MRI volumetry of the hippocampus, amygdala, entorhinal cortex, and perirhinal cortex after status epilepticus

Neuronal damage has been observed in the medial temporal lobe of both humans and animals following status epilepticus. The aim of the present study was to investigate the occurrence of medial temporal lobe damage in status epilepticus patients treated in hospital with a predetermined protocol and to assess whether the changes progress in a long-term follow-up. The volumes of the hippocampus, amygdala, entorhinal and perirhinal cortices were measured using magnetic resonance imaging (MRI) in nine adult patients with status epilepticus 3 weeks, 6 and 12 months after the insult. The control group included 20 healthy subjects. The etiology of status epilepticus was an acute process in one patient and a chronic process in eight cases. The mean duration of secondarily generalized tonic–clonic status epilepticus episodes was 1 h and 44 min. Volumetric MRI indicated that none of the patients developed marked volume reduction in the hippocampus, amygdala, or the entorhinal and perirhinal cortices during the 1-year follow-up period. Status epilepticus does not invariably lead to a progressive volume reduction in the medial temporal lobe structures of adult patients treated promptly in hospital with a predetermined protocol for rapid cessation of seizure activity.     

Limbic system abnormalities associated with Ammon's horn sclerosis do not alter seizure outcome after amygdalohippocampectomy

PURPOSE: To evaluate whether limbic system abnormalities associated with Ammon's horn sclerosis alter seizure outcome after selective amgydalohippocampectomy. METHODS: In 45 patients with unilateral mesial temporal lobe epilepsy, histologically proven Ammon's horn sclerosis, and uneventful postoperative course, volumes of the hippocampus, hemisphere, amygdala, entorhinal cortex, mamillary body, and fornix were measured by using a T(1)-weighted 3-D gradient-echo sequence with roughly isotropic (1.17 x 1.17 x 1-mm) voxels. In addition, signal intensity of the hippocampus and of the temporal lobe white matter was visually assessed and graded on a coronal T(2)-weighted fast-spin-echo sequence with 2-mm-thick slices. Volumetric measurements and visual analysis were compared between seizure-free and non-seizure-free patients examined 12 months after surgery. RESULTS: Hippocampal, hemispheric, entorhinal cortex, mamillary body, and fornix volumes, but not amygdalar volumes, were significantly smaller on the operated-on than on the non-operated-on side and significantly smaller in patients compared with controls. No volume differences of the hippocampus, hemisphere, amygdala, entorhinal cortex, mamillary body, and fornix existed between seizure-free (Engel class IA) and non-seizure-free patients (Engel class IB-IV). Increased temporal lobe white matter signal was observed in 15 patients but did not alter seizure outcome. CONCLUSIONS: Limbic system abnormalities are not a surrogate marker to predict postsurgical seizure outcome in patients with unilateral Ammon's horn sclerosis.     

Entorhinal cortex in temporal lobe epilepsy: a quantitative MRI study.

BACKGROUND: The entorhinal cortex (EC) is a distinct anatomic and functional region of the anterior parahippocampal gyrus, which plays a role in seizure generation and propagation in temporal lobe epilepsy (TLE). In tissue resected from TLE patients, cell loss in the EC has been described. OBJECTIVES: To develop a standardized protocol for identifying the anatomic boundaries of the EC using high-resolution MRI and to examine morphologic changes of the EC in TLE. METHODS: We performed T1-weighted MRIs in 20 patients (7 males) with TLE (mean age 34 years) and 18 normal controls (mean age 26 years). Eleven patients had a left and 9 a right epileptic focus as defined by history, video-EEG, and surgical outcome. The volumes of the EC, the hippocampus, and the amygdala were measured using a standardized MRI protocol. Analysis of variance (ANOVA) was used to examine the effect of seizure focus lateralization and hemisphere on these volumes. An asymmetry ratio [A (%) = 100 x (R-L)/(R+L)/2] was also compared between groups using ANOVA. RESULTS: In normal controls the volume of the right EC was 1,247 +/- 127 mm3 (mean +/- standard deviation), and that of the left EC was 1,215 +/- 135 mm3 (p > 0.05). We found a bilateral reduction in the volume of the EC in TLE patients compared with controls (p < 0.05). Examination of the asymmetry ratios showed that the reduction in volume of the EC was greater ipsilateral to the epileptic focus (p < 0.05). The volumes of the hippocampus and the amygdala were smaller on the side of the focus in TLE patients compared with controls (p < 0.05). CONCLUSIONS: With a standardized protocol for the quantitative assessment of the EC, patients with unilateral TLE show bilateral reduction in the volume of the EC. However, this reduction is more severe ipsilateral to the epileptic focus.     

