Hippocampal volume in normal aging and traumatic brain injury.

PURPOSETo present a normative database of hippocampal and temporal horn volume and to clarify the relationship between these measures and cognitive outcome in patients with traumatic brain injury.METHODSNinety-six healthy volunteers and 94 patients with traumatic brain injury were examined with coronal intermediate and T2-weighted MR imaging. Multispectral segmentation and volume analyses were performed. The volumetry of the hippocampus and temporal horn was characterized in the control subjects. Volumetric measures in a group of patients with traumatic brain injury who had received MR imaging 3 months or less after injury were compared with measurements in other patients in the chronic phase of recovery. The relationship between neuropsychological testing and volumetric measures was analyzed with particular emphasis on the correlation between cognitive outcome and hippocampal and temporal horn volumes.RESULTSNo significant age group differences were found in the normative group from age 16 to 65. Left and right hippocampal volumes were interrelated and did not differ from each other. This was also true for the temporal horns. Hippocampal and temporal horn volumes were not significantly related. Women had larger hippocampi relative to cranial volume. Comparisons between patients with traumatic brain injury and control subjects showed significant yet modest bilateral atrophic changes in hippocampal and temporal horn enlargement in the patients with brain injury. Hippocampal and temporal horn volumes correlated significantly with each other in the group with traumatic brain injury. Cognitive outcome was modestly related to hippocampal and temporal horn volumes. However, in a specific subgroup whose images were acquired between 71 and 210 days after injury, strong correlations were noted in which temporal horn volume correlated highly with IQ and hippocampal volume correlated with verbal memory function.CONCLUSIONHippocampal and temporal horn volumes appear to be independent variables in healthy control subjects. Traumatic brain injury results in significant hippocampal atrophy and temporal horn enlargement. The hippocampus and temporal horn volumes were inversely correlated in the group with traumatic brain injury, suggesting a differential relationship of these structures in patients with brain injury as compared with control subjects. In the subacute phase, the volume of the temporal horn may be indicative of intellectual outcome and that of the hippocampus appears to be indicative of verbal memory function.     

癫痫病人MRI海马结构体积测定

目的测量正常成人及癫痫病人海马结构（ＨＦ）体积，探讨其在颞叶癫痫（ＴＬＥ）致痫灶定侧中的价值。材料与方法本组包括５２例正常成人及８９例癫痫病人，把病人分为三组：继发性癫痫４８例、特发颞叶外癫痫１５例、ＴＬＥ２６例，后者有２２例为顽固性癫痫。均作垂直于海马长轴的冠状位自旋回波（ＳＥ）序列Ｔ１加权像、ＴｕｒｂｏＳＥＴ２加权像，测量颞叶、ＨＦ体积和颞角、环池宽度，肉眼观察Ｔ２加权像海马信号强度改变。采用ＨＦ体积绝对值对ＴＬＥ定侧。结果获取了正常成人ＨＦ体积。２２例ＴＬＥＨＦ体积缩小，其中３例为双侧性；６例ＨＦ硬化经手术、病理证实，１例体积正常且致痫灶位于ＨＦ周围者ＨＦ硬化轻，８例其他类型癫痫病人ＨＦ体积略小，ＴＬＥ致痫灶定侧的敏感性为８５％，特异性为８７％。３例ＴＬＥ病人同侧前颞叶萎缩；部分ＴＬＥ病侧颞角、环池宽度增加；萎缩明显的ＨＦＴ２加权像信号弥漫性增高。结论ＨＦ体积缩小、Ｔ２加权像信号弥漫性增高是ＨＦ硬化萎缩的直接征象，与病变严重程度、致痫灶在颞叶的部位有关，前颞叶萎缩和颞角、环池增宽是ＨＦ硬化的辅助征象。ＨＦ萎缩不仅是颞叶癫痫的主要原因，也可能是其他类型癫痫发作的结果     

A quantitative MR study of the hippocampal formation, the amygdala, and the temporal horn of the lateral ventricle in healthy subjects 40 to 90 years of age

