CT与MRI对腔隙性梗死的诊断价值分析

目的比较CT与MRI对腔隙性梗死的诊断价值。方法选择腔隙性梗死患者40例为研究对象,均于入院3h内行急诊螺旋CT及MRI检查。以临床诊断为准,观察CT与MRI对腔隙性梗死病灶数量及部位诊断情况。比较CT与MRI对发病24h、24~72h、72h患者脑内病灶及径线5mm、5~10mm和10~15mm病灶检出情况。结果 (1)脑梗死病灶分布于额叶6例,顶叶6例,颞叶6例,枕叶4例,基底节区8例,丘脑3例,脑干3例,小脑4例。40例患者中,CT共显示21例患者存在脑梗死病灶,共显示病灶45处。MRI共显示38例患者存在脑梗死病灶,共显示病灶79处。MRI对脑梗死病灶检出率显著高于CT,差异具有统计学意义(P0.05)。(2)MRI对24h、24~72h脑梗死病灶的检出率显著高于CT,差异具有统计学意义(P0.05)。两者在72h病灶的检出中,差异无统计学意义(P0.05)。(3)其中MRI对径线5mm及5~10mm腔隙性梗死病灶检出率显著高于CT,差异具有统计学意义(P0.05)。在病灶径线10~15mm病灶的检出中,MRI及CT比较差异无统计学意义(P0.05)。结论在腔隙性梗死的诊断中,MRI较CT更具有优势。     

CT与MRI对多发性脑梗死的诊断价值对比研究

目的对比CT与MRI对多发性脑梗死的诊断价值。方法我院2012-02—2015-02收治的多发性脑梗死患者,选取164例为研究对象,按年龄分为中年组和老年组,对比分析CT和MRI对脑梗死的诊断率;按脑梗死的发生时间、病灶部位、梗死灶的大小以及是否发展为血管性痴呆等分组,对比CT和MRI的检出率,统计CT与MRI对多发性脑梗死的总检出率及检出时间,并进行对比分析。结果老年组嗜睡、偏瘫和锥体束征发生率明显高于中年组(P0.05);入院后6、24h,2组MRI诊断率均明显高于CT(P0.05或P0.01)。在24h内组与24~72h组,CT的检出率均明显低于MRI;72h组中,CT与MRI的检出率比较差异无统计学意义(P0.05);CT对脑干及小脑部位的梗死检出率明显低于MRI(P0.05);MRI对脑梗死微小病灶的检出能力明显优于CT(P0.05);颅脑CT对非血管性痴呆组患者的梗死检出率明显低于MRI(P0.05),而对于血管性痴呆患者梗死的检出率差异无统计学意义(P0.05)。结论对于多发性脑梗死的诊断,MRI检查较CT具有明显优势。     

早期腔隙性脑梗死的临床与磁共振弥散加权成像

目的:从临床角度探讨磁共振弥散加权成像(diffusion weighted i maging,DWI)对早期腔隙性脑梗死(lacu-na cerebral infarction,LI)的诊断价值。方法:分析60例早期腔隙性脑梗死患者的临床资料,同时进行MRI常规序列及DWI序列检查,并由4位经验丰富的医师在不了解患者临床体征的情况下进行阅片,记录出病变所在的详细的神经解剖部位,对同一层面所有的磁共振像进行比较,重点分析信号强度和病灶大小。数据经统计学分析。结果:60例患者中高血压病45例(75%)、高脂血症21例(35%)、糖尿病18例(30%);常见临床类型为纯运动性轻偏瘫(PMH)及变异型20例,腔隙状态(LS)12例,无症状腔隙性梗死(ALI)10例,感觉运动性卒中(SMS)8例。病灶部位主要为尾状核(29.1%)、豆状核(23.3%)、放射冠(15.1%)、丘脑(10.5%)、内囊(7.0%)。60例患者中超急性期(≤6小时)20例,DWI扫描均检出病灶,常规MRI扫描均未检出病灶;急性期(7~24小时)患者22例,DWI扫描均检出病灶,DWI检出率为100%,而常规MRI共检出12例,检出率为55%(P<0.05)。DWI在超早期及急性期可显示T2加权像不能显示的病灶,并随时间延长显影范围逐渐增大。在T2加权像上可显示的病灶中,DWI可更清楚、更全面地显示病灶,大于T2病灶。结论:高血压病是LI的直接原因;腔隙病灶主要位于基底节,LS及ALI的检出率有上升趋势,DWI对早期LI的诊断显著优于常规MRI。DWI应作为早期LI的首选检查方法。     

