18F-FDG PET显像诊断老年性痴呆初步研究

目的：探讨＾１８Ｆ－脱氧葡萄糖（ＦＤＧ）ＰＥＴ显像诊断老年性痴呆（ＡＤ）的影像特征和征和诊断标准。方法 静脉注射＾１８Ｆ－ＦＤＧ后行脑断层显像,获得顶叶,颞叶,额叶单位面积放射性计数与小脑计数的比值,以此作为半定量指标。结果 １２例正常人可见大脑皮质各叶、基底神经节、丘脑及小脑放射性分布均匀对称。１２例ＡＤ影像分为３种：双侧顶叶放射性减低５例,双侧颞顶叶减低４例,单侧颞顶叶减低３例。半定量分析显示     

帕金森病脑18F-FDG PET显像临床研究

目的：探讨帕金森病（PD）患者18F－脱氧葡萄糖（FDG）PET脑代谢显像的影像学特征及其临床意义。方法：静脉注射18F－FDG后行脑断层显像，获得33例PD患者及32例正常人纹状体，丘脑，黑质，顶叶，颞叶，额叶，枕叶，海马单位面积放射性计数与小脑计数的比值（Rcl/cb)，并与MRI进行对照。结果：正常人脑PET显像可见大脑各叶，基底节，丘脑，中脑及小脑放射性分布均匀对称。PD患者的PET异常率为96．97％，MRI异常率为30．30％，PD患者黑质，纹状体，丘脑及大脑半球各叶代谢低于正常人，差异有非常显著性（P＜0．001），并与症状严重程度有关，症状重侧肢体对侧脑半球的黑质，纹状体，丘脑及额叶代谢较另侧降低，PD患者PET显像特征：非对称性黑质（93．94％），纹状体（69．70％），丘脑（36．36％）代谢减低，非对称性纹状体或丘脑代 谢轻度增高，占15．15％，非对称性大脑各叶代谢下降，其中以颞叶（51．52％），额叶（39．39％），海马（45．46％）为著，非对称性额叶，颞叶，海马代谢轻度增高占9．09％，结论：在除外脑内结构特异性损害基础上，18F－FDG，PET发现单侧或不对称性双侧黑质，经纹体，丘脑代谢减低或轻度增高有助PD的早期诊断。     

AD型与非AD型变性痴呆大脑葡萄糖代谢的SPM分析

目的 探讨阿尔茨海默病(AD)型与非AD型变性痴呆患者的大脑葡萄糖代谢特征.方法 对23例AD患者、24例非AD型变性痴呆[包括9例帕金森病痴呆(PDD)、7例额颞痴呆(FTD)及8例路易体痴呆(DLB)]患者及40名健康对照者进行静息状态下的18F-脱氧葡萄糖(FDG)PET脑显像.结果 采用统计参数图(SPM)法进行基于体素水平分析.结果 (1)AD组:AD患者大脑葡萄糖代谢较对照组减低的脑区包括双侧颞-顶联合皮质区、额叶、楔前叶及后扣带回等部位.(2)非AD型变性痴呆组:FTD组大脑葡萄糖代谢较对照组减低的脑区包括双侧额叶、顶叶、岛叶、扣带回及左侧楔前叶、右侧皮质下结构等部位,以双侧额叶及皮质下结构为著;PDD组大脑葡萄糖代谢较对照组减低的脑区包括双侧额叶、颞-顶联合皮质区及皮质下结构,如基底节、丘脑等部位;DLB组大脑葡萄糖代谢较对照组减低的脑区包括双侧枕叶、楔前叶、额叶、顶叶及左侧前扣带回、右侧颞叶及皮质下结构如基底节、丘脑等部位,以双侧颞-顶-枕叶联合皮质区为著.结论 AD型与非AD型变性痴呆的大脑葡萄糖代谢特征不同,18F-FDG PET脑显像可为临床诊断及鉴别诊断神经变性痴呆提供依据.     

