Improved Alignment of PET and CT Images in Whole-Body PET/CT in Cases of Respiratory Motion During CT
Improved Alignment of PET and CT Images in Whole-Body PET/CT in Cases of Respiratory Motion During CT
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DOI：
10.2967/jnumed.119.235804
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发表时间：
2020-09-01
影响因子：
9.3
通讯作者：
Mawlawi, Osama
中科院分区：
文献类型：
--
作者：
Hamill, James J.;Meier, Joseph G.;Mawlawi, Osama
PET/CT扫描的CT和PET部分期间的呼吸运动导致两种模式观察到的解剖特征的不完全对准。在这项工作中，我们集中在CT运动的影响。我们提出了一种新的方法来改善对齐。研究方法：在28例癌症患者的PET/CT扫描的CT和PET部分期间收集呼吸波形数据，这些患者的肺部或上腹部有40处大小达3 cm的病变。通过3种重建方法重建PET列表模式数据：PET/静态（无运动校正的标准方法）; PET/ex（一种计算从最低到最高呼气幅度范围的方法）; PET/匹配（一种使用两种波形的新方法）。对3种方法进行了比较。PET和CT中肿瘤位置之间的距离由医生在视觉解释中以及定量地表征。基于静态方法相对于SUV确定肿瘤SUV（SUVmax和SUVpeak）。在肝脏中评价图像噪声，并与PET/静态进行比较。结果如下：在目视判读中，PET/静态、PET/ex和PET/匹配方法的良好对准率分别为13/21、13/23和18/21，平均PET/CT距离分别为3.5、5.1和2.8 mm。PET/静态和PET/匹配的10例患者中，分别有1例和7例的良好对线率增加。当使用PET/ex或PET/matched时，SUVmax平均比PET/静态高21%。SUV峰值高出12%。对于PET/ex方法，肝脏中的图像噪声比PET/静态高15%，对于PET/匹配高40%;也就是说，噪声远低于门控PET。结论：在PET（如在当前技术水平）和CT（该方法中的一个不寻常的关键步骤）中采集呼吸波形有可能改善PET和CT图像的对齐。对使用这一信息的拟议方法进行了测试。证实了对线改善。
Respiratory motion during the CT and PET parts of a PET/CT scan leads to imperfect alignment of anatomic features seen by the 2 modalities. In this work, we concentrate on the effects of motion during CT. We propose a novel approach for improving the alignment. Methods: Respiratory waveform data were gathered during the CT and PET parts of 28 PET/CT scans of cancer patients with 40 lesions up to 3 cm in size in the lung or upper abdomen. PET list-mode data were reconstructed by 3 reconstruction methods: PET/static (the standard method with no motion correction); PET/ex (a method that calculates a range of expiratory amplitudes from the lowest one to the highest one); and PET/matched (a novel method that uses both waveforms). The 3 methods were compared. The distance between tumor positions in PET and CT were characterized in visual interpretation by physicians as well as quantitatively. Tumor SUVs (SUVmax and SUVpeak) were determined relative to SUV based on the static method. Image noise was evaluated in the liver and compared with PET/static. Results: In visual interpretation, the rate of good alignment was 13 of 21, 13 of 23, and 18 of 21 for the PET/static, PET/ex, and PET/matched methods, respectively, and the mean PET/CT distances were 3.5, 5.1, and 2.8 mm. In visual comparison with PET/ex, the rate of good alignment was increased in 1 of 10 and 7 of 10 cases for PET/static and PET/matched, respectively. SUVmax was on average 21% higher than PET/static when either PET/ex or PET/matched was used. SUVpeak was 12% higher. Image noise in the liver was 15% higher than PET/static for the PET/ex method, and 40% higher for PET/matched; that is, noise was much lower than in gated PET. Conclusion: Acquiring respiratory waveforms both in PET (as in the current state of the art) and in CT (an unusual key step in this approach) has the potential to improve the alignment of PET and CT images. A proposed method for using this information was tested. Improved alignment was demonstrated.