In vivo 31P nuclear magnetic resonance spectroscopy of human temporal lobe epilepsy.

We performed localized 31P nuclear magnetic resonance (NMR) 1H-image-guided in vivo spectroscopy to study regional high-energy phosphate levels in the brains of normal controls and in patients with intractable unilateral temporal lobe epilepsy. We did not observe differences in intracellular pH between controls and patients. The phosphocreatine/inorganic phosphate ratio was reduced by 50% in the epileptogenic temporal lobe compared with controls (p less than 0.005) and by 35% when compared with the unaffected contralateral temporal lobe (p less than 0.05). We did not observe differences in the ratio of phosphomonoesters to phosphodiesters between controls and patients. These findings suggest that in vivo 31P NMR spectroscopy yields a distinctive interictal metabolic profile in patients with intractable unilateral temporal lobe epilepsy and may permit noninvasive lateralizing evidence of the seizure focus.     

颞叶癫痫的磁共振波谱学定侧研究

目的　探讨磁共振波谱学 (magneticResonanceSpectroscopy ,MRS)在颞叶癫痫术前定位中的作用。方法　取 18例接受手术治疗的顽固性颞叶癫痫患者为研究对象 ,其术前已接受EEG、MRI和PET等检查获得定位。接受双侧颞叶内侧的MRS检查 ,测定其N -乙酰天门冬氨酸 (NAA)、肌酐 (Cr)和胆碱 (Cho)含量 ,并计算NAA/(Cr Cho)的比值 ;以NAA/(Cr Cho) <0 .6 8和双侧NAA/(Cr Cho)比值的差别 >7%为标准。结果　在18例病例中 16例患侧颞叶MRS检查结果异常 ,其中 9例为患侧MRS异常 ,7例为双侧MRS异常 ,以患侧为重 ,2例患者的比值正常 ;MRS的敏感性高于MR(15 /18) ,与MR结合 ,可对 17例患者进行术前定侧。结论　MRS对颞叶癫痫的定侧诊断有较高的准确性 ,为颞叶癫痫的定位诊断提供新的手段 ;与MRI、PET等手段结合使用 ,可进一步提高对颞叶癫痫诊断的敏感性和准确性     

耐药性内侧颞叶癫痫患者的功能影像磁共振研究

目的采用功能磁共振功能连接密度(FCD)探索耐药与否的内侧颞叶癫痫患者脑功能活动的差异,并分析其与病程的相关性。方法采用回顾性研究方法,收集从2009年7月至2019年2月在东部战区总医院(南京大学医学院附属金陵医院)就诊的单侧海马硬化的内侧颞叶癫痫患者共146例,根据2010年国际抗癫痫联盟对耐药性癫痫的定义将其分为药物控制组(73例)和耐药组(73例)。对所有受试者均进行3.0 T静息态功能磁共振扫描,比较两组患者FCD的差异,并计算两组患者FCD差异脑区FCD值和病程的相关性。结果药物控制组和耐药组内侧颞叶癫痫患者的FCD显示出广泛差异。相比于药物控制组,耐药组在致痫灶侧岛叶、豆状核、丘脑、海马、中央前回FCD值明显降低。耐药组致痫灶侧楔前叶FCD值与病程呈负相关(r=-0.30,P=0.010)。结论耐药性内侧颞叶癫痫患者较药物控制组FCD值广泛降低,此外大脑可能存在进行性损伤,影像学差异有利于探究内侧颞叶癫痫患者耐药相关的病理生理机制,寻找可靠的耐药相关的神经影像标志物。     

Proton nuclear magnetic resonance spectroscopic imaging of human temporal lobe epilepsy at 4.1 T

