线粒体脑肌病的MRI诊断价值

目的 探讨线粒体脑肌病的脑部MRI表现及其诊断价值。资料与方法 对13例线粒体脑肌病患者的临床、实验室及MRI表现进行回顾性分析。结果 13例头部MRI检查均显示异常，对病变的检出率为100％，主要MRI表现为3类：（1）大脑半球多发单侧或双侧病变（7例），4例呈对称性，病变呈片状等长T1、长T2信号，以一侧或两侧颞顶枕时皮层和皮层下白质最常受累。（2）大脑半球皮层和深部灰质核团同时出现片状等长T1、长T2信号2例。上述两类脑内病变有5例合并脑萎缩。（3）脑实质信号正常，但有脑萎缩4例，其中桥脑、延髓及小脑萎缩3例，大脑半球、脑干、小脑萎缩1例。结论 MRI对线粒体脑肌病的脑内病变显示敏感且准确，对其早期诊断、指导治疗、判断疗效和提示预后具有重要价值。     

儿童线粒体脑肌病的脑部MRI表现与诊断

目的探讨儿童线粒体脑肌病的脑部MRI表现及其诊断价值。方法搜集1996年1月至2002年12月经病理与实验室检查证实的16例儿童线粒体脑肌病及其脑部MRI表现，并进行回顾性分析。结果16例患儿脑MRI均有多发对称性片状略长T1和长T2异常信号，其中单纯脑深部灰质受累9例，大脑皮质和深部灰质同时受累6例，单纯白质受累l例。临床主要表现为进行性智力减退(12例)和肌力减退(10例)。骨骼肌活检病理检查可见破碎样红纤维及异常线粒体。结论进行性智力和肌力减退是儿童线粒体脑肌病最常见的临床表现；脑深部灰质多发对称性斑片状异常信号是儿童线粒体脑肌病脑部MRI的主要表现；脑MRI是诊断儿童线粒体脑肌病的重要手段，但儿童线粒体脑肌病的确诊有赖于肌肉活检和基因检查。     

成人线粒体脑肌病的MRI和1H-MRS诊断价值

目的 分析MRI和1H-MRS对线粒体脑肌病的诊断价值.方法 经病理活检确诊的 6例成人 (男3例,女3例)线粒体脑肌病患者采用1.5T磁共振仪扫描,其中3例行1H-MRS检查,并分析MRI和1H-MRS的表现. 结果6例线粒体脑肌病患者MRI显示病变累及多个脑叶,多位于皮层及皮层下白质,并可同时累及大脑深部灰质和大脑皮层.脑梗死样病灶呈斑片状或楔形,非对称性.T1WI为低信号或等低信号,T2WI为高信号.急性期病变区域脑组织轻度肿胀,慢性期全脑萎缩,并可见皮质层状坏死.4例行MR增强扫描未见强化.3例1H-MRS检查均显示病灶内Lac峰明显升高和NAA峰不同程度的降低.结论 线粒体脑肌病MRI表现具有一定的特征,1H-MRS可提供更多脑组织代谢信息,对本病诊断具有重要的价值.     

线粒体脑肌病综合影像表现

目的:探讨多种影像技术对线粒体脑肌病(ME)的诊断价值.方法:回顾性分析7例线粒体脑肌病患者的影像资料,其中7例行常规MRI扫描,3例行MRA扫描,4例行MRS扫描,1例行DSA检查,6例行CT平扫.结果:6例病变主要累及两侧大脑皮层和皮层下,1例主要表现为白质内改变,均表现为长T1、长T2改变;MRA示2例未见明显改变,1例示病变处血管分支明显增粗;4例MRS在病变处检出乳酸双峰,1例在脑脊液中检出乳酸双峰.1例行DSA检查示病灶内血管分支增粗,血运加快.6例行CT检查病灶均呈低密度改变.结论:影像检查尤其是MRI检查对ME的诊断提供了丰富的信息,当年青患者出现非典型性脑梗死表现,MRS检出乳酸双峰时要考虑到线粒体脑肌病的可能.     

线粒体脑肌病的影像诊断价值

目的探讨多种影像技术对线粒体脑肌病的诊断价值。方法回顾性分析11例线粒体脑肌病的临床资料和影像学表现。本组病例9例行MR扫描，其中2例并行MR血管成像检查和数字减影血管造影，3例行CT平扫检查，1例行正电子发射计算机体层成像。结果CT和MR显示9例脑内病变为多发性或游走性脑梗死样病灶，主要累及颞枕叶后部，病变与血管分布区无关，7例发生于颞顶枕叶，位于双侧丘脑1例，脑干、小脑、侧脑室旁1例。另外小脑萎缩1例，胸髓空洞1例。急性期PET显示病灶中葡萄糖代谢明显升高，缓解期转为低代谢。结论结合多种影像学方法检查线粒体脑肌病，可提高诊断准确性。     

