脑梗死后皮质性出血18例临床分析

18例脑梗死后皮质性出血(CHI)患者，均经CT扫描或MRI证实，发现CHI皆发生于大中面积的脑梗死之后。CT平扫时，在低密度灶周围皮质表面可见蜿蜒走行的高密度或等密度影，MRI加权像其形态呈“脑回强化线样”高信号，MRI是发现脑梗死后皮质性出血的最佳选择。     

脑梗死后皮质性出血18例临床分析

18例脑梗死后皮质性出血 (CHI)患者 ,均经CT扫描或MRI证实 ,发现CHI皆发生于大中面积的脑梗死之后。CT平扫时 ,在低密度灶周围皮质表面可见蜿蜒走行的高密度或等密度影 ,MRI加权像其形态呈“脑回强化线样”高信号 ,MRI是发现脑梗死后皮质性出血的最佳选择。1　临床资料1 1　一般资料　入选者为 1993 0 6～ 2 0 0 3 0 6住院患者 ,经头颅CT扫描或磁共振扫描 (MRI)诊断为脑梗死者 916例 ,确诊为CHI18例 ,占 1 97%。其中男 12例 ,女 6例。年龄 46～ 85岁 ,平均 65 5岁。 18例患者共进行 3 2次CT扫描或MRI ,其中 3例进行磁共振血…     

脑内海绵状血管瘤的MRI和CT诊断

目的分析脑内海绵状血管瘤的CT和MRI影像学特点。方法回顾性分析68例CT和MRI表现,并比较CT和MRI优缺点。结果海绵状血管瘤位于幕上55例,幕下脑干4例,小脑9例。68例病灶有出血54例,钙化17例。MRI检查。T1加权像病灶显示为短T1高信号,周边为轻度低信号影;T2加权像病灶中央呈高、低混杂信号影,周边为极低黑色信号环。增强有轻度强化或无强化。CT平扫为斑片状不规则形高密度区。增强后有轻度强化或无强化。结论应用MRI诊断脑内海绵状血管瘤,其敏感性高,特异性强。对脑内海绵状血管瘤的显示MRI明显优于CT。     

颅内生殖细胞瘤的CT和MRI表现

目的探讨颅内生殖细胞瘤的CT和MRI影像特征。方法回顾性分析18例经病理或放射治疗证实的颅内生殖细胞瘤的CT和MRI表现。结果 18例肿瘤中,9例肿瘤位于松果体区,6例位于鞍区,3例位于基底节区及丘脑。松果体区肿瘤在MRI呈长T1、等或长T2信号,边缘光滑,出血少见;CT呈均匀等密度或稍高密度,松果体钙化常被肿瘤包埋,增强扫描时肿瘤均匀显著强化。鞍区肿瘤MRI表现为垂体柄增粗,垂体后叶正常短T1信号消失,肿瘤在T1WI像呈等信号,T2WI像上信号可呈等或高信号;CT图像见肿瘤实体部分呈高密度,增强扫描时明显强化。基底节区及丘脑肿瘤瘤体较大,信号及密度不均匀,边缘欠清晰,出血多见,增强扫捕呈不均匀强化。结论颅内生殖细胞瘤的影像表现具有一定特征,结合临床表现可进一步提高诊断正确率。     

胚胎发育不良性神经上皮瘤的病理和影像学特点

目的 探讨胚胎发育不良性神经上皮瘤(DNT)的病理诊断分型和影像诊断.方法 对3例DNT作回顾性分析并行文献复习.结果 3例DNT中,1例为单纯型DNT,2例为复杂型DNT.3例在病理上均见特殊胶质一神经原成分(SGNE).2例行头部CT扫描,1例右额皮层低密度灶,1例无异常.3例均行MRI检查,均表现为皮层内T1低信号、T2高信号影,边界清楚,周边无水肿;2例行增强扫描,均见环形增强.结论 SGNE是DNT的病理学特征;MRI影像上DNT表现为周边无水肿脑皮层内病灶.当缺乏DNT典型病理特征时,诊断须结合临床表现、MRI影像特征综合做出.     

