Bunyaviroch Tira, Turkington Timothy G, Wong Terence Z, Wilson John W, Colsher James G, Coleman R Edward
Department of Radiology, Nuclear Medicine Section, Duke University Medical Center, Durham, NC 27710, USA.
Mol Imaging Biol. 2008 Mar-Apr;10(2):107-13. doi: 10.1007/s11307-007-0126-z. Epub 2007 Dec 21.
The presence of contrast materials on computed tomography (CT) images can cause problems in the attenuation correction of positron emission tomography (PET) images. These are because of errors converting the CT attenuation of contrast to 511-keV attenuation and by the change in tissue enhancement over the duration of the PET emission scan. Newer CT-based attenuation correction (CTAC) algorithms have been developed to reduce these errors.
To evaluate the effectiveness of the modified CTAC technique, we performed a retrospective analysis on 20 patients, comparing PET images using unenhanced and contrast-enhanced CT scans for attenuation correction. A phantom study was performed to simulate the effects of contrast on radiotracer concentration measurements.
There was a maximum difference in calculated radiotracer concentrations of 5.9% within the retrospective data and 7% within the phantom data.
Using a CTAC algorithm that de-emphasizes high-density areas, contrast-enhanced CT can be used for attenuation mapping without significant errors in quantitation.
计算机断层扫描（CT）图像上造影剂的存在会在正电子发射断层扫描（PET）图像的衰减校正中引发问题。这是由于将CT造影剂的衰减转换为511keV衰减时出现误差，以及在PET发射扫描期间组织增强情况发生变化所致。已开发出更新的基于CT的衰减校正（CTAC）算法来减少这些误差。
为评估改良CTAC技术的有效性，我们对20例患者进行了回顾性分析，比较了使用未增强和增强CT扫描进行衰减校正的PET图像。进行了体模研究以模拟造影剂对放射性示踪剂浓度测量的影响。
回顾性数据中计算出的放射性示踪剂浓度最大差异为5.9%，体模数据中为7%。
使用一种弱化高密度区域的CTAC算法，增强CT可用于衰减映射，且定量时不会出现显著误差。