阿尔茨海默病与血管性痴呆的18 F-FDG PET脑显像

目的　观察18F 脱氧葡萄糖 (FDG)PET脑显像鉴别诊断阿尔茨海默病 (AD)与血管性痴呆 (VD)的价值。方法　分别对 10例AD、11例VD及 12例对照者进行18F FDGPET脑显像 ,采用统计参数图 (SPM)方法及感兴趣区 (ROI)方法进行分析 ,比较AD及VD的显像特点。结果　SPM图像显示 ,AD组患者两侧大脑皮层顶叶、颞叶、额叶及后扣带回等部位葡萄糖代谢明显降低 ,左、右不对称 ;而两侧皮层下基底节区等结构代谢不受影响。VD组患者代谢弥漫性降低 ,遍及大脑皮层及皮层下结构。ROI分析表明 ,AD组患者大脑皮层顶叶、颞叶、额叶放射性降低 ,差异有显著性 (P <0 0 5 ) ,皮层下神经核团等无明显变化。而VD组患者仅左侧额叶及右侧壳核放射性降低 ,差异有显著性 (P <0 0 5 )。结论　PET脑显像可有效诊断AD并鉴别诊断AD与VD。     

正常人脑局部葡萄糖代谢随年龄变化的PET表现

目的 利用18F-脱氧葡萄糖(FDG)PET/CT脑代谢显像和统计参数图(SPM)软件研究正常人脑局部葡萄糖代谢随年龄变化的趋势.方法 收集本中心252名行18F-FDG PET/CT全身健康体格检查者(21～88岁)的PET脑图像,按年龄分成6组(21～70岁以10岁为1个年龄段分5个组,71～88岁归为1个组).采用SPM软件将≥31岁的各年龄段PET脑图像数据均与21～30岁年龄段作比较,用MNI space utility(MSU)定位软件对差异有统计学意义的像素簇进行立体定位,并计算各葡萄糖代谢减低脑区的体素值.统计学差异以P＜0.0001为界值.结果 SPM及MSU分析显示:以21～30岁年龄段作参照,60岁及其以前各年龄段脑葡萄糖代谢无明显减低;60岁以后(＞60岁)代谢减低进程显著加快,涉及双侧额叶(主要是前运动皮质和前额叶背外侧及额极)、颞叶(主要是颞极)、岛叶、前扣带回及小脑,其中额叶代谢减低最明显,其次是前扣带回、颞叶、岛叶、小脑,且均以右侧半球代谢减低为显著;而顶叶、海马旁回、基底节及丘脑随年龄增长代谢减低不明显.结论 正常人脑老化表现出代谢功能非匀速性及非对称性地减低特征.60岁及以前脑代谢功能减退不明显,60岁以后(＞60岁)双侧额叶、颞叶、岛叶、前扣带回及小脑代谢功能迅速减退,且右侧半球减退比左侧半球明显.     

海洛因海绵状白质脑病的PET影像表现

目的　本研究旨在阐述海洛因所致的海绵状白质脑病的PET影像表现及其诊断价值。方法　海洛因海绵状白质脑病患者 6例 ,均为男性 ,年龄 2 6～ 3 7岁 ,平均 3 0 .4岁。临床表现为不同程度的小脑共济失调 ,构音障碍 ,反应迟钝 ,并且进行性加重。既往均曾吸食海洛因史 1～ 3年 ,有 2例就诊时已戒毒 1.5～ 3个月。吸毒方式均为通过铝箔加热经鼻吸入海洛因蒸汽。以上 6例患者经CT及MRI检查均有特征性表现 ,其中 2例经活检病理证实为脑白质海绵状变性。6例患者均进行常规 18F -FDGPET脑3D显像 ,其中有 1例于 18F -FDGPET检查完第 2天进行 13 N -NH3 PET脑血流灌注显像。结果　18F -FDGPET代谢显像 6例患者均有不同程度的大脑双侧内囊后肢及双侧小脑白质对称性放射性稀疏或缺损 ,大脑双侧枕叶及双侧小脑皮质见对称性放射性减低影。其中 1例 13 N -NH3 PET脑血流灌注显像白质改变与 18F -FDGPET显像所见基本一致 ,还可见双侧枕叶、双侧额叶、双侧颞叶部分皮质放射性明显减低影 ,其中双侧枕叶呈对称性改变。结论　海洛因白质脑病PET影像表现有一定特点 ,结合吸毒史有助于海洛因白质脑病的诊断     