难治性颞叶癫痫的外科治疗(附35例临床分析)

目的总结并分析难治性颞叶癫痫患者术前定位、手术方式和经验。方法回顾性分析2009年6月至2011年6月,采用颞前叶+海马杏仁核切除术治疗的颞叶癫痫病人35例,其中术前MRI及术后病理证实伴有海马硬化者32例,所有病例术中均在皮层电极监测下切除颞叶皮质及同侧海马、杏仁核,手术后均应用抗癫痫药物治疗,术后随访1～3年。结果在35随访病例中,癫痫发作控制结果显示EngelⅠ级24例,Ⅱ级8例,Ⅲ级3例,Ⅳ级0例。其中有12例病人术后2年逐渐停用抗癫痫药物。结论联合应用VEEG、MRI及EcoG能准确确定致痫灶,提高颞叶癫痫手术疗效。手术方式选择及显微理念的应用,能有效减少术后并发症的发生,避免出现永久性神经功能缺失。     

Impaired associative memory in temporal lobe epilepsy subjects after lesions of hippocampus, parahippocampal gyrus, and amygdala

There has been growing interest in the differential role of medial temporal lobe structures in learning and memory. The goal of the present study was to clarify how lesions of hippocampus, parahippocampal gyrus, and amygdala interfere with associative learning and memory. Thirty subjects with pharmacoresistant medial temporal lobe epilepsy (TLE) and temporal lobe removal were compared with 30 matched healthy control subjects. A set of neuropsychological test measures and an associative learning task requiring the learning and recall of objects and faces were administered. The lesions of hippocampus, parahippocampal gyrus, amygdala, and fusiform gyrus of TLE subjects were determined by three-dimensional magnetic resonance imaging (3-D MRI) volumetric assessment. The results indicate that TLE subjects with combined large hippocampal lesions, large parahippocampal gyrus (i.e., perirhinal/entorhinal) lesions, and large amygdala lesions learned and recalled the associative task significantly worse than control subjects or subjects with small lesions of the hippocampus, parahippocampal gyrus, and amygdala. Regression analysis revealed that larger lesions of the parahippocampal gyrus (i.e., perirhinal/entorhinal cortices) were significantly related to increasing deficits on the task, and that hippocampal and amygdala lesion size did not significantly improve the prediction. Our results suggest that perirhinal and entorhinal cortices may contribute predominantly to the associative learning and recall of objects and faces.     

Value of extent of hippocampal resection in the surgical treatment of temporal lobe epilepsy

OBJECTIVE: Unilateral hippocampal atrophy is indicator of good surgical prognosis in patients with temporal lobe epilepsy (TLE). Some patients however do not become seizure free after surgery. We assessed if the extent of hippocampal and amygdala resection is associated with outcome. METHODS: Thirty patients with TLE with unilateral or clearly asymmetric hippocampal atrophy who underwent surgical treatment were evaluated concerning preoperative clinical variables and interictal EEG abnormalities. Amygdala and hippocampal resection was evaluated by post-operative MRI. We compared seizure free versus non-seizure free patients, and patients with good outcome (Engel's classes I and II) versus patients with poor outcome. RESULTS: There was significant association between the extent of hippocampal resection and the outcome. Pre-operative variables and interictal EEG abnormalities did not show relationship with outcome as documented in previous studies. CONCLUSION: The extent of hippocampal resection is associated with outcome. Incomplete resection of atrophic hippocampus may explain most surgical failures in patients with TLE due to unilateral hippocampal sclerosis.     

Stereotactic radiofrequency amygdalohippocampectomy: Does reduction of entorhinal and perirhinal cortices influence good clinical seizure outcome?

