Kolbitsch Christoph, Ahlman Mark A, Davies-Venn Cynthia, Evers Robert, Hansen Michael, Peressutti Devis, Marsden Paul, Kellman Peter, Bluemke David A, Schaeffter Tobias
King's College London, Division of Imaging Sciences and Biomedical Engineering, London, United Kingdom
Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany.
J Nucl Med. 2017 May;58(5):846-852. doi: 10.2967/jnumed.115.171728. Epub 2017 Feb 9.
Cardiac PET is a versatile imaging technique providing important diagnostic information about ischemic heart diseases. Respiratory and cardiac motion of the heart can strongly impair image quality and therefore diagnostic accuracy of cardiac PET scans. The aim of this study was to investigate a new cardiac PET/MR approach providing respiratory and cardiac motion-compensated MR and PET images in less than 5 min. Free-breathing 3-dimensional MR data were acquired and retrospectively binned into multiple respiratory and cardiac motion states. Three-dimensional cardiac and respiratory motion fields were obtained with a nonrigid registration algorithm and used in motion-compensated MR and PET reconstructions to improve image quality. The improvement in image quality and diagnostic accuracy of the technique was assessed in simultaneous F-FDG PET/MR scans of a canine model of myocardial infarct and was demonstrated in a human subject. MR motion fields were successfully used to compensate for in vivo cardiac motion, leading to improvements in full width at half maximum of the canine myocardium of 13% ± 5%, similar to cardiac gating but with a 90% ± 57% higher contrast-to-noise ratio between myocardium and blood. Motion correction led to an improvement in MR image quality in all subjects, with an increase in sharpness of the canine coronary arteries of 85% ± 72%. A functional assessment showed good agreement with standard MR cine scans with a difference in ejection fraction of -2% ± 3%. MR-based respiratory and cardiac motion information was used to improve the PET image quality of a human in vivo scan. The MR technique presented here provides both diagnostic and motion information that can be used to improve MR and PET image quality. Reliable respiratory and cardiac motion correction could make cardiac PET results more reproducible.
心脏正电子发射断层扫描（PET）是一种多功能成像技术，可提供有关缺血性心脏病的重要诊断信息。心脏的呼吸和心脏运动可严重损害图像质量，进而影响心脏PET扫描的诊断准确性。本研究的目的是探究一种新的心脏PET/MR方法，该方法能在不到5分钟的时间内提供呼吸和心脏运动补偿的MR和PET图像。采集自由呼吸的三维MR数据，并将其回顾性地划分为多个呼吸和心脏运动状态。通过非刚性配准算法获得三维心脏和呼吸运动场，并将其用于运动补偿的MR和PET重建，以提高图像质量。在心肌梗死犬模型的同步F-FDG PET/MR扫描中评估了该技术在图像质量和诊断准确性方面的改善情况，并在一名人类受试者中得到了验证。MR运动场成功用于补偿体内心脏运动，使犬心肌的半高宽提高了13%±5%，与心脏门控相似，但心肌与血液之间的对比度噪声比提高了90%±57%。运动校正使所有受试者的MR图像质量都得到了改善，犬冠状动脉的清晰度提高了85%±72%。功能评估显示与标准MR电影扫描具有良好的一致性，射血分数差异为-2%±3%。基于MR的呼吸和心脏运动信息用于改善人体体内扫描的PET图像质量。本文介绍的MR技术提供了可用于改善MR和PET图像质量的诊断和运动信息。可靠的呼吸和心脏运动校正可使心脏PET结果更具可重复性。