BACKGROUND AND PURPOSE: Several investigators have defined normal age-specific values for the medial temporal lobe structures in neurologically normal elderly subjects, but, to our knowledge, no one has reported those values for a large sample of healthy volunteers. The purpose of our study was to define normal age-specific values for the hippocampal formation, the amygdala, and the temporal horn of the lateral ventricle by age group, ranging from 40 to 90 years, in order to generate a guideline for the quantitative MR diagnosis and differential diagnosis for early Alzheimer disease. METHODS: MR-based volumetric measurements of the hippocampal formation, the amygdala, and the temporal horn, standardized by total intracranial volume, were obtained from oblique coronal and sagittal T1-weighted MR images in 619 healthy volunteers and two cadaveric specimens. RESULTS: Differences in standardized volumes of the hippocampal formation, the amygdala, and the temporal horn were significant among the 61- to 70-year-old, 71- to 80-year-old, and 81- to 90-year-old groups, and were not significant between the 40- to 50-year-old and 51- to 60-year-old groups. We found no significant differences in side or sex among the age groups for any of the structures. CONCLUSION: Differences in the mean value and in the 95% normal range of standardized volumes of the hippocampal formation, the amygdala, and the temporal horn correspond to differences in age among healthy subjects; therefore, age should be considered a factor in correlative research, especially in that involving patients in the early stages of Alzheimer disease.     

Linear measures of atrophy in mild Alzheimer disease.

PURPOSETo assess the sensitivity of linear measures of brain atrophy in the diagnosis of Alzheimer disease (AD) in the early stages.METHODSLinear measures of regional frontal (Bifrontal index, interhemispheric fissure width), medial temporal lobe (interuncal distance, minimum thickness of the medial temporal lobe), and hippocampal (hippocampal height, width of the choroid fissure, width of the temporal horn) atrophy were made on magnified MR images obtained in 46 patients with AD (33 with mild severity and 13 with moderate severity) and in 31 control subjects. Gaussian modeling was used to compute sensitivity with specificity set at 95%. Discriminant analysis was used to identify measures independently contributing to the ability to discriminate AD patients from control subjects.RESULTSThe measure with the best sensitivity in discriminating AD patients from control subjects was the width of the temporal horn. A compound measure of width of the temporal horn, width of the choroid fissure, height of the hippocampus, and interuncal distance could discriminate patients with mild AD from control subjects with 86% sensitivity. Cross validation in patients with moderate AD confirmed the usefulness of the model (81% sensitivity). Measures of hippocampal atrophy alone could discriminate patients with mild AD from control subjects with 83% sensitivity; in patients with moderate AD, cross validation produced 87% sensitivity.CONCLUSIONSLinear measures of hippocampal atrophy can be a useful adjunct in the routine diagnosis of AD, even in its early stages.     

MRI测量颞叶癫痫患者海马体积与波谱分析

目的探讨利用磁共振图像判断海马萎缩在颞叶癫痫的意义,揭示颞叶癫痫病灶的质子磁共振波谱的变化特征。材料与方法对7例不同病程癫痫患者进行三维快速扰相位梯度回波序列(3D-FSPGR)和PRESS序列波谱采样,测量双侧海马的体积和海马区域的NAA／Cr、Cho／Cr比值,在同一患者左右侧进行对比。结果早期颞叶癫痫患者海马萎缩、NAA／Cr下降均不明显,Cho／Cr较对侧升高;发展到海马硬化阶段可以有海马萎缩、NAA／Cr下降和Cho／Cr升高;静息状态的癫痫患者有海马萎缩和NAA／Cr下降,但是Cho／Cr无升高表现。结论利用磁共振图像可以准确反映颞叶癫痫患者海马体积的变化;1H-MRS可以反映癫痫患者海马区域的代谢变化,为癫痫的定位提供信息。     

