不同程度阿尔茨海默病PET脑代谢减低的SPM研究

目的 以统计参数图(SPM)为方法、其输出的脑代谢减低范围大小为指标,探讨不同程度阿尔茨海默病(AD)患者PET显像脑葡萄糖代谢减低区的大小和范围.方法 AD组27例,均符合精神障碍诊断和统计工作手册(DSM-Ⅳ-R)中的AD诊断标准,行简易智能量表(MMSE)检查.根据MMSE评分将AD组分为轻度、中度和重度组,每组各9例.对照组9名,均为健康体格检查者.所有受检者静脉注射18F-脱氧葡萄糖(FDG)后行PET三维脑显像.在Matlab 6.5平台上,用SPM2软件对得到的PET图像进行预处理,设P值阈值为0.001,将全部AD患者以及轻、中、重度3个AD患者组分别与对照组进行组间统计分析.结果 与对照组比较,AD组于双侧顶叶、颞叶、额叶及扣带回出现代谢减低区,以k值(即满足P值要求的每一"块"异常脑区的像素值)为指标测量,轻度组减低区k值为929,其中额叶减低区k值为174;中度组k值为6743,额叶减低区k值为2712;重度组k值为24 678,额叶减低区k值为4981.脑白质及脑内灰质核团未见代谢减低.结论 使用SPM,以k值为指标,可对不同程度AD患者脑代谢减低区大小进行评价.随痴呆程度加重,受累脑区范围增加,额叶晚期受累严重.     

图像重建条件对PET脑显像SPM分析结果的影响

目的 探讨不同图像重建条件对^18F—FDG PET脑显像统计参数图（SPM）处理结果的影响。方法对6名健康受试者分别实施真、假针刺条件下的^18F-FDG PET脑显像。分别用4种重建条件进行图像重建。对每一重建结果均用SPM软件进行对齐、归一化及平滑处理，并进行配对t检验。结果 （1）SPM校正多重比较（P校正〈0．05）的统计学处理示，4种条件的重建结果中无一像素超阈值激活；（2）SPM未校正多重比较（P未校正〈0．001）的统计学处理示，4种重建条件的SPM结果不一致。2种重建算法（滤波反投影法和有序子集最大期望值迭代法）间差异最明显，不仅激活的像素总数及区域个数有差异，激活区的空间位置也大多不一致。结论 PET图像重建条件对SPM未校正多重比较的统计学处理结果有影响，下结论要慎重。     

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.     

贫血患者大脑静息葡萄糖代谢改变的研究

目的 探讨不同程度贫血患者大脑静息状态下葡萄糖代谢改变的特点。 方法 回顾性分析2016年12月至2019年4月经郑州大学人民医院临床诊断为贫血的51例患者的脑部18F-氟脱氧葡萄糖（FDG）PET/CT影像资料,其中男性16例、女性35例,年龄21~60（41.13±9.78）岁。根据WHO和相关文献中的贫血诊断标准将患者分为轻度贫血（90 g/L~正常下限）、中度贫血（60~90 g/L）、重度贫血（30~60 g/L）3组。将56名同期行全身PET/CT检查的健康体检者作为对照组,其中男性29名、女性27名,年龄19~58（41.96±9.27）岁。采用统计参数图（SPM）8软件对贫血患者及健康对照者的PET图像进行处理与分析。分别将贫血患者与健康对照者,轻度、中度、重度贫血患者间的脑PET图像进行体素对体素的两独立样本t检验,得到各自组间的脑葡萄糖代谢差异分布图,同时利用xjView软件对差异有统计学意义的脑区进行立体定位分析及体素值定量分析,得出各异常区域的t值。 结果 与健康对照者比较,贫血患者脑PET图像表现为区域性大脑静息葡萄糖代谢减低,累及的脑区包括双侧额上、中、下回,右侧颞叶下回和右侧顶下小叶,未见明显代谢增高脑区,总体素数为3705个（t=5.01~5.85,均P<0.05）。与轻度贫血患者比较,中度贫血患者脑代谢减低区见于双侧额下回、右侧额中回、右侧颞叶下回和右侧顶下小叶,总体素数为832个（t=5.22~5.86,均P<0.05）;重度贫血患者脑代谢减低区见于双侧额上回、双侧额中下回、右侧颞叶下回和右侧顶下小叶,总体素数为1834个（t=5.42~6.05, 均P<0.05）。与中度贫血患者比较,重度贫血患者脑代谢减低区见于左侧额上回、左侧额中下回、右侧额中回、右侧颞叶下回和右侧顶下小叶,总体素数为1598个（t=5.72~6.48,均P<0.05）。 结论 贫血患者大脑静息状态下葡萄糖代谢改变以区域性葡萄糖代谢减低为主,代谢减低区多涉及情感、认知等相关的脑区,且随着贫血程度的加重,脑代谢减低区的范围扩大。     

