慢性腰痛推拿治疗前后默认脑网络功能连接变化研究

目的:探讨慢性腰痛患者推拿治疗前、治疗后静息态下默认脑网络的功能连接变化。方法:收集20例慢性腰痛患者和20名健康对照者的静息态功能磁共振(MRI)数据。采用SPM8软件对脑功能数据进行预处理,并以后扣带回为种子点,分析默认脑网络(DMN)功能连接,比较慢性腰痛组与健康对照组、慢性腰痛组推拿治疗前后DMN功能连接的差异。结果:慢性腰痛人群存在DMN与左侧颞下回、左侧小脑前叶、左恻枕中回、左侧背外恻额上回功能连接异常。推拿治疗后主要变化表现为DMN与左恻背外侧额上回连接恢复,DMN与左侧内侧额上回、后扣带皮质连接增强,DMN与左侧楔前叶、左侧回直肌、中脑功能连接降低。结论:静息状态下腰痛受试者DMN存在特定脑功能异常连接区域,推拿治疗主要影响了慢性腰痛人群的感觉、情绪和认知水平的区域。     

18F-T807 PET/MR对阿尔茨海默病诊断及脑内tau蛋白沉积与认知功能相关性分析价值研究

目的 探讨18 F-T807 PET/MR对阿尔茨海默病(AD)的诊断价值,以及其对脑内tau蛋白沉积与认知功能相关性的分析价值.方法 将北部战区总医院2021年3—10月收治的15例AD患者纳入AD组;将同期招募的15例健康志愿者纳入NC组.两组均完成18 F-T807 PET/MR脑部检查及神经心理学测试.应用基于...     

针灸足三里穴中枢调节机制的PET/CT脑功能成像的实验研究

目的应用PET/CT脑功能成像探讨针灸足三里的中枢调节机制。方法电针刺激8名健康志愿者的右侧足三里,同时行全脑PET/CT功能成像,采用相同技术对同8例受试者行无任何穴位刺激的脑功能成像作为对照组。采用SPM的配对t检验模型得出针刺组与对照组的差异脑功能图。结果(1)针刺诱发的脑功能激活区为:BA11、44、8、9、45以及左侧苍白球、丘脑、小脑;(2)针刺诱发的脑功能抑制区为:BA18、19、25以及右侧内囊后肢、导水管周围灰质。其中苍白球、眶回、额回及小脑的功能激活和枕叶、胼胝体的功能抑制认为是与针刺足三里有关的脑功能反应。结论PET/CT脑功能成像是研究针刺中枢效应的适当方法。     

18F-FDG PET/MR联合动脉自旋标记的儿童癫痫致痫区定位

目的 研究¹⁸F-FDG PET/MR 联合动脉自旋标记(ASL)在癫痫患儿中定位致痫区的价值。资料与方法 回顾性纳入2020 年 6 月—2022 年 2 月在南京市第一医院行¹⁸F-FDG PET/MR 脑代谢显像的 46 例癫痫患儿。视觉及半定量分析 MR、PET及 ASL 图像,以视频脑电图或手术部位为参考,分别计算 MR、PET/MR、ASL/MR 及 PET/MR 联合 ASL 定位致痫区的准确率。采用配对 χ²检验比较不同成像模式定位致痫区的价值;采用 Cohen’s Kappa 一致性分析比较 PET 与 ASL 定位的一致性。结果46 例癫痫患儿中,MR、PET/MR 及 ASL/MR 定位致痫灶的准确率分别为 45.65%(21/46)、69.57%(32/46)、73.91%(34/46)。与单独 MR 比较,PET/MR 及 ASL/MR 定位致痫区的准确率较高,差异有统计学意义(χ²=9.09、11.08,P 均<0.01)。PET/MR联合 ASL 序列定位致痫...     

PET/MR-IVIM在预测宫颈癌同步放化疗患者早期预后中的价值

目的:采用治疗前PET/MR多参数及同步放化疗(CCRT)4周后的MR-体素内不相干运动(IVIM)参数及其百分比变化值来预测治疗6个月后宫颈癌患者的预后情况。方法:回顾性纳入2017年9月到2019年3月间于中国医科大学附属盛京医院接受CCRT的58例宫颈癌患者(年龄：35～78岁)。在治疗前进行PET/MR扫描,在...     

