阻塞性睡眠呼吸暂停低通气综合征的多体素~1H-MRS研究

目的探讨多体素质子磁共振波谱(1H-MRS)在阻塞性睡眠呼吸暂停低通气综合征(OSAHS)中的临床应用价值。材料与方法分别对20例临床诊断为中重度OSAHS病人(病变组)及年龄、性别相匹配的20名健康志愿者(对照组)行头颅多体素1H-MRS检查,记录两组半卵圆中心区、基底节区各代谢物比值,比较两组间的差异,观察有无乳酸(Lac)峰出现。记录病人相关临床指标,包括:睡眠呼吸暂停和低通气指数(AHI)和夜间平均血氧饱和度(SpO2),并与各代谢物比值进行相关性分析。结果病变组半卵圆中心区NAA/Cr、NAA/Cho低于对照组,Cho/Cr高于对照组,差异有统计学意义(P0.05)。基底节区NAA/Cr、NAA/Cho较对照组稍降低,Cho/Cr较对照组稍升高,差异无统计学意义(P0.05)。两组均未检测到Lac峰。AHI与半卵圆中心区NAA/Cho呈负相关(P0.05),SpO2与NAA/Cho呈正相关(P0.05),而AHI和SpO2与NAA/Cr、Cho/Cr无相关性(P0.05)。结论多体素1H-MRI能够早期发现OSAHS脑代谢改变,为临床诊治提供客观的影像学依据。     

Wilson病的脑部MRI表现及MRS变化

目的探讨肝豆状核变性(hepatolenticular degeneration,HLD)的中枢神经系统影像学表现。资料与方法搜集近年来经临床确诊的16例Wilson病患者的脑部影像学资料,回顾分析其中枢神经系统的影像学表现。另选取16名正常人(对照组)行磁共振波谱(MRS)成像作对照。结果 16例中,10例表现为明显的双侧基底节区及丘脑对称性分布的长T2、长T1异常信号;9例累及中脑及脑桥,可见长T2异常信号,其中3例呈现典型的大熊猫脸征及小熊猫脸征;2例可见双侧小脑齿状核异常信号;1例表现为双侧基底节对称性短T2周围环绕长T2信号;2例表现为双侧基底节区及中脑对称性短T1信号;4例表现为侧脑室周围对称性长T2信号;2例脑萎缩较为明显;MRS显示6例兴趣区氮-乙酰天门冬氨酸(NAA)峰减低,8例乳酸(Cho)及肌酸(Cr)峰增高,5例肌醇(mI)峰增高;16例基底节区、丘脑及中脑兴趣区的NAA/Cr较对照组有所减低,mI/Cr有所增高,而Cho/Cr无明显差异。结论 Wilson病脑部的影像学表现具有较明显的特征性,MRI及MRS对于早期发现Wilson病具有重要价值。     

阻塞性睡眠呼吸暂停低通气综合征的多体素^1H-MRS研究

目的探讨多体素质子磁共振波谱（1H-MRS）在阻塞性睡眠呼吸暂停低通气综合征（OSAHS）中的临床应用价值。材料与方法分别对20例临床诊断为中重度OSAHS病人（病变组）及年龄、性别相匹配的20名健康志愿者（对照组）行头颅多体素1H-MRS检查,记录两组半卵圆中心区、基底节区各代谢物比值,比较两组间的差异,观察有无乳酸（Lac）峰出现。记录病人相关临床指标,包括：睡眠呼吸暂停和低通气指数（AHI）和夜间平均血氧饱和度（SpO2）,并与各代谢物比值进行相关性分析。结果病变组半卵圆中心区NAA/Cr、NAA/Cho低于对照组,Cho/Cr高于对照组,差异有统计学意义（P〈0.05）。基底节区NAA/Cr、NAA/Cho较对照组稍降低,Cho/Cr较对照组稍升高,差异无统计学意义（P〉0.05）。两组均未检测到Lac峰。AHI与半卵圆中心区NAA/Cho呈负相关（P〈0.05）,SpO2与NAA/Cho呈正相关（P〈0.05）,而AHI和SpO2与NAA/Cr、Cho/Cr无相关性（P〉0.05）。结论多体素1H-MRI能够早期发现OSAHS脑代谢改变,为临床诊治提供客观的影像学依据。     

小儿脑室周围白质软化症的临床特征和MRI表现

目的 探讨小儿侧脑室周围白质软化症(PVL)的临床特点与MRI影像学表现.方法 对14例PVL的临床资料及磁共振表现进行回顾性分析.结果 PVL的MRI表现包括脑室旁软化灶形成(10例)、侧脑室变形(9例)、脑白质减少(7例)、脑沟及脑裂加深(6例)等,软化灶分布在侧脑室周围及半卵圆中心区,形态大小不一,为长T1、长T2信号、flair为低信号;临床表现为:发育迟缓(6例)、癫痫(7例)、肢体功能障碍(6例)、视力损害(1例)等,7例患儿有缺血缺氧病史.结论 PVL的影像学表现具有一定特征性,MRI是诊断PVL的主要方法.     