颅内原发黑色素瘤的CT和MRI诊断

目的 探讨颅内黑色素瘤的CT和MRI影像学表现特征,进一步提高对本病的认识.方法 对4例颅内黑色素瘤的CT和MRI表现,结合文献进行回顾性分析,全部病例均CT、MRI平扫,其中3例CT进行增强,2例MRI进行增强.结果 单发肿瘤和多发肿瘤各2例,CT表现为类圆形高密度影3例,低密度影1例;4例MRI检查,肿瘤呈短T1短T2信号2例,短T1长T2信号1例, 等T1短T2信号1例,肿瘤信号不均匀,边缘清楚,增强后肿瘤呈均匀性强化.结论 肿瘤内特征性的短T1短T2信号对术前确诊具有决定意义,是颅内黑色素瘤的最佳影像学检查方法 ,而CT高密度影应与出血性脑膜瘤等相鉴别.     

上矢状窦血栓形成早期大脑灰质CT特殊表现(附1例报道及文献复习)

目的分析上矢状窦血栓形成的早期大脑灰质CT特点,提高对上矢状窦血栓形成早期大脑灰质CT特点的认识。方法结合文献对1例上矢状窦血栓形成患者的早期脑CT影像学特点进行分析。结果患者发病后6h行脑CT平扫显示双侧额叶皮质高密度影;第3d时脑MRIT1显示上矢状窦前部血栓形成可疑,脑FLAIR-MRI显示右侧额叶高信号及左侧额叶弧形高信号,脑MRIT1相增强扫描显示双侧额叶皮层弧线型增强,MRV显示上矢状窦前1/3处见一无信号区,周围有侧枝循环形成;治疗第6d时复查脑CT和MRI均无出血征象。结论患者早期脑CT所显示的高密度影可能是皮层静脉和毛细血管血液淤积的显示,并不全是出血,对于该征象的认识并结合病理生理过程给予的合理解释对于及时正确的认识该病具有重要意义。     

中枢神经细胞瘤CT、MRI诊断分析

目的分析总结中枢神经细胞瘤(central neurocytoma,CNC)的影像学特征,以提高诊断率。方法回顾性分析安徽省立医院南区自2010年7月至2018年2月手术病理证实的35例CNC患者的影像学资料,男21例,女14例,年龄24～66岁,平均年龄33岁。结果 35例均位于侧脑室内,其中25例位于侧脑室前部或近孟氏孔区。CT平扫多为等密度或稍高密度,常见钙化及囊变;MRI平扫T1WI表现为等或稍低信号,T2WI表现为稍高信号。30例可见囊变(85%),25例瘤体内或周边见强化血管影(71%);MRI增强扫描28例轻中度强化(80%),7例病例明显强化(20%)。15例行DWI(b值=1000s/mm~2),均为高信号。10例行MRS,表现为NNA下降、CHO升高、CHO/NAA比值升高。结论 CNC影像学表现具有一定的特征性(钙化、囊变、血管影、瘤周轻或无水肿、轻中度强化),CT和MRI有助于中枢神经细胞瘤的诊断和鉴别诊断。     

线粒体脑肌病伴高乳酸血症和卒中样发作22例神经影像学特点分析

目的探讨线粒体脑肌病伴高乳酸血症和卒中样发作（MELAS）的神经影像学特点。方法收集2003年10月至2006年7月间入住我院神经内科的22例MELAS患者的资料，并对头颅CT、MRI平扫及增强、MRA、磁共振波谱（MRS）等影像学检查的结果进行分析。结果22例患者中21例影像学检查结果为阳性，其病灶9例位于单侧，12例位于两侧半球。主要累及枕、顶、颞、额叶，头颅MRI表现为T1WI低信号，T2WI、FLAIR像高信号。其中16例MRI增强中12例病灶被不同程度强化。3例表现较为特殊，1例患者影像学表现为软化灶样改变，1例伴有Fahr综合征样改变，1例MRI增强见强血管反应。MRS表现为N-乙酰天冬氨酸峰降低及高乳酸峰。结论虽然MELAS神经影像学特点复杂多样，但有其特征性的表现，如病灶多位于皮质及皮质下，新旧病灶反复交替等，因此，可利用CT、MRI、MRS等影像学方法辅助该病的诊断。     