一体化PET/MR在脑功能方面的研究进展

影像学是无创研究脑功能的重要途径。随着影像学技术的快速发展,从单模态磁共振成像、正电子发射断层成像,到多模态成像PET/CT、PET/MR,多模态已经成为影像学发展的里程碑。目前最先进的多模态成像设备一体化PET/MR可以同时得到PET成像和MRI多序列成像,将两种成像技术结合,为进一步深入研究脑功能提供了可能。本文对目前脑功能方面的研究做一综述。     

正常大脑静息态功能连接张量的相关特性研究

【摘要】目的：探讨静息态功能磁共振成像（rs-fMRI）中功能连接张量（functional correlation tensor）在群体水平的相关特征。方法：对34例健康受试者行常规及rs-fMRI扫描。将所有数据进行后处理,测量和计算每例受试者脑灰白质基于体素水平的功能连接张量,并经后处理获得所有受试者的平均各项异性指数（FA）以及功能连接张量的迹（trace）参数图。自千人脑连接计划网站上（https://www.nitrc.org/projects/fcon_1000/）下载两组受试者（与本组样本的人口特征相匹配）的rs-fMRI数据,采用相同的数据处理方法,分析比较3组间各项参数的相关性。结果：本组样本的平均功能连接张量FA图与DTI的FA图具有相似的对比度,能较好地区分大脑的灰白质区。在全组平均Trace图上大脑默认网络相关脑区的信号增高。相关性分析显示全组平均Trace值与ReHo值具有高度相关性（r=0.912,P<0.001）,每组平均Trace值与三个数据集的Trace均值之间也具有很好的相关性（两两相关分析的r值均大于0.9,P<0.001）。结论：群体水平大脑静息态功能连接张量的参数图（FA、Trace和ReHo图）能较好地反映大脑功能和结构的相关特性,是研究大脑功能和结构连接的重要手段。     

帕金森病中脑结构性连接组与认知功能障碍

<正>摘要目的探讨伴或不伴轻度认知功能障碍(MCI)帕金森病(PD)病人的脑结构性连接组改变。材料与方法本前瞻性研究经机构伦理委员会批准,所有受试者在入组前均签署知情同意书。利用确定性扩散张量纤维束成像技术获取170例PD病人(其中54例伴有MCI,116例不伴MCI)及41名健康对照组受试者的脑结构性连接组。采用网络分析方法评     

传染性单核细胞增多症的 18F-FDG PET/CT影像学分析

目的:总结传染性单核细胞增多症(IM)成人患者 18F-脱氧葡萄糖(FDG)PET/CT影像表现。 方法:回顾性分析2015年7月至2019年7月同济大学附属东方医院核医学科检出的5例IM患者(均为男性,年龄18～77岁)的 18F-FDG PET/CT影像资料及临床资料,对病变部位(...     

基于三重网络模型的酒精依赖患者静息态动态功能连接分析

目的:探讨酒精依赖(AD)患者静息态三重网络(中央执行网络、突显网络、默认模式网络)动态功能网络连通性(dFNC)的变化。方法:于2020年2月-2021年3月采集15例酒精依赖患者和15例健康志愿者(正常对照组)的静息态fMRI数据。对预处理后的fMRI数据进行独立成分分析以获得大脑网络成分,并通过滑动窗口方法生成大脑网络的动态功能连接矩阵。并对所有dFNC矩阵应用k-means聚类算法确定大脑网络连接模式,获得受试者脑网络的时间属性。最后,使用斯皮尔曼相关分析评估异常时间属性(时间分数、平均停留时间、转换次数)与酒精依赖量表(ADS)评分之间的关系。结果:最终将15例志愿者和12例AD患者纳入本研究,并通过聚类分析得到四种重复出现的功能连接状态。与对照组相比,AD组在弱连接状态下花费时间较长,但在中央执行网络和突显网络之间的强连接状态下花费时间较少(P均<0.05)。双样本t检验结果显示,AD患者中央控制网络内的IC38与IC49之间的功能连接显著增强(P<0.05,FDR校正)。结论:AD患者中央执行网络的功能连接发生了变化,本研究为探索酒精依赖的复杂神经病理学机制提...     