MicroPET显像测定小鼠心肌葡萄糖摄取及代谢率的实验条件分析

目的 建立适合的microPET测定小鼠心肌葡萄糖代谢率(MRGlu)的实验方法和条件,并评价该方法的可行性.方法 控制温度在30～ 34℃,取正常进食的野生型BKS小鼠20只,按随机数字表法分为不同异氟烷体积分数(1.3％、1.5％、1.8％和2.0％)麻醉组,观察小鼠呼吸频率及存活状态,获得最佳浓度;另取BKS小鼠20只,在最佳异氟烷浓度麻醉下,注射不同体积(0、75、150、300 μl)生理盐水,观察各组小鼠血糖变化,获得最适宜注射体积.取BKS小鼠6只,在最佳异氟烷浓度麻醉下,注射最适宜体积18 F-FDG,对小鼠心肌行microPET显像,通过勾画ROI获取心肌TAC,计算SUV.同时,经小鼠尾静脉多点采血获取尾静脉TAC,利用输入函数数学模型显像分析系统,获得代谢速率常数k1,k2,k3,k4,计算心肌MRGlu:MRGlu=Ki ×Glu/LC[Ki=k1×k3/(k2+k3),Glu为平均血糖浓度,LC为集总常数(心肌取1)].数据比较采用单因素方差分析和q检验.结果 小鼠在正常进食的情况下,以体积分数1.5％～1.8％异氟烷麻醉,小鼠呼吸频率在80次/min以上,无任何体位移动.注射生理盐水75μl组小鼠在不同时间点的血糖与不注射生理盐水相比,差异均无统计学意义(F=1.215,P＞0.05).150μl组小鼠血糖在30 min(q=2.485,P=0.024)、45 min(q=2.287,P=0.036)、60 min(q=2.709,P=0.015)与0μl组差异均有统计学意义;300ul组小鼠血糖在45 min(q=2.435,P=0.027)与0山组差异有统计学意义.18F-FDG注射体积≤75止、剂量为7.4～11.1 MBq时,micro-PET显像可获得小鼠相对接近生理状态下的清晰稳定图像,45～55 min小鼠心肌SUV中位数为11.88(范围9.71～14.93),K值中位数为0.19(范围0.10～0.54) ml·min-1·g-1,MRGlu值中位数为19.64(范围5.55～23.28) mg·kg-1· min-1.结论 在microPET18F-FDG显像评估小鼠心肌葡萄糖摄取及代谢率过程中,适宜异氟烷麻醉体积分数为1.5％～1.8％,18F-FDG注射体积需≤75 μl;该方法切实可行.     

短暂性脑缺血发作患者脑血流灌注和葡萄糖代谢显像的影像分析

目的:通过观察单侧或以单侧血管受累为主的短暂性脑缺血发作患者的脑血流灌注和葡萄糖代谢的变化,了解不同发病时期脑血流灌注及葡萄糖代谢的特点。方法:将27例患者根据发病时间不同分为急性期、亚急性期及慢性期三组,比较三组患者的脑血流灌注显像及脑葡萄糖代谢显像的结果。将27例患者按照有无侧枝代偿分为两组,比较侧枝代偿与脑损伤的关系。结果:三组中脑血流灌注和葡萄糖代谢均减低的患者占51.85%,除此之外,血流灌注和葡萄糖代谢还可表现为增高、正常或接近正常。有无侧枝代偿两组患者间脑受累程度分布无显著差异(χ2=6.750,P=0.009)。结论:低灌注、低代谢是脑缺血患者的主要表现,检查距发病时间长短及是否有侧枝循环建立与灌注及代谢变化有关。     