磁共振扩散加权成像在鉴别新陈腔隙性脑白质梗死中的价值

目的分析新陈腔隙性脑白质梗死的T2WI、扩散加权成像(DWI)信号特点，比较两种梗死的病灶与脑白质、病灶与脑脊液对比度及表观扩散系数(ADC)，评价DWI在鉴别新陈腔隙性脑白质梗死方面的作用。方法急性期腔隙性脑白质梗死患者27例，选择43例陈旧腔隙性脑白质梗死患者作对照。测量病灶、正常脑白质、脑脊液信号强度，计算病灶与脑白质、病灶与脑脊液的对比度。测量病灶、正常脑组织、脑脊液的ADC值并比较。结果(1)急性脑白质腔隙性梗死DWI呈高信号，ADC图呈等或低信号。DWI的病灶与脑白质、病灶与脑脊液对比度均优于T2WI。(2)陈旧脑白质腔隙性梗死DWI呈等信号，ADC图呈高信号。DWI的病灶与脑白质对比度不如T2WI。(3)DWI图像上，急性腔隙性脑白质梗死病灶与脑白质、病灶与脑脊液对比度明显高于陈旧病灶，ADC则明显低于陈旧病灶，有助于区分新陈腔隙性梗死。结论DWI的检查时间短，诊断和鉴别意义大，建议在可能的情况下，将DWI作为急性卒中样发作患者的常规检查序列。     

MRI与CT在多发性脑梗死中的诊断价值

目的分析MRI与CT在多发性脑梗死中的诊断价值。方法选取2012-01—2014-01我院180例多发性脑梗死患者,均常规行CT与MRI检查,按脑梗死的发生时间、梗死灶大小、梗死部位以及是否发展为血管性痴呆等分组,对比CT与MRI对多发性脑梗死患者的诊断准确率及效率。结果本组患者的CT检查总检出率为60.0%,MRI为95.6%,2组比较差异有统计学意义(χ2=66.04,P0.01)。24h以内组及24~72h组MRI的检出率明显高于CT(分别为89.6%vs43.8%,96.6%vs 53.4%),差异有统计学意义(P0.01);72h组MRI和CT的检出率分别为100%、90.9%,差异无统计学意义(P0.05)。梗死灶2mm以内组,MRI的检出率明显高于CT(P0.05),而梗死灶≥2mm组,CT和MRI的检出率比较,差异无统计学意义(P0.05)。MRI对脑干及小脑梗死的检出率明显高于CT,差异有统计学意义(P0.05)。结论对于多发性脑梗死的诊断,MRI检查较CT检查更具优势,但费用较高,临床应对患者的梗死部位及其他具体情况作初步判断,以便采取更合适的检查方法。     

核磁共振在腔隙性梗死中的诊断价值

目的探讨核磁共振对腔隙性梗死的诊断价值。方法选取2010—2011年我院收治的腔隙性梗死老年患者100例,均在CT颅脑扫描后行MRI检查,对病灶分布特点及两种方式的检出结果进行分析。结果 100例患者中MRI病灶共检出为964个,病灶分布主要为豆状核（50.31%）,其次为放射冠（28.63%）、丘脑（10.89%）,CT共检出病灶179个。CT漏检病灶以直径〈10mm为主。结论腔隙性梗死病灶以多发居多,容易在CT影像学检查中忽略,尤其是直径〈10mm的病灶,在临床诊断中以核磁共振为主,应结合临床表现与病理诊断谨慎判断,避免延误病情。     

CT与MRI在腔隙性梗死诊断中的对比分析

腔隙性梗死是指脑血管深穿动脉阻塞后形成的微梗死,在脑实质中遗留下不规则的大小2～50mm的腔隙。常见于50岁以上老年人。病灶好发于基底节、内囊、丘脑和脑干[1]。此病发展变化快,如不及时治疗,后果严重。早期明确诊断对腔隙性梗死的治疗至关重要[2]。本文通过回顾性分析我院神经内科2012-01—12收治的31例腔隙性梗死患者的CT和MRI检查资料,对比研究CT与MRI在腔隙性梗死中的诊断价值。     

