磁共振质子波谱在颞叶癫痫诊断中的应用

目的　评价磁共振质子波谱 (1HMRS)诊断颞叶癫痫的价值。方法　对 30例颞叶癫痫患者和 30例健康志愿者用 2 0T场强的MR成像系统分别进行双侧颞叶的质子波谱采集 ,定量分析N 乙酰天门冬氨酸 (NAA)、肌酸 (Cr)和胆碱复合物 (Cho)等代谢产物的变化。结果　癫痫病人NAA峰降低。以NAA/ (Cr Cho)值为判断标准 ,2 5例病人可以定侧诊断 ,敏感性 83% ,并发现 14例双侧病变 ,占 47%。结论　1HMRS可无创性探测脑组织内生化改变 ,对癫痫灶的定侧诊断具有很高的价值     

Temporal lobe epilepsy: Correlation of proton magnetic resonance spectroscopy and 18F-fluorodeoxyglucose positron emission tomography

Proton magnetic resonance spectroscopy (MRS) has demonstrated reduction of N-acetylaspartate (NAA) in the epileptogenic temporal lobe. However, the correlation of NAA reduction with cerebral metabolic abnormalities is unknown in temporal lobe epilepsy (TLE). Proton MRS and ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG/PET) were used to study 12 unilateral TLE patients with medically intractable seizures and 26 age-matched healthy volunteers. The epileptogenic temporal lobe of each patient was determined by both electroencephalography and FDG/PET. The NAA/choline-plus-creatine (NAA/(Cho+Cr)) ratio correlated significantly with the interictal glucose metabolism (r = 0.54, P 0.01) in 12 TLE patients. The mean NAA/(Cho + Cr) ratio in the epileptogenic temporal lobe was significantly less than that in the contralateral side (P < 0.01), and less than that in normal control temporal lobes (P < 0.0001). These results suggest that quantitative MRS abnormalities reflect underlying metabolic pathology in TLE.     

MR单体素波谱和化学位移成像在颞叶癫痫中的研究

目的　应用MR氢质子波谱 (1HMRS)不同成像方法 ,包括单体素波谱 (SVS)、化学位移成像 (CSI) ,探讨1HMRS对颞叶癫痫 (TLE)的诊断价值。方法　设对照组 4 0例、颞叶癫痫组 (TLE) 2 0例。应用1HMRS分别进行海马结构 (HF)的SVS和CSI,应用SVS比较TLE患侧组、对侧组及对照组各代谢物比值 ,并行致痫灶定侧诊断。应用CSI分析TLE患侧组、对侧组及对照组HF从前到后各体素氮 乙酰天门冬氨酸 / (胆碱 肌酸复合物 ) [NAA/ (Cho Cr) ]的变化规律 ,并进行三组间、各体素间两两比较。结果　SVS示TLE组患侧组HF的NAA/ (Cho Cr) (0 4 8± 0 10 )、NAA/Cr(1 2 0± 0 19)下降 ,与对照组、对侧组 (分别为 0 71± 0 0 7、1 4 8± 0 16 ;0 6 1± 0 12、1 4 4± 0 2 3)差异有显著性意义 (F值分别为 4 1 95 8、15 5 75 ,P值 <0 0 0 0 1)。SVS对TLE定侧敏感度为 85 % ,特异度为 93%。CSI示对照组、TLE患侧、对侧组HF的NAA/ (Cho Cr)与HF部位间呈直线相关关系 ,后部较前部大 ;与正常组比较 ,患侧组前部NAA/ (Cho Cr)的降低程度较后部大。结论　SVS可帮助TLE致痫灶定侧。CSI显示HF从前到后存在NAA/ (Cho Cr)渐变现象 ,TLE患侧头部代谢改变较尾部大。在比较代谢改变时 ,保证定位于HF的相同部位很重要。     