Purpose: Stereotactic radiofrequency amygdalohippocampectomy (SAHE) has been modified recently in our center for the therapy of mesial temporal epilepsy (MTLE). It has promising clinical results comparable with microsurgical amygdalohippocampectomy despite smaller volume reduction of the hippocampus. We hypothesized that the extent of perirhinal and entorhinal cortex (PRC, EC) reduction could explain the clinical outcome. Therefore, we performed, retrospectively, volumetric analysis of PRC and EC and compared it with the seizure control. Methods: Twenty‐six consecutive patients with MTLE treated by SAHE were included. PRC and EC volumes were measured from magnetic resonance imaging (MRI) records obtained before and 1 year after SAHE. The clinical outcome was assessed each year after SAHE using Engel’s classification. Key Findings: Twenty‐six patients were analyzed. The volume of PRC decreased by 46 ± 17% (p < 10⁻¹²); EC volume decreased by 56 ± 20% (p < 10⁻¹⁰). Two years after the procedure, 73% of patients were classified as Engel’s I, 19% as Engel’s II; in 2 (8%) the treatment failed (were reoperated). Eighteen patients finished 3 years follow‐up; 72% of them were classified as Engel’s I, 17% as Engel’s II, and in 2 (11%) above‐mentioned patients the treatment failed. Thirteen patients finished 4 years of follow‐up, 11 of them as Engel’s I. There was no significant correlation of the clinical outcome to PRC and EC volume reductions. Significance: The clinical effect of SAHE is not clearly explained by the volume reductions of PRC and EC (nor of the hippocampus and the amygdala). It promotes opinion that the extent of resection/destruction is not important for seizure outcomes.     

MRI-guided SPECT perfusion measures and volumetric MRI in prodromal Alzheimer disease

OBJECTIVE: To identify group differences in the prodromal phase of Alzheimer disease (AD) using quantitative single-photon emission computed tomography (SPECT) perfusion and magnetic resonance imaging (MRI) volume measures within specific volumes of interest. SETTING: Gerontology research unit. PARTICIPANTS: There were 17 healthy controls, 56 nondemented patients with memory problems who did not develop AD during 3 to 5 years of follow-up (questionables), and 27 nondemented patients with memory problems who developed AD during follow-up (converters). METHODS: A Tc 99m hexamethylpropyleneamine oxime SPECT study and an MRI were performed in each participant at baseline. Mean SPECT activity concentration and MRI volume were estimated within 9 structures: rostral anterior cingulate, caudal anterior cingulate, posterior cingulate, hippocampus, entorhinal cortex, basal forebrain, temporal horn, amygdala, and the banks of the superior temporal sulcus. Data were analyzed using overall and pairwise discriminant analysis, and performance in pairwise group discrimination was measured using correlated receiver operating characteristic curve analysis. RESULTS: The overall (3-group) discriminant function was significant for SPECT (F test, P<.001) and MRI (F test, P<.0001). For the SPECT analysis, the ranking of structures for discriminating among the 3 groups was, in order of decreasing discriminating power, caudal anterior cingulate, temporal horn, superior temporal sulcus, entorhinal cortex, hippocampus, rostral anterior cingulate, amygdala, basal forebrain, and posterior cingulate. For the MRI analysis, this ranking was entorhinal cortex, superior temporal sulcus, temporal horn, hippocampus, amygdala, caudal anterior cingulate, rostral anterior cingulate, basal forebrain, and posterior cingulate. Combining the 2 modalities yielded significantly better discrimination performance than did either alone. Furthermore, the correlation between SPECT and MRI measures was low. CONCLUSION: Measures of structure activity concentration and volume carry independent information; both reveal group differences in prodromal AD.     

The epileptogenic zone in pharmaco‐resistant temporal lobe epilepsy with amygdala enlargement