比较CT MRI对出血性脑梗死的诊断价值

目的探讨CT(电子计算机断层扫描)、MRI(核磁共振成像)对出血性脑梗死(HI)的诊断价值。方法回顾性分析我院2011-03—2012-03 72例HI患者的CT与MRI诊断表现,比较CT与MRI对HI不同出血分期、不同出血部位、病灶大小、检出病灶距离发病时间间隔及检测所需时间。结果 MRI检出率(86.11%)高于CT(59.72%),差异有统计学意义(P0.05)。MRI幕上出血检出率65.28%,幕下出血检出率15.28%,高于CT的16.67%、2.78%,差异具有统计学意义(P0.05)。MRI检测的病灶(9.02±4.31)mm小于CT(12.12±4.89)mm,差异有统计学意义(P0.05);MRI检出病灶距离发病时间间隔(0.71±0.42)d短于CT(1.45±0.51)d,检测所需时间(20.06±6.18)min长于CT(9.35±4.67)min,差异有统计学意义(P0.05)。结论 MRI诊断HI的灵敏度比CT高,能判断出血分期、出血部位,可发现亚急性、慢性出血,缩短检出病灶距离发病时间间隔,但检测时间稍长,可为临床治疗提供一定的指导意义。     

DWI在诊断脑梗死超急性期中的应用分析

目的探讨磁共振弥散加权成像在诊断脑梗死超急性期中的应用情况。方法选取我院2012-04—2015-04收治的66例超急性脑梗死患者为研究对象,使用磁共振弥散加权成像在不同时间点对其进行诊断,并与磁共振成像平扫的结果进行比较。结果 3组超急性脑梗死患者中病灶部位比较差异无统计学意义(χ~2=0.429,P=0.807);病灶部位在脑干、顶叶、小脑、额叶、枕叶的3组患者人数差异无统计学意义(χ~2=0.795,P=0.672);存在大面积脑梗死的3组人数差异无统计学意义(χ~2=0.214,P=0.898);在第1组患者中,使用磁共振弥散加权成像检查出患者脑部病灶18例,使用磁共振成像检出10例,差异具有统计学意义(χ~2=6.286,P=0.012);在第2组患者中,使用磁共振弥散加权成像检查出患者脑部病灶20例,使用磁共振成像检出13例,差异具有统计学意义(χ~2=5.254,P=0.022);在第3组患者中,使用磁共振弥散加权成像检查出脑部病灶19例,使用磁共振成像检出11例,差异具有统计学意义(χ~2=7.467,P=0.006)。结论对超急性期脑梗死患者使用磁共振弥散加权成像可较T2和T2FLAIR等平扫技术更早发现病变,在临床上具有较高的应用价值。     

脑小血管病患者认知状态与神经影像学特征的相关性分析

目的:本研究旨在探讨脑小血管病患者认知状态与皮质下腔隙性梗死部位及病灶数、白质病变和内侧颞叶萎缩之间的关系。方法:本研究纳入59例在上海交通大学医学院附属仁济医院神经内科脑血管病二级预防门诊登记的最近一次症状性缺血性卒中病史3个月的脑小血管病患者。根据详细的神经心理学评估结果,将59例患者分入无认知障碍组(24例)、轻度认知障碍组(22例)和血管性痴呆组(13例),采用头颅磁共振成像多重序列检查及斜冠状面重建,依据所得图像进行皮质下腔隙性梗死病灶计数、白质病变评分和内侧颞叶萎缩评分。结果:脑小血管病患者认知障碍的发生与皮质下腔隙性梗死病灶总数有关(P=0.004),其中皮质下白质部位腔隙性梗死病灶数在3组之间的差异有统计学意义(P=0.001);轻度认知障碍组和血管性痴呆组患者丘脑部位腔隙性梗死病灶数多于无认知障碍组的患者,但差异无统计学意义(P=0.058)。大部分的白质病变病灶位于额叶和顶枕叶,颞叶和基底节的白质病变较少。3组之间双侧额叶(P=0.033)和双侧基底节(P=0.009)的白质病变评分差异有统计学意义。59例患者中,43例完成磁共振成像斜冠状面重建。左右内侧颞叶萎缩一般呈同步发展;3组之间左或右内侧颞叶萎缩评分的差异均有统计学意义(P值均0.001)。在13例左内侧颞叶萎缩评分≥2分的患者中,11例为无认知障碍组和轻度认知障碍组患者;血管性痴呆组患者均有内侧颞叶萎缩,其中6例患者的左右侧平均内侧颞叶萎缩评分≥2分。多因素分析结果显示,皮质下白质腔隙性梗死病灶数[比值比:2.39(95%可信区间:1.19~5.80),P=0.005]和左内侧颞叶萎缩评分[比值比:10.21(95%可信区间:2.02~51.75),P=0.003]是脑小血管病认知功能的独立危险因素。结论:脑小血管病患者的认知损害程度与皮质下白质腔隙性梗死病灶数和左内侧颞叶萎缩评分相关。     