混合型多系统萎缩病程与脑葡萄糖代谢相关性研究

目的探讨混合型多系统萎缩（MSA）病程与脑葡萄糖代谢之间的关系。方法46例符合Gilman诊断标准的混合型MSA患者,按病程分为3组：组1（14例）,病程≤12个月;组2（13例）,病程13～24个月;组3（19例）,病程≥25个月。另选择年龄匹配的对照组18名（均为体格检查健康者）。所有纳入对象均行头部^18F—FDGPET／CT动态显像。应用SPM8软件将对照组分别与组1、2、3的^18F—FDGPET目标图像行两样本t检验,P〈0．005为差异有统计学意义。结果与对照组相比,在检验水平P〈0．005时,组1低代谢脑区（均t〉3．49）主要位于额叶、颞叶外侧、岛叶、前扣带回、尾状核及小脑前叶;组2低代谢脑区（均t〉3．21）除了上述部位以外,还出现在壳核后部及小脑后叶局部;组3低代谢脑区（均t〉4．08）扩大至双侧壳核及双侧小脑半球。另外,3组患者均存在稳定的高代谢脑区,主要位于顶叶、颞叶内侧及丘脑;组1、组2、组3对应t值范围分别为均f〉3．27、均￡〉3．02、均t〉3．30。结论混合型MSA的病程与脑葡萄糖代谢模式有关。额叶、颞叶外侧、前扣带回及尾状核在病变早期即可受累,随后壳核由后至前逐渐出现代谢减低,而丘脑一直保持高代谢状态。小脑代谢减低由前叶延伸至后叶。^18F—FDGPET／CT可较好反映混合型MSA病变的进展情况。     

~(18)F-FDGPET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AD患者顶颞叶代谢显著低于正常人 ,并与痴呆程度相关。 11例非AD痴呆影像也分 3种 :多发性非对称性放射性减低 8例 ,双侧颞顶叶伴其他多灶性放射性减低 2例 ,显像正常 1例。MRI检查 10例AD可见颞叶、杏仁核、海马体积缩小 ;2例轻度AD虽有代谢减低 ,但MRI未见海马体积缩小。 10例非AD痴呆MRI可见脑内陈旧出血、梗死、软化灶等病灶 ,而这些表现AD患者未见到。结论　在MRI除外脑内结构损害病灶基础上 ,18F FDGPET发现双侧或单侧顶叶或颞顶叶代谢减低可诊断AD ;半定量分析有助于痴呆程度的评价。     

^18F-FDG PET／CT显像全身骨髓代谢弥漫增高原因分析

目的分析^18F—FDG PET／CT所示全身骨髓代谢弥漫性增高临床原因。方法收集2005年8月至2009年11月期间在该院行^18F-FDG PET／CT检查,发现全身骨髓代谢弥漫性增高且已确诊的病例66例,分析影像学表现,并进行临床病程随访和病理结果分析。选择79名健康人作为对照组;分别测量骨髓代谢增高组和对照组的骨髓SUVmax和SUVmean以及纵隔SUVmax和SUVmean,并计算最大值比（SUVmax／纵隔SUVmax）及平均值比（骨髓SUVmean／纵隔SUVmean）,采用单因素方差分析对结果进行分析。结果（1）全身骨髓代谢弥漫l生增高原因有：近期升白细胞药物注射史27例,血液病21例,发热18例。（2）将上述3组及对照组SUVmean比（3．076±1．955,3．633±2．405,2．546±0．791,1．026±0．190）进行方差分析,F=34．465,P〈0．001,差异有统计学意义。健康对照组与3组骨髓代谢增高组进行多重比较,P均〈0．001,提示对照组与骨髓代谢增高组的SUVmean比差异均有统计学意义。（3）根据SUVmean比将骨髓代谢增高的程度分为2级：轻度（SUVmean比2．0—3．0）和重度（SUVmean大于3．0）。（4）3组骨髓代谢弥漫增高组中部分患者会伴有肝脾肿大及代谢增高,较常见的为血液病和发热。结论^18F-FDG PET／CT显像可以较敏感和准确地观察全身骨髓代谢的改变情况,良性和恶性病变均可引起骨髓代谢不同程度增高。     