蜂蛰致中枢神经系统损伤的磁共振表现(附3例报告并文献复习)

目的探讨蜂蛰伤中枢神经系统损伤的磁共振影像表现及治疗后的影像转归。方法收集3例蜂蛰伤后出现中枢神经系统异常患者的临床及影像资料,3例均行头颅磁共振检查,经治疗后均行磁共振复查。结果2例表现为双侧基底核团对称性病变,在T1WI、T2WI上呈稍高信号,DWI呈高及稍高信号,其中1例合并双侧额顶枕叶皮层层状坏死,T1WI呈条状高信号;1例表现为右侧额顶颞枕叶、基底节区、侧脑室旁、左侧枕顶叶急性期脑梗塞;3例经治疗后临床症状好转,磁共振复查范围均较前减小,T1信号由高到低,T2信号由高到稍高,DWI由高到稍高。结论蜂蛰致中枢神经系统损伤可表现为双侧苍白球纹状体坏死、皮层层状坏死及脑梗塞等,影像表现有一定的特点,及时治疗后病变的MRI影像变化与临床症状好转相符。     

脑梗死与皮质下缺血性血管性痴呆MRI相关研究

目的深入研究皮质下多发性脑梗死磁共振成像(MRI)表现与皮质下缺血性血管性痴呆(SIVD)之间关系。方法对照分析98例SIVD患者及作为对照的68例无痴呆型脑梗死患者MRI表现。结果 SIVD组与对照组比较:1)SIVD组中丘脑、额顶颞叶皮质下白质、侧脑室体部旁前部白质、半卵圆中心前部及基底节区豆状核、尾状核、内囊膝部发生率均明显高于对照组(P0.05);2)SIVD组中丘脑、额颞叶皮质下白质、侧脑室体部旁前部白质、半卵圆中心前部及基底节区豆状核、尾状核、内囊前支、外囊平均脑梗死灶数目均明显高于对照组(P0.05);3)SIVD组中丘脑、额颞叶皮质下白质、侧脑室体部旁前部白质、半卵圆中心前部及基底节区豆状核、内囊前支平均脑梗死灶体积均明显大于对照组(P0.05)。结论皮质下血管性痴呆的发病与MRI检查显示脑梗死灶的位置、数目、体积有着密切的关联。     

新生儿色素失禁症中枢神经系统受累的MRI表现

目的 探讨新生儿色素失禁症(IP)中枢神经系统受累的MRI表现.方法 17例经临床、皮肤活检或NEMO基因检测证实的新生儿IP的MRI及临床资料进行回顾性分析.结果 新生儿IP 17例,12例头颅MRI检查发现病灶,其中3例MRI平扫发现病灶,T2WI呈稍高信号、T1WI呈稍低信号,其余9例MRI平扫未发现病灶.12例扩散加权成像(DWI)扫描均发现病灶,DWI图表现为双侧大脑皮层及皮层下、基底节、半卵圆中心、侧脑室旁多发的非对称性点片状高信号,相应部位表观扩散系数(ADC)图呈低信号,其中累及基底节4例、胼胝体5例,丘脑2例.结论 新生儿IP中枢神经系统受累的MRI表现有一定特征性,DWI对病变的早期发现及预后评估有重要价值.     

单发急性炎性脑脱髓鞘疾病的MRI及MRS诊断

目的 探讨单发急性炎性脑脱髓鞘疾病(MAID)的影像学征象.方法 搜集近年来本院经临床确诊的12 例MAID病例的影像学资料,回顾分析其中枢神经系统的影像学征象.结果 12例病变的MRI表现为脑白质(11例)或基底节区(1例)体积较大的T1WI低信号,T2WI高信号,FLIAR为低信号,周边为高信号;DWI病变中心为低信号,周边呈高信号;强化扫描病变呈不规则开环状强化,环开口指向基底节区或皮层灰质,病变占位效应不明显.MRS检查中所有病例的NAA峰减低,其中6例Cr峰明显减低,所有病例均可见Cho峰明显增加,NAA/Cr比值降低,Cho/Cr比值增加,4例mI峰增加,2例出现MP峰增高及异常高大的Lac峰.经临床治疗后随访复查可见病变范围明显缩小,环状强化消失,病变NAA峰明显恢复,Cho峰明显降低.结论 MAID的影像学表现及其临床过程具有一定的特征性.     

