磁共振弥散成像对急性脑梗死的诊断价值

目的探讨磁共振弥散成像对超急性、急性脑梗死的诊断价值。方法对80例疑似急性期脑梗死患者,行磁共振常规T1WI、T2WI、水抑制序列(FLAIR)、弥散加权扫描(DWI)。结果80例中,超急性期脑梗死10例,急性期32例,超急性期、急性期脑梗死在DWI上表现为高信号,T2WI上为等信号或部分稍高信号,ADC图上表现为低信号。MRI扫描未见异常2例。结论磁共振弥散成像对超急性期、急性期脑梗死病变较常规MRI敏感,在多发梗死灶中可以发现责任病灶、为临床选择治疗方案提供依据。     

1,2-二氯乙烷中毒性脑病的影像学表现

目的 探讨1,2-二氯乙烷中毒性脑病的CT、MR表现.方法 对6例临床具有脑病症状并且有1,2-二氯乙烷接触史的患者进行检查,检查包括神经学体检,CT,磁共振波谱(MR spectroscopy,MRS),弥散加权成像(diffusion weighted imaging,DWI),T1、T2加权成像及磁共振增强扫描.结果 5例进行CT检查的患者,病灶均表现为低密度,两侧对称.病灶大多累及两侧大脑半球白质(累及皮层下弓形纤维为主)、两侧齿状核、丘脑、苍白球.4例进行MRI检查的患者,均表现为上述部位广泛性T2加权高信号.CT、MRI都显示脑回肿胀,脑室系统受压变小.1例进行MR增强检查的病例未见明显异常强化.3例进行DWI检查的病例表现为双侧对称性高信号,病灶区域表观弥散系数(ADC)值降低.1例进行MRS检查的病例表现为:病灶NAA/Cr比值明显降低,而Cho/Cr比值升高.结论 神经系统体征及CT、MRI检查对1,2-二氯乙烷中毒性脑病有助于早期诊断,DWI及MRS还可以进一步反映病灶代谢改变.     

急性轻、重型胰腺炎的MRI表现与评价

目的:探讨急性轻、重型胰腺炎的MRI表现与价值.方法:对114例采用腹部屏气磁共振序列进行扫描的急性胰腺炎MRI进行回顾性分析.结果:98例诊断为急性轻型胰腺炎,表现为胰腺肿大,花边样轮廓消失.T1 WI胰腺信号降低,可低于肝脏信号,而与脾脏信号强度无明显差异;T2WI呈高或稍高信号.16例诊断为急性重型胰腺炎,T1WI可呈斑片状高信号,T2WI可出现低信号环.结论:MRI对于急性胰腺炎的诊断具有重要价值.     

新生儿胆红素脑病的MRI表现

目的 探讨磁共振成像(MRI)对新生儿胆红素脑病(NBE)诊断的价值.方法 回顾性分析28例胆红素脑病新生儿的常规MRI表现和临床资料.结果 28例患儿中27例T1WI苍白球对称性高信号.19例患儿底丘脑T1WI呈高信号,T2WI呈等信号,主要表现为底丘脑点状或"八"字形对称性短T1WI信号.8例患儿中脑、桥脑背侧、延髓T1WI呈高信号,而桥脑腹侧信号正常.扩散加权成像(DWI)显示所有胆红素脑病患儿的基底节无异常信号.结论 常规MRI及DWI有助于新生儿胆红素脑病的诊断.     

侧脑室表皮样囊肿的磁共振影像表现及其扫描技术分析

目的回顾性分析侧脑室表皮样囊肿的磁共振成像(MRI)表现,探讨磁共振(MR)扫描技术在侧脑室表皮样囊肿诊断中的价值。方法分析12例手术病理证实为侧脑室表皮样囊肿的MR影像表现及术前做MR常规平扫、增强扫描和T2FLAIR以及磁共振弥散加权成像(DWI)资料。结果 11例T1WI呈低信号,1例T1WI呈高信号,脂肪抑制像未能抑制。12例T2WI呈高信号,稍高于脑脊液。10例T2FLAIR囊内见不同数量的絮状稍高信号影,其中有2例仅在边缘出现少量絮状等高信号影。DWI均表现为明显高信号,信号不均匀。增强多无强化或或囊壁轻度强化,其中2例发生恶性变者局部囊壁呈结节状及花环状明显强化。结论侧脑室表皮样囊肿MR表现具有一定的特征性,对本病的诊断与鉴别诊断具有价值。侧脑室表皮样囊肿病灶检出方面,DWI均优于MRI平扫以及T2FLAIR,是首选扫描技术。     