阿尔茨海默病患者脑葡萄糖代谢变化PET/CT研究

目的 探讨阿尔茨海默病(AD)患者脑区葡萄糖代谢变化特征及意义.方法 依据临床诊断标准纳入AD患者17例(AD组),同时选择基本特征匹配的15例健康志愿者做对照(HC组),2组患者均行18 F-FDG PET脑显像,计算机处理获得三维重建图像.采用视觉分析、感兴趣区(ROI)技术与脑功能分析软件对2组PET图像进行统计分析.结果 ①AD患者葡萄糖代谢减低主要累及顶叶、颞叶、额叶皮质、后扣带回和海马,不累及枕叶、基底核、丘脑和小脑,不影响躯体感觉和运动功能.②与轻度AD比较,中重度AD顶叶、颞叶、额叶、后扣带回和海马区葡萄糖代谢减低程度更为显著,范围也有所扩大,部分患者可累及视觉与语言中枢.③系统自带脑代谢分析软件较视觉评价和ROI分析技术更加客观,精细度更高,能够精确反映脑区葡萄糖代谢变化,适合推广应用.结论 AD患者大脑皮层葡萄糖代谢减低区分布具有一定特点和规律,18 F-FDG PET显像对于AD的诊断、鉴别诊断与疗效评价有一定意义.     

偏侧帕金森病患者葡萄糖代谢与多巴胺转运蛋白PET显像

目的 评价葡萄糖代谢与多巴胺转运蛋白PET显像在偏侧帕金森病(PD)患者诊断中的价值。方法 正常对照组16例。偏侧PD患者34例，Hoehn—YahrⅠ～Ⅱ级。其中16例偏侧(右侧肢体)PD患者进行^18F—脱氧葡萄糖(FDG)PET显像，18例偏侧(右侧或左侧)PD患者进行^18F-N—(3—氟丙基)—2β—甲酯基—3β—(4′—碘苯基)去甲基托烷(FP—β—CIT)显像，6例患者同时进行两种显像。静脉注射^18F—FDG 185～259MBq 30min后进行脑三维采集，结果应用感兴趣区(ROI)半定量分析和统计参数地图(SPM)分析。^18F—FP—β—CIT显像于注射后2～3h进行，计算(各ROI计数—小脑计数）小脑计数比值。结果 PD组与对照组比较，患侧肢体对侧基底节葡萄糖代谢减低，但差异无显著性。SPM分析结果示，PD患者与对照组比较，葡萄糖代谢减低位于左侧前额叶、中额叶、下额叶及左侧中颞叶，而摄取增加区域除双侧额叶中央前回、双侧顶叶楔前叶、左侧枕叶外，还累及左侧丘脑。偏侧PD患者豆状核后部^18F—FP—β—CIT摄取显著减低，且不仅见于症状对侧豆状核，同侧豆状核后部也可见摄取减低。结论 ^18F—FDG PET显像对PD的早期诊断无特异性。^18F—FP—β—CIT可早期发现PD纹状体多巴胺转运蛋白的变化，有助于PD的早期诊断和鉴别诊断；与^18F—FDG PET显像结合，可显示大脑皮层的葡萄糖代谢变化。     

一氧化碳中毒迟发脑病患者高压氧综合治疗前后脑葡萄糖代谢的变化

目的 观察一氧化碳中毒迟发脑病高压氧综合治疗前后患者脑葡萄糖代谢的变化,探讨高压氧综合治疗的作用.方法 一氧化碳中毒迟发脑病(DNS)患者30例(DNS组),高压氧综合治疗前及治疗40次后分别接受18F标记的脱氧葡萄糖正电子发射断层扫描(18F-FDG PET)检查,同时对17例年龄匹配的健康体检者(对照组)进行18F-FDG PET检查.记录DNS组与对照组的双侧额叶、顶叶、颞叶、枕叶与同侧小脑单位面积的放射性计数;计算双侧额叶、顶叶、颞叶、枕叶与同侧小脑单位面积放射性计数的比值,以此比值作为PET研究的半定量观察指标.结果 DNS组高压氧综合治疗前双侧的额/小脑、顶/小脑、颞/小脑、枕/1h脑的比值明显低于对照组(P＜0.05);高压氧综合治疗40次后,双侧的顶/小脑、枕/小脑、左侧颞/小脑的比值明显高于治疗前(P＜0.05),双侧的额/小脑及右侧颞/小脑比值较治疗前无明显变化(P＞0.05).结论 DNS患者发病初期脑葡萄糖代谢下降,高压氧综合治疗可提高脑部葡萄糖代谢,改善脑功能.     