轻微型肝性脑病患者后扣带回与双侧海马间功能连接静息态功能MRI研究

目的：探讨轻微型肝性脑病（MHE）患者静息态下后扣带回（PCC）与双侧海马间功能连接（FC）的改变情况。方法：采用静息态功能磁共振成像（rs-fMRI）技术，分析17例 MHE患者（MHE组）和17例健康对照者（HC组）静息态下脑功能活动，观察 MHE患者静息态下PCC与双侧海马间的功能连接情况，并与数字-符号试验（DST）和数字连接试验-A （NCT-A）评分进行相关分析。结果：与 HC组相比，MHE组 PCC 与右侧海马间 FC 减低（P＜0．05，K≥10体素）；MHE组PCC和右侧海马FC分数与DST评分呈显著正相关，与NCT-A评分呈显著负相关（P＜0．05，K≥体素）。结论：MHE患者脑功能存在损伤，海马与后扣带回间连接强度可以提示 MH E患者的认知功能状态。     

Altered dynamic functional connectivity in the default mode network in patients with cirrhosis and minimal hepatic encephalopathy

Purpose

Abnormal brain intrinsic functional connectivity (FC) has been documented in minimal hepatic encephalopathy (MHE) by static connectivity analysis. However, changes in dynamic FC (dFC) remain unknown. We aimed to identify altered dFC within the default mode network (DMN) associated with MHE.

Methods

Resting-state functional MRI data were acquired from 20 cirrhotic patients with MHE and 24 healthy controls. DMN seed regions were defined using seed-based FC analysis (centered on the posterior cingulate cortex (PCC)). Dynamic FC architecture was calculated using a sliding time-window method. K-means clustering (number of clusters = 2–4) was applied to estimate FC states.

Results

When the number of clusters was 2, MHE patients presented weaker connectivity strengths compared with controls in states 1 and 2. In state 1, decreased FC strength was found between the PCC/precuneus (PCUN) and right medial temporal lobe (MTL)/bilateral lateral temporal cortex (LTC); left inferior parietal lobule (IPL) and right MTL/left LTC; right IPL and right MTL/bilateral LTC; right MTL and right LTC; and medial prefrontal cortex (MPFC) and right MTL/bilateral LTC. In state 2, reduced FC strength was observed between the PCC/PCUN and bilateral MTL/bilateral LTC; left IPL and left MTL/bilateral LTC/MPFC; and left LTC and right LTC. Altered connectivities from state 1 were correlated with patient cognitive performance. Similar findings were observed when the number of clusters was set to 3 or 4.

Conclusion

Aberrant dynamic DMN connectivity is an additional characteristic of MHE. Dynamic connectivity analysis offers a novel paradigm for understanding MHE-related mechanisms.

     

Disrupted functional connectivity of the hippocampus in patients with hyperthyroidism: Evidence from resting-state fMRI

Objective

The hippocampus expresses high levels of thyroid hormone receptors, suggesting that hippocampal functions, including cognition and regulation of mood, can be disrupted by thyroid pathology. Indeed, structural and functional alterations within the hippocampus have been observed in hyperthyroid patients. In addition to internal circuitry, hippocampal processing is dependent on extensive connections with other limbic and neocortical structures, but the effects of hyperthyroidism on functional connectivity (FC) with these areas have not been studied. The purpose of this study was to investigate possible abnormalities in the FC between the hippocampus and other neural structures in hyperthyroid patients using resting-state fMRI.

Methods

Seed-based correlation analysis was performed on resting-state fMRI data to reveal possible differences in hippocampal FC between hyperthyroid patients and healthy controls. Correlation analysis was used to investigate the relationships between the strength of FC in regions showing significant group differences and clinical variables.

Results

Compared to controls, hyperthyroid patients showed weaker FC between the bilateral hippocampus and both the bilateral anterior cingulate cortex (ACC) and bilateral posterior cingulate cortex (PCC), as well as between the right hippocampus and right medial orbitofrontal cortex (mOFC). Disease duration was negatively correlated with FC strength between the bilateral hippocampus and bilateral ACC and PCC. Levels of depression and anxiety were negatively correlated with FC strength between the bilateral hippocampus and bilateral ACC.

Conclusion

Decreased functional connectivity between the hippocampus and bilateral ACC, PCC, and right mOFC may contribute to the emotional and cognitive dysfunction associated with hyperthyroidism.     

Differences in dynamic and static functional connectivity between young and elderly healthy adults

Purpose

Brain connectivity is highly dynamic, but functional connectivity (FC) studies using resting-state functional magnetic resonance imaging (rs-fMRI) assume it to be static. This study assessed differences in dynamic FC between young healthy adults (YH) and elderly healthy adults (EH) compared to static FC.

