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.     

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.     

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。     

Magnetic resonance imaging and temporal lobe epilepsy

Surgical treatment is a well established option for patients with medically refractory temporal lobe epilepsy. Magnetic resonance imaging (MRI) has revolutionized the evaluation of these patients. New techniques can identify structural, metabolic and functional abnormalities associated with the epileptogenic zone. Mesial temporal sclerosis is the most common pathological finding and presents as hippocampal atrophy, which can be detected by visual inspection in most cases. Volumetric analysis of medial temporal structures offers the advantage of detecting bilateral abnormalities. Magnetic resonance spectroscopy can detect metabolic abnormalities associated with the epileptogenic focus. Functional MRI allows for the non-invasive evaluation of cognitive function, allowing for the localization of the neuroanatomic substrate of motor, sensory and cognitive functions. Intraoperative MRI-based image guided systems are a useful adjunct in the surgical treatment of this epileptic syndrome.     

Visual assessment of medial temporal lobe atrophy on magnetic resonance imaging: Interobserver reliability

We conducted an interobserver study to assess agreement on visual rating of medial temporal lobe atrophy on coronal T1-weighted MRI. A total of 100 studies of elderly individuals, using two different MRI techniques (spin echo and inversion recovery sequences), were analysed by four raters (three neurologists and one neuroradiologist) using a five-point rating scale. Complete agreement was found in 37% of the total sample. Interobserver agreement as expressed by kappa values was 0.44 (95% CIl0.34–0.54) and 0.51 (95% Cl=0.41–0.61) for the two techniques. After dichotomizing medial temporal lobe atrophy into present or absent, a post hoc analysis revealed higher complete agreeement (70%), with kappa values of 0.59 (95% Cl=0.51–0.67) and 0.62 (95% Cl=0.48–0.075), for the two techniques (all four raters). From this study we conclude that visual rating of medial temporal lobe atrophy on MRI in the coronal plane yields fair to good agreement among observers. We recommend this type of visual rating for use in clinical settings when a quick judgement on the presence of medial temporal lobe atrophy is needed.     

磁源性影像对颞叶癫(癎)定位的临床价值

目的探讨磁源性影像（MSI）对颞叶癫癎患者癫癎灶的定位价值。方法23例颞叶癫癎的患者进行了MSI检查,将结果与普通EEG、视频EEG和皮质EEG结果进行比较。其中8例行手术治疗,5例行伽玛刀治疗。结果23例患者中MEG显示单致癎灶15例,多致癎灶8例,MEG于V-EEG的符合率为84.6%,17例MRI检查异常,MEG与MRI结果符合率76.4%。8例术中ECoG定位检查,与MEG定侧定位均完全符合。13例患者MEG定位后行手术或伽玛刀治疗,疗效满意。结论MSI对颞叶癫癎定位准确,具有指导临床进一步治疗的价值。     

31P magnetic resonance spectroscopy of the medial temporal lobe of schizophrenic patients with neuroleptic-resistant marked positive symptoms

³¹P magnetic resonance spectroscopy was performed in 16 medicated schizophrenic patients with neuroleptic-resistant marked positive symptoms and in 16 healthy volunteers matched for age and sex in order to determine what changes in phosphorus metabolites are detected in such patients as compared to the controls. The schizophrenic patients showed an increased level of phosphodiesters in the bilateral medial temporal lobes. They also showed a decrease in the level of -ATP in the left medial temporal lobe. These findings suggest that schizophrenic patients with prominent positive symptoms refractory to neuroleptics may have a disturbance of bilateral membrane phospholipid and left-sided high-energy phosphate metabolism in the medial temporal lobe.     

