Boucher Luc, Rodrigue Serge, Lecomte Roger, Bénard François
Metabolic and Functional Imaging Center, Clinical Research Center, Centre Hospitalier Universitaire de Sherbrooke/Hôpital Fleurimont, 3001 12th Avenue North, Sherbrooke, Quebec, Canada J1H 5N4.
J Nucl Med. 2004 Feb;45(2):214-9.
Respiratory motion may reduce the sensitivity of (18)F-FDG PET for the detection of small pulmonary nodules close to the base of the lungs. This motion also interferes with attempts to use fused PET/CT images through software or combined PET/CT devices. This study was undertaken to assess the feasibility of respiratory gating for PET of the chest and the impact of respiratory motion on quantitative analysis.
Ten healthy subjects were enrolled in this study. Three-dimensional studies were acquired with 8 gates per respiratory cycle on a commercial PET scanner with a temperature-sensitive respiratory gating device built in-house. All scans were obtained over 42 cm of body length with 3 bed positions of 10 min each after injection of (18)F-FDG at 4.5 MBq/kg. The reconstructed images were assembled to produce gated whole-body volumes and maximum-intensity projections. The amplitude of respiratory motion of the kidneys (as a surrogate for diaphragmatic incursion) as well as the apex of the heart was measured in the coronal plane. Phantom studies were acquired to simulate the impact of respiratory motion on quantitative uptake measurements.
The respiratory gating device produced a consistent, reliable trigger signal. All acquisitions were successful and produced reconstructed volumes with excellent image quality. Mean +/- SD motion amplitude and maximal motion amplitude values were 6.7 +/- 3.0 and 11.9 mm for the heart, 12.0 +/- 3.7 and 18.8 mm for the right kidney, and 11.1 +/- 4.8 and 17.1 mm for the left kidney, respectively. In phantom studies, the standardized uptake value for a 1-mL lesion was underestimated by 30% and 48% for the average and maximal respiratory motion values, respectively.
Respiratory gating of PET of the thorax and upper abdomen is a practical and feasible approach that may improve the detection of small pulmonary nodules. Further work is planned to assess prospectively the diagnostic accuracy of this new method.
呼吸运动可能会降低¹⁸F-FDG PET检测靠近肺底部小肺结节的敏感性。这种运动还会干扰通过软件或PET/CT组合设备使用融合PET/CT图像的尝试。本研究旨在评估胸部PET呼吸门控的可行性以及呼吸运动对定量分析的影响。
本研究纳入了10名健康受试者。使用内置温度敏感呼吸门控装置的商用PET扫描仪，在每个呼吸周期采集8个门控的三维图像。注射4.5 MBq/kg的¹⁸F-FDG后，在42 cm的身体长度上，分3个床位位置，每个位置采集10分钟，获得所有扫描图像。重建图像后组装成门控全身容积图像和最大强度投影图像。在冠状面测量肾脏（作为膈肌运动的替代指标）以及心脏尖部的呼吸运动幅度。进行体模研究以模拟呼吸运动对定量摄取测量的影响。
呼吸门控装置产生了一致、可靠的触发信号。所有采集均成功，并生成了图像质量优异的重建容积图像。心脏的平均±标准差运动幅度和最大运动幅度值分别为6.7±3.0和11.9 mm，右肾为12.0±3.7和18.8 mm，左肾为11.1±4.8和17.1 mm。在体模研究中，对于1 mL病变，平均和最大呼吸运动值分别使标准化摄取值低估了30%和48%。
胸部和上腹部PET的呼吸门控是一种实用且可行的方法，可能会提高小肺结节的检测率。计划进一步开展工作，前瞻性评估这种新方法的诊断准确性。
