MR imaging volumetry of subcortical structures and cerebellar hemispheres in temporal lobe epilepsy

BACKGROUND AND PURPOSE: There is mounting evidence of extratemporal volume changes associated with medically refractory temporal lobe epilepsy (TLE). This MR imaging study aimed to characterize volume changes in subcortical structures and cerebellar hemispheres with respect to lateralization of the seizure focus, onset and duration of epilepsy, and frequency of generalized tonic-clonic seizures (GTCS). METHODS: Amygdalar, hippocampal, thalamic, caudate head, and cerebellar volume measurements were obtained in the preoperative MR images of 40 patients with TLE (20 right, 20 left), who underwent temporal lobe resection with good outcome, and in 20 right-handed control participants. All 3D MR images were spatially aligned and normalized before measurements were obtained. Standardized volumes and right-to-left volume ratios (VRs) were compared between control participants and right and left TLE groups. Multiple regression analyses were performed to study the effects of epilepsy onset and duration and GTCS frequency on ipsilateral-to-contralateral VRs with respect to the resected seizure focus. RESULTS: Thalamic volumes were smaller bilaterally in patients with TLE. Hippocampal volumes were smaller ipsilateral to the seizure focus, but there was no significant volume loss involving the amygdala, caudate, or cerebellum. Hippocampal and amygdalar right-to-left VRs differed significantly between right and left TLE groups and controls, whereas thalamic right-to-left VRs differed only between the TLE groups. Thalamic ipsilateral-to-contralateral VRs were correlated positively with epilepsy onset and negatively with epilepsy duration. Caudate ipsilateral-to-contralateral VRs were positively, whereas amygdalar and cerebellar VRs were negatively, correlated with GTCS frequency. CONCLUSIONS: Unilateral amygdalar and bilateral thalamic volume loss, in the absence of caudate head atrophy, is likely to reflect seizure-induced injury due to TLE. Correlations of VRs affecting the amygdala, caudate, and cerebellum with GTCS frequency may also reflect injury or a prediposition for secondary generalization. Potential effects of complex partial seizures, febrile seizures, or antiepileptic medications on subcortical structures need to be evaluated in future studies.     

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.     

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.     

Validation of hippocampal volumes measured using a manual method and two automated methods (FreeSurfer and IBASPM) in chronic major depressive disorder

INTRODUCTION: To validate the usefulness of the packages available for automated hippocampal volumetry, we measured hippocampal volumes using one manual and two recently developed automated volumetric methods. METHODS: The study included T1-weighted magnetic resonance imaging (MRI) of 21 patients with chronic major depressive disorder (MDD) and 20 normal controls. Using coronal turbo field echo (TFE) MRI with a slice thickness of 1.3 mm, the hippocampal volumes were measured using three methods: manual volumetry, surface-based parcellation using FreeSurfer, and individual atlas-based volumetry using IBASPM. In addition, the intracranial cavity volume (ICV) was measured manually. RESULTS: The absolute left hippocampal volume of the patients with MDD measured using all three methods was significantly smaller than the left hippocampal volume of the normal controls (manual P = 0.029, FreeSurfer P = 0.035, IBASPM P = 0.018). After controlling for the ICV, except for the right hippocampal volume measured using FreeSurfer, both measured hippocampal volumes of the patients with MDD were significantly smaller than the measured hippocampal volumes of the normal controls (right manual P = 0.019, IBASPM P = 0.012; left manual P = 0.003, FreeSurfer P = 0.010, IBASPM P = 0.002),. In the intrarater reliability test, the intraclass correlation coefficients (ICCs) were all excellent (manual right 0.947, left 0.934; FreeSurfer right 1.000, left 1.000; IBASPM right 1.000, left 1.000). In the test of agreement between the volumetric methods, the ICCs were right 0.846 and left 0.848 (manual and FreeSurfer), and right 0.654 and left 0.717 (manual and IBASPM). CONCLUSION: The automated hippocampal volumetric methods showed good agreement with manual hippocampal volumetry, but the volume measured using FreeSurfer was 35% larger and the agreement was questionable with IBASPM. Although the automated methods could detect hippocampal atrophy in the patients with MDD, the results indicate that manual hippocampal volumetry is still the gold standard, while the automated volumetric methods need to be improved.     