母亲苯丙酮尿症后代的脑MRI表现

目的 提高对母亲苯丙酮尿症(MPKU)后代脑MRI表现的认识。资料与方法 报告2例生化及临床检查证实为MPKU双胞胎的．MRI改变，并复习文献。结果 文中2例表现与文献报道不一致．与苯丙酮尿症患儿的表现相似。常规T2WI及FLAIR均显示室周白质、侧脑室三角区、半卵圆中心条片状高信号。弥散加权成像(DWI)除更清楚地显示上述改变外，尚显示双侧内囊后肢及胼胝体压部信号增高。结论 常规T2WI及FIJAIR上可显示MPKU后代脑白质异常，DWI可提供更多诊断依据。     

磁共振弥散加权成像在新生儿早期缺氧缺血性脑病的临床应用

目的探讨磁共振弥散加权成像(DWI)在新生儿早期缺氧缺血性脑病(HIE)的应用及价值。方法收集本院经临床确诊为HIE共72例,对其进行常规T1W、T2W和DWI扫描,并对影像学进行分析,评价DWI在早期HIE的诊断优势。结果 DWI出现高信号病灶53例,T1W信号异常25例,T2W信号异常4例,其中DWI高信号病灶多见于大脑皮层、基底节区、侧脑室体旁及前后角周围白质区、半卵圆中心,T1W高信号以侧脑室周围白质区多见,出血性病变在T1W呈高信号而T2W和DWI表现为低或无信号。结论 DWI可作为HIE早期检测的重要手段,在显示病灶范围、数目等方面明显优于常规T1W、T2W,能对临床HIE早期诊断、早期干预治疗提供可靠的客观依据,对评估预后有重要价值。     

MR imaging of periventricular leukomalacia in childhood

Eight children with clinical and radiologic abnormalities consistent with periventricular leukomalacia were investigated with MR imaging of the brain that employed both inversion-recovery and T2-weighted spin-echo imaging sequences. The more precise delineation of white and gray matter on inversion-recovery images as compared with CT allows a detailed demonstration of the anatomic features of periventricular leukomalacia; specifically, a reduced quantity of white matter in the periventricular region and centrum semiovale and, in more severe cases, cavitated infarcts that replace the immediate periventricular white matter. The T2-weighted spin-echo and short inversion time inversion-recovery images demonstrated abnormally increased signal in white matter that appeared normal on CT scans and only minimally abnormal on conventional inversion-recovery images. These abnormalities most probably represent white matter gliosis that extends beyond the immediate periventricular regions. MR recognition of cerebral white matter abnormalities associated with periventricular leukomalacia may confirm the clinical suspicion of this diagnosis in children with spastic diplegia or quadriplegia.     

儿童异染性脑白质营养不良的MRI表现

目的 观察异染性脑白质营养不良（MLD）的特征性表现。方法 回顾分析我院经生化检查证实的MLD共11例,观察MRI上脑内白质病变的部位和特殊结构（白质纤维束、丘脑、胼胝体）受累的情况。结果 11例均表现为双侧脑室周围白质T2WI对称高信号,10例双侧半卵圆中心T2WI对称高信号;4例累及皮层下白质。8例累及胼胝体膝部,9例累及压部,两者同时受累为8例;7例累及内囊后肢,4例累及外囊,4例累及脑干皮质脊髓束（3例中脑,1例桥脑）。1例累及小脑白质,8例半卵圆中心T2WI有虎纹征,8例T2WI丘脑呈低信号;5例侧脑室扩大,1例全脑萎缩。结论 MLD的典型表现为双侧半卵圆中心和侧脑室周围白质T2WI对称高信号,早期皮层下白质不受累,胼胝体膝部和压部受累为重要征象;另外征象包括脑干皮质脊髓束和内、外囊受累及虎纹征。     

Diffusion-weighted MR imaging of early methotrexate-related neurotoxicity in children

BACKGROUND AND PURPOSE: Methotrexate is a major cause of treatment-related acute neurotoxicity in children with hematologic malignancies. The purpose of this study was to investigate whether diffusion-weighted MR imaging (DWI) detects acute methotrexate white matter neurotoxicity in this patient population. METHODS: Six children-three female and three male-with hematologic malignancies were studied at time of onset of neurologic dysfunction during the delayed intensification or consolidation phase of therapy, when intensive intrathecal methotrexate is given. MR imaging including DWI was performed on 1.5 T MR scanners. RESULTS: DWI demonstrated abnormal restriction of motion of water in the centrum semiovale in all six patients. This finding correlated to the acute onset of hemiparesis or aphasia. Fluid-attenuated inversion recovery imaging was not positive at this time, but it was positive in all five patients in whom follow-up imaging was performed. CONCLUSION: Early detection of methotrexate white matter injury by DWI has the potential to alert the oncologist to this event and provide a technique by which treatment of neurotoxicity can be monitored.     