肺结核瘤的磁共振诊断价值研究

目的探讨肺结核瘤的磁共振诊断价值。方法对病理证实的10例肺结核瘤行磁共振成像(MRI)平扫、磁共振扩散加权成像(DWI)和动态增强扫描的影像特点进行分析,并测量分析病变的表观弥散系数值(ADC)值。结果肺部结核瘤全部病例T1WI显示低信号,T2WI显示8例为周边高信号,中央区低信号;2例为高信号。DWI图像显示均为高信号或稍高信号,平均ADC值为(1.60±0.18)s/mm2。动态增强扫描动脉期全部病例边缘环状强化,中央区无强化或轻度强化。时间-强度曲线6例表现为缓慢爬升型,4例表现为缓慢下降型。结论磁共振平扫、DWI及ADC值结合磁共振动态增强扫描在肺部结核瘤诊断中具有重要价值,具有一定的特征性。     

原发性脑淋巴瘤的MRI功能成像和延迟强化特点

目的:探讨原发性脑淋巴瘤的MRI延迟强化方式及弥散加卡义成像、氢质了磁共振波谱、灌注加权成像的特点.方法:同顾性分析23例原发性颅内淋巴瘤的MRI延迟强化以及弥敞加权特点,同时对其中12例磁共振波谱成像和9例灌注加权成像表现进行仔细分析.结果:多发16例,单发7例,共检出50个病灶,T1.WI呈等或稍低信号,T2WI呈等或稍高信号,23例DWI呈高或稍高信号.延迟强化显示15个强化灶范围增大、8个新增强化灶、9个不均匀强化灶趋十均匀、6个强化灶内低信号范围缩小.行磁共振波谱成像的12例中增强后首次扫描即出现强化的病灶表现为Cho升高、NAA下降、出现高Lip峰,其中5个病灶出现Lac峰,另外4个新增延迟强化病灶的MRS表现为NAA轻微下降、Cho稍升高、Iip峰矮小、未见Lac峰.9例灌注加权成像显示脑淋巴瘤呈低灌注趋势.结论:综合分析常规MRI表现及其延迟强化方式、弥散加权成像、磁共振波谱成像及灌注加权成像的特点,能够做出脑淋巴瘤的定性诊断.延迟强化或许可以更充分反映病灶的数量和范围.     

乳腺黏液腺癌钼靶X线与磁共振成像特点及诊断价值

目的探讨磁共振成像(MRI)及钼靶X线摄影检查对乳腺黏液腺癌的诊断价值。方法收集本院经手术病理证实的乳腺黏液腺癌12例,回顾性分析MRI成像、X线钼靶摄影及影像表现特点。结果单纯性8例,混合性4例。MRI表现:所有病例均表现为肿块,平扫T1WI为低信号或等低信号,T2WI为高信号或极高信号;动态增强扫描病灶呈渐进性明显强化,2例呈轻度强化;磁共振弥散加权成像(DWI)病灶呈高信号,表观扩散系数(ADC)值增高。X线表现:肿块9例,不规则团片状2例,结构扭曲变形1例,内有钙化1例。病灶均表现为高密度,边缘清7例,边缘不清5例,其中边缘毛刺3例。MRI准确率71%,X线准确率67%,MRI和X线敏感性均100%。结论乳腺黏液腺癌由于含有黏液成分,MRI和X线影像表现上有一定特征,对本病诊断有一定价值,MRI准确性高于X线,二者应相互结合。     