Hippocampal alterations in children with temporal lobe epilepsy with or without a history of febrile convulsions: evaluations with MR volumetry and proton MR spectroscopy

BACKGROUND AND PURPOSE: The causal effect of early febrile convulsions (FC) on later-onset temporal lobe epilepsy (TLE) remains unclear. In this study, we sought to examine the hippocampal alterations in epileptic children with or without FC history by using MR spectroscopy and volumetry. METHODS: Fifty-five children ranging in age from 18 months to 15 years were enrolled in this study. Subjects were divided into three groups: the control group without either TLE or history of FC (n = 16), the TLE group with early history of FC (TLE + FC; n = 22), and the TLE group without FC history (n = 17). Measurement of hippocampal volume (HV) was performed on thin section T1-weighted images acquired with a 3D gradient echo MR image and normalized by the intracranial volume. Each individual subject had two measures of lateralization; one gives the smaller side of HV and the other the contralateral larger side of HV, assuming that the side with smaller HV is the possible primary site of seizure focus and the contralateral larger HV the secondary or normal site. Single-voxel proton MR spectroscopy of the hippocampi was performed, with metabolic ratio n-acetylaspartate (NAA)/choline (Cho) + creatine plus phosphocreatine (Cr) calculated and grouped separately as were with volumetry. RESULTS: The overall mean HV for the control group was 2.61 +/- 0.21 cm(3) at an average intracranial volume of 965 +/- 241 cm(3), and the asymmetry index for hippocampal volume was (2.32 +/- 1.58)%. The overall mean HV was 2.30 +/- 0.33 cm(3) for TLE + FC group and 2.34 +/- 0.33 cm(3) for TLE group. Mean HV differed significantly for the three groups (P < .01). When the small and large sides were analyzed separately, significant differences were found between control and TLE as well as between control and TLE + FC for the smaller side (P < .05), whereas for the larger side significant differences were found only between control and TLE + FC. In MR spectroscopic measurements, the mean NAA/(Cr + Cho) of bilateral hippocampi was 0.77 +/- 0.06 for control group, 0.62 +/- 0.12 for TLE + FC group, and 0.66 +/- 0.11 for TLE group. In terms of statistically significant difference between groups, spectroscopic results were similar to volumetric measurements, except that there was no significant interaction effect between groups and measures of asymmetrical indices (P = .272). CONCLUSION: Children with TLE and early history of FC tend to have lower hippocampal volumes and NAA/(Cr + Cho) ratios than do TLE children without FC history. The TLE + FC group seems to have increased vulnerability of the contralateral hippocampus as compared with TLE group. MR volumetry and spectroscopy are equally capable of showing the trends of hippocampal alternations in children with TLE with or without FC history.     

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.     

抑郁症患者海马及杏仁核容积异常的MRI研究

目的探讨抑郁症患者海马及杏仁核容积改变特点。方法研究22例抑郁症患者及13例健康志愿者,运用MRI容积分析软件测量两侧海马及杏仁核容积。结果抑郁症患者及对照组均显示两侧海马容积不对称(左侧<右侧;抑郁组t=2180,P<001;对照组t=2490,P<001);抑郁症患者两侧海马容积比对照组有明显减小(左侧t=996,P<001;右侧t=1188,P<001);右侧杏仁核明显小于对照组(t=550,P<001);抑郁症患者海马容积缩小与病程缺乏相关性。结论海马及杏仁核容积异常可能构成抑郁症的神经生物学基础,也说明边缘系统在抑郁症的发病机理中起着重要作用。     

