MRI在胼胝体梗死中的诊断价值

目的 探讨胼胝体梗死的磁共振影像特点及其临床特征。方法 对32例胼胝体梗死患者的图像进行分析，分析梗死的部位及在不同扫描序列中的表现，结合患者的临床表现进行对比研究。结果 胼胝体膝部梗死9例、胼胝体体部梗死11例胼胝体压部梗死12例；其中超急性梗塞1例，急性梗死2例，亚急性梗死6例。结论 MRI是诊断胼胝体梗死最有意义的检查方法，可以直接清晰显示梗死的有无、部位、范围，并能对病灶的新旧分期指导临床治疗。     

MRI诊断胼胝体萎缩2例报告

本文报道MRI诊断胼胝体萎缩2例如下。 例1,男,54岁。4年前自觉双手做精细动作不能,注意力不集中,记忆力减退,易激怒。1周前出现步态不稳,吃饭时易掉筷子,时强哭强笑。高血压病4年,长期饮酒20余年,每日约0.5kg。血压20/12kPa,表情欣快,理解判断迟钝,计算力差,吸吮反射阳性,双下肢肌张力增高,膝腱反射活跃,肌力正常,慌张步态,四肢远端痛温觉减退,双     

胼胝体损伤的诊治体会

自从MRI广泛运用于临床之后,临床上对于胼胝体损伤有了比较明确的认识.我院自1999年3月至2002年8月共收治该种病例6例,现报告如下.     

胼胝体病变的临床与CT、MRI表现

目的：分析胼胝体病变临床表现及CT、MRI影像学特征。材料与方法：搜集经CT、MRI检查后发现胼胝体病变37例（其中15例经手术及定向穿刺后病理证实）。结果与结论：37例胼胝体病变包括所胼胝体发育不全6例、脂肪瘤5例，外伤及脑血管意外致血肿11例、肿瘤13例（胶质母细胞瘤3例、Ⅰ～Ⅱ级星形细胞瘤5例、淋巴瘤3例、转移后2例）、血管畸形及多发性硬化各1例。除8例脑外伤以外，其他病人临床上均有长期头晕、头痛、突发意识障碍、癫痫等表现、但非特征性改变。CT、MRI对胼胝体病变（无论是原发或是继发）的发现、诊断及鉴别诊断均有重要的价值，MRI在定位上较CT更为精确．从而为术前手术方式的选择，术后放疗的定位准确提供更多有用信息。     

外伤性颅内静脉窦血栓形成的MRI诊断

目的探讨磁共振成像(MRI)结合磁共振静脉成像(MRV)在外伤性颅脑静脉窦血栓形成中的诊断价值。方法回顾性分析28例经临床及影像学诊断为外伤性颅脑静脉窦血栓形成的 MRI与MRV资料。磁共振均行常规SE序列T1WI、T2WI以及液性衰减反转恢复序列(FLAIR)扫描,并全部行二维时间飞跃法静脉成像(2d-TOF MRV)检查。结果外伤性静脉窦血栓形成最常累及上矢状窦、下矢状窦、横窦,表现为受累静脉窦流空效应消失,为不同信号的血栓所阻断。MRV则表现为受累静脉窦管腔的狭窄、中断以及属支的迂曲扩张。结论 MRI结合MRV能无创性的同时显示外伤性颅脑静脉窦血栓形成与脑挫裂伤,为外伤性颅脑静脉窦血栓形成的首选检查方法。     

胼胝体压部可逆性病变的MRI诊断与临床分析

目的探讨胼胝体压部(splenium of the corpus callosum,SCC)可逆性病变的MRI表现及临床特点。方法回顾性分析8例脑MRI表现为单纯胼胝体压部可逆性病变患者的临床和影像学资料。结果 8例患者的SCC可逆性病变均为继发性,原发病分别为脑内感染5例,肝豆状核变性、低血糖脑病及脑外伤各1例。8例患者均急性起病,临床表现为发热、头痛5例,急性意识障碍2例,肌张力增高2例,颈强2例,均符合原发病的临床表现。8例均行脑MRI检查,均表现为T1低或等信号,T2及FLAIR序列高信号,DWI高信号(提示细胞源性水肿),其中4例行增强扫描未见强化。8例患者均于临床症状好转或消失后复查MRI提示病灶消失。结论 SCC可逆性病变在多种疾病中均可出现,无该病变相关的特异性临床表现,MRI表现提示病灶为细胞源性水肿可能。     