MR of childhood metachromatic leukodystrophy.

PURPOSETo investigate the MR findings of childhood metachromatic leukodystrophy (MLD).METHODSNine MR imaging studies in seven children (five girls and two boys, 10 to 32 months old) with MLD were evaluated retrospectively for the extent and progression of white matter abnormalities and the presence of contrast enhancement.RESULTSAll seven cases showed symmetric, confluent high signal intensity on T2-weighted images in the periventricular white matter and centrum semiovale. A posterior predominance of white matter abnormalities was noted in all cases. Although initially spared from demyelination in all cases, in one case, the subcortical U fibers were later involved in demyelination of follow-up MR studies. Other sites of involvement were the genu (n = 5) and splenium (n = 6) of the corpus callosum, the posterior limbs of the internal capsule (n = 5), the descending pyramidal tracts (n = 4), the claustrum (n = 4), and the cerebral white matter (n = 2); diffuse brain atrophy was seen in two cases. No enhancement of the lesion was seen on any of the five postcontrast examinations. A "tigroid" pattern, previously described in cases of Pelizaeus-Merzbacher disease, was noted in the centrum semiovale in six cases.CONCLUSIONIn late-infantile MLD, demyelination is more prominent in the occipital region. In addition to demyelination of the periventricular white matter, common manifestations include a "tigroid" pattern and involvement of the corpus callosum, the internal capsule, and the corticospinal tract.     

Conventional and diffusion-weighted MRI in the evaluation of methanol poisoning

Cerebral lesions were studied in 2 methanol-poisoned patients using conventional magnetic resonance imaging (MRI). In 1 patient, diffusion-weighted MRI (DWI) was also performed. In this patient, conventional MRI showed symmetrical, bilateral increased signal in the lentiform nuclei, involving predominantly putamina, but also extending into the corona radiata, centrum semiovale and subcortical white matter. DWI showed decreased diffusion, which most probably reflects cytotoxic edema. In the other patient, fluid attenuated-inversion recovery (FLAIR) and T2-weighted images showed hyperintensity in the putamina, characteristic of post-necrotic changes.     

Delayed encephalopathy of acute carbon monoxide intoxication: diffusivity of cerebral white matter lesions

BACKGROUND AND PURPOSE: Carbon monoxide intoxication has delayed effects on the cerebral white matter characterized by bilateral, confluent lesions that reflect diffuse demyelination. To increase our understanding of this process, we assessed the diffusion characteristics of these lesions. METHODS: Five consecutive patients with delayed encephalopathy of CO intoxication were examined with diffusion MR imaging. Diffusion-weighted images (DWIs) were obtained 25-95 days after their exposure to CO and during a relapse of neuropsychiatric symptoms, which occurred after an initial recovery. Imaging was performed at 1.5 T by using a spin-echo echo-planar sequence with diffusion gradients of 0, 500, and 1000 s/mm(2). DWIs and apparent diffusion coefficient (ADC) maps were visually evaluated, and mean ADCs were calculated from the periventricular white matter and the centrum semiovale, where confluent hyperintensity was seen on T2-weighted images. Findings were compared with those of normal-looking white matter. RESULTS: In all five patients, both T2-weighted images and DWIs showed the white matter lesions as bilateral, diffuse, confluent areas of hyperintensity in the periventricular white matter and centrum semiovale. On ADC maps, these lesions were isointense, with focal areas of hypointensity (n = 4) or diffuse hypointensity (n = 1). Mean ADC values of the white matter lesions were significantly lower than those of normal-looking white matter, regardless of their isointensity or hypointensity on ADC maps (P <.05). CONCLUSION: Bilateral, confluent, white matter lesions in patients with delayed encephalopathy of CO intoxication show decreased diffusivity.     