磁共振质子波谱分析对颞叶癫(癇)定侧的研究

目的探讨在磁共振质子波谱分析(1HMRS)对颞叶癫疒间的定侧作用及其影响因素。方法用1.5T场强的MR成像系统1HMRS,对40例不同病程的颞叶癫疒间患者和20名正常对照者分别进行双颞叶内侧N乙酰天门冬氨酸(NAA)、胆碱(Cho)、肌酸(Cr)浓度测定,根据颞叶癫疒间患者两侧NAA/(Cho Cr)值进行定侧。结果NAA/(Cho Cr)值正常对照组为0.58±0.09,癫疒间组病灶侧为0.45±0.12,病灶对侧为0.51±0.10,癫疒间组两侧显著小于正常对照组(均P<0.05);24例患者1HMRS癫疒间灶定侧与EEG一致,符合率63%;病灶侧内、中、外各亚区NAA/(Cho Cr)值较正常对照组低,差异有显著性(均P<0.05);病灶侧NAA/(Cho Cr)值下降程度与单或双侧NAA/(Cho Cr)值下降及发作频率无关(P>0.05);双侧NAA/(Cho Cr)值异常者两侧EEG异常率高于单侧异常者(P<0.05);病灶侧NAA/(Cho Cr)值与病程呈负相关(r=-0.361,P<0.05)。结论癫疒间患者脑代谢异常弥散;1HMRS在颞叶癫疒间有定侧作用;NAA/(Cho Cr)值与病程呈负相关。     

多体素氢质子磁共振波谱对颞叶癫(癎)定位作用的临床研究

目的研究多体素氢质子磁共振波谱（1H-MRS）对颞叶癫癎的致癎灶定位作用。方法对36例颞叶癫癎病人和15例正常人进行MRI扫描和1H-MRS成像,采样容积为8.8mm×8.8mm×8.0mm,选取海马前部相邻3个体素,取平均值,比较病侧、健侧以及对照组氮-乙酰天门氨酸（NAA）/肌酸＋胆碱复合物（Cr＋Cho）等比值的差异。并分析MRI与1H-MRS在定位致癎灶方面的差异。结果与对照组比较,病侧NAA/（Cr＋Cho）明显降低,差异具有统计学意义。MRS定位率50%,联合应用MRI与1H-MRS定位准确率可达到83.3%;MRI阴性病例中45.5%的病人MRS为阳性。结论1H-MRS可有效定位颞叶致癎灶,尤其是MRI阴性表现的颞叶癫癎。联合应用MRI与1H-MRS可提高定位致癎灶的比例。     

Efferent cortical connections of multimodal cortex of the superior temporal sulcus in the rhesus monkey.

The cortex of the upper bank of the superior temporal sulcus (STS) in the rhesus monkey contains a region that receives overlapping input from post-Rolandic sensory association areas and is considered multimodal in nature. We have used the fluorescence retrograde tracing technique in order to answer the question of whether multimodal areas of the STS project back to post-Rolandic sensory association areas. Additionally, we have attempted to answer the question of whether the projections from the multimodal areas directed to the parasensory association areas originate from common neurons via axon collaterals or from individual neurons. The results show that multimodal area TPO of the STS projects back to specific unimodal parasensory association areas of the parietal lobe (somatosensory), superior temporal gyrus (auditory), and posterior parahippocampal gyrus (visual). In addition, a substantial number of projections from area TPO are directed to distal parasensory association areas, area PG-Opt in the inferior parietal lobule, areas Ts1 and Ts2 in the rostral superior temporal gyrus, and areas TF and TL in the parahippocampal gyrus. These latter regions are themselves considered to be higher-order association areas. It was also noted that the majority of the projections to these higher-order association areas originate from the middle divisions of area TPO (TPO-2 and TPO-3). These neurons are organized in a significantly overlapping manner. Despite this overlap of the projection neurons, only an occasional double labeled neuron was observed in area TPO. Thus, our observations indicate that the multimodal region of the superior temporal sulcus has reciprocal connections with the unimodal parasensory association cortices subserving somatosensory, auditory and visual modalities, as well as with other post-Rolandic higher-order association areas. These connections from area TPO to post-Rolandic association areas may have a modulating influence on the sensory association input leading to multimodal areas in the superior temporal sulcus.     

Lateralization of temporal lobe epilepsy using resting functional magnetic resonance imaging connectivity of hippocampal networks