MRI在小儿线粒体脑肌病中的诊断价值

目的　探讨MRI在小儿线粒体脑肌病中的诊断价值。方法　搜集自 1996 -0 1～ 2 0 0 0 -12经MRI检查、病理及实验室检查证实的小儿线粒体脑肌病 16例进行回顾性分析。结果　 16例患者脑内病灶均表现为多发对称性略长T1、长T2 信号 ,其中单纯脑深部灰质受累 9例 ,大脑皮质和深部灰质同时受累 4例 ,灰、白质同时受累 2例 ,单纯白质受累 1例。结论　多样化的临床和MRI表现是小儿线粒体脑肌病的特点 ;MRI对小儿线粒体脑肌病的诊断有较大帮助。     

MELAS 综合征的 MRI 诊断

目的：回顾性分析线粒体脑肌病伴高乳酸血症和卒中样发作(MELAS)综合征的 MR 表现特点,提高对 MELAS 综合征早期诊断的能力。方法收集经临床诊断的 MELAS 综合征共16例,均由肌肉病理活检证实。所有患者均行 MR 平扫,其中3例行 ASL 扫描,15例行 MRA 检查,14例行 DWI 扫描,3例行 MRS 扫描,并回顾性综合分析其影像学资料。结果MRI 检查发现,本组 MELAS 综合征多表现为大脑半球各叶大小不等片状病灶,病变多位于大脑半球后部脑皮质区,向皮层下的白质蔓延,病灶的分布与脑血供分布不一致;自旋回波 T1 WI 呈低信号、T2 WI 呈高信号,FLAIR 呈高信号;DWI 呈高信号;3例行 MRS 分析提示病灶区典型乳酸峰;其中1例 MRA 检查提示病灶区分支血管增多,1例分支血管减少;3例行 ASL 检查提示病灶区高灌注。16例中4例随访病灶具有游走性、多变性、此起彼伏等表现,旧病灶有脑萎缩、脑软化等表现。16例行肌组织活检见破碎样红纤维(RRF);电镜见线粒体体积增大、数量增多,肌纤维粗细不等,少数萎缩变细。3例行线粒体基因测序发现线粒体 DNA(mtDNA)A3243G 点突变。结论DWI、MRS 及 ASL 在 MELAS 综合征诊断中具有良好的价值。     

线粒体脑肌的MRI表现特征及其诊断价值

目的:总结线粒体脑肌病的MRI表现特征并分析磁共振在线粒体脑肌病诊断中的价值。方法:搜集2005年1月～2007年7月经临床及病理证实的线粒体脑肌病患者资料21例,男5例,女16例。所有病例均行常规MRI检查(平扫加增强扫描),7例患者行磁共振波谱检查。结果:21例中有17例患者脑内病灶均表现为T1WI低信号、T2WI高信号,病变主要累及颞、顶、枕叶皮层、及深部灰质核团(以基底节多见),部分患者伴有不同程度的脑萎缩,病灶对称或不对称,且具有多发性,迁移性和与血管分布区不一致性;4例患者头部常规扫描仅见轻度脑萎缩。FLAIR及DWI序列能更清楚和准确显示较隐匿的病灶,7例磁共振波谱检查表现为病变区、无信号异常的脑区和/或脑室系统均可见较特征性的乳酸峰。结论:线粒体脑肌病的MRI表现有一定的特征性,磁共振成像(包括DWI、FLAIR、MRS)在线粒体脑肌病的诊断、鉴别诊断以及对该病代谢物改变的检测方面均具有重要的价值。     

慢性脑血吸虫病的MR影像表现(附12例分析)

目的探讨慢性脑血吸虫病的MR影像特点,提高MRI对本病的诊断水平.材料与方法对12例慢性脑血吸虫病患者进行脑部MR检查,分析其MR影像表现.结果病灶主要位于额叶(3例)、顶叶(2例)、颞叶(3例)、顶枕交界区(4例),形态为结节状肉芽肿,聚集成簇,表现为长T1、长T2信号和显著的增强效应,周围有明显水肿.结论慢性脑血吸虫病MR影像特点是脑实质内多个结节状肉芽肿聚集成簇,颅脑MR检查尤其是增强扫描对本病的诊断和鉴别诊断有重要价值.     

病毒性脑炎的MRI诊断

目的探讨病毒性脑炎MR I表现特点及与急性播散性脑脊髓炎(ADEM)鉴别的可能性。方法分析56例病毒性脑炎及50例ADEM的脑部MR I表现,重点分析病毒性脑炎的脑部MR I表现。结果病毒性脑炎脑内有多发或单发的对称或不对称大片状病灶,主要位于皮层、皮层下及基底节-丘脑区,MR I呈长T1长T2信号,增强扫描27例,显示病灶强化者17例,其中呈大片状或脑回状强化者10例。ADEM则脑内有多发不对称斑点、斑片状病灶,主要位于双侧脑室周围及额颞顶枕叶脑白质区,MR I呈长T1长T2信号,增强扫描20例,显示病灶强化者15例,均为环形或斑点状强化。结论MR I是诊断病毒性脑炎重要的辅助检查方法,可在一定程度上为临床的早期诊断及鉴别诊断提供依据。     