Magnetic resonance imaging study of the brain in aged volunteers: T2 high intensity lesions and higher order cortical function

Abstract The aims of the present study were to clarify the findings of magnetic resonance imaging (MRI) in the aging brain, and to relate the MRI findings to higher order cortical function. A total of 118 healthy aged volunteers (41 men, 77 women) underwent cranial MRI electroencephalography (EEG), Benton visual retention test (BVRT) and interview. The subjects had no past history or clinical evidence of cerebrovascular disorder, head trauma or dementia and were living at home without any difficulty. The majority of the subjects have participated in this series of studies since 1982. Using a 1.5 T superconductive MR instrument, T1-weighted, proton density and T2-weighted images were obtained. The MRI data were rated visually by regarding 12 items according to fixed criteria. T2 high signal intensity (T2HSI) lesions were found in 69.5% of subjects, the prevalence of which increased with age. T2HSI lesions were most frequently found in the basal ganglia (61.9%), followed by the thalamus (39.0%), parietal lobe (37.0%), temporal lobe (12.7%) and pons (8.5%). Among these lesions, lacunar infarction showed low signal intensity in T1-weighted images and was found in 24.6% of subjects, the prevalence also increasing with age. These findings, including brain atrophy determined according to similar criteria, were correlated closely with the subjects' age. The results of BVRT showed a close relation with T2HSI, suggesting that T2HSI may influence cognitive function. When the subjects were classified according to the presence of T2HSI, lacunar infarction and EEG abnormalities, brain atrophy was significantly milder in a group of subjects with T2HSI(-), lacunar infarction(-) and normal EEG than in the other groups. This suggests that changes seemingly representing physiological aging may be promoted by another pathological which also exerts influences on higher order cerebral function.     

A case showing Wallerian degeneration of the bilateral middle cerebellar peduncles on MRI followed by the right pontine infarction]

We report a 63-year-old man who presented with the left facial palsy, the left hemiparesis, the left limb ataxia, and the bilateral truncal ataxia. On admission, magnetic resonance imaging (MRI) showed an abnormal high intensity lesion at the right paramedian region of the upper to middle pons on T2-weighted images (T2WI). He was diagnosed as having a pontine lacunar infarction. The contralateral cerebellar lesions were caused by involvement of the pontocerebellar fibers. On the 29th day from the onset, MRI showed the new abnormal high intensity lesions at the bilateral middle cerebellar peduncles on T2WI. These lesions were supposed to be Wallerian degeneration caused by involvement of the pontocerebellar fibers. This case suggests that Wallerian degeneration occurs followed by a unilateral infarction involving pontocerebellar fibers.     

Predictive value of clinical lacunar syndromes for lacunar infarcts on magnetic resonance brain imaging

OBJECTIVE: We prospectively investigated the predictive value of clinical and CT-supported lacunar syndromes for lacunar infarcts on magnetic resonance (MR) brain imaging. PATIENTS AND METHODS: The 54 prospective, consecutive patients had clinical lacunar syndromes of acute onset and early computed tomography (CT; on admission day, i.e. < or =48 h after onset of symptoms) showing either a small deep infarct or no corresponding lesion. Taking MR (at day 2 to 4 after admission) as the gold standard, the positive predictive value of the CT-supported clinical syndrome for corresponding lacunar lesions was calculated. RESULTS: In 27 (50%) patients, early CT showed a lacunar infarct corresponding to the clinical syndrome, a further 27 (50%) patients had no fresh ischemic lesion. In 51 patients (94%), MR showed a recent lacunar infarct (hyperintense lacune in T2-weighted scans, no demarcation on T1-weighted scans and/or positive gadolinium-enhancement) corresponding to the clinical syndrome (positive predictive value 0.94, 95%, CI: 0.88 to 0.98). In 3 (6%) patients MR was normal. Aside from old unrelated ischemic (macro- and/or microangiopathic) lesions, MR revealed no acute non-lacunar infarct. CT and MR sites of lacunar lesions were matching. Compared to gold standard MR, the sensitivity of early CT for suspected lacunar lesions was 0.53 (95% CI: 0.38 to 0.67). CONCLUSION: Lacunar syndromes were highly predictive for small deep infarcts on MR. Magnetic resonance brain imaging may be redundant in the setting of a lacunar syndrome supported by a CT that excludes non-ischemic causes of stroke; it may therefore be abandoned in order to reduce costs in the health care system.     