Apparent diffusion coefficient mapping of the hippocampus and the amygdala in pharmaco-resistant temporal lobe epilepsy

BACKGROUND AND PURPOSE: The purpose of this study is to determine whether interictal apparent diffusion coefficients (ADC) provide a robust means for detecting amygdalo-hippocampal abnormalities in adult patients with localization-related chronic temporal lobe epilepsy (TLE) undergoing presurgical evaluation. METHODS: Fifty-five patients and 20 age-matched controls were studied with hippocampal and amygdala ADC maps (HADC and AMYADC), volumes (HCVOL, AMYVOL), T2 relaxometry (HCT2, AMYT2), and hippocampal N-acetylaspartate to choline and creatine/phosphocreatine ratios (HCSI). Mean values and 99% confidence ellipses were computed for the groups. Individual ADC mapping was compared with electroencephalography (EEG) data and further correlated with the quantitative MR measures and with the age at onset and duration of TLE. Moreover, we evaluated the association and the predictive value of HADC and AMYADC with respect to the surgical outcome in a subgroup of patients (n = 21) operated on the side of maximal EEG lateralization and with MR imaging criteria for hippocampal sclerosis, 71% of which became seizure-free. RESULTS: In controls, there was no relation between ADC values and age, sex, or right-left asymmetries. In TLE groups with right (n = 29) or left epileptogenic foci (n = 26), group comparisons showed that ADC mapping detected changes ipsilateral to the focus in the hippocampus (P < .01) and the amygdala (P < .05), accordingly with the volumes, T2 maps, and HCSI. Significant Pearson correlations (2-tailed) were obtained between ADC maps and the volume of the hippocampus (r = -0.64) and of the amygdala (r = -0.55; both P < .01), T2 (r = 0.70, r = 0.29; both P < .01), but not with HCSI. Individual ADC analysis showed ipsilateral pathology in 82% of cases (hippocampus) and 35% (amygdala) and included a moderate association between ipsilateral HADC and AMYADC (r = 0.54; P < .01). Bilateral abnormalities were found in 7% (hippocampus) and 5% (amygdala) of cases. Except for HCSI and the amygdala data, there were significant correlations between the asymmetry indices and the duration of epilepsy (HADC: r = 0.42; HCT2: r = 0.50; HCVOL: r = 0.35; all P < .01). Age at onset was associated only with ipsilateral HADC (r = 0.35; P < .01) and HCVOL and HCT2 (both P < .05). The association with postsurgical successes was characteristic of HADC (Fisher exact test, 2-tailed: P =.031; Spearman correlation: r(s) = -0.75; P = .0002), but not AMYADC. The predictive value regarding a favorable outcome was 0.87 (odds ratio 26; 95% confidence interval 2.33-38.86). As determined by regression models, both larger ipsilateral HADCs and asymmetry indices predicted surgical success. CONCLUSION: Interictal ADC mapping lateralizes efficiently the lesion side in accordance with the EEG data and might be used to study the differential regional aspects of mesio-temporal sclerosis. HADC--not AMYADC--maps discriminate favorably postoperative outcome and can be added to the multidisciplinary evaluation workout of pharmacoresistant TLE patients.     

