Chmielowska J, Coghill R C, Maisog J M, Carson R E, Herscovitch P, Honda M, Chen R, Hallett M
Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892-1428, USA.
J Cereb Blood Flow Metab. 1998 Apr;18(4):433-43. doi: 10.1097/00004647-199804000-00012.
Use of short interscan interval [15O]water positron emission tomography (PET) studies reduces the overall study duration and may allow an increased number of scans for single-subject analysis of unique cases (e.g., stroke). The purpose of this study was to examine how subtraction of residual radioactivity from the previous injection (corrected scan) compared to nonsubtraction (uncorrected scan) in a PET short interscan interval (6 minutes) study affects single-subject and group data analysis using a motor activation task. Two currently widely used analytic strategies, Worsley's method and the SPM technique, were applied. Excellent agreement between activation maps obtained from corrected and uncorrected data sets was obtained both in single-subject analyses performed on data sets from the six normal subjects and three stroke (subcortical infarct) patients, and in group analysis (six normal subjects) within a particular statistical method. The corrected and uncorrected data were very similar in the (1) number of activated brain regions; (2) size of clusters of activated brain voxels; (3) Talairach coordinates of the activated region; and (4) t or Z value of the peak intensity for every significantly activated motor brain structure (both for large activations such as in motor cortex and small activations such as in putamen and thalamus). [15O]Water PET data obtained with a short interscan interval (6 minutes) produce similar results whether or not the background is subtracted. Thus, if injection dose and timing are constant, one can achieve the advantage of a short interscan interval without the added complexity of correcting for background radioactivity.
使用短扫描间隔的[15O]水正电子发射断层扫描（PET）研究可缩短整体研究时间，并可能增加对独特病例（如中风）进行单受试者分析的扫描次数。本研究的目的是探讨在PET短扫描间隔（6分钟）研究中，与不减去（未校正扫描）相比，减去前一次注射的残留放射性（校正扫描）如何影响使用运动激活任务的单受试者和组数据分析。应用了两种目前广泛使用的分析策略，即沃斯利方法和统计参数映射（SPM）技术。在对六名正常受试者和三名中风（皮质下梗死）患者的数据集进行的单受试者分析以及特定统计方法内的组分析（六名正常受试者）中，从校正和未校正数据集中获得的激活图之间都取得了极好的一致性。校正和未校正的数据在以下方面非常相似：（1）激活脑区的数量；（2）激活脑体素簇的大小；（3）激活区域的Talairach坐标；以及（4）每个显著激活的运动脑结构的峰值强度的t或Z值（无论是运动皮层等大激活还是壳核和丘脑等小激活）。无论是否减去背景，以短扫描间隔（6分钟）获得的[15O]水PET数据都会产生相似的结果。因此，如果注射剂量和时间恒定，则可以在不增加校正背景放射性复杂性的情况下实现短扫描间隔的优势。