颅脑损伤后血脑屏障通透性的MRI评估

颅脑损伤后的血脑屏障（blood—brain barrier,BBB）破坏早已被证实。颅脑损伤使毛细血管内皮细胞损伤、星形胶质细胞肿胀,直接导致了BBB、脑血流和大脑代谢过程的异常。目前,颅脑损伤后的BBB通透性增加正越来越受到重视,甚至有学者提出将针对BBB破坏的治疗作为治疗颅脑损伤的新目标。因此,如何准确高效地定量检测BBB通透性备受关注。     

可逆性胼胝体压部病变综合征一例

目的探讨可逆性胼胝体压部病变综合征的临床特点、磁共振(MRI)影像学特征、治疗方法及预后。方法分析1例可逆性胼胝体压部病变综合征临床资料并结合相关资料对此例胼胝体压部局灶性孤立病变进行分析。结果患者胼胝体压部椭圆形长T1、长T2信号,Flair及DWI高信号影,经抗病毒及对症处理后发病第14天病灶消失。结论可逆性胼胝体压部病变综合征临床特征以MRI发现胼胝体压部孤立病灶为特点,病因、发病机制尚不明确,有一定自愈性。     

健康成人胼胝体核磁共振影像解剖学研究

目的 探讨健康成人胼胝体各部分径值及与年龄的相关性,为相关疾病的诊断提供正常胼胝体数据. 方法 选择120例健康成人自愿者(男、女各半),行头部T1加权序列MR扫描.在正中矢状面上测量胼胝体的膝部、压部、体部的宽度以及胼胝体长度与高度. 结果 120例健康成人胼胝体膝部、压部、体部的宽度以及胼胝体长度与高度分别为(11.35±2.16) mm、(9.97±2.09)mm、(5.93±1.32)mm、(73.33±3.77)mm、(25.34±3.01)mm.经统计学分析发现健康成人腩随年龄的增加胼胝体的膝部、乐部、体部的宽度逐渐减小,而胼胝体的长度与高度随年龄增加而增加,呈显著相关性(P<0.05).胼胝体形态随年龄的增长而呈弓背样增高. 结论 胼胝体的各部分径值及形态与年龄密切相关.     

磁共振成像在颅脑创伤诊断中的应用

磁共振成像(MRI)自上世纪八十年代应用于临床以来迅速发展,在颅内肿瘤、脑血管病、神经变性疾病诊断方面显示了强大优势,但在颅脑创伤(traumatic brain injury,TBI)方面,MRI由于显示骨折及超急性期血肿差、检查时间长、对危重病人难以安全成像等缺点而限制了其使用.得益于MRI显示脑实质全貌及细节方面的明显优势,随着新技术的开发应用,MRI在颅脑创伤中的应用前景愈加广阔.     

The morphology of the corpus callosum in schizophrenia: An MRI study

40 schizophrenic patients and 17 normal controls underwent magnetic resonance imaging (MRI) of the brain. All subjects were consenting males. The size and form of the corpus callosum in the mid-sagittal cut of MRI were evaluated. This study revealed that the mean size of the anterior region of the corpus callosum was significantly greater in schizophrenics than in controls. The elongated anterior corpus callosum, which did not correlate with age, duration of illness, birth complications or any measures of brain areas in the midsagittal cut, was regarded as a primary change. Schizophrenics with the elongated corpus callosum seemed to have an unfavorable prognosis, because the large corpus callosum suggested poor heterosexual relations, reduced number of hospitalizations, low academic grades and mild anxiety-depression syndrome. A smooth and even corpus callosum seen in schizophrenics was likely a change dependent on duration of illness.     

Locations and Clinical Significance of Non-Hemorrhagic Brain Lesions in Diffuse Axonal Injuries

Objective

Detection of focal non-hemorrhagic lesion (NHL) has become more efficient in diffuse axonal injury (DAI) patients using an MRI. The aims of this study are to find out the radiological distribution, progress of NHL and its clinical significance.