Aims. Temporal lobe epilepsy with amygdala enlargement (TLE‐AE) has been considered a subtype of TLE. We evaluated the epileptogenic zone in patients with TLE‐AE, who underwent intracranial video‐EEG (ivEEG) and/or intraoperative electrocorticography (ioECoG) as well as epilepsy surgery. Methods. Eleven patients with TLE‐AE were enrolled and investigated based on seizure profile, volumetric MRI, the Wechsler Memory Scale‐Revised (WMS‐R), the location of seizure onset zone (SOZ) and irritative zone (IZ) based on ivEEG (n=8), the location of interictal epileptiform discharges (IEDs) based on ioECoG (11), surgical procedure, and seizure outcome. Results. The mean age at seizure onset was 34.9 years (range: 23–57). The mean duration of seizures was 5.0 years (range: 1–10). The number of AEDs was 2.3 (range: 1–5). The mean seizure frequency was nine per month (range: 1–30/month). All patients presented with focal impaired awareness seizures with (n=9) and without (2) secondary generalized convulsions. Volumetric MRI analysis showed unilateral enlarged amygdala with statistical significance (p<0.01). None of the patients' hippocampi had any abnormality based on MRI. Pre‐operative mean verbal, visual, and delayed recall scores based on the WMS‐R were over 100. The SOZ and IZ were identified in both the amygdala and hippocampus in seven patients and in only the amygdala in one patient based on ivEEG. IEDs were identified in the hippocampus in six patients and in both the amygdala and hippocampus in four patients based on ioECoG. All 11 patients underwent anterior temporal lobectomy, including amygdala resection, with multiple hippocampal transections (dominant hemisphere: seven patients) and resection (non‐dominant hemisphere: three patients). Nine (81.8%) of 11 patients achieved seizure freedom with a mean follow‐up of 26 months (range: 12–47). Post‐operative WMS‐R results did not show any significant deterioration, with a mean follow‐up of 15 months (range: 12–24). The resected amygdala showed no histopathological abnormality. Conclusion. The epileptogenic zone of TLE‐AE involves both the amygdala and hippocampus. ivEEG may be needed to explore the SOZ in normal hippocampus in addition to enlarged amygdala. Amygdala resection and multiple hippocampal transections may control the epileptogenic limbic system and save memory function in patients with TLE‐AE.     

Predictors of outcome after temporal lobectomy for refractory temporal lobe epilepsy

Objective – To identify predictors of outcome after epilepsy surgery in patients with temporal lobe epilepsy (TLE). Methods – Seventy‐six patients with normal magnetic resonance imaging (MRI) or hippocampal sclerosis on MRI who underwent anterior temporal lobe resections were included. Outcome 2 years after surgery was classified as good (Engel I and II) or poor (Engel III and IV). Gender, age at onset and duration of epilepsy, history of febrile convulsions, auras, right‐ or left‐sided TLE, memory ipsilateral to seizure onset (Wada test), hippocampal asymmetry (HA) and T2 relaxation time, amygdala, temporal lobe and hemispheral volume were tested for associations with outcome. Results – Sixty‐seven percent had a good outcome. Of all parameters tested, only a history of febrile convulsions and HA on quantitative MRI were significantly associated with a good seizure outcome. The absence of these parameters did not exclude a good outcome, but only five of 18 patients (28%) without HA and without a history of febrile convulsions had a good outcome. Conclusion – Febrile convulsions and HA were predictors of outcome after epilepsy surgery in TLE. Subtle volume loss in amygdala, temporal lobe or hemispheres and the memory ipsilateral to the side of resection were not associated with outcome.     

Entorhinal cortex MRI assessment in temporal,extratemporal, and idiopathic generalized epilepsy

PURPOSE: We previously showed a reduction in the volume of the entorhinal cortex (EC) ipsilateral to the seizure focus in patients with intractable temporal lobe epilepsy (TLE). The purpose of this study was to examine the specificity of EC atrophy in epilepsy. METHODS: We performed volumetric measurement of the EC on high-resolution magnetic resonance imaging (MRI) in patients with TLE (n = 70), extratemporal lobe epilepsy (ETE; n = 18), and idiopathic generalized epilepsy (IGE; n = 20). EC volumes of epilepsy patients were compared with those of 48 age- and sex-matched normal controls. Within the TLE group, 63 patients were selected prospectively with hippocampal atrophy ipsilateral to the seizure focus. The remaining seven patients were chosen retrospectively based on normal volumetric MRI of the hippocampus and amygdale, as well as normal histopathologic examination of the resected tissue. RESULTS: Compared with normal controls, EC volume was smaller ipsilateral but not contralateral to the seizure focus in patients with TLE (p < 0.001). No difference in the EC volumes ipsilateral and contralateral to the seizure focus was seen in patients with ETE and IGE compared with normal controls. The individual analysis showed that the EC was atrophic in 73% of TLE patients with hippocampal atrophy. Three of the seven TLE patients with normal volumetric MRI of the hippocampus and amygdala and normal histopathologic examination had EC atrophy ipsilateral to the seizure focus. In no patient with ETE or IGE was the EC found to be atrophic. CONCLUSIONS: EC atrophy ipsilateral to the seizure focus appears to be specific to mesial temporal lobe structural damage associated with TLE.     

Does Resection of the Medial Temporal Lobe Improve the Outcome of Temporal Lobe Epilepsy Surgery?