Multisection proton MR spectroscopy for mesial temporal lobe epilepsy

BACKGROUND AND PURPOSE: Extensive metabolic impairments have been reported in association with mesial temporal lobe epilepsy (mTLE). We investigated whether proton MR spectroscopy ((1)H-MRS) depicts metabolic changes beyond the hippocampus in cases of mTLE and whether these changes help lateralize the seizure focus. METHODS: MR imaging and (1)H-MRS were performed in 15 patients with mTLE with a postoperative diagnosis of mesial temporal sclerosis and in 12 control volunteers. Point-resolved spectroscopy and multisection (1)H-MRS measured N-acetylaspartate (NAA), creatine (Cr), and choline (Cho) in the hippocampus, temporal opercular and lateral cortices, insula and cerebellum, and frontal, parietal, and occipital lobes. Metabolites were assessed as ratios to Cr and in absolute units. RESULTS: Twelve patients had ipsilateral hippocampal atrophy; three had negative imaging results. In the ipsilateral hippocampus, absolute NAA (/NAA/) was 27.3% lower in patients compared with that in control volunteers (P <.001) and 18.5% lower compared with that in the contralateral side (P <.01). /NAA/ averaged over selected regions in the ipsilateral temporal lobes of patients with mTLE was 19.3% lower compared with the mean in the control group (P <.0001) and by 17.7% lower compared with the contralateral values (P <.00001). Using only hippocampal data, 60% of the cases of mTLE were correctly lateralized. Lateralization, determined using whole temporal lobe data, had 87% sensitivity and 92% specificity. /NAA/ was bilaterally reduced in the frontal, parietal, and occipital lobes of patients with mTLE compared with that in control volunteers (P <.01). CONCLUSION: Multisection (1)H-MRS depicts interictal reductions of NAA in the ipsilateral temporal lobe beyond the hippocampus and accurately lateralizes seizure foci.     

1H MR spectroscopy in histopathological subgroups of mesial temporal lobe epilepsy

The aim of the study was to analyze the lateralizing value of proton magnetic resonance spectroscopy (¹H MRS) in histopathologically different subgroups of mesial temporal lobe epilepsies (MTLE) and to correlate results with clinical, MRI and seizure outcome data. A group of 35 patients who underwent resective epilepsy surgery was retrospectively studied. Hippocampal ¹H MR spectra were evaluated. Metabolite concentrations were obtained using LCModel and NAA/Cr, NAA/Cho, NAA/(Cr+Cho), Cho/Cr ratios and coefficients of asymmetry were calculated. MRI correctly lateralized 89% of subjects and ¹H MRS 83%. MRI together with ¹H MRS correctly lateralized 100% of patients. Nineteen subjects had “classical” hippocampal sclerosis (HS), whereas the remaining 16 patients had “mild” HS. Nineteen patients had histopathologically proven malformation of cortical development (MCD) in the temporal pole; 16 subjects had only HS. No difference in ¹H MRS findings was found between patients in different histopathological subgroups of MTLE. Our results support the hypothesis that ¹H MRS abnormalities do not directly reflect histopathological changes in MTLE patients. Subjects with non-lateralized ¹H MRS abnormalities did not have a worse postoperative seizure outcome. We found no significant impact of contralateral ¹H MRS abnormality on post-surgical seizure outcome.     

Effect of seizure on hippocampus in mesial temporal lobe epilepsy and neocortical epilepsy: an MRS study

This study was performed to evaluate the effect of seizures on the bilateral hippocampus in mesial temporal lobe epilepsy (mTLE) and neocortical epilepsy by single voxel proton magnetic resonance spectroscopy (MRS). Forty-one patients with mTLE having unilateral hippocampal sclerosis and 43 patients with a neocortical epilepsy who underwent subsequent epilepsy surgery were recruited. Ninety-five percent confidence intervals of N-acetyl aspartate/choline (NAA/Cho) and NAA/creatine (NAA/Cr) ratios in 20 healthy control subjects were used as threshold values to determine abnormal NAA/Cho and NAA/Cr. NAA/Cho and NAA/Cr were significantly lower in the ipsilateral hippocampus of mTLE and neocortical epilepsy. Using asymmetry indices for patients with bilaterally abnormal ratios of NAA/Cho and NAA/Cr in addition to using unilateral abnormal ratio, the seizure focus was correctly lateralized in 65.9% of patients with mTLE and 48.8% of neocortical epilepsy patients. Bilateral NAA/Cho abnormality was significantly related to a poor surgical outcome in mTLE. No significant relationship was found between the results of NAA/Cho or NAA/Cr and surgical outcome in neocortical epilepsy. The mean contralateral NAA/Cr ratio of the hippocampus in mTLE was significantly lower in patients with a history of secondary generalized tonic-clonic seizure (SGTCS) than in those without. Our results demonstrate effects of seizures on the hippocampi in neocortical epilepsy and the relation between SGTCS and NAA/Cr of the contralateral hippocampus in mTLE. This proves the presence of a seizure effect on the hippocampus in neocortical epilepsy as well as in mTLE.     