Methods

Between September 2005 and October 2011, 32 individuals with NHLs on brain MRI were enrolled. NHLs were classified by brain location into 4 major districts and 13 detailed locations including cortical and subcortical, corpus callosum, deep nuclei and adjacent area, and brainstem. The severity of NHL was scored from grades 1 to 4, according to the number of districts involved. Fourteen patients with NHL were available for MRI follow-up and an investigation of the changes was conducted.

Results

Thirty-two patients had 59 NHLs. The most common district of NHL was cortical and subcortical area; 15 patients had 20 NHSs. However the most common specific location was the splenium of the corpus callosum; 14 patients had 14 lesions. The more lesions patients had, the lower the GCS, however, this was not a statistically meaningful difference. On follow-up MRI in 14 patients, out of 24 lesions, 13 NHLs resolved, 5 showed cystic change, and 6 showed atrophic changes.

Conclusion

NHLs were located most commonly in the splenium and occur frequently in the thalamus and the mesial temporal lobe. Because most NHS occur concomitantly with hemorrhagic lesions, it was difficult to determine their effects on prognosis. Since most NHLs resolve completely, they are probably less significant to prognosis than hemorrhagic lesions.     

Anatomical MRI study of corpus callosum in unipolar depression

Previous studies have suggested abnormal cerebral lateralization in major depressive disorder (MDD). Few controlled MRI studies have investigated the corpus callosum (CC), the largest commissura connecting the two cerebral hemispheres, in MDD. This study investigated anatomical abnormalities in the CC and its subdivisions in MDD patients. Twenty-two unmedicated MDD patients and 39 healthy subjects underwent brain magnetic resonance imaging (MRI). Measurements of the CC and its sub-regions were performed with a semi-automated software (NIH Image, version 1.62). ANCOVA with age, gender, and intra-cranial volume (ICV) as covariates showed no significant differences in CC measurements between patients and controls (df=1,56; p>0.05). However, patients with familial MDD had a significantly larger middle genu area (F(1,45)=4.252; p=0.045) compared to healthy controls, and significantly larger middle genu (F(1,13)=5.366; p=0.037), anterior splenium (F(1,13)=6.27; p=0.026), and middle splenium areas (F(1,13)=4.706; p=0.049) compared to patients with non-familial MDD. Although preliminary, our findings suggest that anatomical abnormalities in CC may be restricted to patients with familial MDD, with possible enlargement of CC in this particular sub-group. The possible role of callosal abnormalities in the pathogenesis of mood disorders should be further examined.     

The added prognostic value of magnetic resonance imaging in traumatic brain injury: The importance of traumatic axonal injury when performing ordinal logistic regression

Background and purposeThis study was performed to investigate the prognostic value of traumatic axonal injury (TAI) in severe head trauma.MethodsWe attempted to determine whether any MR imaging findings of TAI could be related to prognosis in 264 patients with severe head trauma. We performed an ordinal logistic regression, adjusted for the prognostic factors according to the IMPACT studies, adding each MR feature related to prognosis one at a time. A new prognostic model was described by adding these MR features to the classic prognostic factors. The model was externally validated in a prospective series. Harrel's c-statistic and ordinal c-index (ORC) were calculated to measure its predictive accuracy.ResultsWe found 178 patients with TAI lesions. Lesions in the basal ganglia/thalamus, corpus callosum (CC) and brain stem were associated with poor outcome (P < 0.01). The highest OR was for TAI lesions in the splenium (OR: 2.6) and brain stem dorsal lesions (OR: 3.1). We only found significant differences in outcome between haemorrhagic and non-haemorrhagic TAI lesions in the subgroup of patients with white matter and basal ganglia/thalamus lesions (P = 0.01). We obtained a superior discriminatory capacity by adding these MR findings to the previous prognostic model (Harrel's c-statistic 0.72 and ORC 0.7) in a prospective series of 93 patients.ConclusionsThe prognostic model including MR findings maintained a superior discriminatory capacity than that obtained for the model with the classic prognostic factors alone.     