MRI海马结构体积分割分析对颞叶癫痫的诊断价值及临床相关性研究

目的　利用MRI体积分割分析的方法研究海马萎缩的不同形式 ,探讨颞叶癫痫的病因和发病机制 ,提高颞叶癫痫诊断的敏感性。方法　采用GE 1 5TSignaHorizonLX超导型磁共振机 ,行垂直于海马长轴的倾斜冠状面T1WI。将颞叶内侧结构分为杏仁核和海马头、体、尾部 4段 ,采用体积测量、逐层比较的方法对 5 0例病理诊断为海马硬化的颞叶癫痫患者行颞叶内侧结构体积分割分析 ,并比较各组间的临床特征及手术预后的差异。结果　 5 0例海马硬化患者中 ,海马弥漫萎缩者 2 2例(44 % ) ,同时伴杏仁核萎缩者 5例 (10 % )。海马局限性萎缩者 2 0例 (40 % ) ,无萎缩者 8例 (16 % )。 38例 (76 % )海马硬化萎缩累及海马体部 ,其次累及海马头部者 2 9例 (5 8% ) ,累及海马尾部者 2 4例(48% ) ,累及杏仁核者 8例 (16 % )。 10例患者MRI体积分割分析提示海马局限性萎缩而海马绝对体积正常。海马不同萎缩形式各组间的癫痫病程长短、发作频率及手术预后的差异具有显著性意义 (P<0 0 5 ) ;各组间的有无高热惊厥史、起病年龄及有无大发作史的差异不具有显著性意义 (P >0 0 5 )。结论　颞叶内侧结构体积分割分析能提高颞叶癫痫诊断的敏感性 ,对探讨颞叶癫痫的病因和发病机制提供帮助。     

Is radiological evaluation as good as computer-based volumetry to assess hippocampal atrophy in Alzheimer’s disease?

Introduction

Hippocampus volumetry is a useful surrogate marker for the diagnosis of Alzheimer??s disease (AD). Our purpose was to compare visual assessment of medial temporal lobe atrophy made by radiologists with automatic hippocampal volume and to compare their performances for the classification of AD, mild cognitive impairment (MCI) and cognitively normal (CN).

Methods

We studied 30 CN, 30 MCI and 30 AD subjects. Six radiologists with two levels of expertise performed two readings of medial temporal lobe atrophy. Medial temporal lobe atrophy was evaluated on coronal three-dimensional T1-weighted images using Scheltens scale and compared with hippocampal volume obtained using a fully automatic segmentation method (Spearman??s rank coefficient).

Results

Visual assessment of medial temporal lobe atrophy was correlated with hippocampal volume (p?<?0.01). Classification performances between MCI converter and CN was better using volumetry than visual assessment of non-expert readers whereas classification of AD and CN did not differ between visual assessment and volumetry except for the first reading of one non-expert (p?=?0.03).

Conclusions

Visual assessment of medial temporal lobe atrophy by radiologists was well correlated with hippocampal volume. Radiological assessment is as good as computer-based volumetry for the classification of AD, MCI non-converter and CN and less good for the classification of MCI converter versus CN. Use of Scheltens scale for assessing hippocampal atrophy in AD seems thus justified in clinical routine.     

Predicting memory performance in normal ageing using different measures of hippocampal size

A number of different methods have been employed to correct hippocampal volumes for individual variation in head size. Researchers have previously used qualitative visual inspection to gauge hippocampal atrophy. The purpose of this study was to determine the best measure(s) of hippocampal size for predicting memory functioning in 102 community-dwelling individuals over 80 years of age. Hippocampal size was estimated using magnetic resonance imaging (MRI) volumetry and qualitative visual assessment. Right and left hippocampal volumes were adjusted by three different estimates of head size: total intracranial volume (TICV), whole-brain volume including ventricles (WB+V) and a more refined measure of whole-brain volume with ventricles extracted (WB). We compared the relative efficacy of these three volumetric adjustment methods and visual ratings of hippocampal size in predicting memory performance using linear regression. All four measures of hippocampal size were significant predictors of memory performance. TICV-adjusted volumes performed most poorly in accounting for variance in memory scores. Hippocampal volumes adjusted by either measure of whole-brain volume performed equally well, although qualitative visual ratings of the hippocampus were at least as effective as the volumetric measures in predicting memory performance in community-dwelling individuals in the ninth or tenth decade of life.     

Quantitative NMR measurements of hippocampal atrophy in Alzheimer's disease

Nuclear magnetic resonance (NMR) imaging was employed to study 10 patients with Alzheimer's disease (AD) and seven healthy elderly control subjects. Coronal sections were used to make volumetric measurements of the hippocampus, ventricles, subarachnoid space, and brain parenchyma. The hippocampal volume (normalized relative to the size of the lenticular nucleus) was reduced by 40% in the AD group compared to the controls, with no overlap between the two groups. Overall measures of brain atrophy and ventricular and sulcal enlargement also showed significantly different group means, although with overlap between the two groups. Hippocampal atrophy did not correlate with either overall brain atrophy or dementia severity, although the degree of brain atrophy was correlated with dementia severity. These results show that NMR is capable of providing in vivo quantification of diminished hippocampal size in AD which is not correlated with overall brain atrophy and which may differentiate AD from normal aging.     