青年人与老年人海马体积及形态的MR研究

目的 在区分海马标志点的基础上,测量青年人和老年人正常海马及其头、体、尾3个部位的体积、形态.方法 选择正常青年人(年龄20～29岁,青年组)和老年人(60岁以上,老年组)志愿者各30名进行头部MR扫描,所得图像经后处理软件分析,确定较恒定、易辨认的解剖标志点后对海马进行分割.测量青年组和老年组海马的体积、平均扫描层面积及扫描层数,两组间以及青年组和老年组不同性别、不同侧别海马体积的比较采用独立样本t检验,并作海马的三维重建.结果 60名受试者钩隐窝、脑室三角、钩顶等均能清晰显示.青年组和老年组不同性别间海马体积差异均无统计学意义.青年组左侧海马头部、体部、尾部及整体体积分别为(1250±174)、(653±115)、(372±116)、(2277±109)mm~3,右侧分别为(1255±147)、(657±129)、(386±105)、(2298±213)mm~3,左、右侧间差异均无统计学意义(t值分别为0.08、0.10、0.33、0.35,P值均＞0.05).老年组左侧海马头部、体部、尾部及整体体积分别为(660±109)、(472±92)、(181±73)、(1313±163)mm~3,右侧分别为(717±116)、(474±95)、(240±75)、(1432±171)mm~3,右侧海马尾部体积明显大于左侧,差异具有统计学意义(t=2.21,P＜0.05);其他部位左、右侧海马体积差异均无统计学意义(t值分别为1.39、0.06、1.95,P值均＞0.05).青年组和老年组左侧海马头部、体部、尾部及整体体积差异均有统计学意义(t值分别为15.78、6.71、7.70、20.83,P值均＜0.05),右侧各部位差异也均有统计学意义(t值分别为15.76、6.26、6.15、17.36,P值均＜0.05).老年组各部位体积明显小于青年组,其中以头部最为明显.青年组及老年组海马头部左侧层面积分别为(75±24)、(56±21)mm~2,右侧层面积分别为(73±22)、(58±19)mm2,两组间差异均有统计学意义(t值分别为3.33、2.81,P值均＜0.01).青年组及老年组左侧层数分别为(11.1±3.2)、(7.9±3.9)层,右侧层数分别为(11.5±3.7)、(8.2±3.1)层,两组间差异也均有统计学意义(t值分别为3.48、3.75,P值均＜0.05).老年组的海马头部层数和层面积均小于青年组,呈短而窄的外形.结论 根据海马标志点确认的原则,其所提出的标志点为海马形态体积的标准化测量提供了测量的基础,其所测的正常值有助于疾病的诊断或为某些疾病发病机制的研究提供基础.     

抑郁症患者杏仁核、海马形态功能变化的MR研究

目的 综合形态学测量及功能MR检查对抑郁症患者杏仁核、海马形态及功能进行研究,探讨其变化规律及其机制.方法 60例抑郁症患者[按病情及汉密尔顿抑郁量表(HAMD)分为轻(17分≥HAMD＞8分)、中(24分≥HAMD>17分)及重度组(HAMD>24分),每组20例]及20名健康志愿者行MR形态及fMRI扫描,根据形态图像勾画海马和杏仁核,计算其体积,并进行标准化处理.使用统计参数图(SPM)5软件对功能图像进行后处理,得到受试者脑激活图.体积测量数据采用方差分析及多个试验组与1个对照组均数差别比较的Dunnett-t检验进行分析,并分别对患者组海马、杏仁核体积及信号强度与疾病程度(HAMD评分)进行Pearson相关性分析.结果 抑郁症轻、中及重度组海马体积均小于对照组(左侧2296±202,右侧2283±199),以重度组最为显著(左侧1978±176,Dunnett-t=-10.0,P<0.01;右侧1981±171,Dunnett-t=-9.2,P<0.01),中度组次之(左侧2127±180,Dunnett-t=-3.0,P<0.05;右侧2135±183,Dunnett-t=-3.0,P<0.05),轻度组改变轻微(左侧2207±189,Dunnett-t=-1.4,P>0.05;右侧2210±191,Dunnett-t=-1.6,P>0.05).抑郁症组杏仁核体积依病情由轻到重呈由大至小的趋势,对照组左侧为1762±185,右侧为1749±182.轻度组显著增大(左侧1992±200,Dunnett-t=4.8,P<0.01;右侧1989±191,Dunnett-t=5.0,P<0.01),中度组轻度增大(左侧1889±192,Dunnett-t=2.8,P<0.05;右侧1896±195,Dunnett-t=2.8,P<0.05),重度组显著缩小(左侧1539±178,Dunnett-t=-6.8,P<0.01;右侧1543±180,Dunnett-t=-7.0,P<0.01).功能MR显示抑郁症患者杏仁核、海马对负性图片刺激有着更为显著的脑活动信号,并具有一定的规律,轻度组杏仁核最为显著,中度组信号有所减低,重度组信号最弱,但仍高于对照组.抑郁组海马杏仁核体积、信号强度与疾病程度(HAMD评分)均呈明显的相关性(r值范围为-0.80～-0.90,P值均＜0.05).结论 抑郁症患者海马体积缩小,且这种改变可能与杏仁核有关,杏仁核依病情不同而体积不同;抑郁患者杏仁核、海马对负性图片有着更为显著的脑活动信号.

