Department of Investigative Radiology, National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan.
J Nucl Cardiol. 2012 Jun;19(3):524-33. doi: 10.1007/s12350-012-9522-0.
Patient movement has been considered an important source of errors in cardiac PET. This study was aimed at evaluating the effects of such movement on myocardial blood flow (MBF) and perfusable tissue fraction (PTF) measurements in intravenous ¹⁵O-water PET.
Nineteen ¹⁵O-water scans were performed on ten healthy volunteers and three patients with severe cardiac dysfunction under resting conditions. Motions of subjects during scans were estimated by monitoring locations of markers on their chests using an optical motion-tracking device. Each sinogram of the dynamic emission frames was corrected for subject motion. Variation of regional MBF and PTF with and without the motion corrections was evaluated.
In nine scans, motions during ¹⁵O-water scan (inter-frame (IF) motion) and misalignments relative to the transmission scan (inter-scan (IS) motion) larger than the spatial resolution of the PET scanner (4.0 mm) were both detected by the optical motion-tracking device. After correction for IF motions, MBF values changed from 0.845 ± 0.366 to 0.780 ± 0.360 mL/minute/g (P < .05). In four scans with only IS motion detected, PTF values changed significantly from 0.465 ± 0.118 to 0.504 ± 0.087 g/mL (P< .05), but no significant change was found in MBF values.
This study demonstrates that IF motion during ¹⁵O-water scan at rest can be source of error in MBF measurement. Furthermore, estimated MBF is less sensitive than PTF values to misalignment between transmission and ¹⁵O-water emission scans.
患者运动被认为是心脏 PET 中误差的一个重要来源。本研究旨在评估这种运动对静脉注射¹⁵O-水 PET 中心肌血流（MBF）和可灌注组织分数（PTF）测量的影响。
在休息状态下，对 10 名健康志愿者和 3 名严重心功能障碍患者进行了 19 次¹⁵O-水扫描。使用光学运动跟踪设备监测受试者胸部标志物的位置来估计扫描过程中的运动。对动态发射帧的每个正电子发射断层扫描数据进行校正，以校正受试者的运动。评估了校正和未校正运动时的区域 MBF 和 PTF 的变化。
在 9 次扫描中，¹⁵O-水扫描期间的运动（帧间（IF）运动）和相对于透射扫描的失准（扫描间（IS）运动）大于 PET 扫描仪的空间分辨率（4.0mm）都被光学运动跟踪设备检测到。校正 IF 运动后，MBF 值从 0.845 ± 0.366 降至 0.780 ± 0.360 mL/minute/g（P<.05）。在仅检测到 IS 运动的 4 次扫描中，PTF 值从 0.465 ± 0.118 显著增加至 0.504 ± 0.087 g/mL（P<.05），但 MBF 值无明显变化。
本研究表明，¹⁵O-水扫描期间的 IF 运动可能是 MBF 测量的误差源。此外，与传输和¹⁵O-水发射扫描之间的失准相比，估计的 MBF 对传输和¹⁵O-水发射扫描之间的失准不敏感。