MR volumetric analysis of the piriform cortex and cortical amygdala in drug-refractory temporal lobe epilepsy

BACKGROUND AND PURPOSE: The assessment of patients with temporal lobe epilepsy (TLE) traditionally focuses on the hippocampal formation. These patients, however, may present structural abnormalities in other brain areas. Our purpose was to develop a method to measure the combined volume of the human piriform cortex and cortical amygdala (PCA) by using MR imaging and to investigate PCA atrophy. METHODS: The definition of anatomic landmarks on MR images was based on histologic analysis of 23 autopsy control subjects. Thirty-nine adults with chronic TLE and 23 age-matched control subjects were studied. All underwent high-spatial-resolution MR imaging at 1.5T, including a tilted T1-weighted 3D dataset. The PCA volumes were compared with the control values and further correlated with hippocampal, amygdala, and entorhinal cortex volumes. RESULTS: The normal volume was 530 +/- 59 mm(3) (422-644) [mean +/- 1 SD (range)] on the right and 512 +/- 60 mm(3) (406-610) on the left PCA (no asymmetry, and no age or sex effect). The intraobserver and interobserver variability were 6% and 8%, respectively. In right TLE patients, the mean right PCA volume was 18% smaller than in control subjects (P < .001) and 15% smaller than in left TLE (P < .001). In left TLE, the mean left PCA volume was 16% smaller than in control subjects (P < .001) and 19% smaller than in right TLE (P < .001). Overall, 46% (18/39) of the patients had a greater than 20% volume reduction in the ipsilateral PCA. There was bilateral atrophy in 18% (7/39). Patients with hippocampal volumes of at least 2 SDs below the control mean had an 18% reduction in the mean PCA volume compared with patients without hippocampal atrophy (P < .001). Ipsilaterally, hippocampal (r = 0.756, P < .01), amygdaloid (r = 0.548, P < .01), and entorhinal (r = 0.500, P < .01) volumes correlated with the PCA volumes. CONCLUSION: The quantification of PCA volume with MR imaging showed that the PCA is extensively damaged in chronic TLE patients, particularly in those with hippocampal atrophy.     

Brain volume, intracranial volume, and dementia

RATIONALE AND OBJECTIVES: Using a large magnetic resonance (MR) imaging data set (n = 532), we investigated the utility of total intracranial volume (TICV) as a correction factor for head size variability when assessing total brain volume (TBV) and the subcortical volumes of the temporal horn of the lateral ventricular system and the hippocampus. METHODS: A uniform tissue segmentation procedure (analyze) was used to calculate volumes. Total brain volume was compared with TICV in 357 control subjects and 175 patients with various dementing and neuropsychiatric disorders (mixed dementia/neuropsychiatric group). These MR-based TBV/TICV relationships were compared with actual postmortem (n = 87) values obtained from a study of neurologically healthy subjects at the time of death. Comparisons were also made in which temporal horn and hippocampal volumes were corrected by TICV and TBV. Lastly, the ability of corrected TBV and temporal horn and hippocampal volumes to distinguish subjects in the mixed dementia/neuropsychiatric group from controls was examined by logistic regression. RESULTS: In the control sample, brain volume averaged 9% of TICV, regardless of age. In contrast, TBV in the mixed dementia/neuropsychiatric subjects showed, on average, a 22% reduction compared with TICV. By plotting TBV/TICV curves, highly significant but different regression lines emerged, wherein a reduction in brain volume in conditions of mixed dementia/neuropsychiatric disorder showed a distinct separation from the norm. The TBV/TICV regression line generated from MR imaging in controls did not differ from the postmortem TBV/TICV regression line. Logistic regression showed a 96% correct classification of mixed dementia/neuropsychiatric subjects from controls by using the TBV/TICV ratio. This technique has the advantage that each subject serves as his or her own control. CONCLUSIONS: In cases of dementia and neuropsychiatric disorder in persons 65 and older, TBV corrected by TICV readily differentiated this clinical population from controls. This technique is easy and simple to use and has various clinical applications. For temporal horn and hippocampal volume, corrections with TBV rather than TICV may provide more clinically meaningful corrections.     

