Single-Phase CT Aligned to Gated PET for Respiratory Motion Correction in Cardiac PET/CT
Single-Phase CT Aligned to Gated PET for Respiratory Motion Correction in Cardiac PET/CT
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DOI：
10.2967/jnumed.109.070011
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发表时间：
2010-08-01
影响因子：
9.3
通讯作者：
Beanlands, Rob S.
中科院分区：
文献类型：
--
作者：
Wells, R. Glenn;Ruddy, Terrence D.;Beanlands, Rob S.
由于CT衰减图和发射数据的配准不良，呼吸运动会在心脏PET/CT中诱发伪影。呼吸运动问题的一些解决方案使用4维CT，但这增加了患者的辐射暴露。三维CT和PET图像的重新对准可以消除由PET发射数据在CT扫描上的肺部区域中的错误定位引起的明显摄取缺陷。这种重新调整通常作为定期临床质量保证的一部分进行。我们评估了一种方法，通过采集呼吸门控PET扫描并分别将三维CT扫描与PET研究的每个阶段对齐，在不增加患者辐射暴露的情况下改进了该标准方法。方法：回顾性评估了310例临床PET灌注扫描（82例Rb [n = 187]和13例N-氨[n = 123]）。研究是呼吸门控的，在吸气和呼气阶段之间测量运动。对于运动>= 8 mm的研究，评价了吸气和呼气之间的显著差异。具有显著差异的研究用相位对准方法重新处理。还比较了（82）Rb和（13）N-氨在静息和应激成像中观察到的运动。结果如下：23次扫描（7.41%）的运动>= 8 mm，其中9次在吸气和呼气之间存在显著差异，表明存在呼吸伪影。相位对齐的呼吸运动补偿减少了9例中的8例（89%）的这种差异。（82）Rb与（13）N-NH3之间无显著性差异，运动负荷显像与静息运动负荷显像相关（r = 0.61，P < 0.001）。结论：相位校正通过减少呼吸运动引起的差异，提高了PET/CT灌注图像的一致性。这种基于CT的衰减校正的新方法没有额外的患者辐射暴露，并且可以提高PET灌注成像的特异性。
Respiratory motion can induce artifacts in cardiac PET/CT because of the misregistration of the CT attenuation map and emission data. Some solutions to the respiratory motion problem use 4-dimensional CT, but this increases patient radiation exposure. Realignment of 3-dimensional CT and PET images can remove apparent uptake defects caused by mispositioning of the PET emission data into the lung regions on the CT scan. This realignment is typically done as part of regular clinical quality assurance. We evaluated a method to improve on this standard approach, without increasing the radiation exposure to the patient, by acquiring a respiration-gated PET scan and separately aligning the 3-dimensional CT scan to each phase of the PET study. Methods: Three hundred ten clinical PET perfusion scans ((82)Rb [n = 187] and (13)N-ammonia [n = 123]) were retrospectively assessed. Studies were respiration-gated, and motion was measured between inspiration and expiration phases. Those studies with motion >= 8 mm were evaluated for significant differences between inspiration and expiration. Studies with significant differences were reprocessed with the phase-alignment approach. The observed motion with (82)Rb and (13)N-ammonia for rest and stress imaging was also compared. Results: Twenty-three scans (7.41%) had motion >= 8 mm, and 9 of these had significant differences between inspiration and expiration, suggesting the presence of respiratory artifacts. Phase-aligned respiratory motion compensation reduced this difference in 8 of 9 cases (89%). No significant differences were observed between (82)Rb and (13)N-ammonia, and motion during stress imaging was correlated with motion at rest (r = 0.61, P < 0.001). Conclusion: Phase-aligned correction improves the consistency of PET/CT perfusion images by reducing discrepancies caused by respiratory motion. This new approach to CT-based attenuation correction has no additional patient radiation exposure and may improve the specificity of PET perfusion imaging.