We performed proton magnetic resonance spectroscopic imaging (MRSI) at high magnetic field (4.1 T) to study N-acetylaspartate, creatine, and choline levels in the brains of normal control subjects and patients with intractable temporal lobe epilepsy. We compared the results of MRSI to those of other presurgical techniques to determine the sensitivity of this method in the lateralization of the epileptic focus. The normal hippocampal creatine—N-acetylaspartate ratio was 0.71 ± 0.14 with no differences between left and right. Using the mean control hippocampal creatine—N-acetylaspartate ratio plus 2 standard deviations to identify statistically significant changes, we found lateralizing metabolic abnormalities corresponding to the operated temporal lobe in all patients. Four patients (40%) had contralateral abnormalities, and 2 of them had bilateral independent seizure onset confirmed by intracranial electroencephalographic studies. Statistically significant increases in the choline—N-acetylaspartate ratio in comparison to healthy volunteers were observed in 8 of the 10 patients. With the creatine—N-acetylaspartate ratio, MRSI demonstrated a 100% sensitivity compared to magnetic resonance imaging, which identified pathology in 70% of the patients. These findings suggest that proton MRSI yields a distinctive metabolic profile in patients with temporal lobe epilepsy and is sensitive in detecting bilateral metabolic abnormalities in some patients. These preliminary findings suggest that MRSI is more sensitive than magnetic resonance imaging in the lateralization of epileptic foci in temporal lobe epilepsy.     

Proton magnetic resonance spectroscopy in children with temporal lobe epilepsy

We performed proton magnetic resonance spectroscopy of the mesial temporal regions in 20 children with intractable temporal lobe epilepsy and compared results with those from 13 normal subjects. Abnormalities of the ratio of N-acetylaspartate to choline plus creatine (NAAI[Cho+Cr]) were seen in 15 patients (75%). The ratio NAA/(Cho+Cr) was correctly lateralizing in 55% and incorrectly lateralizing in none. Bilateral abnormalities were seen in 45%. Overall there was a unilateral decrease in N-acetylaspartate on the side ipsilateral to the seizure focus (mean 19% decrease vs normals, with 5% decrease on the contralateral side), suggesting neuronal loss or dysfunction. There was also a bilateral increase in creatine and choline (mean l8%), consistent with reactive astrocytosis. We conclude that proton magnetic resonance spectroscopy can contribute to lateralization of the seizure focus, and by detection of bilateral abnormalities, can contribute to the understanding of the underlying pathophysiology in temporal lobe epilepsy.     

Quantitative magnetic resonance imaging in patients with temporal lobe epilepsy

Quantitative brain changes on magnetic-resonance-weighted imaging (MRI) were studied in 30 patients with temporal lobe epilepsy (TLE) who showed negative findings on computed tomography and no visible abnormality on MRI, and 20 healthy controls in order to detect changes not visible by standard imaging. The patients with TLE showed a significant decrease in size and a significant increase in T1 values of the mesial temporal area in both hemispheres compared to controls who had normal values bilaterally. Patients with a current or past history of organic delusional disorder (ICD-10) resembling schizophrenia showed a significant increase in the size of the third ventricle. The data suggest that (a) there are atrophic changes in the mesial temporal areas of patients with TLE, reflecting an increased water content in these areas, (b) TLE patients often have bilateral atrophic changes in the mesial temporal areas, even if there is only unilateral abnormality of EEG, and (c) TLE patients with schizophrenia-like organic symptoms may have some structural changes around the third ventricle, including limbic system structures. Further research needs to clarify the exact structures involved and the factors responsible for these abnormalities.     

A short-echo-time proton magnetic resonance spectroscopic imaging study of temporal lobe epilepsy