Analysis of the cerebral cortex in holoprosencephaly with attention to the sylvian fissures

BACKGROUND AND PURPOSE: Analysis of specific features in the brain of patients with holoprosencephaly (HPE) may clarify normal and abnormal brain development and help predict outcomes for specific children. We assessed sulcal and gyral patterns of cerebral cortex in patients with HPE and developed a method of grading brain development. METHODS: Neuroimaging studies (75 MR imaging, 21 CT) of 96 patients with HPE were retrospectively reviewed, with specific attention paid to the cerebral cortex. Thickness of cortex, width of gyri, and depth of sulci were assessed subjectively and by measurement. The angle between lines drawn tangential to the sylvian fissures ("sylvian angle") was measured in each patient with HPE and in 20 control patients. RESULTS: Thickness of cortex was normal in all 96 patients. Gyral shape and width and sulcal depth were normal in 80 patients. Twelve patients, all with very severe HPE and microcephaly, had reduced sulcal depth, diffusely in eight and limited to the anteromedial cortex in four with lobar HPE. Four patients had subcortical heterotopia, located anterior to the interhemispheric fissure, associated with shallow sulci in the overlying cortex. Sylvian fissures were displaced further anteriorly and medially as HPE became more severe, until, in the most severe cases, no sylvian fissures could be identified. Sylvian angle measurements corresponded closely with severity of HPE, being largest in the most severe and smallest in the least severe cases. All patients with HPE had sylvian angles significantly larger than the mean of 15 degrees measured in the control patients. CONCLUSION: The only true malformations of cortical development were subcortical heterotopia. However, diffuse and focal abnormal sulci were observed. We propose our sylvian angle measurement of extent of frontal lobe development as an objective means of quantifying the severity of HPE.     

Three-dimensional fast low-angle shot imaging and computerized volume measurement of the hippocampus in patients with chronic epilepsy of the temporal lobe

This study investigated the use of three-dimensional fast low-angle shot (FLASH) imaging and computer-assisted morphometry for identifying hippocampal changes associated with unilateral temporal lobe seizures. Contiguous 3.1-mm coronal FLASH images were obtained in 28 patients with electroencephalographically verified left (n = 17) or right (n = 11) temporal lobe seizures and 28 age- and sex-matched control subjects. Hippocampal volumes were calculated with the use of a computerized mensuration system developed for detailed morphometric assessment. The results of a multivariate analysis of variance revealed a significant group difference by hemisphere interaction (F = 26.3, p less than .001). Significant reductions in left hippocampal volume (32%, p less than .001) were exhibited in patients with left temporal lobe seizures, and significant reductions in right hippocampal volume (35%, p less than .001) were seen in patients with right temporal lobe seizures. A discriminant analysis with the use of left and right hippocampal volumes classified patients with left temporal lobe seizures with 94% sensitivity and 73% specificity and patients with right temporal lobe seizures with 89% sensitivity and 94% specificity. The results of this study demonstrate that unilateral temporal lobe seizures are accompanied by significant reductions in hippocampal volume ipsilateral to the seizure focus. The use of FLASH imaging and computer-assisted morphometry of the hippocampus appears to provide valuable structural information for confirming the laterality of the electroencephalographic seizure focus.     

cerebellar atrophy after moderate-to-severe pediatric traumatic brain injury

BACKGROUND AND PURPOSE: Although the cerebellum has not attracted the same degree of attention as cortical areas and the hippocampus in traumatic brain injury (TBI) literature, there is limited structural and functional imaging evidence that the cerebellum is also vulnerable to insult. The cerebellum is emerging as part of a frontocerebellar system that, when disrupted, results in significant cognitive and behavioral consequences. We hypothesized that cerebellar volume would be reduced in children following TBI and wished to examine the relation between the cerebellum and known sites of projection, including the prefrontal cortex, thalamus, and pons. MATERIALS AND METHODS: Quantitative MR imaging was used to measure cerebellar white and gray matter and lesion volumes 1-10 years following TBI in 16 children 9-16 years of age and 16 demographically matched typically developing children 9-16 years of age. Cerebellar volumes were also compared with volumetric data from other brain regions to which the cerebellum projects. RESULTS: A significant group difference was found in cerebellar white and gray matter volume, with children in the TBI group consistently exhibiting smaller volumes. Repeating the analysis after excluding children with focal cerebellar lesions revealed that significant group differences still remained for cerebellar white matter (WM). We also found a relation between the cerebellum and projection areas, including the dorsolateral prefrontal cortex, thalamus, and pons in 1 or both groups. CONCLUSION: Our finding of reduced cerebellar WM volume in children with TBI is consistent with evidence from experimental studies suggesting that the cerebellum and its related projection areas are highly vulnerable to fiber degeneration following traumatic insult.     