液体衰减反转恢复脉冲对DWI图像信噪比及ADC值的影响

目的:探讨液体衰减反转恢复(FLAIR)脉冲序列对扩散加权图像(DWI)信噪比及ADC值的影响.方法:17名健康志愿者在3.0T MRI上行常规轴位DWI和FIAIR-DWI扫描,分别测量两侧半卵圆区、扣带回、丘脑及胼胝体膝部和压部的ADC值及DWI信号强度,同时测量基底节层面的DWI信号强度作为噪声,计算以上5个部位DWI图像的信噪比.结果:扣带回和胼胝体压部的ADC值在施加FLAIR脉冲后显著下降,而半卵圆区、丘脑及胼胝体膝部在施加FLAIR脉冲前后无明显变化;5个部位的DWI图像信噪比在施加FLAIR脉冲后均显著下降(P＜0.01).结论:FLAIR显著提高了脑组织和脑脊液ADC值测量的准确性,但是也明显降低了DWI图像的信嗓比.     

MR of the brain in Sjögren-Larsson syndrome.

Cerebral MR was performed in three patients with Sjögren-Larsson syndrome. In each case, a 1.5-T system was used, and the patient was under general anesthesia. The MR findings included confluent hyperintense white matter lesions in the periventricular and deep white matter of the centrum semiovale, with sparing of the subcortical U fibers. The topography of the white matter abnormalities correlated well with the clinical signs and symptoms.     

Development and aging of the cerebrum: assessment with proton MR spectroscopy

BACKGROUND AND PURPOSE: MR spectroscopy allows the noninvasive evaluation of in vivo brain metabolites. Our purpose was to use this technique to assess metabolic alterations in the human cerebrum during growth, maturation, and aging. METHODS: Ninety normal human brains in subjects aged 4 to 88 years were examined with multivoxel proton MR spectroscopy. Spectra were obtained from specific voxels of 2.5 cm3 in the gray and white matter of the centrum semiovale. The ratios of N-acetylaspartate (NAA) to choline (Cho) were calculated to describe age-dependent alterations in cerebral metabolites. RESULTS: White matter NAA/Cho ratios showed rapid growth during the first decade and reached a maximum value in the second or early third decade, followed by a steady decline starting in the latter half of the third decade. The maximum peak ages for NAA/Cho were 21.9, 17.6, and 15.9 years (mean, 18.5 years) for the anterior, middle, and posterior white matter, respectively. A significant cerebral laterality of the white matter NAA/Cho was found in male subjects during development. The growth spurt and age-related decline of the white matter NAA/Cho were steeper in male than in female subjects. In contrast, the gray matter NAA/Cho showed a gradual decline with age. CONCLUSION: Proton MR spectroscopy shows significant regional and sex differences in the level of cerebral metabolites during the process of growth, maturation, and aging. This technique may play an important role in clinical applications for various conditions of metabolic disorders of the human brain.     

Evaluation of brain metabolism in steno-occlusive carotid artery disease by proton MR spectroscopy: a correlative study with oxygen metabolism by PET.

Carotid occlusive diseases may cause ischemic changes in both the gray matter and the white matter as a result of hemodynamic compromise. To validate the use of proton magnetic resonance spectroscopy (MRS) in evaluating the carotid occlusive diseases, we compared changes in peaks of choline, in the sum of creatine and phosphocreatine, and in N-acetyl-aspartate (NAA) of the white matter with cortical oxygen metabolism measured by PET. METHODS: Eleven patients with unilateral steno-occlusive carotid artery disease underwent PET and MRS. Ten age-matched healthy volunteers underwent MRS. No subjects had cortical infarction. MRS was performed bilaterally in the centrum semiovale. Regional blood flow, regional metabolic rate of oxygen (rCMRO2), and regional oxygen extraction fraction (rOEF) of the cerebral cortex were measured by the steady-state method with 15O gas. RESULTS: The asymmetry index of the ratio of NAA to the sum of creatine and phosphocreatine (NAA/Cr) correlated positively with the asymmetry index of rCMRO2 (r = 0.77; P < 0.01). Because rCMRO2 is a marker of tissue viability, the NAA/Cr of the centrum semiovale may reflect viable neuronal cells. The asymmetry index of the ratio of choline to the sum of creatine and phosphocreatine (Cho/Cr) showed a significant positive correlation with the asymmetry index of rOEF (r = 0.65; P < 0.05). All but 1 patient with an increased Cho/Cr (>1.03) showed an increase in rOEF of the ipsilateral cortex (>0.56). This finding may indicate membrane damage caused by ischemia, because the centrum semiovale is the deep watershed zone. CONCLUSION: The metabolic changes in the centrum semiovale detected by proton MRS reflect a hemodynamically compromised state and are useful in evaluating tissue viability.