Abstract：

Objective To explore the morphometric and functional alterations of amygdale and hippocampus in patients with depression by anatomical and functional MRI, and try to reveal the pattern and pathogenesis of the changes in depression. Methods Sixty patients (divided equally into mild, moderate and major groups according to patient′s scores of HAMD) and 20 healthy control groups were scanned using T1WI and fMRI. The outlines of hippocampus and amygdale were drawn manually by observer and the volumes were calculated and normalized subsequently. Functional MRI was processed using SPM5 and individual activation map was got subsequently. Dunnett-t test and Pearson correlation analysis were separately used to analyze the morphometric and functional changes and the correlations between cerebral changes and clinical severity. Results The hippocampal volumes of control groups were 2296±202 left for left side and 2283±199 for right side. The hippocampal volumes of depressive patients were smaller than those of control groups, especially for the major group (left 1978±176,Dunnett-t=-10.0,P<0.01,right 1981±171,Dunnett-t=-9.2,P<0.01). The moderate group showed moderate reduced volume(left 2127±180,Dunnett-t=-3.0,P<0.05,right 2135±183,Dunnett-t=-3.0,P<0.05), while the mild ones showed slightly decreased volume (left 2207±189,Dunnett-t=-1.4,P>0.05,right 2210±191,Dunnett-t=-1.6,P>0.05). The amygdale′s volumes of control groups was 1762±185,the right was 1749±182, while those in patient group reduced along with the patient′s condition, i.e., the mild groups (left 1992±200,Dunnett-t=4.8,P<0.01,right 1989±191, Dunnett-t=5.0,P<0.001), the moderate groups (left 1889±192, Dunnett-t=2.8,P<0.05,right 1896±195,Dunnett-t=2.8,P<0.05), and the major groups (left 1539±178,Dunnett-t=-6.8,P<0.01,right 1543±180,Dunnett-t=-7.0,P<0.01).For fMRI study, patient group demonstrated more activation of the amygdale and hippocampus under the stimulations of negative images than controls. Furthermore, the strengthens of activation decreased along with the patient′s condition, i.e., the major ones showed the weakest activation among the patients, though it was higher than that of control group. In patient group, both the volumes and activations of hippocampus and amygdale showed significant negative correlations with HAMD scores(r=-0.80--0.90,P＜0.05). Conclusion The hippocampal volumes of depressive patients reduced, which may be due to the change of the amygdale, and the amygdale′s volumes were changed along with the patient′s condition. There were more activation in the amygdale and hippocampus of depressive patients under the stimulations of negative images.     

创伤后应激障碍患者海马活体MR波谱研究

目的探讨创伤后应激障碍（PTSD）患者双侧海马活体MR波谱（MRS）的特点,为创伤后应激障碍的诊断和病因学机制提供线索.方法应用多体素活体MRS成像技术,对12例PTSD患者和12例正常对照者进行波谱分析,检测双侧海马的N-乙酰天门冬氨酸（NAA）,肌酸（Cr）和含胆碱化合物（Cho）峰值,并进行统计学比较.结果PTSD患者左侧海马的NAA/Cr比值明显低于正常对照组（F=9.99,P=0.006）,Cho/Cr比值差异无统计学意义（F=0.36,P=0.55）;右侧海马的NAA/Cr比值、Cho/Cr比值差异均无统计学意义（F=1.44,P=0.25）.性别之间的波谱差异比较无统计学意义（F=0.56,P=0.82）;年龄、受教育时间、PTSD症状严重程度与左侧海马NAA/Cr比值的相关系数分别为0.47、0.35和0.18,差异无统计学意义（P＞0.05）.结论PTSD患者左侧海马存在病理性变化,NAA/Cr比值低于正常人.     