MRI findings of small subcortical “lacunar-like” infarction resulting from large vessel disease

Small subcortical infarctions resulting from large-vessel disease are often observed. It is important to distinguish these from pure lacunar infarction resulting from small-vessel disease because the investigations and examinations differ. We investigated the differences on brain magnetic resonance imaging (MRI) between small subcortical "lacunar-like" infarcts resulting from large-vessel disease and pure lacunar infarcts. Thirteen subjects with small lacunar-like infarcts (size < 2 cm), resulting from large-vessel disease, and 30 subjects with lacunar infarcts (< 2 cm), without large-vessel disease were studied. We measured infarction size using a 1.5-T MRI device and evaluated silent subcortical hyperintensity lesions using the modified Scheltens' score. Large-vessel lesion was confirmed by conventional angiography, duplex carotid scan, and magnetic resonance angiography. There was no difference in the mean age of the two groups. Cerebrovascular risk factors and atherosclerotic complications were also comparable for the two groups. Progressive stroke was more common in the lacunar-like infarction group than in the lacunar infarction group (P = 0.004). Scores for periventricular hyperintensity, white matter hyperintensity, basal ganglia hyperintensity, and total subcortical hyperintensity scores were significantly higher in the lacunar infarction group than in the lacunar-like infarction group. The difference in basal ganglia hyperintensity scores was remarkable (P = 0.001). The enlargement of the perivascular space was also significantly greater in the lacunar infarction group than in the lacunar-like infarction group. These findings seem to reflect differences in the pathogenesis of infarction between the two groups. Silent subcortical hyperintensity lesions and enlargement of perivascular space are useful for between distinguishing small lacunar-like infarct resulting from large-vessel disease and pure lacunar infarction. This may have significant implications for the management of patients with lacunar-sized infarctions. It suggests that the pathogenesis of lacunar-sized infarction is variable.     

Chronological changes of lacunar infarctions on fluid-attenuated inversion recovery magnetic resonance images]

In 26 patients with lacunar syndromes, emergence of new lacunar infarctions were identified within 13 days from onset by diffusion-weighted magnetic resonance images. The identified lacunar infarctions were repeatedly imaged using fluid-attenuated inversion recovery (FLAIR) sequence up to 600 days from onset. On FLAIR images taken by 23 days from onset, lacunar infarctions showed homogeneous hyperintensity. On the later FLAIR images beyond 25 days from onset they were observed as heterogeneously hyperintense lesions in half of the patients. In the other patients, lacunar infarctions were observed as hypointense areas with a hyperintense rim beyond 41 days from onset, which indicates cystic transformation with surrounding gliosis. These FLAIR images of lacunar infarction differ from those of dilated perivascular space which is observed as an area of simple hypointensity.     