Methods

Using rs-fMRI data from 12 YH and 31 EH, FC was assessed in six functional regions (subcortical, auditory [AUD], sensorimotor [SM], visuospatial [VS], cognitive control [CC], and default mode network [DMN]). Static FC was calculated as Fisher’s z-transformed correlation coefficient. The sliding time window correlation (window size 30 s, step size 3 s) was applied for dynamic FC, and the standard deviation across sliding windows was calculated. Differences in static and dynamic FC between EH and YH were calculated and compared by region.

Results

EH showed decreased static FC in the subcortical, CC, and DMN regions (FDR corrected p = 0.0013; 74 regions), with no regions showing static FC higher than that in YH. EH showed increased dynamic FC in the subcortical, CC, and DMN regions, whereas decreased dynamic FC in CC and DMN regions (p < 0.01). However, the regions showing differences between EH and YH did not overlap between static and dynamic FC.

Conclusion

Dynamic FC exhibited differences from static FC in EH and YH, mainly in regions involved in cognitive control and the DMN. Altered dynamic FC demonstrated both qualitatively and quantitatively distinct patterns of transient brain activity and needs to be studied as an imaging biomarker in the aging process.

     

Functional MRI Shows Altered Deactivation and a Corresponding Decrease in Functional Connectivity of the Default Mode Network in Patients with Gliomas

BACKGROUND AND PURPOSE:The default mode network normally decreases in activity during externally directed tasks. Although default mode network connectivity is disrupted in numerous brain pathologies, default mode network deactivation has not been studied in patients with brain tumors. We investigated default mode network deactivation with language task–based fMRI by measuring the anticorrelation of a critical default mode network node, the posterior cingulate cortex, in patients with gliomas and controls; furthermore, we examined default mode network functional connectivity in these patients with task-based and resting-state fMRI.MATERIALS AND METHODS:In 10 healthy controls and 30 patients with gliomas, the posterior cingulate cortex was identified on task-based fMRI and was used as an ROI to create connectivity maps from task-based and resting-state fMRI data. We compared the average correlation in each default mode network region between patients and controls for each correlation map and stratified patients by tumor location, hemisphere, and grade.RESULTS:Patients with gliomas (P = .001) and, in particular, patients with tumors near the posterior default mode network (P < .001) showed less posterior cingulate cortex anticorrelation in task-based fMRI than controls. Patients with both left- and right-hemisphere tumors, as well as those with grade IV tumors, showed significantly lower posterior cingulate cortex anticorrelation than controls (P = .02, .03, and <.001, respectively). Functional connectivity in each default mode network region was not significantly different between task-based and resting-state maps.CONCLUSIONS:Task-based fMRI showed impaired deactivation of the default mode network in patients with gliomas. The functional connectivity of the default mode network in both task-based and resting-state fMRI in patients with gliomas using the posterior cingulate cortex identified in task-based fMRI as an ROI for seed-based correlation analysis has strong overlap.