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。     

MR measurement of regional relative cerebral blood volume in epilepsy

The purpose of this study was to evaluate the utility of magnetic resonance (MR) relative cerebral blood volume (rCBV) maps for studying regional hemodynamic changes in interictal and ictal epilepsy patients. Ten epilepsy patients were examined on a 1.5 T MR system. Nine patients were investigated interictally and one patient ictally. In the nine interictal patients, the dynamic plane was defined coronally through the hippocampus symmetrically. For the ictal patient, an axial dynamic plane was defined and the patient was scanned during seizure. Positron emission tomography (PET) studies were performed in 8 of the 10 patients. Lower rCBV of the left hippocampus was predicted by rCBV maps in seven of the nine interictal patients. The mean ratios of rCBV were 1.96 for left hippocampus/white matter and 2.49 for right hippocampus/white matter. The difference between these two ratios is statistically significant (P = 0.01, t-test). In two of the nine interictal temporal lobe epilepsy patients, lower rCBV areas were observed in the right hippocampus. In the ictal patient, the regional rCBV map demonstrated increased blood volume in the lesions. In eight of eight patients who underwent PET studies, MR rCBV findings were consistent with PET findings. The results show that regional hemodynamic changes in epilepsy can be evaluated with dynamic contrast-enhanced MR imaging. MR rCBV maps are sensitive to characterize seizure foci both ictally and interictally.     

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     

中国汉族正常成人海马体积的高分辨率MRI测量

目的 测量中国汉族成人海马体积的正常值范围,为各种导致海马结构改变疾病的临床诊断和科学研究提供基础性数据.方法 采用全国多中心临床研究形式,选取18～70岁健康志愿者1000名,按照年龄18～30、31～40、41～50、51～60、61～70岁进行分组,每组男、女各100名.所有受试者均行3D磁化强度预备梯度回波序列T1WI,应用3D体积分析软件手工勾绘ROI,测量健康中国成年人海马的体积.采用多元线性回归方法探讨海马体积与性别、年龄、体重和身高的关系.不同性别、侧别间海马体积的差别采用两独立样本t检验.不同性别和年龄分组间采用方差分析.结果 左、右侧海马体积分别为(4752±659)、(5032±660)mm3,与性别和年龄相关(左、右侧r值分别为0.283和0.311,F值分别为30.127和37.050,P值均<0.01),而与身高和体重不相关(P<0.05).男性左、右侧海马体积分别为(4897±670)、(5192±667)mm3,女性左、右侧海马体积分别为(4647±624)、(4904±630)mm3,右侧海马体积均大于左侧(t值分别为7.030、6.696,P值均<0.05),男性左、右海马体积均大于女性(t值分别为6.586、7.326,P值均<0.05).男性5组左侧海马体积分别为(4981±684)、(5003±609)、(4976±657)、(4841±631)、(4631±681)mm3,右侧海马体积分别为(5340±647)、(5276±582)、(5264±620)、(5133±661)、(4894±699)mm3,5组间差异均有统计学意义(左、右侧F值分别为5.737和7.607,P值均<0.01),其中男性两侧海马结构在18～30、31～40、41～50岁组分别与61～70岁组比较,差异均有统计学意义(P值均<0.05),其余各组间差异无统计学意义(P>0.05).女性不同组别的海马体积差异无统计学意义(P>0.05).结论 采用高分辨率MRI获得中国汉族正常人不同年龄段的海马体积数据,为进一步研究海马相关疾病提供了基础性数据.     