海马硬化MR质子波谱分析与MRI的对比研究

目的　评价MR质子波谱分析 (1HMRS)和MRI对海马硬化的诊断价值。方法　对 8例病理证实的海马硬化病人和 8例健康志愿者分别进行1HMRS和MRI海马体积定量研究。通过计算峰下面积 ,对代谢产物氮 乙酰天门冬氨酸 (NAA)、肌酸 (Cr)及胆碱复合物 (Cho)的浓度进行定量并观察NAA/Cr、NAA/ (Cr Cho)及Cho/Cr各参数的变化 ,同时用右侧海马体积和左侧海马体积差值(DHF)的方法分析形态学的异常。结果　病变组病侧NAA/Cr、NAA/ (Cr Cho)及Cho/Cr值分别为0 5 5、1 77及 1 38,对照组分别为 0 77、1 38及 1 0 6。海马硬化病人NAA/Cr和NAA/ (Cr Cho)值下降 ,统计学上差异有显著性意义 (t值分别为 2 15和 4 83,P值均 <0 0 5 ) ,Cho/Cr值升高 ,统计学上差异有显著性意义 (t值为 2 34 ,P <0 0 5 )。根据NAA/ (Cr Cho)值的不对称降低可对 6例病人进行定侧诊断 ,其中错误 1例 ;根据DHF值的变化可诊断海马萎缩 2例。所有病例均经手术病理证实为海马硬化 ,病变程度与NAA/ (Cr Cho)值的降低相一致。NAA/ (Cr Cho)减低与癫痫发作次数无相关性 (r=- 0 134 ,P >0 0 5 )。结论　1HMRS能够早期发现海马硬化。1HMRS和MRI互相补充有利于海马硬化的术前诊断。     

Lateralizing ability of single-voxel proton mr spectroscopy in hippocampal sclerosis: comparison with mr imaging and positron emission tomography

BACKGROUND AND PURPOSE: Proton MR spectroscopy (MRS) is still in the early stages in the evaluation of epilepsy, and comparisons with MR imaging and positron emission tomography (PET) in the same patients have rarely been documented. The purpose of this study was to evaluate the lateralizing ability of single-voxel MRS in comparison with MR imaging and PET in patients with hippocampal sclerosis. METHODS: Thirty-three patients with intractable temporal lobe epilepsy whose MR imaging diagnosis was unilateral hippocampal sclerosis and who underwent anterior temporal lobectomy and had good postsurgical outcome over 1-year follow-up were included in the study. MR spectra were obtained from the hippocampus bilaterally, using the point-resolved spectroscopy sequence. Metabolite ratios of NAA/Cho and NAA/Cr were calculated from the relative peak height measurements. An NAA/Cho ratio of 0.8 or less and an NAA/Cr ratio of 1.0 or less were regarded as abnormal. The MRS results were compared retrospectively with those of MR imaging and PET as to the ability to lateralize the epileptogenic focus. RESULTS: The sensitivity of MRS and PET (concordance with MR imaging) was 85% each in the lateralization of the ipsilateral lesion side. Bilateral abnormalities were seen in 30% of the patients. False-lateralization rates for MRS and PET were 3% and 6%, respectively. The concordance rate of MRS and PET was 73%, when comparing the results of the ipsilateral lesion side. CONCLUSION: MRS may be used as an adjunct tool in the evaluation of hippocampal sclerosis, like PET, although its sensitivity has to be improved and the clinical significance of bilateral abnormality is still to be determined.     