原发性颅内绒毛膜癌的影像学表现

目的总结原发性颅内绒毛膜癌(PICCC)的影像学表现,以提高该病影像诊断的正确率。方法回顾性分析经穿刺或手术病理证实的4例PICCC的CT和MRI影像学表现,包括分布和形态、密度、信号特点和强化特征。结果1例PICCC位于松果体区,1例位于鞍上,1例位于基底节区,1例沿侧脑室旁分布。CT平扫以高密度为主,CT值为45~65 HU,病灶内可见钙化和出血,增强扫描呈中等程度或明显强化。MRI平扫呈混杂信号,3例T1WI呈等低信号,1例呈高信号;T2WI呈低信号为主的混杂信号。增强扫描2例呈明显不均匀强化,2例呈花环状强化,1例伴室管膜明显强化。结论PICCC好发于青少年,易合并瘤内出血和钙化,结合血清β-HCG水平升高和临床症状,术前应考虑到PICCC的可能。     

Functional MR imaging with venography for neurosurgical identification of the central sulcus

We evaluated the applicability of functional MR imaging overlaid onto brain images superimposed venography for neurosurgical identification of the central sulcus. In 20 volunteers and 12 patients with brain tumors located around the sensorimotor cortex, gradient echo and large flip angle functional MR image was performed to allow visualization of flow effect and susceptibility related changes in relative large vein by motor hand task. Functional MR image acquired was overlaid on 3D anatomical image with 3D venography. Based on the 3D mapping, intra-operative cortical somatosensory evoked potentials (SEPs) were recorded. The significant activation area obtained from functional MR imaging was projected on an ascending cortical vein in 16 volunteers (80%) and 10 patients (83%). Comparing the anatomical activation map with visual inspection of the exposed cortical surface made it easy to identify the activation area during surgery. The cortical veins in 9 of 10 were validated as a central vein by intra-operative cortical recording of SEPs. Combination of functional MR imaging overlaid onto 3D anatomical image with venography and intra-operative SEPs permitted rapid and accurate localization of the central sulcus during surgery.     

Lack of correlation between cortical demyelination and white matter pathologic changes in multiple sclerosis

BACKGROUND: Histopathologic studies have shown that subpial cortical demyelination is extensive in chronic multiple sclerosis (MS). OBJECTIVE: To study whether subpial cortical demyelination in MS is associated with focal or diffuse white matter (WM) pathologic features on magnetic resonance imaging (MR imaging). DESIGN: Comparison of postmortem MR imaging findings with histopathologic findings. SETTING: Brain donations from a general community. PATIENTS: Three patients with MS with extensive cortical demyelination and 3 patients with minor cortical demyelination were selected from an MS autopsy data set. The postmortem MR imaging and histopathologic data of the patients were compared. MAIN OUTCOME MEASURES: Two observers blinded to the results of each other assessed the presence, extent, and distribution of focal and diffuse pathologic changes in WM by MR imaging and by histopathology. RESULTS: Extensive subpial demyelination was not associated with a significant increase in the area of focal and diffuse WM pathologic changes as assessed by Luxol fast blue histochemistry or by MR imaging or with the presence or extent of juxtacortical abnormalities on MR imaging. CONCLUSIONS: The lack of association of MS gray matter demyelination with diffuse or focal WM changes indicates that gray matter demyelination in MS occurs largely independent of WM pathologic changes. The extent or distribution of WM abnormalities cannot be used to identify extensive cortical demyelination in the clinical setting.     

心源性脑梗死的影像表现

目的：评价CT和MRI-DWI在心源性脑梗死诊断中的临床应用价值。方法选择临床资料完整的89例心源性脑梗死患者的首次和治疗中复查影像表现进行回顾性分析。结果（1）首次影像学检查表现：单发47例,多发42例。C T检查57例,超急性期2例,急性期21例,亚急性期34例;M RI-DWI检查32例,超急性期15例,急性期10例,亚急性期7例。多呈片状、斑片状分布于皮质或（和）皮质下区,CT呈低密度灶,T2 WI呈高信号,DWI呈异常高信号,范围较 T2 WI大。大梗死灶（面积＞3 cm2）55个,小梗死灶（1.5～3.0 cm2）42个,腔隙性梗死灶（＜1.5 cm2）63个。（2）栓塞的血管分布：颈内动脉系统受累73例,其中大脑前动脉18例,大脑中动脉55例;椎基底动脉系受累11例,颈内动脉与椎基底动脉同时受累5例。（3）出血性脑梗死的影像表现：72例治疗中复查检出出血性脑梗死34例,1～3 d检出5例,3～7 d 9例,7～14 d 17例,14 d以上3例;影像表现为在片状梗死区内斑点、片状,血肿样出血灶或多处皮质区梗死灶内出血征象,斑点片状28例,血肿样6例,中心型10例,边缘型19例,混合型5例。结论 C T和M RI能够为心源性脑梗死的诊断、随访复查及判断预后提供更多直接可靠的影像学依据,DWI比CT与常规MRI在超急性期脑梗死治疗决策的确立中更具临床应用价值。     