PURPOSE: We used short-echo-time proton magnetic resonance spectroscopy imaging (MRSI) to study metabolite concentration variation through the temporal lobe in patients with temporal lobe epilepsy (TLE) with and without abnormal MRI. METHODS: MRSI was performed at TE = 30 ms to study 10 control subjects, 10 patients with TLE and unilateral hippocampal sclerosis, and 10 patients with TLE and unremarkable MRI (MRI negative). We measured the concentrations of N-acetyl aspartate +N-acetyl aspartyl-glutamate (NAAt), creatine (Cr), choline (Cho), glutamate + glutamine (Glx), and myoinositol, in the anterior, middle, and posterior medial temporal lobe (MTL), and in the posterior lateral temporal lobe. Segmented volumetric T1-weighted MRIs gave the tissue composition of each MRSI voxel. Normal ranges were defined as the control mean +/- 3 SD. RESULTS: In the hippocampal sclerosis group, seven of 10 had abnormally low NAAt in the ipsilateral anterior MTL. In the MRI-negative group, four of 10 had low NAAt in the middle MTL voxel ipsilateral to seizure onset. Metabolite ratios were less sensitive to abnormality than was the NAAt concentration. Group analysis showed low NAAt, Cr, and Cho in the anterior MTL in hippocampal sclerosis. Glx was elevated in the anterior voxel contralateral to seizure onset in the MRI-negative group. Metabolite concentrations were influenced by voxel position and tissue composition. CONCLUSIONS: (a) Low NAAt, Cr, and Cho were features of the anterior sclerotic hippocampus, whereas low NAAt was observed in the MRI-negative group in the middle MTL region. The posterior temporal lobe regions were not associated with significant metabolite abnormality; (b) The two patient groups demonstrated different metabolite profiles across the temporal lobe, with elevated Glx a feature of the MRI-negative group; and (c) Voxel tissue composition and position influenced obtained metabolite concentrations.     

MRI对颞叶癫痫的定侧诊断的价值

目的 观察颞叶癫痫患者的头颅MRI变化，探讨MRI对颞叶癫痫的定侧诊断价值。方法 采用头颅MRI检查，对40例颞叶癫痢患者及40例正常对照组的海马体积进行测量，将海马萎缩严重侧作为致瘌侧。结果 定量MRI对颞叶癫痢定侧敏感性为72．5％，特异性为85．3％。结论 头颅MRI扫描对颞叶癫痫的定位及定侧有着重要的诊断价值。     

Reduction in temporal lobe size in siblings with schizophrenia: a magnetic resonance imaging study

Twenty-eight individuals with familial schizophrenia, from 16 unrelated families (12 sibling pairs and 4 individuals whose siblings refused scanning), and 21 normal control subjects were examined by cerebral magnetic resonance imaging (MRI). Measurements of the cerebrum, temporal lobes, and cerebral lateral ventricles were obtained using consecutive coronal sections containing these structures. Temporal lobe volume was significantly decreased by approximately 10% in these early onset schizophrenic siblings compared with normal controls. These findings add to recent post-mortem and neuroradiological evidence for morphological alteration in the temporal lobes in schizophrenia.     

Quantitative and qualitative MRI changes in temporal lobe epilepsy. A comparison with normal parameters of nuclear magnetic resonance tomography]

Magnetic resonance imaging (MRI) often reveals no pathology in patients with temporal lobe epilepsy (TLE) who are candidates for surgery, even though post-surgery histology reveals atrophy or sclerosis. To differentiate these pathologies in MRI, we performed a standardized acquisition and a quantitative analysis of MRI data (qMRI). The standard values of 43 healthy subjects (both sex, left and right handed) were compared with those of 10 patients with TLE and unilateral EEG focus. A reduced estimated total brain extension, a significant atrophy of both temporal lobes with accentuation on the focus side and a significant hippocampal atrophy on focus-side were seen even in patients with no visually detectable pathology. The analysis of the signal intensities did not give additional information. Thus, qMRI is a helpful additional tool in the course of presurgical evaluation for focus lateralization.     