Wilson病脑局部葡萄糖代谢变化的18F-FDG PET研究

目的 研究肝豆状核变性(即Wilson病,WD)患者脑局部葡萄糖代谢变化特征.方法 对13例伴有神经系统症状的WD患者和12名健康对照者进行脑18F-脱氧葡萄糖(FDG)PET静态显像,采用视觉分析、半定量分析和统计参数图(SPM)分析方法判断FDG PET显像结果.采用SPSS11.0软件进行统计学处理,将WD患者组与健康对照组进行组间统计分析.结果 WD患者FDGPET脑静态显像示双侧豆状核和尾状核放射性摄取较对照组对称性减低,前者比后者更明显;大脑皮质、丘脑、小脑放射性分布基本均匀、对称.WD患者豆状核和尾状核与大脑皮质放射性比值(0.95±0.05和1.02±0.06)明显低于对照组(1.26±0.05和1.17±0.05,t=15和8,P均<0.05),WD组豆状核与尾状核的放射性比值(0.93±0.06)明显低于对照组(1.09±0.06,t=9,P<0.05),丘脑和小脑与大脑皮质放射性比值与对照组差异无统计学意义(WD组:0.99±0.06和0.98±0.06,对照组:1.00±0.05和0.99±0.05;t=0.7和0.8,P均>0.05).结论 WD患者FDG PET脑静态显像特征为双侧豆状核和尾状核放射性摄取对称性减低,豆状核放射性摄取减低程度比尾状核更明显,FDG PET脑静态显像对鉴别诊断表现为神经系统异常的WD患者有价值.     

Voxel-based statistical analysis of cerebral glucose metabolism in the rat cortical deafness model by 3D reconstruction of brain from autoradiographic images

PURPOSE: Animal models of cortical deafness are essential for investigation of the cerebral glucose metabolism in congenital or prelingual deafness. Autoradiographic imaging is mainly used to assess the cerebral glucose metabolism in rodents. In this study, procedures for the 3D voxel-based statistical analysis of autoradiographic data were established to enable investigations of the within-modal and cross-modal plasticity through entire areas of the brain of sensory-deprived animals without lumping together heterogeneous subregions within each brain structure into a large region of interest. METHODS: Thirteen 2-[1-(14)C]-deoxy-D: -glucose autoradiographic images were acquired from six deaf and seven age-matched normal rats (age 6-10 weeks). The deafness was induced by surgical ablation. For the 3D voxel-based statistical analysis, brain slices were extracted semiautomatically from the autoradiographic images, which contained the coronal sections of the brain, and were stacked into 3D volume data. Using principal axes matching and mutual information maximization algorithms, the adjacent coronal sections were co-registered using a rigid body transformation, and all sections were realigned to the first section. A study-specific template was composed and the realigned images were spatially normalized onto the template. Following count normalization, voxel-wise t tests were performed to reveal the areas with significant differences in cerebral glucose metabolism between the deaf and the control rats. RESULTS: Continuous and clear edges were detected in each image after registration between the coronal sections, and the internal and external landmarks extracted from the spatially normalized images were well matched, demonstrating the reliability of the spatial processing procedures. Voxel-wise t tests showed that the glucose metabolism in the bilateral auditory cortices of the deaf rats was significantly (P<0.001) lower than that in the controls. There was no significantly reduced metabolism in any other area, and no area showed a significant increase in metabolism in the deaf rats with the same threshold, demonstrating the high localization accuracy and specificity of the method developed in this study. CONCLUSION: This study established new procedures for the 3D reconstruction and voxel-based analysis of autoradiographic data which will be useful for examining the cerebral glucose metabolism in a rat cortical deafness model.     

SPECT image analysis using statistical parametric mapping in patients with Parkinson's disease.

