Bewegungsartefakte in PET/CT-Bildern und deren Korrekturen

Zusammenfassung

Die klinische Bildgebung mittels hybrider PET/CT-Systeme ist seit über einem Jahrzehnt Standard in der medizinischen Diagnostik. Trotz des großen Erfolgs dieser kombinierten Technik existieren immer noch Probleme, die gerade in der alltäglichen Anwendung die tatsächlich erreichte Bildqualität limitieren. Zu den wichtigsten Herausforderungen für die PET/CT-Bildgebung zählen dabei Patientenbewegungen, im thorakalen und abdominalen Bereich speziell unvermeidliche Organbewegungen verursacht durch Atmung und Herzschlag. Begründet liegt dies v. a. in den vergleichsweise langen PET-Akquisitionszeiten (einige Minuten pro Bettposition), die Aufnahmen in Atemanhalt-Technik verbieten. Folgen dieser Bewegungen sind zum einen Artefakte bei der CT-basierten Schwächungskorrektur und Probleme bei der PET/CT-Bildfusion, zum anderen eine merkliche Bewegungsunschärfe in den rekonstruierten PET-Bildern, was letztlich insbesondere zu Problemen in der Quantifizierung der Radiotracer-Aufnahme führen kann. Strategien zur Vermeidung dieser Probleme erlangen derzeit auch im klinischen Alltag immer größere Verbreitung. Zu nennen sind insbesondere verschiedene Gating-Verfahren, bei denen die PET-Daten gemäß einer zusätzlich gemessenen Atemkurve des Patienten rekonstruiert werden. Hiermit lassen sich die erwähnten Bildartefakte in der Regel deutlich reduzieren. Weiterführende Konzepte wie die volle Bewegungskorrektur der PET-Daten während der Bildrekonstruktion warten derzeit noch auf eine gründliche klinische Validierung, dürften aber mittelfristig ebenfalls im klinischen Alltag verfügbar sein. Der vorliegende Artikel gibt einen Überblick über verschiedene aktuelle und zukünftig geplante Korrekturverfahren.

Abstract

Clinical imaging using hybrid PET/CT systems is used now for over a decade in the field of medical diagnosis. However, despite the great success of combining these 2 modalities into a single scanner, there are still issues that limit the actually achieved image quality in everyday practice. Amongst the most important ones of these are patient movements during the scan, and specifically in scans of the thorax and abdomen inevitable organ motion introduced by respiration and heartbeat. The primary reason for these problems is based on the prolonged acquisition times of PET in the order of a few minutes per bed position, therefore prohibiting scans in breath hold. These motion types potentially result in problems with the CT-based attenuation correction of PET data and PET/CT image fusion. Furthermore, motion blurring is introduced into the PET images, leading to problems with quantification of radiotracer uptake. Strategies to overcome these obstacles are now finding their way into clinical practice. Of these, methods based on gating techniques are of highest interest. Here, PET data is reconstructed with respect to an additionally acquired respiratory curve, effectively reducing the aforementioned image artifacts. More advanced correction concepts like fully motion-corrected reconstruction of PET data are still awaiting thorough validation, but are expected to be clinically available in the foreseeable future. This paper will give an overview on a range of current and future correction methods.

Schlüsselwörter

PET/CT-Artefakte - Atembewegungen - Herzbewegungen - gegatete PET - datengetriebenes Gating - Bewegungsartefakte - Bewegungskorrektur

Key words

PET/CT artifacts - respiratory motion - cardiac motion - gated PET - data-driven gating - motion artifacts - motion correction