Structural connectivity of the human anterior temporal lobe: A diffusion magnetic resonance imaging study

The anterior temporal lobes (ATL) have been implicated in a range of cognitive functions including auditory and visual perception, language, semantic knowledge, and social‐emotional processing. However, the anatomical relationships between the ATLs and the broader cortical networks that subserve these functions have not been fully elucidated. Using diffusion tensor imaging (DTI) and probabilistic tractography, we tested the hypothesis that functional segregation of information in the ATLs is reflected by distinct patterns of structural connectivity to regions outside the ATLs. We performed a parcellation of the ATLs bilaterally based on the degree of connectivity of each voxel with eight ipsilateral target regions known to be involved in various cognitive networks. Six discrete segments within each ATL showed preferential connectivity to one of the ipsilateral target regions, via four major fiber tracts (uncinate, inferior longitudinal, middle longitudinal, and arcuate fasciculi). Two noteworthy interhemispheric differences were observed: connections between the ATL and orbito‐frontal areas were stronger in the right hemisphere, while the consistency of the connection between the ATL and the inferior frontal gyrus through the arcuate fasciculus was greater in the left hemisphere. Our findings support the hypothesis that distinct regions within the ATLs have anatomical connections to different cognitive networks. Hum Brain Mapp 37:2210–2222, 2016. © 2016 Wiley Periodicals, Inc.     

MRI对颞叶癫(癎)的定侧诊断的价值

目的 观察颞叶癫(癎)患者的头颅MRI变化,探讨MRI对颞叶癫(癎)的定侧诊断价值.方法 采用头颅MRI检查,对40例颞叶癫(癎)患者及40例正常对照组的海马体积进行测量,将海马萎缩严重侧作为致癎侧.结果 定量MRI对颞叶癫(癎)定侧敏感性为72.5%,特异性为85.3%.结论 头颅MRI扫描对颞叶癫(癎)的定位及定侧有着重要的诊断价值.     

Lateralization of epileptic foci by magnetic resonance imaging in temporal lobe epilepsy.

A retrospective single-blind study was carried out to assess the reliability of magnetic resonance imaging (MRI) for determining lateralization of the electrographic focus in 45 patients with intractable temporal lobe epilepsy. With strictly defined MRI diagnostic criteria, the electroencephalographic (EEG) focus was correctly lateralized in 86% of patients. Excluding patients with structural lesions, the criteria provided for correct lateralization of the epileptogenic focus in 78% and false lateralization in 5%. Hippocampal atrophy on T1-weighted images and increased signal intensity from mesial structures on T2-weighted scans were highly reliable for lateralization. Postoperative outcome did not differ between the patients with normal and those with abnormal findings on MRI, but the group sample was inadequate to assess the issue of surgical outcome. These findings suggest that with appropriate techniques and strictly defined diagnostic criteria, MRI can provide reliable seizure lateralization in patients with intractable temporal lobe epilepsy.     

Seizure-associated hippocampal volume loss: a longitudinal magnetic resonance study of temporal lobe epilepsy

This longitudinal quantitative magnetic resonance imaging study of 24 patients with mild temporal lobe epilepsy shows an ipsilateral hippocampal volume decrease of 9% (range, -30 to +0.5%; p = 0.002, paired t test) over a period of 3.5 +/- 0.7 years. The hippocampal volume loss was correlated to the number of generalized seizures between the scans (p = 0.0007, r = 0.6), suggesting seizure-associated hippocampal damage.     

Verbal fluency activates the left medial temporal lobe: a functional magnetic resonance imaging study

Verbal fluency tests (VFTs) are suggested to assess frontal lobe function. This view is supported by functional imaging studies that report left frontal activation during VFTs. VFTs require retrieval of semantically associated words from long-term memory storage. The neural networks that participate in this process, however, are largely unknown. These neural networks are of interest, given that patients with early Alzheimer's disease, typically without frontal pathology, are often impaired in VFTs. In the present study, functional magnetic resonance imaging was performed to determine brain activation areas during VFTs in young subjects. In the activation task, category fluency was contrasted with orderly listing of numbers. As judged from using this comparison, there was activation in the left medial temporal lobe, in the inferior frontal and retrosplenial cortices bilaterally, and in the left superior parietal lobule. Left medial temporal lobe activation was present in 13 of the 14 study subjects either in the hippocampal formation (11 of 14) or in the posterior parahippocampal gyrus (12 of 14). These results suggest that the medial temporal lobe is required for the process of retrieval by category. Functional magnetic resonance imaging combined with a category fluency task may provide a new method to study patients with early Alzheimer's disease.     