This study investigated alterations in regional cerebral blood flow (rCBF) in patients with Parkinson's disease using statistical parametric mapping (SPM). METHODS: Noninvasive rCBF measurements using 99mTc-ethyl cysteinate dimer (ECD) SPECT were performed on 28 patients with Parkinson's disease and 48 age-matched healthy volunteers. The Parkinson's disease patients were divided into two groups, 16 patients with Hoehn and Yahr stage I or II and 12 patients with Hoehn and Yahr stage III or IV. We used the raw data (absolute rCBF parametric maps) and the adjusted rCBF images in relative flow distribution (normalization of global CBF for each subject to 50 mL/100 g/min with proportional scaling) to compare these groups with SPM. RESULTS: In patients with stage I or II Parkinson's disease, we found a diffuse decrease in absolute rCBF in the whole brain with sparing of the central gray matter, hippocampus and right lower temporal lobe compared with healthy volunteers. Adjusted rCBF increased in both putamina and the right hippocampus. In patients with stage III or IV disease, rCBF decreased throughout the whole brain. Adjusted rCBF increased bilaterally in the putamina, globi pallidi, hippocampi and cerebellar hemispheres (dentate nuclei) and in the left ventrolateral thalamus, right insula and right inferior temporal gyrus. CONCLUSION: SPM analysis showed that significant rCBF changes in Parkinson's disease accompanied disease progression and related to disease pathophysiology in the functional architecture of thalamocortex-basal ganglia circuits and related systems.     

A comparison of 99mTc-HMPAO SPET changes in dementia with Lewy bodies and Alzheimer's disease using statistical parametric mapping

Differences in regional cerebral blood flow (rCBF) between subjects with Alzheimer's disease (AD), dementia with Lewy bodies (DLB) and healthy volunteers were investigated using statistical parametric mapping (SPM99). Forty-eight AD, 23 DLB and 20 age-matched control subjects participated. Technetium-99m hexamethylpropylene amine oxime (HMPAO) brain single-photon emission tomography (SPET) scans were acquired for each subject using a single-headed rotating gamma camera (IGE CamStar XR/T). The SPET images were spatially normalised and group comparison was performed by SPM99. In addition, covariate analysis was undertaken on the standardised images taking the Mini Mental State Examination (MMSE) scores as a variable. Applying a height threshold of P < or = 0.001 uncorrected, significant perfusion deficits in the parietal and frontal regions of the brain were observed in both AD and DLB groups compared with the control subjects. In addition, significant temporoparietal perfusion deficits were identified in the AD subjects, whereas the DLB patients had deficits in the occipital region. Comparison of dementia groups (height threshold of P < or = 0.01 uncorrected) yielded hypoperfusion in both the parietal [Brodmann area (BA) 7] and occipital (BA 17, 18) regions of the brain in DLB compared with AD. Abnormalities in these areas, which included visual cortex and several areas involved in higher visual processing and visuospatial function, may be important in understanding the visual hallucinations and visuospatial deficits which are characteristic of DLB. Covariate analysis indicated group differences between AD and DLB in terms of a positive correlation between cognitive test score and temporoparietal blood flow. In conclusion, we found evidence of frontal and parietal hypoperfusion in both AD and DLB, while temporal perfusion deficits were observed exclusively in AD and parieto-occipital deficits in DLB.     

Change of diffusion anisotropy in patients with acute cerebral infarction using statistical parametric analysis

Purpose We conducted statistical parametric comparison of fractional anisotropy (FA) images and quantified FA values to determine whether significant change occurs in the ischemic region. Materials and methods The subjects were 20 patients seen within 24 h after onset of ischemia. For statistical comparison of FA images, a sample FA image was coordinated by the Talairach template, and each FA map was normalized. Statistical comparison was conducted using SPM99. Regions of interest were set in the same region on apparent diffusion coefficient (ADC) and FA maps, the region being consistent with the hyperintense region on diffusion-weighted images (DWIs). The contralateral region was also measured to obtain asymmetry ratios of ADC and FA. Results Regions with areas of statistical significance on FA images were found only in the white matter of three patients, although the regions were smaller than hyperintense regions on DWIs. The mean ADC and FA ratios were 0.64 ± 0.16 and 0.93 ± 0.09, respectively, and the degree of FA change was less than that of the ADC change. Significant change in diffusion anisotropy was limited to the severely infarcted core of the white matter. Conclusion We believe statistical comparison of FA maps to be useful for detecting different regions of diffusion anisotropy. This article was presented at a Japan Radiological Society meeting in April 2005     

Decreased cerebral glucose metabolism associated with mental deterioration in multi-infarct dementia

Summary Cerebral glucose metabolism of 18 patients with multi-infarct dementia (MID) and 10 age-matched normal subjects were examined with positron emission tomography and the¹⁸-F-fluoro-deoxy-glucose technique. MID patients had significantly lower glucose metabolism in all the grey matter regions measured and were also characterized by more individuality in metabolic pattern. MID patients were also evaluated as to intelligence quotient (IQ). A positive correlation between IQ as shown by the Tanaka-Binet test and glucose metabolism for the entire grey matter was found. The clinical applicability of this test for predicting cerebral metabolism is discussed.     