Post-shunting corpus callosal signal change and review of the literature

MRI signal changes in the corpus callosum can be seen in 8.3% of patients following shunt insertion for obstructive hydrocephalus. Several causes have been hypothesised, including mechanical compression, decompression associated oedema and ischaemia, and overshunting. We present a case of a patient with a pineal tumour of intermediate differentiation (WHO grade III), which had caused long-term obstructive hydrocephalus due to compression of the tectal plate and cerebral aqueduct. Following insertion of a shunt, prominent changes in the corpus callosum became evident on CT and MRI characterised by oedema and swelling, particularly affecting the dorsal surface of the corpus callosum. This pattern of signal change, although dramatic, should not be mistaken for other pathologies.     

Visualization of maturation of the corpus callosum during childhood and adolescence using T2 relaxometry

Previous studies have shown that maturation of the white matter in terms of its relative signal intensity changes on MRI is almost complete at 2-3 years of age. We hypothesized that quantitative analysis may show maturation of the white matter during childhood and adolescence. In the present study we performed multi-echo T2 relaxometry in 33 healthy subjects (girls, 15; boys, 18) aged 3-15 years. T2 relaxation times of the genu and splenium were measured. In healthy subjects, the T2 relaxation times were significantly correlated with age in both girls (r=0.611, p=.016) and boys (r=0.721, p=.001) in the splenium, but not in the genu (p>.05). To further confirm genu-to-splenium signal intensity ratio changes, a total of 389 brain MRIs were retrospectively selected from the patients who had normal results (189 girls/women, 200 boys/men; age range, 3-20 years). The genu-to-splenium signal intensity ratio was obtained from the T2-weighted images. In patients with normal MRI, the genu-to-splenium signal intensity ratio was significantly decreased with age (p<.001) by 16 years. The T2 relaxation times gradually increase in the splenium during childhood and adolescence, suggestive of maturation.     

Forward and inverse electroencephalographic modeling in health and in acute traumatic brain injury

Objective

EEG source localization is demonstrated in three cases of acute traumatic brain injury (TBI) with progressive lesion loads using anatomically faithful models of the head which account for pathology.

Methods

Multimodal magnetic resonance imaging (MRI) volumes were used to generate head models via the finite element method (FEM). A total of 25 tissue types—including 6 types accounting for pathology—were included. To determine the effects of TBI upon source localization accuracy, a minimum-norm operator was used to perform inverse localization and to determine the accuracy of the latter.

Results

The importance of using a more comprehensive number of tissue types is confirmed in both health and in TBI. Pathology omission is found to cause substantial inaccuracies in EEG forward matrix calculations, with lead field sensitivity being underestimated by as much as ∼200% in (peri-) contusional regions when TBI-related changes are ignored. Failing to account for such conductivity changes is found to misestimate substantial localization error by up to 35 mm.

Conclusions

Changes in head conductivity profiles should be accounted for when performing EEG modeling in acute TBI.

Significance

Given the challenges of inverse localization in TBI, this framework can benefit neurotrauma patients by providing useful insights on pathophysiology.     

Meta-analysis of magnetic resonance imaging studies of the corpus callosum in schizophrenia

OBJECTIVES: The corpus callosum plays a pivotal role in inter-hemispheric transfer and integration of information. Magnetic resonance studies have reported callosal abnormalities in schizophrenia but findings have been inconsistent. Uncertainty has persisted despite a meta-analytic evaluation of this structure several years ago. We set out to perform a further meta-analysis with the addition of the numerous reports published on the subject to test the hypothesis that the corpus callosum is abnormal in schizophrenia. METHOD: A systematic search was carried out to identify suitable magnetic resonance studies which reported callosal areas in schizophrenia compared to controls. Results from the retrieved studies were compared in a meta-analysis whilst the influence of biological and clinical variables on effect size was ascertained with meta-regression analysis. RESULTS: Twenty-eight studies were identified. Corpus callosum area was reduced in schizophrenia in comparison to healthy volunteers. This effect was larger in first episode patients. Similarly, heterogeneity detected among the studies was associated with course of illness indicating that chronic subjects with schizophrenia showed larger callosal areas. There was no evidence of publication bias. CONCLUSIONS: This study confirms the presence of reduced callosal areas in schizophrenia. The effect is of a larger magnitude at first presentation and less so in subjects with a chronic course generally medicated with antipsychotics.