Fractional anisotropy asymmetry and the side of seizure origin for partial onset-temporal lobe epilepsy

This paper presents a fractional anisotropy asymmetry (FAA) method to detect the asymmetry of white matter (WM) integrity and its correlation with the side of seizure origin for partial onset temporal lobe epilepsy (TLE) using diffusion tensor image (DTI). In this study, FAA analysis is applied to 30 patients of partial TLE (15 left, 15 right) and 14 matched normal controls. Specifically, after registering all the images with the JHU-DTI-MNI template the average FA value of each FA skeleton section is calculated using the tract-based spatial statistics (TBSS) method. Then, FAA is calculated to quantify the WM diffusivity asymmetry of the corresponding region-pairs between the left and right hemispheres. Using FAA the regional asymmetry contributing significantly to the group differences of controls and left/right TLE, as well as the left and right TLE, is identified. As a comparison, the ROI-based average FA values for WM and corresponding FAAs are also calculated. TBSS-based analysis reflects the average of local maximal FA values along the white matter skeleton sections, and ROI-based analysis shows the average of WM FA values within each anatomical region. The FAA statistical results indicated that the FA values of anatomical region-pairs are asymmetric in the ipsilateral hemisphere with seizure origin against the contralateral hemisphere. Particularly, FAA values within the temporal lobe (superior, middle, and inferior temporal WM) are significantly different between the left and right TLE patients, consistently found from both analysis methods. The study suggests that FAA values can be potentially used to identify the seizures of origin of TLE and to help understand the relationship between fiber tracts with the side of seizure origin of TLE.     

Uncinate fasciculus fiber tracking in mesial temporal lobe epilepsy. Initial findings

In temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS), ictal discharge spread to the frontal and insulo-perisylvian cortex is commonly observed. The implication of white matter pathways in this propagation has not been investigated. We compared diffusion tensor imaging (DTI) measurements along the uncinate fasciculus (UF), a major tract connecting the frontal and temporal lobes, in patients and controls. Ten right-handed patients referred for intractable TLE due to a right HS were investigated on a 1.5-T MR scanner including a DTI sequence. All patients had interictal fluorodeoxyglucose PET showing an ipsilateral temporal hypometabolism associated with insular and frontal or perisylvian hypometabolism. The controls consisted of ten right-handed healthy subjects. UF fiber tracking was performed, and its fractional anisotropy (FA) values were compared between patients and controls, separately for the right and left UF. The left-minus-right FA UF asymmetry index was computed to test for intergroup differences. Asymmetries were found in the control group with right-greater-than-left FA. This asymmetrical pattern was lost in the patient group. Right FA values were lower in patients with right HS versus controls. Although preliminary, these findings may be related to the preferential pathway of seizure spread from the mesial temporal lobe to frontal and insulo-perisylvian areas.     

脑梗死后抑郁症患者海马及杏仁核体积的MRI研究

目的：探讨脑梗死后抑郁症（PSD）患者海马及杏仁核体积改变特点及与抑郁症关系。方法：研究11例梗死后抑郁症（PSD）患者及13例脑梗死无抑郁症（CONT）患者和15例健康志愿（NORM）者,运用容积分析软件测量两侧海马及杏仁核体积。结果：各组均显示海马及杏仁核体积左侧〈右侧,其中PSD组与NORM组两侧海马及杏仁核体积差异有显著性;PSD组中两侧海马及杏仁核体积均明显〈对照组（海马左右P=0.001,0.040;杏仁核左右P=0.000,0.000）,PSD组右侧海马体积明显〈正常组（P=0.034）;PSD患者双侧海马及杏仁核体积缩小与HAMD抑郁量表评分均缺乏相关性。结论：海马及杏仁核体积异常可能构成梗死后抑郁症的神经生物学基础,也说明边缘系统在抑郁症的发病机制中起着重要作用。     