PURPOSE: Surgical removal of the hippocampus is the standard of care of patients with drug-resistant medial temporal lobe epilepsy (MTLE). The procedure carries a success rate of approximately 75%, but the reasons that some patients fail to achieve seizure control after surgery remain inexplicable. The question of whether the resection of medial temporal lobe structures in addition to the hippocampus would influence the surgical outcome in patients with MTLE was examined. METHODS: We conducted voxel-based statistical analyses of postoperative high-resolution MRI of MTLE patients who underwent anteromedial temporal resection. We applied a cost function transformation of the resection maps for each patient to a common set of spatial coordinates, and we analyzed the contribution of histologically distinct segments of the medial temporal lobe cortex to the surgical outcome. We also performed a voxel-wise mapping of surgical outcome to the temporal lobe. RESULTS: We observed that the extent of hippocampal removal was associated with better outcomes. However, when the resection of the hippocampus was combined with the resection of the medial temporal lobe, specifically the entorhinal cortex, a greater likelihood of higher seizure control after surgery was found. CONCLUSIONS: Based on this finding, it is possible that the efficiency of the surgical treatment of MTLE can be improved by adjusting the procedure to include the resection of the entorhinal cortex, in addition to the resection of the hippocampus.     

Predicting surgical outcome in temporal lobe epilepsy patients using MRI and MRSI

OBJECTIVE: To develop a classifier that uses MR data to predict surgical outcome in patients with temporal lobe epilepsy (TLE). METHODS: Eighty-one patients with medically refractory TLE who underwent surgical treatment were studied. Patients underwent comprehensive presurgical investigation, including ictal video-EEG recording, 1H MRS imaging, and volumetric MRI. Outcome was measured using Engel's classification system, condensed into two outcome groups. Two approaches were taken. First, outcome was defined as experiencing worthwhile improvement with >90% reduction of seizure frequency (Classes I, II, and III) or not (Class IV). A second approach was to define outcome as experiencing freedom from seizures following surgery (Class I) or not (Classes II, III, and IV). For each approach, a Bayesian classifier was constructed to predict outcome by calculating the probability of a patient's pattern of results from spectroscopic analysis of the temporal lobes and volumetric analysis of the amygdala and hippocampus being associated with the various outcome groups. RESULTS: The worthwhile improvement classifier correctly predicted the surgical outcomes of 60 of 65 (92%) of patients who experienced worthwhile improvement and 10 of 16 (63%) of patients who did not. The seizure-free classifier correctly predicted the surgical outcomes of 39 of 52 (75%) of patients who became seizure free and 21 of 29 (72%) of patients who did not. CONCLUSION: MR features are important markers of surgical outcome in patients with TLE and can provide assistance in identifying surgical candidates.     

Entorhinal cortex atrophy in epilepsy patients exhibiting normal hippocampal volumes

OBJECTIVE: To determine whether MRI volumetric measurement of the entorhinal cortex could detect structural damage and lateralize the seizure focus in patients with temporal lobe epilepsy in whom no measurable hippocampal abnormalities were found. BACKGROUND: A reduction in the volume of the entorhinal cortex ipsilateral to the seizure focus in patients with intractable temporal lobe epilepsy and hippocampal atrophy was recently shown. METHODS: MRI volumetric analysis of the entorhinal cortex was performed using a T1-weighted three-dimensional gradient echo sequence in 24 control subjects and 22 patients with temporal lobe epilepsy and normal hippocampal volumes. Thirteen patients underwent surgery, with a mean postoperative follow-up of 36 months. RESULTS: Group analysis (multivariate analysis of variance) showed a reduction in the volume of the entorhinal cortex ipsilateral to the seizure focus in patients with left (p < 0.0001) and right temporal lobe epilepsy (p < 0.0001). Lateralization of the seizure focus could be done in 14 of 22 patients (64%) based on entorhinal cortex volumetry. CONCLUSION: Entorhinal cortex atrophy ipsilateral to the seizure focus supports the presence of structural damage in the mesial temporal lobe in patients with temporal lobe epilepsy and normal hippocampal volumes and emphasizes the participation of the entorhinal cortex in the pathogenesis of this disorder.     