儿童线粒体脑肌病的MRI表现

目的回顾性研究20例线粒体脑肌病患儿(年龄10个月到14岁)的MRI表现.方法20例由肌肉活检及实验室检查证实为线粒体脑肌病的患儿,脑内均有MRI阳性表现,研究其MRI表现的类型.结果20例患儿脑内病灶均表现为T1WI低、T2WI高信号,8例有不同程度的脑萎缩.18例患儿主要为灰质受累,其中10例为只有深部灰质病变;4例为深部灰质和大脑皮质同时受累.4例为深部灰质病变合并脑梗塞而同时累及灰质和白质.2例主要为白质受累,表现侧脑室后角旁白质异常信号.结论儿童线粒体脑肌病的MRI表现是多样性的.当儿童脑MRI表现为灰质(尤其是深部灰质)异常信号、灰质萎缩、不典型梗塞、不典型白质病变且合并临床难以解释的神经、肌肉等多系统的症状时,应考虑到线粒体肌病的可能.     

MRI of five patients with mitochondrial neurogastrointestinal encephalomyopathy

OBJECTIVE: The purpose of this study was to retrospectively review MR images of the brain in five patients diagnosed with mitochondrial neurogastrointestinal encephalomyopathy. CONCLUSION: Our research supports previously reported findings of confluent abnormal cerebral white matter in patients with mitochondrial neurogastrointestinal encephalomyopathy. In contrast to prior studies, our cohort of five patients showed that involvement of the corpus callosum as well as the capsular white matter, basal ganglia, thalami, midbrain, pons, and cerebellar white matter is not rare and does not preclude the diagnosis of mitochondrial neurogastrointestinal encephalomyopathy.     

Mitochondrial encephalomyopathy: comparison of conventional MR imaging with diffusion-weighted and diffusion tensor imaging: case report

Summary: Conventional MR imaging, MR spectroscopy, diffusion-weighted imaging, and diffusion tensor imaging were performed in a 5-month-old male patient with mitochondrial encephalomyopathy. On conventional T2-weighted MR images, symmetric, confluent high signal intensity was found in the temporoparietal white matter. A large lactate peak and decreased N-acetylaspartate were found in this region on proton MR spectroscopic images. Diffusion-weighted imaging showed increased apparent diffusion coefficient, representing vasogenic edema. Diffusion tensor imaging revealed decreased anisotropy, consistent with injury to the oligodendro-axonal unit. A muscle biopsy specimen revealed an isolated complex III enzyme respiratory chain deficiency. Diffusion-weighted and diffusion tensor imaging are valuable techniques for the characterization of hyperintense lesions on T2-weighted MR images in cases of mitochondrial encephalomyopathy.     

Proton MR spectroscopy of mitochondrial diseases: analysis of brain metabolic abnormalities and their possible diagnostic relevance

BACKGROUND AND PURPOSE: Proton (hydrogen-1 [(1)H]) MR spectroscopy is a useful diagnostic tool in many metabolic diseases, but only scattered and inconclusive data are available on mitochondrial diseases. We performed MR imaging and (1)H MR spectroscopy of the brain in patients with different types of primary mitochondrial diseases to investigate the role of (1)H MR spectroscopy in the clinical evaluation of these disorders. METHODS: In 15 patients (11 adults, four children) with mitochondrial diseases, localized MR spectra were obtained at short TEs in cerebellar white matter, paratrigonal white matter, and parieto-occipital cortex that appeared normal on MR images. Additional spectra of basal ganglia and cortical gray matter structural lesions were obtained in three patients. RESULTS: A significant choline reduction and N-acetylaspartate reduction were found in areas that appeared normal on MR images. Lactate was never found in areas that appeared normal on MR images, except in two children in whom MR studies were performed during episodes of symptom exacerbation and revealed elevated lactate both in areas that appeared damaged on MR images and in normal-appearing areas. An additional abnormal signal at 0.9 ppm was found in a consistent number of studies. CONCLUSION: (1)H MR spectroscopy proved to be a useful investigational tool for mitochondrial diseases, as it enabled detection of metabolic abnormalities even in areas of brain that appeared normal on MR images, especially when it was performed during episodes of clinical relapses or clinical exacerbation.     

MR imaging of optic pathways in patients with neurofibromatosis

Twenty-one patients with documented neurofibromatosis had MR examinations to evaluate possible intracranial disease. In five cases the indication was a known or suspected optic glioma. Two patients were examined because of a history of seizures; the rest were examined as part of a baseline evaluation. Eighteen patients showed evidence of signal hyperintensity on T2-weighted images. Lesions involved the optic nerves, optic chiasm, optic tracts, lateral geniculate body, optic radiations, basal ganglia, periventricular white matter, cerebellar white matter, and dentate nucleus of the cerebellum. Comparison between MR and concurrent CT scans showed MR to be superior in demonstrating the posterior extent of optic-pathway gliomas. In addition, MR showed focal areas of hyperintensity in the basal ganglia, internal capsule, cerebellum, and/or white matter that were not detected on CT. Although we found MR to be superior to CT in detecting intracranial tumors in patients with neurofibromatosis, and in evaluating the extensive involvement of known lesions, the full clinical implications of our findings remain to be determined.