单侧颞叶癫痫病人双侧基底节区多体素MRS研究

目的 采用多体素MRS探讨单侧颞叶癫痫（TLE）病人双侧基底节区代谢物改变。方法 选取根据临床发作症状和脑电图综合诊断的左侧TLE病人10例,右侧TLE病人10例,正常志愿者10例纳入研究。所有TLE病人均进行利物浦痫性发作严重程度量表2.0（LSSS 2.0）评估,采用Simens 3.0 T超导MR设备进行多体素1H-MRS数据采集,对称性测量双侧尾状核头、豆状核和丘脑的N-乙酰天门冬氨酸（NAA）、乙酰胆碱（Cho）、肌酸（Cr）含量,计算各兴趣区NAA/Cr和Cho/Cr比值并进行统计学分析,将代谢物比值与LSSS 2.0评分进行Pearson相关分析。结果 左侧TLE组双侧丘脑NAA/Cr比值分别为1.92±0.15（左）和2.02±0.26（右）,右侧TLE组双侧丘脑NAA/Cr比值分别为2.19±0.16（左）和1.79±0.16（右）,均明显低于对照组[2.37±0.14（左）和2.36±0.10（右）,P＜0.05]。右侧TLE组,其致痫灶同侧丘脑的NAA/Cr比值较对侧丘脑要低（P＜0.05）。TLE组致痫灶同侧丘脑NAA/Cr比值与LSSS 2.0评分呈负相关（左侧 r=-0.667;右侧r=-0.643,均P＜0.05）。结论 单侧TLE病人存在双侧丘脑神经元丢失和/或功能障碍,且致痫灶同侧丘脑NAA/Cr比值与LSSS 2.0评分可以一致性反映近期痫性发作严重程度。     

Lateralized anterior mesiotemporal lobe activation: semirandom functional MR imaging encoding paradigm in patients with temporal lobe epilepsy--initial experience

PURPOSE: To prospectively demonstrate anterior mesiotemporal lobe (MTL) activation in healthy volunteers by using a semirandom memory-encoding paradigm and to prospectively compare lateralized functional magnetic resonance (MR) imaging activation with intracarotid amobarbital procedure (IAP) memory test results in patients with temporal lobe epilepsy (TLE) who were scheduled to undergo surgery. MATERIALS AND METHODS: The study was approved by a local ethics committee, and written informed consent was obtained from all subjects. Eight healthy volunteers and 18 patients with TLE who were scheduled for surgery were included in the functional MR imaging study involving the use of a memory-encoding paradigm with variable epoch lengths. Subjects were instructed to memorize new pictures that were mixed among pictures that they had seen before. Data analysis entailed computations of the contrast between the MTL activation induced by the new pictures and the MTL activation induced by the old pictures and of the lateralization index, defined as the relative difference in the number of activated voxels between the left and right MTLs. Lateralization indexes were compared between the patients and the volunteers and statistically correlated with the patients' IAP memory test results. To study deviations from perfect correspondence between the functional MR imaging- and IAP-derived lateralization indexes, orthogonal regression analysis was applied. Proportional relations for the patients with left-sided TLE and for those with right-sided TLE were calculated separately. RESULTS: The memory paradigm consistently activated the posterior and anterior MTL structures in both the healthy volunteers and the patients. Regression analysis revealed that functional MR imaging activation was stronger than the IAP results when it was lateralized to the contralateral MTL. This analysis also revealed a significant (P < .001) correlation between the functional MR imaging results and the IAP results in the patients with right-sided TLE but not in those with left-sided TLE (P > .1). CONCLUSION: The functional MR imaging memory-encoding paradigm consistently yielded MTL activation in the volunteers and the patients with TLE, but lateralized functional MR imaging activation was in concordance with the IAP results in only those patients with right-sided TLE.