颈动脉粥样硬化斑块与脑梗死关系的高分辨磁共振研究

目的探讨高分辨磁共振(MRI)对颈动脉粥样硬化斑块与脑梗死关系的评估价值。方法选取驻马店市精神病医院2014-01—2016-01收治的32例经高分辨MRI检查证实的脑梗死患者为试验组,以同期我院体检的行MRI扫描的25例无脑梗死患者作对照(对照组),采用三维时间飞跃法(3D-TOF)、T1加权(T1WI)、T2加权(T2WI)及增强颈部血管成像等扫描序列,分析颈动脉斑块的成分、分型及其与脑梗死的关系。结果试验组有颈动脉粥样硬化斑块者30例(93.75%),无颈动脉粥样硬化斑块者2例(6.25%);对照组有颈动脉粥样硬化斑块者6例(24.00%),无颈动脉粥样硬化斑块者19例(76.00%);试验组颈动脉粥样硬化斑块的发生率明显高于对照组(P0.01)。试验组共发现60块颈动脉粥样硬化斑块,其中Ⅰ~Ⅱ型7块(11.67%),Ⅲ型8块(13.33%),Ⅳ~Ⅴ型19块(31.67%),Ⅵ型21块(35.00%),Ⅶ型2块(3.33%),Ⅷ型3块(5.00%);对照组共发现14块颈动脉粥样硬化斑块,以稳定性斑块为主,Ⅰ~Ⅱ型13块(92.86%),Ⅳ型1块(7.14%)。2组颈动脉不稳定斑块发生率比较差异有统计学意义(P0.05)。脑梗死患者颈总动脉、分叉处及颈内动脉3个部位的粥样硬化斑块分布情况差异无统计学意义(P0.05)。结论高分辨MRI可清晰显示颈动脉粥样斑块的内部成分,且颈动脉粥样硬化斑块与脑梗死的发生有密切的相关性,高分辨MRI可对脑梗死的发生风险作出预测,为临床防治脑梗死及疗效评价提供重要的影像学依据。     

脑膜血管型神经梅毒病灶侧和对侧核磁共振灌注加权成像特征的研究

目的 研究脑膜血管型神经梅毒的影像学特征,指导与脑梗死的鉴别诊断.方法 对神经梅毒患者进行头部MRI平扫+增强、磁共振血管成像(Magnetic Resonance Angiography,MRA)、灌注加权成像(perfusion weighted imaging,PWI)和磁敏感加权成像(Susceptibilit...     

Diffusion-weighted imaging in neonatal cerebral infarction: clinical utility and follow-up

We describe the clinical utility of echo-planar diffusion-weighted imaging in neonatal cerebral infarction. Eight full-term neonates aged 1 to 8 days referred for neonatal seizures were studied. Patients were followed for a mean of 17 months with detailed neurologic examinations at regular intervals. Head computed tomography (CT) and conventional magnetic resonance (MRI) and diffusion-weighted images were obtained. Percent lesion contrast was evaluated for 19 lesions on T2-weighted and diffusion-weighted images. Follow-up conventional MRIs were obtained in seven patients. The findings on diffusion-weighted imaging were correlated with CT and conventional MRI findings as well as with short-term neurodevelopmental outcome. Four patients had focal cerebral infarctions. Four patients had diffuse injury consistent with hypoxic-ischemic encephalopathy. Percent lesion contrast of all 19 lesions was significantly higher on diffusion-weighted images when compared with T2-weighted images. In five patients, there were lesions visualized only with diffusion-weighted imaging. In all patients, there was increased lesion conspicuity and better definition of lesion extent on the diffusion-weighted images compared with the CT and T2-weighted MR images. In seven of eight patients follow-up imaging confirmed prior infarctions. Short-term neurologic outcome correlated with the extent of injury seen on the initial diffusion-weighted imaging scans for all patients. Diffusion-weighted imaging is useful in the evaluation of acute ischemic brain injury and seizure etiology in neonates. In the acute setting, diffusion-weighted imaging provides information not available on CT and conventional MRI. This information correlates with short-term clinical outcome.     

Magnetic resonance imaging and Cogan's syndrome

We report the case of a 25-year old man with vestibulocochlear and ocular impairment compatible with Cogan's syndrome. Later on, severe headache developed. CT scan showed an ischaemic lesion in the right frontal lobe. Magnetic resonance imaging demonstrated multiple bilateral nodular lesions on T2-weighted sequences. These were unmodified at a second MRI examination performed six months later. Under corticosteroids, the neurological and ophthalmic symptoms disappeared, but the patient remained deaf. We believe that this patient had vasculitis involving the brain, with infarcts. To our knowledge, no case of Cogan's syndrome with cerebral magnetic resonance imaging has yet been reported.     

超低场磁共振成象诊断老年人缺血性脑梗塞(273例分析)

回顾分析60岁以上缺血性脑梗塞273例(含792个病灶),剖析病灶的超低场(ULF)磁共振成象(MRI)表现。在T_2权重图象上显示的病灶在T_1权重图象上有36.24％未能显示,强调检查应从T_2权重图象开始。MRI发现病变较CT早,对脑中线及后颅窝病变的显示较CT敏感和清晰。