Proton MR spectroscopy in patients with acute temporal lobe seizures

BACKGROUND AND PURPOSE: Decreases in N-acetyl aspartate (NAA) as seen by proton MR spectroscopy are found in hippocampal sclerosis, and elevated levels of lipids/lactate have been observed after electroconvulsive therapy. Our purpose was to determine whether increased levels of lipids/lactate are found in patients with acute seizures of hippocampal origin. METHODS: Seventeen patients with known temporal lobe epilepsy underwent proton MR spectroscopy of the mesial temporal lobes within 24 hours of their last seizure. Four of them were restudied when they were seizure-free. Five healthy individuals were used as control subjects. All MR spectroscopy studies were obtained using a single-voxel technique with TEs of 135 and 270. The relationship between the presence of lipids/lactate and seizures was tested using Fisher's exact test. Mean and standard deviations for NAA/creatine (Cr) were obtained in the hippocampi in patients with seizures on initial and follow-up studies and these values were compared with those in the control subjects. RESULTS: Seizure lateralization was obtained in 15 patients. Of the 17 seizure locations that involved hippocampi, 16 showed lipids/lactate by proton MR spectroscopy. Of the 13 hippocampi not directly affected by seizures, 10 showed no lipids/lactate and three showed lipids/lactate. The relationship between lipids/lactate and seizure location was confirmed. A comparison of NAA/Cr ratios for the involved hippocampi with those in control subjects showed significant differences on initial MR spectroscopy; however, no significant difference was found between acute and follow-up NAA/Cr ratios in hippocampi affected by seizures. CONCLUSION: Lipids/lactate were present in the hippocampi of patients with acute seizures and decreased when the patients were seizure-free. Thus, lipids/lactate may be a sensitive marker for acute temporal lobe seizures.     

Intractable temporal lobe epilepsy: comparison of positron emission tomography with qualitative and quantitative MR.

PURPOSETo compare the ability of qualitative fludeoxyglucose F 18 positron emission tomography (QPET), qualitative MR imaging (QMR), and quantitative MR imaging with hippocampal formation volumetric assessment (HV MR) to lateralize the seizure focus in patients with temporal lobe epilepsy.METHODSSixteen consecutive patients undergoing presurgical examination for temporal lobe seizures had QPET, QMR, and HV MR. The presence of temporal lobe epilepsy was confirmed by Engel class I or II outcomes at 1-year postoperative follow-up examinations. A QPET, QMR, or HV MR study was considered to be lateralizing if it matched the side of the seizure focus, nonlateralizing if it did not lateralize the seizure focus to either temporal lobe, or incorrectly lateralizing if it lateralized the seizure focus to the incorrect side.RESULTSOf 16 patients with proved temporal lobe seizures, QPET was correctly lateralizing in nine (56%), nonlateralizing in six (37.5%), and incorrectly lateralizing in one (6%). QMR was correctly lateralizing in six (37.5%), nonlateralizing in six (37.5%), and incorrectly lateralizing in four (25%). HV MR was correctly lateralizing in all 16 patients (100%). Age at onset, seizure duration, and total number of seizures did not correlate with QPET, QMR, and HV MR lateralization.CONCLUSIONSOur results show that each imaging technique yields useful information for seizure lateralization in temporal lobe epilepsy and that HV MR yields considerably more information that QPET or QMR.     

磁共振多种成像方法在颞叶癫痫的综合诊断

目的 应用MR不同成像方法探讨MRI对颞叶癫痫的诊断价值。资料与方法 设对照组40例，颞叶癫痫组(TLE)20例，颞叶外癫痫组(ELE)21例。应用MRI测量并比较对照组及TLE、ELE组间海马结构(HF)体积差异，行TLE组致痫侧评判。应用扩散加权成像(DWI)测量并比较对照组与TLE患侧、对侧、ELE组间表观弥散系数(ADC)值差异。应用1H MRS对各组分别进行单体素波谱(SVS)和化学位移成像(CSI)，SVS时比较TLE患侧、对侧及对照组各代谢物比值差异，对TLE组行致痫灶定侧诊断。CSI时分析HF从前到后NAA／(Cho Cr)的变化规律。结果TLE组患侧HF体积、NAA／(Cho Cr)值下降，ADC值升高，与对照组差异有显著性。定量MRI、SVS对TLE组定侧敏感性分别为70％、85％，特异性分别为87．5％、95％。CSI示HF的NAA／(Cho Cr)与HF部位间呈直线相关关系，TLE时前部改变较后部大。结论 定量MRI、SVS可帮助TLE致痫灶定侧，SVS更敏感、特异，两者结合后价值更大。CSI显示HF从前到后代谢物浓度渐变现象，TLE组头部改变较尾部大。DWI可作为MRI诊断颞叶癫痫的补充。     