Purpose: Early surgical intervention can be advantageous in the treatment of refractory temporal lobe epilepsy (TLE). The success of TLE surgery relies on accurate lateralization of the seizure onset. The purpose of this study was to determine whether resting functional MRI (fMRI) connectivity mapping of the hippocampus has the potential to complement conventional presurgical evaluations in distinguishing left from right TLE. In addition, we sought to determine whether this same network might separate patients with favorable from unfavorable postoperative outcomes. Methods: Resting fMRI acquisitions were performed on 21 patients with TLE and 15 healthy controls. The patients included seven patients with left TLE and seven patients with right TLE with seizure-free postoperative outcome, and five patients with left TLE and two patients with right TLE with recurring seizures after surgery. Functional connectivity maps to each hippocampus were determined for each subject and were compared between the controls and the seizure-free patients with left TLE and with right TLE. The one network identified was then quantified in the patients with TLE and recurring seizures. Key Findings: The resting functional connectivity between the right hippocampus and the ventral lateral nucleus of the right thalamus was the most statistically significant network to distinguish between seizure-free patients with left TLE and with right TLE with high sensitivity and specificity. This connectivity was also significantly greater in the seizure-free patients with left TLE than the healthy controls. Finally, six of the seven patients in whom seizures recurred after surgery had connectivity values in this network unlike those who were seizure-free. Significance: This study identified a region in the ventral lateral nucleus of the right thalamus whose connectivity to the hippocampi separates left from right TLE subjects. This suggests that the quantification of resting-state functional magnetic resonance imaging (MRI) connectivity across this network may be a potential indicator of lateralization of TLE that may be added to other presurgical MRI assessments. Further validation in a larger, independent cohort is required.     

丙泊酚Wada试验与功能磁共振在颞叶癫痫词汇记忆功能偏侧化评估中的应用

目的 比较丙泊酚Wada试验与功能磁共振(fMRI)在左颞叶癫痫患者术前记忆功能偏侧化预测中的一致性和敏感性. 方法 对广州军区广州总医院自2009年10月至2011年10月收治的8例左前颞叶切除的癫痫患者术前进行丙泊酚Wada试验和fMRI记忆功能偏侧化评估,结合韦氏记忆测验结果,比较两者记忆功能偏侧化评估的一致性与预测记忆变化的敏感性. 结果 fMRI词汇记忆半球、内侧颞叶功能偏侧化与Wada试验功能偏侧化判定的一致率分别为57.0％和71.4％,术后记忆商数、词汇匹配以及智力改变与fMRI词汇记忆内侧颞叶功能偏侧化指数呈显著相关(r=-0.314,P=0.037;r=-0.387,P=.013;r=0.116,P=0.020),与Wada试验功能偏侧化指数无相关性(r=-0.442,P=.077;r=-0.241,P=0.237;r=-0.070,P=0.107). 结论 丙泊酚Wada试验和fMRI记忆功能偏侧化评估一致性因感兴趣区选择方法不同而不同.相对于Wada试验,fMRI记忆功能偏侧化指数在预测患者术后词汇记忆下降的过程中敏感性更高.     

Use of intraoperative magnetic resonance imaging in tailored temporal lobe surgeries for epilepsy

PURPOSE: We investigated whether intraoperative magnetic resonance imaging (MRI) was able to assess immediately the extent of a tailored temporal lobe resection for epilepsy in comparison to delayed postoperative MRI. The recently proposed concept of an individually tailored procedure, preserving tissue not involved in seizures, leads to a variety of differently shaped resections. METHODS: For intraoperative imaging we used a Magnetom Open 0.2 Tesla scanner. Fifty-eight patients undergoing temporal lobe resections for pharmacoresistant epilepsy were investigated. Half of these were nonlesional. All patients had delayed postoperative follow-up scans, which were compared with the intraoperative, postresection images. RESULTS: In 49 (84%) of 58 cases, intraoperative MRI depicted the resection cavity identical to delayed postoperative studies. Complete resection of the visible lesion was primarily proved in 23 of the 29 cases. In two patients with lesions and in one nonlesional case, the resection was extended after intraoperative imaging, thus increasing the rate of total resections in gliomas from 73 to 87%. In four patients, an extension into eloquent areas did not allow complete removal. In the nonlesional cases (n = 29), the extent of tailored temporal resections also could be exactly documented intraoperatively. CONCLUSIONS: Intraoperative MRI allowed a reliable evaluation of the localization and extent of resection in epilepsy surgery within the operative procedure. Furthermore, it provided the possibility of an image-based correction of an initially incomplete resection, particularly in lesional cases. In the majority of patients, the intraoperative images would have been able to replace delayed postoperative MRI. However, in 16%, there were postoperative changes in the resection volume.     