Quantitative proton magnetic resonance imaging in focal cerebral ischemia in rat brain

Proton magnetic resonance (MR) imaging has been recommended as a diagnostic tool for the detection of focal cerebral ischemia. We compared microscopic MR images of rat brains after focal cerebral ischemia with evidence of histological damage found on corresponding silver-impregnated or cresyl violet-stained brain sections. Ten male Wistar rats were subjected to permanent unilateral occlusions of the right middle cerebral and common carotid arteries under halothane anesthesia. Twenty-four hours later the area of injury on MR images amounted to 26% of the total slice area, whereas only 9% of the total slice area was necrotic on histological sections from the same animals. The infarcted areas on tissue sections were surrounded by regions of selective neuronal injury in the cerebral cortex and occasionally in the hippocampus. The area of injury on MR images was larger than the combined areas of infarction and selective neuronal injury on histological sections. Areas of increased T2 values on MR images extended medially into noninfarcted striatum and laterally and dorsally into noninfarcted cortex. The lateral and dorsal areas on MR images frequently coincided with cortical areas in which considerable selective neuronal injury was present in the upper cortical layers. We hypothesize that the abnormal areas on MR images above histologically normal brain tissue represent the ischemic penumbra. If true, this is the first demonstration of the ischemic penumbra by MR imaging and may reflect our use of Wistar rats, a new image analysis technique, and ultra-high resolution MR imaging.     

Rapid cortical reorganisation and improved sensitivity of the hand following cutaneous anaesthesia of the forearm

The cortical representation of various body parts constantly changes based on the pattern of afferent nerve impulses. As peripheral nerve injury results in a cortical and subcortical reorganisation this has been suggested as one explanation for the poor clinical outcome seen after peripheral nerve repair in humans. Cutaneous anaesthesia of the forearm in healthy subjects and in patients with nerve injuries results in rapid improvement of hand sensitivity. The mechanism behind the improvement is probably based on a rapid cortical and subcortical reorganisation. The aim of this work was to study cortical changes following temporary cutaneous forearm anaesthesia. Ten healthy volunteers participated in the study. Twenty grams of a local anaesthetic cream (EMLA^®) was applied to the volar aspect of the right forearm. Functional magnetic resonance imaging was performed during sensory stimulation of all fingers of the right hand before and during cutaneous forearm anaesthesia. Sensitivity was also clinically assessed before and during forearm anaesthesia. A group analysis of functional magnetic resonance image data showed that, during anaesthesia, the hand area in the contralateral primary somatosensory cortex expanded cranially over the anaesthetised forearm area. Clinically right hand sensitivity in the volunteers improved during forearm anaesthesia. No significant changes were seen in the left hand. The clinically improved hand sensitivity following forearm anaesthesia is probably based on a rapid expansion of the hand area in the primary somatosensory cortex which presumably results in more nerve cells being made available for the hand in the primary somatosensory cortex.     

A case of SSPE that showed watershed infarction like image on MRI initially, and progressed to whole brain atrophy

We reported a 15-year-old male patient of subacute sclerosing panencephalitis (SSPE), progressed from stage I to stage IV. On his admission, his clinical state was stage I with disturbance of generalized attention, myoclonus of upper limbs and no focal cortical signs. After rapid progression to stage III in a month, his clinical state became fairly stable and gradually advanced to stage IV. We followed him with serial CT and MR images. On imagings we found initial lesion in left parietoocipital lobe and spread in right parietoocipital lobe, anterior lobe and then brain stem, showing low density on plain CT scans and high intensity of T2 weighed MR images. This initial lesion situated in watershed area was hardly distinguishable from watershed infarction. In addition, we found blood flow decrease in vertebral artery system with SPECT and Doppler flowmetry. These findings suggested vascular pathogenesis of SSPE. We showed the imaging processes of SSPE progression from formation of initial lesion to demyelination and gliosis of total brain.     