磁共振弥散加权成像对急性皮层下脑梗塞的评价

目的 研究磁共振弥散加权成像（DWI）诊断急性皮层下脑梗塞的准确性以及对急性与非急性皮层下脑梗塞的鉴别诊断。材料与方法 对32例临床诊断为急性皮层下脑梗塞的患者和20例对照者在不同时间内进行常规MRI检查和弥散加权MRI检查,并用盲法进行对照观察。对所有病例的病变部位均按神经解剖进行准确定位并与患者的症状、体征相联系。结果 DWI诊断急性皮层下脑梗塞的敏感性、特异性及准确性分别为97％、95％和96％。32例中有3例常规MRI检查未发现急性梗塞性。另20例常规MRI检查均显示为多发梗塞,而DWI只显示单个急性病灶,且患者的症状、体征与DWI上显示的病灶相符。结论 DWI对诊断急性皮层下脑梗塞有很高的准确性,能发现常规T2WI不能发现的早期脑梗塞,并能鉴别急性与非急性梗塞。     

弥散MRI诊断颅内表皮样囊肿的价值

目的:探讨磁共振弥散加权成像(DWI)及表观弥散系数(ADC)图诊断颅内表皮样囊肿的价值.材料和方法:分析19例表皮样囊肿常规MRI和DWI的信号特征,定量测定表皮样囊肿、正常脑实质和脑脊液的ADC值.结果:17例表皮样囊肿T1WI、T2WI呈等或稍高于脑脊液信号,2例T1WI呈高低混杂信号.肿瘤边缘弧线形增强或不增强.19例肿瘤DWI呈明显高于脑实质和脑脊液信号,肿瘤较脑脊液的平均ADC值显著减低,较脑实质的平均ADC值显著增高.结论:DWI优于常规MRI发现颅内表皮样囊肿,DWI上表皮样囊肿的高信号可能是肿瘤组织的T2余辉效应所致.     

Magnetic resonance imaging in the study of brain changes due to carbon monoxide poisoning

Five cases of carbon monoxide intoxication were studied with MR imaging. The main MR findings were discussed and compared with CT results. MR imaging demonstrated SNC lesions sooner and better than CT--its images corresponding to the anatomic-pathological patterns described in literature. However, severe MR limitations--i.e., the very long execution time and the difficult monitoring of the patients--prevent this methodology from being more extensively employed in this kind of pathology.     

急性一氧化碳中毒后迟发性脑病的MRI研究进展

急性CO中毒后迟发性脑病（DEACMP）是急性CO中毒后最严重的并发症之一,其发病机制迄今不明。MRI能较好的显示DEACMP的脑组织的病理改变有重要的临床应用价值,而功能MR成像技术为该疾病开辟了新的研究方向。本文主要对MRI及功能MR技术在DECAMP中的研究近况予以综述。     

弥漫性轴索损伤的影像诊断比较

目的 :比较CT、常规MR和扩散加权成像 (DWI)对急性、亚急性脑弥漫性轴索损伤 (DAI)的诊断价值。方法 :5 0例患者在脑损伤后 2h～ 2 0d行CT、常规MR及MRDWI ,比较病变在CT、MR各种序列上的表现特点。结果 :5 0例中CT检查阴性者 2 4例 (占 48% ) ,阳性者 2 6例 ,发现DAI病灶 75个。 5 0例在MR各种序列显示病灶 2 40个 ,其中非出血性病灶 182个 ,有 45个病灶在DWI上能观察到而常规MRI无法显示 ,占 2 4.7% ,83个病灶在DWI上信号明显高于T2 WI的病灶 ,占 45 .6% ;出血性病灶 5 8个中 ,有 12个病灶CT显示 ,而在常规MR和DWI上显示不清。结论 :对DAI急性期及亚急性期非出血性病灶的显示 ,MR常规检查比CT敏感 ,MRDWI比常规MRT2 WI敏感 ,统计学差异均有显著性意义 (P <0 .0 1)。非出血性病灶在DWI上的信号强度明显高于常规MRT2 WI ,统计学差异有显著性意义 (P <0 .0 1)。对出血性病灶的显示 ,CT优于常规MRSE序列和MRDWI。     

Pallidoreticular damage in acute carbon monoxide poisoning: diffusion-weighted MR imaging findings

We describe a case of carbon monoxide poisoning that led to pallidoreticular damage and delayed leukoencephalopathy. Serial diffusion-weighted MR imaging was performed. A restricted water diffusion pattern was demonstrated in the globus pallidus and substantia nigra in the early stage. Diffusion-weighted imaging is useful for early identification of the effects of acute carbon monoxide poisoning.     