Resection extent versus postoperative outcomes of seizure and memory in mesial temporal lobe epilepsy

OBJECTIVES: To investigate the effects of the resection of hippocampus and temporal neocortex on postsurgical seizure and memory outcomes in mesial temporal lobe epilepsy (mTLE) patients. METHODS: Sixty-eight mTLE patients underwent pre- and postsurgical brain magnetic resonance imaging (MRI). The patients were divided into seizure-free group (SF, N=54) and non-seizure-free group (NSF, N=14). The resection length of hippocampus was determined by the difference between presurgical and postsurgical hippocampus lengths in MRIs. The lengths of resected temporal gyri were measured on three-dimensional MRI reconstruction. Among SF group, 37 patients performed pre- and postsurgical neuropsychological tests. The postsurgical memory decline (PMD) was calculated by subtracting postsurgical memory score from presurgical one in verbal and visual memory tests. RESULTS: The resection length of hippocampus in SF was significantly longer than in NSF (32.7 +/- 7.7 mm versus 25.1 +/- 7.3 mm, t-test, p=0.002), regardless of intersubject difference in the extent of hippocampal sclerosis (logistic regression, p=0.003) while the resection lengths of the lateral temporal gyri were not different between SF and NSF. Overall postsurgical change of verbal or visual memory was not significant. However, regression analysis showed a significant correlation between the resection length of inferior or basal temporal gyrus and verbal PMD (p<0.001) in left TLE patients with seizure-free outcome. CONCLUSION: More resection of hippocampus may predict a better postsurgical seizure-free outcome. The larger resection of inferior or basal temporal gyrus seems to be related to a postsurgical verbal memory decline in left TLE patients.     

Entorhinal-Hippocampal Interactions in Medial Temporal Lobe Epilepsy

Summary: Experimental studies suggest important interactions between hippocampus and entorhinal cerebral cortex in generation of temporal lobe seizure activity. We studied electrical expression of spontaneous temporallobe ictal activity in hippocampus and entorhinal cortex in 9 medically refractory epileptic patients who had intracranial depth and subdural electrodes implanted during surgical evaluation. All 9 patients subsequently under-went anteromedial temporal lobectomy with hippocam-pectomy, all had >50% decrease in neuronal cell density in hippocampal CA1 and CA3, and all had good to excellent seizure outcome after operation. Two to 10 spontaneous seizures were analyzed per patient (total 41 seizures). Nine patients had variable onset of seizure activity recorded in hippocampus, entorhinal cortex, or both simultaneously. Low-voltage fast activity was observed in either location and varied among seizures in an individual patient. Periodic preictal spikes, when present, were often synchronous in both locations, but were noted independently only in hippocampus. Our data suggest that preictal spikes and low-voltage fast seizure discharges have anatomically distinct origins, and that some syndromes of medial temporal lobe epilepsy involve interactions between entorhinal and hippocampal regions that act together to produce and propagate the seizures in such patients.     

Relations Between EEG Seizure Morphology, Interhemispheric Spread, and Mesial Temporal Atrophy in Bitemporal Epilepsy

Summary: Purpose: A strong relation exists between lateralization of seizure onset in temporal-lobe epilepsy and atrophic mesial structures measured by volumetric magnetic resonance imaging (MRI). We examined whether this relation extended to subregions of the mesial temporal lobe and whether the trend for seizures to spread contralaterally could be related to the localization of atrophy. Methods: We analyzed 362 seizures (with and without clinical signs) from 23 patients having bitemporal epilepsy in whom intracerebral electrodes were implanted for presurgical evaluation. Patients had measurements of hippocampal and amygdala volumes, including comparison with normal controls. We assessed on EEG the laterialization and localization of seizure onset and the trend to spread to the contralateral side (proportion of seizures that spread for each patient). We included all seizures, independent of the presence of clinical manifestations. These features were related to presence and localization of atrophy. Results: Among the 19 patients with mesial atrophy, agreement between side of prevalent seizure onset and predominant atrophy was found in 10 (53%). From 99 seizures starting in a temporal lobe with atrophy limited to the hippocampus, 67% started simultaneously in amygdala and hippocampus, 20% in hippocampus, and 13% in amygdala. From 137 seizures starting in a temporal lobe with amygdala and hippocampal atrophy, 47% started in amygdala and hippocampus, 48% in hippocampus, and 5% in amygdala. The trend to spread was 45% to the most atrophic side and 62% to the normal or less atrophic side. Conclusions: When examining amygdala and hippocampus in this group of patients with bitemporal epilepsy, regions of seizure onset did not correspond to regions of predominant atrophy. The likelihood that seizures spread contralaterally was not influenced by atrophy in the region targeted by the spread. Precise relation between mesial temporal atrophy and seizures remain to be elucidated.     