The default mode network (DMN) is a functionally connected brain network^1,2 that demonstrates deactivation during tasks that require external attention relative to nontask conditions.^3-5 The functions of the DMN appear to be central in spontaneous cognition,⁶ stimulus-independent thoughts,⁷ and self-referential mental activity.⁸ DMN deactivation has been correlated with functions such as memory-encoding⁹ and goal-directed external task performance.¹⁰The DMN has been studied extensively using blood oxygen level–dependent (BOLD) fMRI, both in healthy volunteers and in patients with a variety of neurologic and psychiatric conditions. Because DMN deactivation is known to be important for cognitive function,¹⁰ exploring the impact of brain tumors on DMN deactivation could help elucidate the underpinnings of accelerated cognitive decline in patients with brain tumors.¹¹ Subclinical cognitive decline in middle-aged healthy men has been associated with decreased deactivation of the posterior DMN during a visual-motor task paradigm.¹² Decreased DMN deactivation has also been demonstrated in patients with schizophrenia during a semantic and perceptual encoding task paradigm,¹³ in patients with Alzheimer disease during a face-name recognition paradigm,¹⁴ and in patients with stroke during a motor-task paradigm.¹⁵ However, task-induced deactivation of the DMN has not yet been studied with fMRI in patients with gliomas.Functional connectivity (FC) refers to the degree of the correlation of simultaneous activity of disparate brain regions, either during a task or at rest, as measured by fMRI.¹⁶ Disruptions in the FC of the DMN have been associated with cognitive impairment in patients with focal lesions, including patients with stroke¹⁷ and brain tumors,^18-20 as well as in patients with autism,²¹ schizophrenia,²² and neurodegenerative diseases such as Alzheimer disease²³ and Parkinson disease.²⁴ However, while decreases in the FC of the DMN have been found in patients with brain tumors, the data are varied regarding the impact of tumor location, grade, and hemisphere.^18-20 Additionally, there are no data comparing the FC of the DMN using both task-based fMRI (tb-fMRI) and resting-state fMRI (rs-fMRI) in the same cohort of patients with gliomas.Thus, the purpose of this study was to investigate the effect of gliomas on DMN deactivation using tb-fMRI with a language task paradigm and DMN FC using a seed-based correlation analysis in both tb-fMRI and rs-fMRI. To measure DMN deactivation during tb-fMRI, we recorded the degree of negative correlation (anticorrelation) in the posterior cingulate cortex (PCC), a major node of the DMN, relative to the language task waveform in both healthy volunteers and patients with gliomas. Then, we measured the FC to the PCC of the other major nodes of the DMN: the medial prefrontal cortex (mPFC) and the left and right inferior parietal lobules (LIPL and RIPL).³ We also compared these 2 different methods of measuring tumor-induced functional changes in the DMN. We hypothesized that DMN regions impacted by tumors would demonstrate less anticorrelation in tb-fMRI and a correspondingly reduced resting-state connectivity compared with healthy volunteers.     

Preoperative detection of prostate cancer: A comparison with 11C‐choline PET, 18F‐fluorodeoxyglucose PET and MR imaging

Purpose:

To compare ¹¹C‐choline positron emission tomography (C‐PET), ¹⁸F‐fluorodeoxyglucose PET (FDG‐PET), and MR imaging in the preoperative detection of prostate cancer.

Materials and Methods:

C‐PET, FDG‐PET, and MR images were obtained in 43 consecutive patients with suspected prostate cancer, and prostate cancers were histopathologically confirmed in 26 patients. Unenhanced T1‐weighted, T2‐weighted, and gadolinium‐enhanced MR images were obtained. C‐PET and FDG‐PET were conducted 1.5 and 60 minutes after injection of 5.5 and 5.0 MBq/kg tracers, respectively. A nuclear and a genitourinary radiologist retrospectively reviewed PET and MR images at random, respectively, and assigned a confidence level for the presence of prostate cancer using a four‐point scale. Diagnostic performance was tested using the McNemar test and receiver operating characteristic curve analysis.

Results:

The sensitivity was greater (P < 0.05) with MR (88%) and C‐PET (73%) images than with FDG‐PET images (31%). The accuracy was greater (P < 0.05) with MR images (88%) than with C‐PET (67%) and FDG‐PET (53%) images. The area‐under‐curve value with MR (0.90) was greater than those with C‐PET (0.53) and FDG‐PET (0.54) images (P < 0.01).

Conclusion:

MR imaging should be primarily performed in the preoperative detection of prostate cancer. C‐PET and FDG‐PET did not improve the detection. J. Magn. Reson. Imaging 2010;31:1151–1156. © 2010 Wiley‐Liss, Inc.     

(18)F-fluorodeoxyglucose positron emission tomography and MR imaging findings in Rasmussen encephalitis

BACKGROUND AND PURPOSE: Rasmussen encephalitis is a chronic, progressive encephalitis that manifests as an abrupt-onset, intractable seizure disorder in previously developmentally normal children. The objectives of the current study were to characterize the (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and MR imaging findings in Rasmussen encephalitis and to test the hypotheses that data from both imaging techniques are required to establish the diagnosis and identify the affected cerebral hemisphere in some cases. METHODS: Eleven patients with Rasmussen encephalitis were identified from a review of a computer database. The MR (n = 10) and PET (n = 11) imaging data were reviewed retrospectively and conjointly. RESULTS: On MR images, nine of 10 patients manifested bilateral cerebral atrophy that predominantly involved one hemisphere. One patient had purely unilateral cerebral atrophy. We observed foci of abnormally increased T2 signal intensity in nine of 10 patients. On FDG PET images, all patients showed extensive regions of hypometabolism within the cerebral hemisphere that showed the greatest atrophy. Discrete foci of hypermetabolism, indicative of seizure activity, were observed in six patients. The FDG PET and MR imaging findings were either stable or gradually progressive in patients with multiple imaging studies (MR, n = 5; FDG PET, n = 5). CONCLUSION: Rasmussen encephalitis is characterized by diffuse, unilateral cerebral hypometabolism on FDG PET images, with corresponding regions of cerebral atrophy on MR images. Although MR imaging data alone are sufficient to suggest a diagnosis of Rasmussen encephalitis in many cases, correlation with FDG PET data increases diagnostic confidence and allows the unequivocal identification of the affected cerebral hemisphere in patients whose MR imaging findings are subtle or distributed bilaterally.     