Acute carbon monoxide poisoning: diffusion MR imaging findings

During the acute stage of carbon monoxide poisoning, diffusion MR images obtained at b=1000 s/mm2 revealed high signal intensity lesions in the white matter, consistent with restricted diffusion. Low apparent diffusion coefficient values (0.18-0.34 x 10(-3) mm2/s) were noted in the affected white matter regions. Follow-up MR imaging performed 16 days later revealed disappearance of white matter lesions, suggesting that during the acute stage of carbon monoxide poisoning, white matter can be more sensitive than gray matter to ischemia.     

Delayed encephalopathy after acute carbon monoxide intoxication: MR imaging features and distribution of cerebral white matter lesions.

Magnetic resonance (MR) images obtained in 15 patients with delayed encephalopathy after acute carbon monoxide (CO) intoxication were reviewed. Images had been obtained 4-9 weeks after exposure to CO, during the relapse of neuropsychiatric symptoms after initial recovery. Bilateral symmetric confluent high signal intensity in the periventricular white matter and centrum semiovale was seen on long-repetition-time images (n = 15). The high intensity extended into the corpus callosum (n = 11), subcortical U fibers (n = 12), and external (n = 9) and internal (n = 7) capsules. Bilateral diffuse low-intensity signal in the thalamus and putamen on T2-weighted images, suggesting iron deposition, was demonstrated in 10 patients. Bilateral ischemia or necrosis of the globus pallidus was seen in nine patients. In three of four patients with follow-up MR imaging studies, a decrease in extent and signal intensity of white matter lesions accompanied lessening of clinical symptoms. These results suggest that the main pathologic feature of delayed encephalopathy associated with CO intoxication is a reversible demyelinating process of the cerebral white matter.     

Comparison between patient characteristics and cranial MR findings in chronic thinner intoxication

Chronic thinner intoxication is one of the most serious social problems among teenagers and young adults in Japan. The purpose of this study was to evaluate clinical characteristics of patients with thinner intoxication who had positive MR findings. During the past 4 years, cranial MR imaging of 85 patients (51 males and 34 females) with chronic thinner intoxication was done at a national psychiatric hospital. The MR imaging was performed on a 1.0-T scanner with use of standard pulse sequences including fluid-attenuated inversion recovery (FLAIR). The established characteristic MR findings of chronic thinner intoxication were observed in 8 of the 85 patients: 4 males and 4 females. The female patients tended toward emaciation and were approximately 5 years younger than the male patients. Six of the 8 patients had severe neurological symptoms such as cerebellar ataxia and decreased visual acuity. In contrast, only 3 of 77 (4%) patients with normal MR findings had mild neurological abnormalities such as tremor. If patients with chronic thinner intoxication have significant neurological symptoms, MR imaging should be performed for evaluation of brain abnormalities. Emaciated female patients may be particularly vulnerable to neurological damage caused by thinner intoxication.     

Neonatal hypoxic-ischemic encephalopathy: detection with diffusion-weighted MR imaging