H magnetic resonance spectroscopy in the investigation of intractable epilepsy

We have been using proton magnetic resonance spectroscopy (¹H MRS) in the investigation of adults and children with intractable epilepsy. Spectra were obtained from 2 × 2 times 2 cm cubes in the medial region of the temporal lobe, and were analyzed on the basis of signals from N-acetylaspartate (NAA), creatine+phosphocreatine (Cr), and choline-containing compounds (Cho). In comparison with control subjects, the epilepsy patients as a group show significant reductions in the NAA signal and in the NAA/Cho + Cr ratio, with increases in the Cho and Cr signals. The reduction in NAA is interpreted in terms of neuronal loss or damage, while the increase in Cr and Cho signals may be a reflection of reactive astrocytosis.     

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。     

Cross hippocampal influence in mesial temporal lobe epilepsy measured with high temporal resolution functional magnetic resonance imaging

Purpose Mesial temporal lobe epilepsy (mTLE) is a chronic disorder with spontaneous seizures recurring for years, or even decades. Many structural and functional changes have been detected in both the seizure focus and distal regions throughout the brain over this duration that may reflect the development of epileptogenic networks. Resting state functional magnetic resonance imaging (fMRI) connectivity mapping has the potential to elucidate and quantify these networks. The network between the left and right hippocampus may very likely be one of the most susceptible to changes due to long‐term seizure propagation effects. Therefore, the objective of this study was to quantify cross hippocampal influence in mTLE using high temporal resolution fMRI, and to determine its relationship with disease duration. Methods fMRI images were acquired in the resting (interictal) state with 500 ms temporal resolution across the temporal lobes of 19 mTLE patients (13 left, 6 right). The left and right hippocampi were identified on each subject’s images using both structurally defined and functionally defined boundaries. The cross hippocampal influence was quantified in two ways for each pair of regions: (1) the nondirectional hippocampal functional connectivity calculated as the Pearson’s correlation between the average time series in the left and the right hippocampus regions, and (2) the Granger causality (GC) laterality measure, which implies directional influence by determining temporal precedence. Each of these measures was correlated with age, age of onset, and disease duration across subjects to investigate relationship to disease progression. Key Findings The hippocampal connectivity was not significantly different between patients with left and right mTLE using either the structurally or the functionally defined regions. Across all patients, hippocampal connectivity was not correlated significantly with age of onset or duration of disease. However, as duration of disease increased after 10 years (nine patients), the hippocampal connectivity increased linearly. Using the functionally defined regions, the GC laterality was increased in the right mTLE over the left mTLE, indicating that the left hippocampus was influencing the right hippocampus more than the right influencing left. This was also positively correlated with age of onset. Furthermore, like hippocampal connectivity, the relationship between GC laterality and duration of disease changes after 10 years duration of disease. After this duration, the GC laterality was positive in the three of three patients with right mTLE (left influencing right), whereas the GC laterality was negative in five of six patients with left mTLE (right influencing left). Significance This study reveals a relationship between fMRI functional connectivity and causal influence of the left and right hippocampi and duration of disease in mTLE. During the interictal state, the interhemispheric hippocampal connectivity initially is disrupted and then linearly increases as the epilepsy progresses longer than 10 years. This increase in connectivity appears to be due to the hippocampus contralateral to the epileptogenic focus exerting more influence over the ipsilateral hippocampus. These findings may have implications in understanding the functional development of epileptic networks and possibly prediction of surgical outcome of mTLE.     

Auditory attention in autism spectrum disorder: An exploration of volumetric magnetic resonance imaging findings

Studies have shown that individuals with autism spectrum disorder (ASD) tend to perform significantly below typically developing individuals on standardized measures of attention, even when controlling for IQ. The current study sought to examine within ASD whether anatomical correlates of attention performance differed between those with average to above-average IQ (AIQ group) and those with low-average to borderline ability (LIQ group) as well as in comparison to typically developing controls (TDC). Using automated volumetric analyses, we examined regional volume of classic attention areas including the superior frontal gyrus, anterior cingulate cortex, and precuneus in ASD AIQ (n = 38) and LIQ (n = 18) individuals along with 30 TDC. Auditory attention performance was assessed using subtests of the Test of Memory and Learning (TOMAL) compared among the groups and then correlated with regional brain volumes. Analyses revealed group differences in attention. The three groups did not differ significantly on any auditory attention-related brain volumes; however, trends toward significant size–attention function interactions were observed. Negative correlations were found between the volume of the precuneus and auditory attention performance for the AIQ ASD group, indicating larger volume related to poorer performance. Implications for general attention functioning and dysfunctional neural connectivity in ASD are discussed.     