Lateralisation with magnetic resonance spectroscopic imaging in temporal lobe epilepsy: an evaluation of visual and region-of-interest analysis of metabolite concentration images

We carried out spectroscopic imaging (MRSI) on nine consecutive patients with temporal lobe epilepsy being assessed for epilepsy surgery, and nine neurologically healthy, age-matched volunteers. A volume of interest (VOI) was angled along the temporal horns on axial and sagittal images, and symmetrically over the temporal lobes on coronal images. Images showing the concentrations of N-acetylaspartate (NAA) and of choline-containing compounds plus creatine and phosphocreatine (Cho + Cr) were used for lateralisation. We compared assessment by visual inspection and by signal analysis from regions of interest (ROI) in different positions, where side-to-side differences in NAA/(Cho + Cr) ratio were used for lateralisation. The NAA/(Cho + Cr) ratio from the different ROI was also compared with that in the brain stem to assess if the latter could be used as an internal reference, e. g., for identification of bilateral changes. The metabolite concentration images were found useful for lateralisation of temporal lobe abnormalities related to epilepsy. Visual analysis can, with high accuracy, be used routinely. ROI analysis is useful for quantifying changes, giving more quantitative information about spatial distribution and the degree of signal loss. There was a large variation in NAA/(Cho + Cr) values in both patients and volunteers. The brain stem may be used as a reference for identification of bilateral changes. Received: 19 July 2000/Accepted: 21 December 2000     

Proton MR spectroscopy in patients with seizure disorders.

PURPOSETo evaluate the ability of proton MR spectroscopy to detect metabolic abnormalities in the seizure focus of humans with epilepsy.METHODSSingle-voxel MR spectroscopy and MR imaging was performed in a group of 13 patients with a variety of seizure disorders and in the temporal lobes of 14 healthy volunteers. Signals from choline, creatine, N-acetyl-L-aspartate, and lactate were quantitated in both the epileptogenic focus and the contralateral brain region.RESULTSIn normal temporal lobe, concentrations of choline, creatine, and N-acetyl-L-aspartate were 2.0 +/- 0.7, 7.8 +/- 1.9, and 11.0 +/- 2.1 mumol/g wet weight, respectively, with no detectable lactate. In all patients, a reduction in the N-acetyl-L-aspartate signal was observed in the electrically defined (scalp electroencephalogram) seizure focus compared with the mirror-image contralateral side. Lactate was elevated only in patients who had seizures during or immediately before the MR examination. Seven of 13 patients studied had normal MR examinations.CONCLUSIONSProton spectroscopy demonstrates alterations in N-acetyl-L-aspartate and lactate levels that can be used to locate the epileptogenic focus and may be a useful adjunctive diagnostic technique for the evaluation of patients with seizures who are eligible for resective surgery.     

Inter-modality comparisons of seizure focus lateralization in complex partial seizures

Anterior temporal lobectomy offers a high chance of seizure-free outcome in patients suffering from drug-refractory complex partial seizure (CPS) originating from the temporal lobe. Other than EEG, several functional and morphologic imaging methods are used to define the spatial seizure origin. The present study was undertaken to compare the merits of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET), magnetic resonance imaging (MRI) and single-voxel proton MR spectroscopy (MRS) for the lateralization of temporal lobe seizure foci. The clinical charts and imaging data of 43 consecutive CPS patients were reviewed. Based on surface EEG, 31 patients were classified with temporal lobe epilepsy (TLE; 25 lateralized, 6 not lateralized) and 12 with non-temporal lobe epilepsy. All were examined by FDG-PET, MRS and MRI within 6 weeks. FDG-PET and MRI were interpreted visually, while the N-acetyl-aspartate to creatine ratio was used for MRS interpretation. One FDG-PET scan was invalid due to seizure activity post injection. The MR spectra could not be evaluated in five cases bilaterally and three cases unilaterally for technical reasons. A total of 15 patients underwent anterior temporal lobectomy. All showed a beneficial postoperative outcome. When the proportions of agreement between FDG-PET (0.77), MRI (0.58) and MRS (0.56) and surface EEG in TLE cases were compared, there were no significant differences (P>0.10). However, FDG-PET showed a significantly higher agreement (0.93) than MRI (0.60; P=0.03) with the side of successful temporal lobectomy. The concordance of MRS with the side of successful temporal lobectomy was intermediate (0.75). When the results of functional and morphologic imaging were combined, no significant differences were found between the rates of agreement of FDG-PET/MRI and MRS/MRI with EEG (0.80 vs 0.68; P=0.50) and with the side of successful temporal lobectomy (0.87 vs 0.92; P=0.50) in TLE cases. However, MRS/MRI showed significantly more lateralized temporal lobe abnormalities in non-temporal lobe epilepsy cases than FDG-PET/MRI (0.90 vs. 0.17; P<0.01). Although FDG-PET seems to be the most reliable and stable method for this purpose, we conclude that in TLE cases it may be justified to perform MRS, which is less expensive, faster and has no radiation exposure, in combination with MRI before FDG-PET, since FDG-PET offers little additional diagnostic information if MRS and MRI indicate the same seizure focus lateralization.     