^18F—FDG PET脑显像在癫痫图型，病灶定位及预后预测中的价值

目的 分析各种癫痫患者的^18F－脱氧葡萄糖（FDG）PET图像与致痫灶的关系,以期术前较准确地定位,选择手术适应证和预测疗效。方法 73例癫痫患者（男51例,女22例,平均年龄23．3岁）行FDG PET脑显像,并与同期脑电图和MRI结果进行比较,40例进行了手术疗效随访,其中8例术后复查了FDG PET,并比较FDG PET,视频脑电图（VEEG）,MRI对致痫灶术前定位的准确性及脑代谢改变的不同图型与手术疗效的关系,结果（1）72 例癫痫患者发作间期皮层局灶为低代谢表现,仅1例部分癫痫持续状态者表现出发作期的高代谢。（2）FDG PET病变定侧率高于VEEG,低代谢灶检出率高于MRI,（3）40例手术患者中,属于Engels疗效分级I,II级的30例手术切除部位应为确定的致痫灶,FDG PET＜VEEG与MRI定侧定位准确性分别为93．3％,73．3％,53．3％,经X2检验,差异有显著性（P＜0．05）,（4）单侧颞叶低代谢手术效果好;对部分双侧颞叶低代谢者,切除其代谢减低更严重的一侧,发作也会改善,颞叶外癫痫手术效果不如颞叶癫痫好,病灶局限者,手术效果优于伴有其他部位皮层代谢改变者：单侧多脑叶代谢改变者,半大脑切除术效果好;双侧大脑多脑叶弥漫性病变者,手术效果差。结论 FDG PET对癫痫灶定位的灵敏度和准确性优于VEEG和形态学影像技术。FDG PET的代谢图形可帮助临床医生确定病灶部位,选择手术适应证和预测疗效。     

FDG PET imaging in patients with pathologically verified dementia.

The purpose of this study was to confirm with pathologic verification 2 beliefs related to Alzheimer's disease (AD): (a) the long-standing impression that bilateral temporo-parietal hypometabolism, as noted on FDG PET imaging, is the metabolic abnormality associated with Alzheimer's disease (AD) and (b) that the sensitivity, specificity, and diagnostic accuracy of the metabolic pattern of bilateral temporo-parietal hypometabolism allows differentiation between other degenerative causes of dementia. METHODS: Twenty two individuals (8 women, 14 men) with difficult-to-characterize memory loss or dementia (using standard clinical criteria), and who eventually received pathologic confirmation of diagnosis, were evaluated. FDG PET brain scans were obtained and visually graded by an experienced nuclear medicine physician as to the presence of classic bilateral temporo-parietal hypometabolism as seen in Alzheimer's type dementia. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of the metabolic pattern of bilateral temporo-parietal hypometabolism were determined using pathologic diagnosis as the gold standard. RESULTS: The clinical diagnosis of possible or probable AD was determined as the primary cause of dementia in 12 patients. The sensitivity and specificity of the clinical diagnosis for probable AD were 63% and 100%, respectively. The sensitivity and specificity of the clinical diagnosis for possible and probable AD were 75% and 100%, respectively. The sensitivity, specificity, and diagnostic accuracy of bilateral temporo-parietal hypometabolism being associated with AD were 93%, 63%, and 82%, respectively. CONCLUSION: This study confirms that bilateral temporo-parietal hypometabolism is indeed the classic metabolic abnormality associated with AD. Furthermore, in individuals with dementia whose FDG PET scans indicated a metabolic pattern other than bilateral temporo-parietal hypometabolism, a cause of dementia other than AD should be suspected. These observations may be of clinical importance in differentiating dementia syndromes. The sensitivity, specificity, and diagnostic accuracy of FDG PET are acceptable as tests to be used in the evaluation of dementia and particularly to confirm the clinical suspicion of AD.     

(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.     