Neuronal metabolic changes in the cortical region after subcortical infarction: a proton MR spectroscopy study

OBJECTIVES: To investigate whether proton magnetic resonance spectroscopy ((1)H MRS) can detect neuronal metabolic changes in the cortical region in patients with cortical dysfunction after subcortical infarction. METHODS: Fifteen patients with subcortical large (diameter>/=20 mm) infarcts were studied; nine patients with cortical dysfunction (group A), and six without (group B). Seven patients with lacunar infarction served as controls. Infarct volume was measured on T2 weighted images with an image analyser. (1)H MRS data were obtained in three regions; high signal intensity area on T2 weighted image, overlying cortex with a normal T2 MRI appearance, and contralateral homologous cortical region. RESULTS: Infarct volume was not different between groups A and B. N-acetylaspartate (NAA)/creatine+phosphocreatine (Cr) ratios in the cortical region overlying subcortical infarcts in group A were significantly lower than those in group B and the control group (p=0.002). The NAA/Cr ratios in the overlying cortex were significantly lower than those in the contralateral normal cortex in group A on the initial (p=0. 015) and follow up (p=0.028) (1)H MRS, but these differences were not found in group B and the control group. CONCLUSIONS: The results support the idea that the cerebral cortex is a responsible location for cortical dysfunction after subcortical infarctions. (1)H MRS can be used as a sensitive method for the detection of a neuronal metabolic damage, which is not demonstrated by conventional MRI.     

Pathology of the trigeminal nerve

Imaging of the trigeminal nerve requires a thorough understanding of its anatomy and function, clinical symptoms related to malfunction, and its key pathologies. Because of the nerve's long course from the brainstem nuclei to the peripheral branches, MR imaging and CT studies have to cover a large anatomic area while providing high-resolution images. Although MR imaging has almost completely replaced CT as the diagnostic modality of choice for investigating trigeminal neuropathy, CT still plays a role in the assessment of skull base foramina and facial skeleton. In this article, the clinical, radiologic, and pathologic features of the most common conditions causing trigeminal nerve dysfunction at each specific anatomic level are discussed.     

Diagnosis of acute cerebral infarction using diffusion-weighted imaging by low field (0.2 T) magnetic resonance image]

The purpose of this study is to confirm the diagnosis of acute cerebral infarction on diffusion-weighted imaging using low field (0.2 T) magnetic resonance image(MRI). Acute cerebral infarctions in 51 patients were examined on diffusion-weighted imaging using low field MRI within 48 hours after clinical symptoms. Diffusion-weighted imaging was examined using line scan method. Twenty-four cases were cortical infarction, and twenty-two cases were perforating infarction. In five cases out of 51 cases, ischemic regions were not detected as abnormal high signal intensity area on diffusion-weighted imaging. Four cases of no abnormal detection were transient ischemic attack, and the other one was a perforating infarction. The earliest detection time in cortical infarction cases was 1 hour and 20 minutes. On the other hand, the earliest detection time in perforating infarction cases was 3 hours. Detective ability for acute cerebral infarction on diffusion-weighted imaging by low field MRI was depending on both size and lesion of infarction. That is to say, either small size or brain stem infarction was hard to detect. Thin slice and vertical slice examination for the infarction may improve to diagnose in low field MRI. Our conclusion is acute cerebral infarction was able to be diagnosed on diffusion-weighted imaging by low field as well as high field MRI.     

DWI及MRA在大面积脑梗塞早期诊断中的价值

目的:评价弥散加权磁共振成像DWI和磁共振血管成像MRA对早期大面积脑梗塞的诊断价值。方法:对24例早期大面积脑梗塞的临床和磁共振资料进行分析,全部患者均行DWI及MRA检查。结果:24例早期大面积脑梗塞中,13例急性期CT扫描未检测出确切病灶,DWI扫描全部出现大片异常高信号,病灶检出率为100％。而在常规T2WI检查中,7例为阴性,病灶检出率为69％。MRA发现血管异常24例,表现为供血动脉闭塞,狭窄、硬化。结论: DWI有助于明确早期大面积脑梗塞病变范围,且能区别新旧病灶。MRA能直接显示大面积脑梗塞闭塞的供血脑血管,联合使用DWI和MRA对早期大面积脑梗塞诊断有重要的临床价值,也有利于早期合理的治疗方案制定及预后判断。