Comparison of a Free-Breathing CT and an Expiratory Breath-Hold CT with Regard to Spatial Alignment of Amplitude-Based Respiratory-Gated PET and CT Images
Comparison of a Free-Breathing CT and an Expiratory Breath-Hold CT with Regard to Spatial Alignment of Amplitude-Based Respiratory-Gated PET and CT Images
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DOI：
10.2967/jnmt.114.145748
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发表时间：
2014-12-01
影响因子：
1.3
通讯作者：
Visser, Eric P.
中科院分区：
文献类型：
--
作者：
van der Vos, Charlotte S.;Grootjans, Willem;Visser, Eric P.
PET期间的呼吸运动对PET图像中放射性示踪剂摄取的量化具有显著影响。即使当使用PET门控技术考虑呼吸运动时，由于PET和CT之间的空间不匹配，不适当的衰减校正也可能导致标准化摄取值的不准确。在这项研究中，屏气CT成像的CT和基于振幅的门控PET图像之间的空间匹配的效果进行了研究。方法：对52例患者的125个肺部病灶进行全身F18-FDGPET/CT显像。使用优化的基于振幅的呼吸门控进行F-18 -FDG PET。对于CT，36例患者被随机分配到自由呼吸（FB）组和16例再呼气屏气（BH）组。通过测量PET和CT病灶质心之间的距离并计算Jaccard相似系数（JSC）来量化PET和CT图像之间的空间失配。结果如下：在上叶，FB和BH组PET和CT病变质心之间的平均距离分别为4.7 ± 3.1和6.0 ± 3.0 mm（P = 0.11）。中叶和下叶的距离分别为5.8 +/- 4.3和5.1 +/- 2.9 mm（P = 0.70），中央区分别为4.8 +/- 4.6和5.6 +/- 2.0 mm（P = 0.24）。FB组和BH组上叶的JSC分别为0.28 +/- 0.17和0.28 +/- 0.19（P = 0.83）。中叶和下叶的JSC分别为0.22 +/- 0.16和0.28 +/- 0.18（P = 0.20），中央区分别为0.39 +/- 0.17和0.13 +/- 0.04（P = 0.04）。结论：在CT采集过程中向患者提供呼吸指令并没有改善CT门控PET图像和CT图像之间的空间对齐。在使用该临床方案中遇到的困难，如患者依从性和操作员依赖性，强调了对其他策略的需求。
Respiratory motion during PET has a significant effect on the quantification of radiotracer uptake in PET images. Even when respiratory motion is considered using PET gating techniques, inaccuracies in standardized uptake values can be caused by inappropriate attenuation correction due to a spatial mismatch between PET and CT. In this study, the effect of breath-hold CT imaging on the spatial match between CT and amplitude-based respiratory-gated PET images is investigated. Methods: Whole-body F-18-FDG PET/CT imaging was performed in 52 patients with 125 lung lesions. F-18 -FDG PET was performed using optimized, amplitude-based respiratory gating. For CT, 36 patients were randomly assigned to the free-breathing (FB) group and 16 to the restexpiratory breath-hold (BH) group. Spatial mismatch between the PET and CT images was quantified by measuring the distance between the centroids of PET and CT lesions and calculating the Jaccard similarity coefficient (JSC). Results: In the upper lobes, the average distance between the centroids of the PET and CT lesions was 4.7 +/- 3.1 and 6.0 +/- 3.0 mm for the FB and BH groups, respectively (P = 0.11). For the middle and lower lobes, the distances were 5.8 +/- 4.3 and 5.1 +/- 2.9 mm (P = 0.70), respectively, and for the central region 4.8 +/- 4.6 and 5.6 +/- 2.0 mm (P = 0.24), respectively. The JSC for the upper lobes was 0.28 +/- 0.17 and 0.28 +/- 0.19, for the FB and the BH group, respectively (P = 0.83). For the middle and lower lobes, the JSC was 0.22 +/- 0.16 and 0.28 +/- 0.18 (P = 0.20), respectively, and for the central region 0.39 +/- 0.17 and 0.13 +/- 0.04 (P = 0.04), respectively. Conclusion: Providing breathing instructions to the patients during the CT acquisition did not improve the spatial alignment between the respiratory-gated PET images and the CT images. The difficulty experienced in using this clinical protocol, such as patient compliance and operator dependence, emphasizes the need for other strategies.