Evidence of neuronal injury outside the medial temporal lobe in temporal lobe epilepsy: N-acetylaspartate concentration reductions detected with multisection proton MR spectroscopic imaging--initial experience

PURPOSE: To determine whether magnetic resonance (MR) spectroscopic imaging reveals metabolic changes, especially decreased N-acetylaspartate (NAA) concentrations outside the medial temporal lobe in patients with mesial temporal lobe epilepsy (TLE), consistent with neuropathologic findings of extratemporal neuronal impairment. MATERIALS AND METHODS: Eleven patients with mesial TLE and 13 control subjects were examined with multisection MR spectroscopic imaging. Three MR spectroscopic imaging sections were acquired. Thirteen brain regions in each hemisphere and the midbrain were analyzed in each patient, and the NAA to creatine-phosphocreatine (Cr) plus choline-containing compounds (Ch) (NAA/[Cr + Ch]) ratios were determined. In addition, hemispheric and whole-brain values were calculated and statistically analyzed. RESULTS: The NAA/(Cr + Ch) ratio in the ipsilateral hippocampus was significantly reduced, compared with that in the contralateral hippocampus (P <.002) and compared with that in control subjects (P <.03), confirming findings in previous studies. In patients, whole-brain NAA/(Cr + Ch) ratio outside the hippocampus was significantly lower than that in control subjects (P <.002). For the ipsilateral hemisphere in patients, NAA/(Cr + Ch) ratio was significantly lower than that in control subjects (P <.0002). Comparisons between individual brain regions revealed trends toward lower NAA/(Cr + Ch) ratios in many areas of the ipsilateral and, to a lesser extent, the contralateral hemisphere outside the hippocampus and temporal lobe, suggesting diffuse impairment. CONCLUSION: Results suggest that repeated seizure activity damages neurons outside of the seizure focus.     

Inter-modality comparisons of seizure focus lateralization in complex partial seizures.

Anterior temporal lobectomy offers a high chance of seizure-free outcome in patients suffering from drug-refractory complex partial seizure (CPS) originating from the temporal lobe. Other than EEG, several functional and morphologic imaging methods are used to define the spatial seizure origin. The present study was undertaken to compare the merits of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET), magnetic resonance imaging (MRI) and single-voxel proton MR spectroscopy (MRS) for the lateralization of temporal lobe seizure foci. The clinical charts and imaging data of 43 consecutive CPS patients were reviewed. Based on surface EEG, 31 patients were classified with temporal lobe epilepsy (TLE; 25 lateralized, 6 not lateralized) and 12 with non-temporal lobe epilepsy. All were examined by FDG-PET, MRS and MRI within 6 weeks. FDG-PET and MRI were interpreted visually, while the N-acetyl-aspartate to creatine ratio was used for MRS interpretation. One FDG-PET scan was invalid due to seizure activity post injection. The MR spectra could not be evaluated in five cases bilaterally and three cases unilaterally for technical reasons. A total of 15 patients underwent anterior temporal lobectomy. All showed a beneficial postoperative outcome. When the proportions of agreement between FDG-PET (0.77), MRI (0.58) and MRS (0.56) and surface EEG in TLE cases were compared, there were no significant differences (P>0.10). However, FDG-PET showed a significantly higher agreement (0.93) than MRI (0.60; P=0.03) with the side of successful temporal lobectomy. The concordance of MRS with the side of successful temporal lobectomy was intermediate (0.75). When the results of functional and morphologic imaging were combined, no significant differences were found between the rates of agreement of FDG-PET/MRI and MRS/MRI with EEG (0.80 vs 0.68; P=0.50) and with the side of successful temporal lobectomy (0.87 vs 0.92; P=0.50) in TLE cases. However, MRS/MRI showed significantly more lateralized temporal lobe abnormalities in non-temporal lobe epilepsy cases than FDG-PET/MRI (0.90 vs. 0.17; P<0.01). Although FDG-PET seems to be the most reliable and stable method for this purpose, we conclude that in TLE cases it may be justified to perform MRS, which is less expensive, faster and has no radiation exposure, in combination with MRI before FDG-PET, since FDG-PET offers little additional diagnostic information if MRS and MRI indicate the same seizure focus lateralization.     