Conversion of brain SPECT images between different collimators and reconstruction processes for analysis using statistical parametric mapping

To make it possible to share a normal database in single photon emission computed tomography (SPECT) studies, we developed a new method for converting a SPECT image in one physical condition to that in another condition for data acquisition and reconstruction. A Hoffman 3-dimensional brain phantom experiment was conducted to determine systematic differences between collimators and reconstruction processes. SPECT images for the brain phantom were obtained using fan-beam collimators with scatter and attenuation corrections and using parallel-hole collimators without any correction. Dividing these two phantom images after anatomical standardization by Statistical Parametric Mapping 99 (SPM99) created a 3-dimensional conversion map. This conversion map was applied to convert an anatomically standardized SPECT image using parallel-hole collimators without any correction to that using fan-beam collimators with scatter and attenuation corrections in eleven subjects who underwent sequential SPECT measurements using different collimators after injection of 99mTc ethyl cysteinate dimer. The SPM99 demonstrated adequate validity of this conversion in comparative analyses of these sequential SPECT images with different collimators. This may be a promising approach for further sharing of a normal database in SPECT imaging between different cameras.     

Evaluation of ictal brain SPET using statistical parametric mapping in temporal lobe epilepsy

An automated voxel-based analysis of brain images using statistical parametric mapping (SPM) is accepted as a standard approach in the analysis of activation studies in positron emission tomography and functional magnetic resonance imaging. This study aimed to investigate whether or not SPM would increase the diagnostic yield of ictal brain single-photon emission tomography (SPET) in temporal lobe epilepsy (TLE). Twenty-one patients (age 27.14 +/- 5.79 years) with temporal lobe epilepsy (right in 8, left in 13) who had a successful seizure outcome after surgery and nine normal subjects were included in the study. The data of ictal and interictal brain SPET of the patients and baseline SPET of the normal control group were analysed using SPM96 software. The t statistic SPM?t? was transformed to SPM?Z? with various thresholds of P<0.05, 0.005 and 0.001, and corrected extent threshold P value of 0.05. The SPM data were compared with the conventional ictal and interictal subtraction method. On group comparison, ictal SPET showed increased uptake within the epileptogenic mesial temporal lobe. On single case analysis, ictal SPET images correctly lateralized the epileptogenic temporal lobe in 18 cases, falsely lateralized it in one and failed to lateralize it in two as compared with the mean image of the normal group at a significance level of P<0.05. Comparing the individual ictal images with the corresponding interictal group, 15 patients were correctly lateralized, one was falsely lateralized and four were not lateralized. At significance levels of P<0.005 and P<0.001, correct lateralization of the epileptogenic temporal lobe was achieved in 15 and 13 patients, respectively, as compared with the normal group. On the other hand, when comparison was made with the corresponding interictal group, only 7 out of 21 patients were correctly lateralized at the threshold of P<0.005 and five at P<0.001. The result of the subtraction method was close to the single case analysis on SPM at P<0.05. However, at higher thresholds (P<0.005 and 0.001) the subtraction method was comparable to the SPM results only when individual ictal images were compared with the normal control group, and not when comparison was with the interictal group. It is concluded that SPM is an alternative diagnostic method for the localization or lateralization of the seizure focus in temporal lobe epilepsy and that interictal SPET could be omitted if a normal brain SPET database were to be established. The medical cost of seizure localization would thereby be reduced.     