Comparison of I-123 IMP and Tc-99m HMPAO SPECT studies with PET in dementia

We compared I-123 IMP and 99m-Tc HMPAO SPECT studies with 0-15 H2O and F-18 FDG PET studies, and evaluated the clinical significance of SPECT studies in dementia. Seventeen patients including 9 patients with Alzheimer's disease, 3 patients with Pick's disease and 5 patients with multi-infarct dementia were studied. IMP and HMPAO SPECT studies could not detect mildly affected areas when compared with FDG PET. However, they revealed decreased perfusion in the bilateral parietal regions in Alzheimer's disease and in the bilateral frontal regions in Pick's disease, while MRI and/or CT showed mild to moderate cerebral atrophy. IMP and HMPAO SPECT studies can be easily performed in clinical practice, and these findings were useful in the differential diagnosis of dementia. Our preliminary results suggested that SPECT studies with I-123 IMP and Tc-99m HMPAO, despite their limitations, are useful in the differential diagnosis of dementia.     

晚期帕金森病患者脑内18F-FDG摄取变化及其异常脑内环路机制的探讨

目的　用1 8F 脱氧葡萄糖 (FDG)PET显像显示晚期帕金森病患者异常的脑内环路。方法　对 10例双侧症状的晚期帕金森病患者和 10例正常人分别行静息状态下1 8F FDGPET显像 ,用统计参数图 (SPM)方法对晚期帕金森病患者和正常人的PET图像进行组间t检验分析 ,比较 2组间脑内葡萄糖代谢的差异。结果　与正常人相比 ,帕金森病患者双侧丘脑、海马、中央前回皮质 (Brodmann6区 ,BA6 )及豆状核代谢增加 (P <0 0 0 1) ;前额叶运动区 (BA4 6、BA4 7)及顶叶 (BA7、BA39)代谢减低(P <0 0 0 1)。结论　帕金森病脑内异常代谢环路的显示有助于帕金森病的辅助诊断及其发病机理的探讨。     

Positron emission tomography imaging of regional cerebral glucose metabolism

The (F-18) fluorodeoxyglucose (FDG) technique to measure local cerebral metabolic rate for glucose (LCMRglu) is well accepted and widely used by many institutions around the world. A large number of studies has been carried out in normal volunteers and patients with a variety of CNS disorders. Several investigators have noted that no significant age-related changes in cerebral glucose use occur with normal aging. Some important and interesting findings have been revealed following sensory, motor, visual, and auditory stimulations. Functional imaging with FDG in certain neurologic disorders has dramatically improved our understanding of their underlying pathophysiologic phenomena. Some abnormalities detected on the positron emission tomography (PET) images have no corresponding changes on either x-ray computed tomograms (XCT) or magnetic resonance images (MRI). In patients with Alzheimer's disease, primary sensorimotor, visual, and cerebellar metabolic activity appears relatively preserved. In contrast, parietal, temporal, and to some degree, frontal glucose metabolism is significantly diminished even in the early stages of the disease. Patients with Huntington's disease and those at risk of developing this disorder have a typical pattern of diminished CMRglu in the caudate nuclei and putamen. In patients with stroke, PET images with FDG have demonstrated abnormal findings earlier than either XCT or MRI and with a wider topographic distribution. FDG scans have revealed interictal zones of decreased LCMRglu in approximately 70% of patients with partial epilepsy. The location of the area of hypometabolism corresponds to the site of the epileptic focus as determined by electroencephalography and microscopic examination of the resected tissue. Ictal scans during partial seizures demonstrate areas of hypermetabolism corresponding to the sites of seizure onset and spread. Several investigators have reported relative hypofrontal CMRglu in patients with schizophrenia. In our center, FDG scans from patients with schizophrenia were successfully differentiated from those obtained in normal controls. Finally, our preliminary data (using PET, XCT, and MRI) in patients with CNS disorders indicate that MRI provides excellent delineation of the structural abnormalities. It may prove to be superior to XCT in the evaluation of certain diseases such as cerebral ischemia and infarcts, head injury, tumors, and white matter lesions. Metabolic imaging with FDG provides functional information not obtainable with either MRI or NMR spectroscopy. Therefore, PET studies will play a complementary role to the anatomic imaging in the management of patients with CNS disorders.     