Altered default mode network activity in patient with anxiety disorders: an fMRI study

Anxiety disorder, a common mental disorder in our clinical practice, is characterized by unprovoked anxiety. Medial prefrontal cortex (MPFC) and posterior cingulate cortex (PCC), which closely involved in emotional processing, are critical regions in the default mode network. We used functional magnetic resonance imaging (fMRI) to investigate whether default mode network activity is altered in patients with anxiety disorder. Ten anxiety patients and 10 healthy controls underwent fMRI while listening to emotionally neutral words alternating with rest (Experiment 1) and threat-related words alternating with emotionally neutral words (Experiment 2). In Experiment 1, regions of deactivation were observed in patients and controls. In Experiment 2, regions of deactivation were observed only in patients. The observed deactivation patterns in the two experiments, which included MPFC, PCC, and inferior parietal cortex, were similar and consistent with the default model network. Less deactivation in MPFC and greater deactivation in PCC were observed for patients group comparing to controls in Experiment 1. Our observations suggest that the default model network is altered in anxiety patients and dysfunction in MPFC and PCC may play an important role in anxiety psychopathology.     

Mapping functionally related regions of brain with functional connectivity MR imaging

BACKGROUND AND PURPOSE: In subjects who are performing no prescribed cognitive task, functional connectivity mapped with MR imaging (fcMRI) shows regions with synchronous fluctuations of cerebral blood flow. When specific tasks are performed, functional MR imaging (fMRI) can map locations in which regional cerebral blood flow increases synchronously with the performance of the task. We tested the hypothesis that fcMRI maps, based on the synchrony of low-frequency blood flow fluctuations, identify brain regions that show activation on fMRI maps of sensorimotor, visual, language, and auditory tasks. METHODS: In four volunteers, task-activation fMRI and functional connectivity (resting-state) fcMRI data were acquired. A small region of interest (in an area that showed maximal task activation) was chosen, and the correlation coefficient of the corresponding resting-state signal with the signal of all other voxels in the resting data set was calculated. The correlation coefficient was decomposed into frequency components and its distribution determined for each fcMRI map. The fcMRI maps were compared with the fMRI maps. RESULTS: For each task, fcMRI maps based on one to four seed voxel(s) produced clusters of voxels in regions of eloquent cortex. For each fMRI map a closely corresponding fcMRI map was obtained. The frequencies that predominated in the cross-correlation coefficients for the functionally related regions were below 0.1 Hz. CONCLUSION: Functionally related brain regions can be identified by means of their synchronous slow fluctuations in signal intensity. Such blood flow synchrony can be detected in sensorimotor areas, expressive and receptive language regions, and the visual cortex by fcMRI. Regions identified by the slow synchronous fluctuations are similar to those activated by motor, language, or visual tasks.     

Metabolism of human gliomas: assessment with H-1 MR spectroscopy and F-18 fluorodeoxyglucose PET

Localized hydrogen-1 magnetic resonance (MR) spectroscopy and fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) were employed to obtain metabolic information from intracranial gliomas. Advantages and difficulties associated with comparison of results from the two modalities were realized. Forty patients were studied with H-1 MR spectroscopy. MR signal intensities from lactate, N-acetylaspartate (NAA), choline, and creatine from a volume of interest containing the tumor and a contralateral volume were obtained and evaluated. NAA signal intensities were generally decreased in the tumor spectra, and choline signal intensities were elevated. H-1 MR spectroscopy was unsuccessful in eight patients, and FDG PET scans were not obtained in four of the patients with successful MR spectroscopic examinations. Lactate signal intensity was detected in 10 of the 28 patients who had successful H-1 MR spectroscopic and FDG PET studies. Lactate signal intensities were observed in lesions shown at FDG PET to be hypermetabolic, as well as in lesions found to be hypometabolic.