BACKGROUND AND PURPOSE: Although diffusion-weighted imaging has been shown to be highly sensitive in detecting acute cerebral infarction in adults, its use in detecting neonatal hypoxic-ischemic encephalopathy (HIE) has not been fully assessed. We examined the ability of this technique to detect cerebral changes of acute neonatal HIE in different brain locations. METHODS: Fifteen MR examinations were performed in 14 neonates with HIE (median age, 6.5 days; range, 2-11 days). Imaging comprised conventional T1-weighted, proton density-weighted, and T2-weighted sequences and echo-planar diffusion-weighted sequences. The location, extent, and image timing of ischemic damage on conventional and diffusion-weighted sequences and apparent diffusion coefficient (ADC) maps were compared. RESULTS: Although conventional sequences showed cerebral changes consistent with ischemia on all examinations, diffusion-weighted imaging showed signal hyperintensity associated with decreased ADC values in only seven subjects (47%). All subjects with isolated cortical infarction on conventional sequences had corresponding hyperintensity on diffusion-weighted images and decreased ADC values, as compared with 14% of subjects with deep gray matter/perirolandic cortical damage. The timing of imaging did not significantly alter diffusion-weighted imaging findings. CONCLUSION: Diffusion-weighted imaging, performed with the technical parameters in this study, may have a lower correlation with clinical evidence of HIE than does conventional MR imaging. The sensitivity of diffusion-weighted imaging in detecting neonatal HIE appears to be affected by the pattern of ischemic damage, with a lower sensitivity if the deep gray matter is affected as compared with isolated cerebral cortex involvement.     

Cerebral blood flow and glucose metabolism measurements in a patient surviving one year after carbon monoxide intoxication.

A 29-yr-old woman was studied for 1 yr after acute carbon monoxide intoxication following an attempted suicide by inhalation of automobile exhaust fumes. The patient demonstrated impaired responsiveness to stimuli without any specific neurological deficits for 1 yr after carbon monoxide intoxication. Repeated brain magnetic resonance imaging consistently displayed only bilateral globus pallidus lesions, but no lesions in either deep white matter or cerebral cortex. Position emission tomography measurements of regional cerebral blood flow, and glucose utilization rate were made in this patient at 6 mo and 1 yr following carbon monoxide intoxication. Impairment of both blood flow and glucose metabolism were found not only in the basal ganglia but also in morphologically normal frontal cortex. The decrease in glucose utilization in the frontal cortex was greater than that in the basal ganglia. During the period of 6 mo to 1 yr, blood flow and glucose metabolism in the basal ganglia recovered to the normal range. In the frontal cortex, however, blood flow and glucose metabolism remained approximately 20% lower than the normal mean values. This prolonged dysfunction in the frontal cortex may therefore be responsible for the impaired responsiveness of the subject.     

The magnetic resonance imaging appearances of the brain in acute carbon monoxide poisoning

AIMS: To describe the magnetic resonance imaging (MRI) appearances of the brain in acute carbon monoxide poisoning, the commonest cause of accidental poisoning in Europe and the U.S.A. To attempt to correlate the imaging findings with patient outcome as an aid to prognosis. MATERIALS AND METHODS: Brain MRI was performed on 19 consecutive patients, who had sustained acute carbon monoxide poisoning, as soon as possible after their referral to the regional Hyperbaric Unit at the Royal Hospital, Haslar. All patients were unconscious on arrival, and had received at least one treatment with hyperbaric oxygen by the time of first MR. The imaging findings were analysed independently by two experienced MR radiologists, with a third radiologist arbitrating on discrepant results. RESULTS: Thirteen male and six female patients, age range 21-70 years (mean 38.7 years) underwent MR an average of 35.6 h (range 6-126 h) following presentation at the referring centre. MR (at 0.5T) revealed abnormalities in the following areas: globus pallidus (n = 12); other basal ganglia [ n = 5: entire lentiform (globus pallidus and putamen), putamen alone, caudate nucleus, thalamus]; white matter (n = 6: periventricular, subcortical, other); cerebral cortex (n = 5), either localized or general; medial temporal lobe in the region of the hippocampus (n = 4). The majority of the patients with hyperintensity in the region of the hippocampus (n = 3) had no other area of cortical involvement. Two patients showed abnormalities in the cerebellum. Normal appearances were seen on the initial MR in seven patients. CONCLUSION: The appearances of the brain following acute CO poisoning are varied, and have previously been the subject of case reports or small studies, most of which have have addressed the delayed sequelae of this condition. This study, the first large series undertaken in the acute phase, confirms that, although the globus pallidus is the commonest site of abnormality in the brain, the effects of CO poisoning are widespread. The extent of damage correlates with clinical outcome, and therefore aids management and prognosis.