Morphometric MRI alterations and postoperative seizure control in refractory temporal lobe epilepsy

Refractory mesial temporal lobe epilepsy (mTLE) is a debilitating condition potentially amenable to resective surgery. However, between 40 and 50% patients continue to experience postoperative seizures. The development of imaging prognostic markers of postoperative seizure outcome is a crucial objective for epilepsy research. In the present study, we performed analyses of preoperative cortical thickness and subcortical surface shape on MRI in 115 of patients with mTLE and radiologically defined hippocampal sclerosis being considered for surgery, and 80 healthy controls. Patients with excellent (International League Against Epilepsy outcome (ILAE) I) and suboptimal (ILAE II–VI) postoperative outcomes had a comparable distribution of preoperative atrophy across the cortex, basal ganglia, and amygdala. Conventional volumetry of whole hippocampal and extrahippocampal subcortical structures, and of global gray and white matter, could not differentiate between patient outcome groups. However, surface shape analysis revealed localized atrophy of the thalamus bilaterally and of the posterior/lateral hippocampus contralateral to intended resection in patients with persistent postoperative seizures relative to those rendered seizure free. Data uncorrected for multiple comparisons also revealed focal atrophy of the ipsilateral hippocampus posterior to the margins of resection in patients with persistent seizures. This data indicates that persistent postoperative seizures after temporal lobe surgery are related to localized preoperative shape alterations of the thalamus bilaterally and the hippocampus contralateral to intended resection. Imaging techniques that have the potential to unlock prognostic markers of postoperative outcome in individual patients should focus assessment on a bihemispheric thalamohippocampal network in prospective patients with refractory mTLE being considered for temporal lobe surgery. Hum Brain Mapp 36:1637–1647, 2015. © 2015 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.     

立体定向热凝毁损海马杏仁核治疗海马病变所致难治性颞叶内侧癫

目的探讨立体定向手术热凝毁损海马杏仁核治疗海马病变所致难治性颞叶内侧癫癎的疗效。方法回顾分析19例由海马病变所致难治性颞叶内侧癫癎患者的临床表现、影像学（CT/MRI）脑电图（EEG/VEEG）资料和手术疗效。所有病例术前均行动态脑电图检查明确致癎灶完成定位诊断、术中行立体定向组织活检、快速冰冻病理确诊病变性质完成定性诊断。全部患者在计算机辅助下行致癎灶侧海马杏仁核立体定向热凝毁损术。手术效果按谭启富的评定标准进行评价。结果随访12～42个月，13例癫癎未再发作（满意），4例发作次数减少75%以上（明显改善），2例发作次数减少50%（改善）。未发现神经心理学改变及神经功能障碍等并发症。结论对于由海马病变所致难治性颞叶内侧癫癎，采用立体定向手术行海马杏仁核热凝毁损是控制癫癎发作的一种安全有效方法。     

Quantitative MRI volumetry of the entorhinal cortex in temporal lobe epilepsy.

The entorhinal cortex (Brodmann's area 28) is located at the anterior aspect of the parahippocampal gyrus ventral to the amygdala and the hippocampus. It is reciprocally interconnected with the hippocampus via glutamatergic pathways. We investigated whether the entorhinal cortex is damaged in human temporal lobe epilepsy (TLE). The volume of the entorhinal cortex was measured using magnetic resonance imaging (MRI) in 36 patients with cryptogenic TLE and in 21 controls. The mean volumes of the entorhinal cortex on the focal side did not differ from controls. In 11 of 36 patients, however, the entorhinal cortex volume was reduced by 25%. Entorhinal volume correlated with hippocampal volume in TLE (ipsilaterally, r= 0.454, P<0.01; contralaterally, r = 0.340, P<0.05). Further, 64% of patients with 25% entorhinal cortex damage had ipsilateral hippocampal atrophy. On the other hand, right focal TLE patients with hippocampal atrophy had a 19% volume reduction of the ipsilateral entorhinal cortex (P<0.05). The volume of the entorhinal cortex correlated with the duration of TLE (r= -0.335, P< 0.05). The present study indicates that the entorhinal cortex might be damaged in a subpopulation of patients with cryptogenic TLE. In most cases, volume reduction was associated with hippocampal damage. These data suggest that entorhinal damage contributes to the symptomatology in TLE.