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。     

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。     

Developmental delay in children: assessment with proton MR spectroscopy

BACKGROUND AND PURPOSE: The cause of developmental delay frequently is unknown, and clinicians and families can be frustrated by the lack of neuroimaging correlation especially when considering therapeutic options and long-term prognosis. We sought to determine if proton MR spectroscopy can depict abnormalities in patients with developmental delay who have structurally normal brain MR images. METHODS: Children with developmental delay who were older than 2 years (mean age, 5.0 years; range, 3.0-10.0 years) and those aged 2 years or younger (mean age, 1.5 years; range, 0.5-2.0 years) and age-matched control subjects for each patient group underwent brain MR imaging and proton MR spectroscopy. A point-resolved spectroscopy sequence (2000/144 [TR/TE]) was used. Voxels (8 cm(3)) were placed in the subcortical white matter of the frontal and parieto-occipital lobes bilaterally. N-acetylaspartate (NAA)/creatine (Cr) and choline (Cho)/Cr ratios were assessed. RESULTS: All patients had normal brain MR images. In children with developmental delay who were aged 2 years or younger, no statistically significant differences were detected in the NAA/Cr or Cho/Cr ratios compared with those of the control subjects. In children with developmental delay who were older than 2 years, decreases in the NAA/Cr ratio were observed in frontal (P <.001) and parieto-occipital (P <.017) subcortical white matter, and elevations in the Cho/Cr ratio were detected in the frontal (P <.24) and parieto-occipital (P <.002) subcortical white matter compared with age-matched control subjects. CONCLUSIONS: In children with developmental delay who are older than 2 years, proton MR spectroscopy depicted abnormalities in the NAA/Cr and Cho/Cr ratios. Proton MR spectroscopy should be performed as part of the neuroimaging evaluation of developmental delay. Further studies will be needed to determine if abnormalities detected with proton MR spectroscopy can be used as a diagnostic tool and neuroimaging marker to assess long-term functional outcome.     

Hemispheric language dominance studied with functional MR: preliminary study in healthy volunteers and patients with epilepsy.

PURPOSEWe used functional MR imaging to compare hemispheric language dominance in healthy volunteers and in patients with epilepsy.METHODSWe retrospectively reviewed the functional MR images of 23 healthy volunteers and 16 patients with epilepsy obtained by using an echo-planar technique designed for whole-brain imaging. The activation paradigm used was a silent word generation task. Hemispheric language dominance was assessed as the percentage of activated pixels in the left hemisphere minus the percentage of activated pixels in the right hemisphere x 100.RESULTSWe found no significant difference in language lateralization between right-handed male and right-handed female volunteers. However, a statistically significant difference in language distribution was found between left- and right-handed female volunteers. The left-handed female volunteers showed a more bilateral hemispheric language lateralization. Language lateralization in right-handed male epilepsy patients with early age at seizure onset and seizure locus in the left temporal lobe was not significantly different from that of healthy right-handed male volunteers. Similarly, we found no difference in language lateralization between right-handed female volunteers and right-handed female epilepsy patients with late age at seizure onset and seizures in the left temporal lobe.CONCLUSIONHandedness has a significant influence on hemispheric language dominance in healthy volunteers. Sex has no influence on hemispheric language dominance, regardless of the task used to assess such dominance, nor does age at seizure onset influence language lateralization in patients with left temporal lobe epilepsy. Therefore, hemispheric language dominance can be assessed and compared effectively with functional MR imaging.