in the detection of callosal injuries. All 9 hemorrhagic lesions were visualized on both MR imaging and CT. Fifteen of 23 nonhemorrhagic lesions were not visualized on CT, although all nonhemorrhagic lesions were visualized on MR imaging. Twenty-four lesions of the corpus callosum were located in the splenium, but no lesion was located in the rostrum. Diffuse axonal shear injuries were visualized in 25 patients with callosal injury as associated traumatic lesions. Twenty-three patients with callosal injury had low initial Glasgow Coma Scale scores (less than 9), but 9 patients had high scores. Associated diffuse axonal shear injuries, especially in the brain stem could be a possible explanation for this difference. MR imaging is useful to detect traumatic lesions of the corpus callosum.     

Prediction of recovery from a post-traumatic coma state by diffusion-weighted imaging (DWI) in patients with diffuse axonal injury

Introduction To determine whether diffusion-weighted magnetic resonance (MR) imaging findings combined with initial clinical factors indicate the depth of shearing lesions in the brain structure and therefore relate to coma duration in diffuse axonal injury (DAI). Methods A total of 74 adult patients (48 male and 26 female) with DAI were examined with conventional MR imaging and diffusion-weighted MR imaging between 2 hours and 20 days after injury. Apparent diffusion coefficient (ADC) maps were obtained and the mean ADC values of each region of interest (ROI) were measured using MRI console software. The involvement of the brainstem, deep gray matter, and corpus callosum was determined for each sequence separately as well as for the combination of all sequences. The correlations between MR imaging findings indicating the presence of apparent brain injury combined with initial clinical factors were determined. Results Clinical characteristics, such as initial score on the Glasgow coma scale (GCS), age and number of all lesions, and ADC scores were predictive of the duration of coma. Conclusion It was possible to predict post-traumatic coma duration in DAI from cerebral MR imaging findings combined with clinical prognostic factors in the acute to subacute stage after head injury. Age, ADC scores, GCS score and number of lesions were highly significant in predicting coma duration. The technique presented here might provide a tool for in vivo detection of DAI to allow the prediction of the coma duration during the early stages in patients with traumatic brain injury. This paper is funded by Guangdong Provincial Department of Science and Technology, China (Grant No. 2005B33801010).     

Conspicuity of diffuse axonal injury lesions on diffusion-weighted MR imaging

OBJECTIVE: (1) To detect diffuse axonal injury (DAI) lesions by diffusion-weighted imaging (DWI), as compared with fluid-attenuated inversion recovery (FLAIR) imaging and (2) to evaluate hemorrhagic DAI lesions by b0 images obtained from DWI, as compared with gradient-echo (GRE) imaging. METHODS: We reviewed MR images of 36 patients with a diagnosis of DAI. MR imaging was performed 20 h to 14 days (mean, 3.7 days) after traumatic brain injury. We evaluated: (1) conspicuity of lesions on DWI and FLAIR and (2) conspicuity of hemorrhage in DAI lesions on b0 images and GRE imaging. RESULTS: DWI clearly depicted high-signal DAI lesions. The sensitivity of DWI to lesional conspicuity in DAI lesions was almost equal to that of FLAIR. The sensitivity of b0 images to identification of hemorrhagic DAI lesions was inferior to that of GRE. CONCLUSION: DWI is as useful as FLAIR in detecting DAI lesions. GRE imaging is still the superior tool for the evaluation of hemorrhagic DAI.     

磁共振扩散加权成像对结肠癌术后肝转移灶检出的临床研究

目的:探讨磁共振扩散加权成像对结直肠癌肝转移的诊断价值。方法:27例结直肠癌患者行肝脏磁共振扩散加权成像、非增强磁共振和多层CT检查。阅片前告知阅片者患者为结直肠癌术后,但不提供临床病史和既往影像学资料。结果:多层CT、非增强磁共振和扩散加权成像对肝转移灶的敏感度分别为72%(45/63)、76%(48/63)和93%(58/63),扩散加权成像对肝转移灶具有更高的敏感度且与多层CT和非增强MRI相比,差异有显著性意义。扩散加权成像对肝转移患者敏感度最高(82%),而多层CT和非增强MRI分别为77%和66%。结论:磁共振扩散加权成像对结直肠癌肝转移灶的检出率高于多层CT和非增强MRI。