Development of the temporal lobe in infants and children: analysis by MR-based volumetry.

BACKGROUND AND PURPOSE: Recent advances in data-processing techniques have allowed more accurate MR-based volumetric measurement than was possible in the past. The purpose of this study was to use this technique to evaluate the development of the temporal lobes in childhood. METHODS: The study group consisted of 42 subjects aged 3 weeks to 14 years (mean age, 5 years), all with normal findings on a routine MR study and none with a history of epilepsy. MR images were acquired on a 1.0-T system using a T1-weighted 3D ultrafast gradient-echo sequence. The volumes of the hippocampal formations and temporal lobes were measured by using a workstation, and the percentage of hippocampal formations in the temporal lobes was calculated. Myelination in the limbic system and related structures was also evaluated. RESULTS: The volume of the hippocampal formations increased sharply until the age of 2 years, and continued to increase slowly thereafter. However, the percentage of hippocampal formations in the temporal lobes showed a negative correlation with age. The hippocampal formations on the right side were larger than those on the left in 38 cases (91%), and the anterior temporal lobes on the right were larger than those on the left in 32 cases (76%). This right-left asymmetry of the hippocampal formations and anterior temporal lobes was observed from early infancy, and these differences were statistically significant. A longitudinal fasciculus of high signal intensity was seen in the white matter beneath the subiculum by about 3 months of age. CONCLUSION: MR-based volumetry established developmental characteristics of the temporal lobe, such as a hippocampal growth spurt, a growth difference between the hippocampal formation and the rest of the temporal lobe, and right-left asymmetry. Knowledge of these characteristics may aid in the understanding of hippocampal and temporal lobe abnormalities in children.     

Correlations of hippocampal atrophy and focal low-frequency magnetic activity in Alzheimer disease: volumetric MR imaging-magnetoencephalographic study

BACKGROUND AND PURPOSE: Patients with Alzheimer disease (AD) have more low-frequency activity on conventional EEG and increased focal magnetoencephalographic (MEG) dipole density (DD) in delta and theta bands. This activity concurs with atrophy and reduced metabolic and perfusion rates, particularly in temporoparietal structures. The relationship between functional and structural measures and their conjoined capability to improve the diagnosis of AD were assessed in this study. METHODS: Whole-head MEG recordings were obtained in 15 patients in whom the diagnosis of AD had been made and in 16 healthy control subjects during a resting condition. MR imaging volumetric data were also obtained; these included global cerebral, temporal lobe, and hippocampal volumes. RESULTS: DD in the delta and theta bands was enhanced in the AD group compared with the healthy control subjects. Slow-wave activity differed significantly between the groups in the temporoparietal regions of both hemispheres. Left hippocampal volume was correlated with left temporal and parietal delta DD and left temporal theta DD. A combination of left hippocampal volume and left temporal theta DD enabled correct classification in 87.1% of the patients with AD or control subjects. CONCLUSION: Results support the predominant role of temporoparietal hypofunction as defined by DD and hippocampal structural deficits shown on MR images in patients with AD. A multidisciplinary perspective of different techniques may improve our understanding of the disease and our diagnostic abilities.     

Effect of partial volume correction on muscarinic cholinergic receptor imaging with single-photon emission tomography in patients with temporal lobe epilepsy

Animal experiments and preliminary results in humans have indicated alterations of hippocampal muscarinic acetylcholine receptors (mAChR) in temporal lobe epilepsy. Patients with temporal lobe epilepsy often present with a reduction in hippocampal volume. The aim of this study was to investigate the influence of hippocampal atrophy on the quantification of mAChR with single photon emission tomography (SPET) in patients with temporal lobe epilepsy. Cerebral uptake of the muscarinic cholinergic antagonist [¹²³I]4-iododexetimide (IDex) was investigated by SPET in patients suffering from temporal lobe epilepsy of unilateral (n=6) or predominantly unilateral (n=1) onset. Regions of interest were drawn on co-registered magnetic resonance images. Hippocampal volume was determined in these regions and was used to correct the SPET results for partial volume effects. A ratio of hippocampal IDex binding on the affected side to that on the unaffected side was used to detect changes in muscarinic cholinergic receptor density. Before partial volume correction a decrease in hippocampal IDex binding on the focus side was found in each patient. After partial volume no convincing differences remained. Our results indicate that the reduction in hippocampal IDex binding in patients with epilepsy is due to a decrease in hippocampal volume rather than to a decrease in receptor concentration.     