Neural damage due to temporal lobe epilepsy: dual-nuclei (proton and phosphorus) magnetic resonance spectroscopy study

The aim of this study was to evaluate the usefulness of proton and phosphorus (1H and 31P) magnetic resonance spectroscopy (MRS) for temporal lobe epilepsy (TLE) patients, and to evaluate neural damage and metabolite dysfunction in the TLE patient brain. We performed 1H and 31P MRS of medial temporal lobes (MTL) in the same TLE patients (n = 14) with a relatively wide range of severity from almost seizure-free to intractable, and calculated the ratio of N-acetylasparate to choline-containing compounds and creatine + phosphocreatine (NAA/Cho + Cr) in 1H MRS and inorganic phosphate to all main peaks (%Pi) in 31P MRS. There was no significant correlation between NAA/(Cho + Cr) and %Pi in each side (ipsilateral, r = -0.20; contralateral, r =-0.19). The values of NAA/(Cho + Cr) showed a significant difference between ipsilateral and contralateral MTLs to the focus of TLE patients (P < 0.01, paired t-test). Although %Pi also had a tendency to show the laterality of TLE, there was no significance. Ipsilateral (r = -0.90, P < 0.0001) and contralateral (r = -0.70, P < 0.005) NAA/(Cho + Cr) decreases and contralateral %Pi increase (r = 0.81, P < 0.001) had significant correlation with seizure frequency. 1H MRS provides more important information concerning neuronal dysfunction in MTL of TLE patients than 31P MRS.     

A case of psychotic disorder associated with a right temporal lesion: a special reference to magnetic resonance imaging and single photon emission computed tomography findings

A case of psychotic disorder with a right temporal lesion was reported. The patient, a 19 year old male, who underwent a brain surgery to remove the trigeminal Schwannoma, occupying from the right cerebellopontine angle to the right middle cranial fossa. One year postoperatively, he presented with a psychotic disorder, including auditory hallucinations, delusions of persecution and reference, thought hearing, thought insertion and passive experiences. T1-weighted images on magnetic resonance imaging (MRI) demonstrated a low intensity signal area in the right temporal cortex and white matter. T2-weighted images demonstrated a high intensity signal within the same region. Single photon emission computed tomograghy (SPECT) demonstrated a severe low perfusion corresponding to the region in which the MRI demonstrated the abnormalities. The clinical and neuroimaging studies of this case suggest that psychotic disorder may occur in association with a right temporal lesion and MRI and SPECT are useful to evaluate an organic basis for the psychotic disorder.     

Extrahippocampal gray matter atrophy and memory impairment in patients with medial temporal lobe epilepsy

Memory impairment observed in patients with medial temporal lobe epilepsy (MTLE) is classically attributed to hippocampal atrophy. The contribution of extrahippocampal structures in shaping memory impairment in patients with MTLE is not yet completely understood, even though atrophy in MTLE extends beyond the hippocampus. We aimed to evaluate the neuropsychological profile of patients with MTLE focusing on memory, and to investigate whether gray matter concentration (GMC) distribution within and outside the medial portion of the temporal lobes would be associated with their neuropsychological performance. We performed a voxel based morphometry study of 36 consecutive patients with MTLE and unilateral hippocampal atrophy. We observed a significant simple regression between general and verbal memory performance based on Wechsler Memory Scale-Revised and the GMC of medial temporal and extratemporal structures in patients with left MTLE. We also performed a "regions of interest analysis" of the medial temporal lobe, and we observed that the GMC of the hippocampus, entorhinal, and perirhinal cortices were consistently associated with general and verbal memory performance in patients with MTLE. We also observed that the GMC of the cingulate and orbito-frontal cortex are independently associated with verbal and general memory performances. Our results suggest that general and verbal memory impairments in patients with left MTLE are associated with atrophy of the hippocampus, the entorhinal, and the perirhinal cortex. We also suggest that atrophy and dysfunction of limbic and frontal structures such as the cingulate and the orbito-frontal cortex contribute to memory impairment in MTLE.