N-isopropyl I-123 p-iodoamphetamine (IMP) brain SPECT in Alzheimer's disease

Eighteen patients with Alzheimer's disease (AD), 5 patients with Pick disease (PD), 6 patients with other types of degenerative dementia (O) and 12 age-matched normal control subjects (N) were studied using N-isopropyl p-[I-123]iodoamphetamine (I-123 IMP) with SPECT. Regional to cerebellar activity (R/CE) ratio and frontal to parietal (F/P) activity ratio were evaluated in each case. I-123 IMP-SPECT revealed focal abnormality in all cases in AD, PD, O group, while XCT and/or MRI were normal or showed cerebral atrophy without focal abnormal density or intensity. In AD group, R/CE ratio in all the regions except for bilateral Rolandic area and left primary visual cortex were significantly lower (p less than 0.05 or p less than 0.01) than that in N group, and F/P ratio were significantly higher (p less than 0.01) than that in P and O group. In conclusion, I-123 IMP-SPECT is useful to detect focal perfusion abnormality in dementia and may be of value in differentiating Alzheimer's disease from dementia of non-Alzheimer type.     

阿尔茨海默病等痴呆疾病的脑功能影像学研究

痴呆类疾病可分为阿尔茨海默病(AD)、皮克病、多发性梗死性痴呆(MID)等类型,它们各具不同的临床特点。神经心理学检查对痴呆的诊断及鉴别诊断起一定作用。AD等痴呆疾病的神经影像学发展越来越迅速,其中18F-FDG PET脑功能显像技术可以早期发现AD患者大脑皮层顶、颞叶等区域葡萄糖代谢率降低,并且左、右半球不对称。18F-FDG PET方法还可以鉴别诊断AD与其他痴呆类疾病。     

Extratemporal hypometabolism on FDG PET in temporal lobe epilepsy as a predictor of seizure outcome after temporal lobectomy

We investigated the relationship between the presence of extratemporal hypometabolism on fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) and seizure outcome after temporal lobectomy in patients with medically intractable temporal lobe epilepsy (TLE). In 47 patients with intractable unilateral mesial TLE, regional metabolic changes on FDG PET images obtained during the 2 months preceding anterior temporal lobectomy were compared with postoperative seizure outcome. Postoperative seizure outcome was evaluated with a mean follow-up period of 6.1+/-0.6 years (range 5.2-7.2 years). Forty-two (89%) of the 47 patients achieved a good postoperative seizure outcome (Engel class I or II). All patients had hypometabolism in the temporal cortex ipsilateral to the epileptogenic region on FDG PET scans. Fourteen (78%) of the 18 patients with hypometabolism only in the ipsilateral temporal cortex were completely seizure free (Engel class Ia) after surgery. In contrast, five (45%) of the 11 patients with extratemporal cortical hypometabolism confined to the ipsilateral cerebral hemisphere and only four (22%) of the 18 patients with hypometabolism in the contralateral cerebral cortex were completely seizure free after surgery. The postoperative seizure-free rates were significantly different across the three groups of patients with different cortical metabolic patterns ( P<0.005). Furthermore, all of the nine patients with a non-class I outcome (Engel class II-IV) had extratemporal (including contralateral temporal) cortical hypometabolism. Thalamic hypometabolism was noted in 20 (43%) of the 47 patients (ipsilateral in 12, bilateral in 8). Sixteen (59%) of the 27 patients with normal thalamic metabolism were completely seizure free after surgery, while only seven (35%) of the 20 patients with thalamic hypometabolism became completely seizure free ( P<0.05). Multivariate analysis revealed that among variables including clinical, EEG, magnetic resonance imaging, pathological and FDG PET metabolic findings, only cortical metabolic pattern was an independent factor for the prediction of postoperative seizure outcome ( P<0.005). It is concluded that extratemporal cortical hypometabolism outside the seizure focus, in particular hypometabolism in the contralateral cerebral cortex, may be associated with a poorer postoperative seizure outcome in TLE and may represent underlying pathology that is potentially epileptogenic. Thalamic hypometabolism, which was associated, but not independently, with a higher likelihood of postoperative seizures, may be secondary to extratemporal or temporal pathology.