van den Heuvel Odile A, Boellaard Ronald, Veltman Dick J, Mesina Catalina, Lammertsma Adriaan A
Clinical PET Centre, VU University Medical Centre, PO Box 7057, 1007 MB Amsterdam, the Netherlands.
Neuroimage. 2003 Aug;19(4):1501-9. doi: 10.1016/s1053-8119(03)00216-7.
Motion-induced misalignment between transmission and emission scans can result in erroneous estimation of regional tissue activity concentrations. If this motion is of a random nature, mismatch between transmission and emission scans is likely to result in diminished signal-to-noise ratios. In the case of task-related motion, however, corresponding systematic reconstruction artefacts may lead to false-positive or false-negative results. The purpose of the present study was to investigate whether implementation of an image registration (IR) method, which allows for motion-corrected attenuation correction, would improve accuracy of H(2)(15)O PET activation studies. To evaluate the performance of this method, phantom studies as well as studies in human subjects were performed. Results were compared with three alternative methods: standard attenuation correction without motion correction, calculated attenuation correction, and no attenuation correction. The phantom measurements showed that, for quantitative assessment of regional activity concentrations, the IR method was superior to the other attenuation correction methods. In a single-subject study with intentional task-related motion during a visual stimulation paradigm, false-positive results, obtained with the standard attenuation correction method, disappeared after attenuation correction using the IR method. Finally, a group analysis of 11 patients indicated that an increase in signal-to-noise ratio was obtained with the IR method. Therefore, in our view, the IR method should be considered as a first choice for attenuation correction in PET activation studies.
发射扫描与透射扫描之间因运动引起的不对准可能会导致对局部组织活性浓度的错误估计。如果这种运动是随机性质的，发射扫描与透射扫描之间的不匹配很可能会导致信噪比降低。然而，在与任务相关的运动情况下，相应的系统性重建伪影可能会导致假阳性或假阴性结果。本研究的目的是调查实施一种允许进行运动校正衰减校正的图像配准（IR）方法是否会提高H(2)(15)O正电子发射断层显像（PET）激活研究的准确性。为了评估该方法的性能，进行了体模研究以及人体研究。将结果与三种替代方法进行比较：无运动校正的标准衰减校正、计算衰减校正和无衰减校正。体模测量结果表明，对于局部活性浓度的定量评估，IR方法优于其他衰减校正方法。在一项单受试者研究中，在视觉刺激范式期间存在故意的与任务相关的运动，使用标准衰减校正方法获得的假阳性结果在使用IR方法进行衰减校正后消失。最后，对11名患者的组分析表明，使用IR方法可提高信噪比。因此，我们认为，在PET激活研究中，IR方法应被视为衰减校正的首选方法。