海马硬化的MRI诊断

目的 探讨海马硬化的ＭＲＩ表现和病理特征。方法 对１６例海马硬化患者进行ＭＲ横断面和垂直于海马长轴的段斜冠状面ＳＥＴ１ＷＩ、Ｔ２ＷＩ和液体衰减恢复序列（ＦＬＡＩＲ）扫描。结果 １６例患者中,１例为双侧海马硬化,１５例为单侧海马硬化（左侧９例,右侧６例）,１５例经手术病理证实,１６例１７个患侧ＭＲＩ表现为患侧海马萎缩变小;Ｔ２ＷＩ（１５侧）和ＦＬＡＩＲ成像（１７例）呈高信号;１１个患侧海马头部浅沟消     

MR volumetry of the entorhinal, perirhinal, and temporopolar cortices in drug-refractory temporal lobe epilepsy

BACKGROUND AND PURPOSE: The occurrence of damage in the entorhinal, perirhinal, and temporopolar cortices in unilateral drug-refractory temporal lobe epilepsy (TLE) was investigated with quantitative MR imaging. METHODS: Volumes of the entorhinal, perirhinal, and temporopolar cortices were measured in 27 patients with unilateral drug-refractory TLE, 10 patients with extratemporal partial epilepsy, and 20 healthy control subjects. All patients with TLE were evaluated for epilepsy surgery and underwent operations. RESULTS: In left TLE, the mean volume of the ipsilateral entorhinal cortex was reduced by 17% (P <.001 compared with control subjects) and that of the ipsilateral temporopolar cortex by 17% (P <.05). In right TLE, the mean ipsilateral entorhinal volume was reduced by 13% (P < or =.01), but only in patients with hippocampal atrophy. Asymmetry ratios also indicated ipsilateral cortical atrophy. When each patient was analyzed individually, the volume of the ipsilateral hippocampus was reduced (> or = 2 SD from the mean of controls) in 63% and that of the entorhinal cortex in 52% of patients with TLE. Furthermore, ipsilateral entorhinal (left: r = 0.625, P <.001; right: r = 0.524, P < or =.01), perirhinal (left: r = 0.471, P <.05), and temporopolar (right: r = 0.556, P <.01) volumes correlated with ipsilateral hippocampal volumes. There was no association, however, with clinically or pathologically identified causes of epilepsy, duration of epilepsy, or age at onset of epilepsy. Mean cortical volumes were unaffected in extratemporal partial epilepsy. CONCLUSION: Subpopulations of patients with unilateral TLE have ipsilateral damage in the entorhinal and temporopolar cortices. The damage is associated with hippocampal damage.     

Alzheimer病的海马体积测量及脑组织分割分析的初步研究

目的采用ＭＲ体积测量和组织分割分析对Ａｌｚｈｅｉｍｅｒ病（Ａｌｚｈｅｉｍｅｒｄｉｓｅａｓｅ，ＡＤ）患者和正常对照组进行研究，探讨其对ＡＤ的诊断价值。方法对临床诊断为ＡＤ患者和正常老年人各１６例作对照进行ＭＲＩ比较研究。测量两组的海马结构（ＨＦ）体积，脑灰质、脑白质、脑室外脑脊液（ＣＳＦ）和脑室ＣＳＦ体积所占颅内体积百分比，计数两组脑实质Ｔ２ＷＩ上的高信号灶并测量其最大径。结果体积测量显示ＡＤ组左、右侧ＨＦ体积均小于对照组。组织分割分析显示ＡＤ组脑灰质较对照组明显减少，脑室外ＣＳＦ和脑室ＣＳＦ体积所占颅内体积百分比较对照组增加，而脑白质两组间无显著性差异。ＡＤ组和对照组脑实质内高信号灶在大小和分布上无差异。结论ＭＲＨＦ体积测量和脑组织分割分析有助于临床了解ＡＤ的脑部形态结构改变，并能为ＡＤ的进一步诊断提供有价值的影像学评价指标。