Evaluation of ictal brain SPET using statistical parametric mapping in temporal lobe epilepsy

An automated voxel-based analysis of brain images using statistical parametric mapping (SPM) is accepted as a standard approach in the analysis of activation studies in positron emission tomography and functional magnetic resonance imaging. This study aimed to investigate whether or not SPM would increase the diagnostic yield of ictal brain single-photon emission tomography (SPET) in temporal lobe epilepsy (TLE). Twenty-one patients (age 27.14LJ.79 years) with temporal lobe epilepsy (right in 8, left in 13) who had a successful seizure outcome after surgery and nine normal subjects were included in the study. The data of ictal and interictal brain SPET of the patients and baseline SPET of the normal control group were analysed using SPM96 software. The t statistic SPM{t} was transformed to SPM{Z} with various thresholds of P<0.05, 0.005 and 0.001, and corrected extent threshold P value of 0.05. The SPM data were compared with the conventional ictal and interictal subtraction method. On group comparison, ictal SPET showed increased uptake within the epileptogenic mesial temporal lobe. On single case analysis, ictal SPET images correctly lateralized the epileptogenic temporal lobe in 18 cases, falsely lateralized it in one and failed to lateralize it in two as compared with the mean image of the normal group at a significance level of P<0.05. Comparing the individual ictal images with the corresponding interictal group, 15 patients were correctly lateralized, one was falsely lateralized and four were not lateralized. At significance levels of P<0.005 and P<0.001, correct lateralization of the epileptogenic temporal lobe was achieved in 15 and 13 patients, respectively, as compared with the normal group. On the other hand, when comparison was made with the corresponding interictal group, only 7 out of 21 patients were correctly lateralized at the threshold of P<0.005 and five at P<0.001. The result of the subtraction method was close to the single case analysis on SPM at P<0.05. However, at higher thresholds (P<0.005 and 0.001) the subtraction method was comparable to the SPM results only when individual ictal images were compared with the normal control group, and not when comparison was with the interictal group. It is concluded that SPM is an alternative diagnostic method for the localization or lateralization of the seizure focus in temporal lobe epilepsy and that interictal SPET could be omitted if a normal brain SPET database were to be established. The medical cost of seizure localization would thereby be reduced.     

Influence of mild hyperglycemia on cerebral FDG distribution patterns calculated by statistical parametric mapping

OBJECTIVE: In clinical cerebral 2-[(18)F]fluoro-2-deoxy-D: -glucose positron emission tomography (FDG-PET) studies, we sometimes encounter hyperglycemic patients with diabetes mellitus or patients who have not adhered to the fasting requirement. The objective of this study was to investigate the influence of mild hyperglycemia (plasma glucose range 110-160 mg/dl) on the cerebral FDG distribution patterns calculated by statistical parametric mapping (SPM). METHODS: We studied 19 healthy subjects (mean age 66.2 years). First, all the subjects underwent FDG-PET scans in the fasting condition. Then, 9 of the 19 subjects (mean age 64.3 years) underwent the second FDG-PET scans in the mild hyperglycemic condition. The alterations in the FDG-PET scans were investigated using SPM-and region of interest (ROI)-based analyses. We used three reference regions: (1) SPM global brain (SPMgb) used for SPM global mean calculation, (2) the gray and white matter region computed from magnetic resonance image (MRIgw), and (3) the cerebellar cortex (Cbll). RESULTS: The FDG uptake calculated as the standardized uptake value (average) in SPMgb, MRIgw, and Cbll regions in the mild hyperglycemic condition was 42.7%, 41.3%, and 40.0%, respectively, of that observed in the fasting condition. In SPM analysis, the mild hyperglycemia was found to affect the cerebral distribution patterns of FDG. The FDG uptake was relatively decreased in the gray matter, mainly in the frontal, temporal, and parietal association cortices, posterior cingulate, and precuneus in both SPMgb-and MRIgw-reference-based analyses. When Cbll was adopted as the reference region, those decrease patterns disappeared. The FDG uptake was relatively increased in the white matter, mainly in the centrum semiovale in all the reference-based analyses. CONCLUSIONS: It is noteworthy that the FDG distribution patterns were altered under mild hyperglycemia in SPM analysis. The decreased uptake patterns in SPMgb-(SPM default) and MRIgw-reference-based analyses resembled those observed in Alzheimer's disease. Under mild hyperglycemia, we can recommend Cbll as the reference region to detect decreased uptake patterns. We should pay special attention to controlling the diet condition, monitoring hyperglycemia, and optimizing the reference region in SPM analysis, particularly in the diagnosis of early Alzheimer's disease in clinical FDG-PET.