Visual association encoding activates the medial temporal lobe: A functional magnetic resonance imaging study

The involvement of structures in the medial temporal lobe during the encoding of visual associations was studied with functional magnetic resonance imaging. In 11 out of 12 normal healthy volunteers this task resulted in activation in posterior portions of the parahippocampal region, close to the collateral sulcus. In seven subjects activation was encountered in the hippocampal formation. The visual association task as adapted for this study may provide a sensitive measure to study anterograde amnesia prevalent in Alzheimer's disease. Therefore, the present paradigm enables the study of individual changes in learning and memory capacities over time. Hippocampus 1997;7:594–601. © 1997 Wiley-Liss, Inc.     

Identification of the human medial temporal lobe regions on magnetic resonance images

The medial temporal lobe (MTL) plays a key role in learning, memory, spatial navigation, emotion, and social behavior. The improvement of noninvasive neuroimaging techniques, especially magnetic resonance imaging, has increased the knowledge about this region and its involvement in cognitive functions and behavior in healthy subjects and in patients with various neuropsychiatric and neurodegenerative disorders. However, cytoarchitectonic boundaries are not visible on magnetic resonance images (MRI), which makes it difficult to identify precisely the different parts of the MTL (hippocampus, amygdala, temporopolar, perirhinal, entorhinal, and posterior parahippocampal cortices) with imaging techniques, and thus to determine their involvement in normal and pathological functions. Our aim in this study was to define neuroanatomical landmarks visible on MRI, which can facilitate the examination of this region. We examined the boundaries of the MTL regions in 50 post‐mortem brains. In eight cases, we also obtained post‐mortem MRI on which the MTL boundaries were compared with histological examination before applying them to 26 in vivo MRI of healthy adults. We then defined the most relevant neuroanatomical landmarks that set the rostro‐caudal limits of the MTL structures, and we describe a protocol to identify each of these structures on coronal T1‐weighted MRI. This will help the structural and functional imaging investigations of the MTL in various neuropsychiatric and neurodegenerative disorders affecting this region. Hum Brain Mapp 35:248–256, 2014. © 2012 Wiley Periodicals, Inc.     

Seizure frequency and bilateral temporal abnormalities: a proton magnetic resonance spectroscopy of temporal lobe epilepsy.

Proton magnetic resonance spectroscopy ((1)H-MRS) was performed in seven healthy volunteers and 17 patients with temporal lobe epilepsy (TLE) to clarify the correlation of the severity of epilepsy with bilateral temporal changes in N-acetylaspartate (NAA), choline-containing compounds (Cho) and creatine + phosphocreatine (Cr). Despite unilateral EEG focus, bilateral temporal reduction in NAA /(Cho + Cr) was revealed in patients with intractable seizures. The potential for seizure generation correlated with the NAA /(Cho + Cr) reduction not only on the ipsilateral side but also on the contralateral side. Proton MRS proved to be a useful measurement for obtaining important information about the neuronal changes as well as the lateralization of the epileptogenic focus in TLE patients.     

Sylvian fissure and medial temporal lobe structures in patients with schizophrenia: a magnetic resonance imaging study

Volumes of the medial temporal lobe structures (i.e. the amygdala, hippocampus, and parahippocampal gyrus), Sylvian fissure, and inferior horn of the lateral ventricle relative to the cerebral hemisphere were measured in 24 patients with schizophrenia and 23 normal controls using magnetic resonance imaging. The patients had significantly larger Sylvian fissures and inferior horns bilaterally than the controls. In the patients the right Sylvian fissure size showed a significant positive correlation with the duration of illness. Moreover, earlier onset of illness was significantly correlated with decreased volume of the left medial temporal lobe structures. These results replicate previous finding of inferior horn enlargement and suggest the significance of the Sylvian fissure and the medial temporal lobe structures in pathophysiology of schizophrenia.