• Literatur

• 1 Allen-Auerbach M, Yeom K, Park J et al. Standard PET/CT of the chest during shallow breathing is inadequate for comprehensive staging of lung cancer. J Nucl Med 2006; 47: 298-301
• 2 Alessio AM, Kohlmyer S, Branch K et al. Cine CT for attenuation correction in cardiac PET/CT. J Nucl Med 2007; 48: 794-801
• 3 Beyer T, Townsend DW, Brun T et al. A combined PET/CT scanner for clinical oncology. J Nucl Med 2000; 41: 1369-1379
• 4 Beyer T, Antoch G, Blodgett T et al. Dual-modality PET/CT imaging: the effect of respiratory motion on combined image quality in clinical oncology. Eur J Nucl Med Mol Imaging 2003; 30: 588-596
• 5 Boucher L, Rodrigue S, Lecomte R et al. Respiratory gating for 3-dimensional PET of the thorax: Feasibility and initial results. J Nucl Med 2004; 45: 214-219
• 6 Büther F, Dawood M, Stegger L et al. List mode-driven cardiac and respiratory gating in PET. J Nucl Med 2009; 50: 674-681
• 7 Büther F, Ernst I, Dawood M et al. Detection of respiratory tumour motion using intrinsic list mode-driven gating in positron emission tomography. Eur J Nucl Med Mol Imaging 2010; 37: 2315-2327
• 8 Büther F. Corrections for Physical Factors. In Correction Techniques in Emission Tompgraphy. Dawood M, Jiang X, Schäfers KP. Eds. CRC Press; 2012: 67-103
• 9 Büther F, Vehren T, Schäfers KP et al. Respiratorisches Gating in der klinischen PET/CT: Vergleich konventionelller und datengetriebener Techniken. Nuklearmedizin 2015; 54: A76
• 10 Chi PC, Balter P, Luo DS et al. Relation of external surface to internal tumor motion studied with cine CT. Med Phys 2006; 33: 3116-3123
• 11 Chi PC, Mawlawi O, Nehmeh SA et al. Design of respiration averaged CT for attenuation correction of the PET data from PET/CT. Med Phys 2007; 34: 2039-2047
• 12 Dasari PKR, Shazeeb MS, Könik A et al. Adaptation of the modified Bouc – Wen model to compensate for hysteresis in respiratory motion for the list-mode binning of cardiac SPECT and PET acquisitions: Testing using MRI. Med Phys 2014; 41: 112508
• 13 Dawood M, Büther F, Lang N et al. Respiratory gating in positron emission tomography: a quantitative comparison of different gating schemes. Med Phys 2007; 34: 3067-3076
• 14 Dawood M, Büther F, Jiang X et al. Respiratory motion correction in 3-D PET data with advanced optical flow algorithms. IEEE Transactions on Medical Imaging 2008; 27: 1164-1175
• 15 Dawood M, Büther F, Stegger L et al. Optimal number of respiratory gates in positron emission tomography: a cardiac patient study. Med Phys 2009; 36: 1775-1784
• 16 Didierlaurent D, Ribes S, Batatia H et al. The retrospective binning method improves the consictency of phase-binning in respiratory-gated PET/CT. Phys Med Biol 2012; 57: 7829-7841
• 17 Fieseler M, Kugel H, Gigengack F et al. A dynamic thorax phantom for assessment for cardiac and respiratory motion correction in PET/MRI: A preliminary evaluation. Nucl Instrum Methods Phys Res A 2013; 702: 59-63
• 18 Fürst S, Grimm R, Hong I et al. Motion correction strategies for integrated PET/MR. J Nucl Med 2015; 56: 261-269
• 19 Gigengack F, Ruthotto L, Burger M et al. Motion correction in dual gated cardiac PET using mass-preserving image registration. IEEE Trans Med Imaging 2012; 31: 698-712
• 20 Grootjans W, de Geus-Oei L, Meeuvis APW et al. Amplitude-based optimal respiratory gating in positron emission tomography in patients with primary lung cancer. Eur Radiol 2014; 24: 3242-3250
• 21 He J, O’Keefe GJ, Jones G et al. Evaluation of geometrical sensitivity for respiratory motion gating by GATE and NCAT Simulation. In: 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBS) 2007; 4165-4168
• 22 Hess M, Büther F, Gigengack F et al. A dual-Kinect approach to determine torso surface motion for respiratory motion correction in PET. Med Phys 2015; 42: 2276-2286
• 23 Kalender WA, Rienmüller R, Seissler W et al. Measurement of pulmonary parenchymal attenuation: Use of spirometric gating with quantitative CT. Radiology 1990; 175: 265-268
• 24 Kesner AL, Kuntner C. A new fast and fully automated software based algorithm for extracting respiratory signal from raw PET data and its comparison to other methods. Med Phys 2010; 37: 5550-5559
• 25 Kesner AL, Abourbeh G, Mishani E et al. Gating, enhanced gating, and beyond: information utilization strategies for motion management, applied to preclinical PET. EJNMMI Res 2013; 3: 29
• 26 Kesner AL, Schleyer PJ, Büther F et al. On transcending the impasse of respiratory motion correction applications in routine clinical imaging – a consideration of a fully automated data driven motion control framework. EJNMMI Physics 2014; 1: 8
• 27 Kesner AL, Chung J, Koo P et al. Modern software gating vs. Hardware gating – a large population comparison. J Nucl Med 2015; 56: 1804
• 28 Klein GJ, Reutter BW, Botvinick EH et al. Fine-scale motion detection using intrinsic list mode PET information. In: Proceedings of the IEEE Workshop on Mathematical Methods in Biomedical Image Analysis (MMBIA’01). IEEE Computer Society 2001: 71
• 29 Koch N, Liu HH, Starkschall G et al. Evaluation of internal lung motion for respiratory-gated radiotherapy using MRI: Part I–correlating internal lung motion with skin fiducial motion. Int J Radiat Oncol Biol Phys 2004; 60: 1459-1472
• 30 Lamare F, Ledesma Carbayo MJ, Cresson T et al. List-mode-based reconstruction for respiratory motion correction in PET using non-rigid body transformations. Phys Med Biol 2007; 52: 5187-5204
• 31 Lamare F, Le Maitre A, Dawood M et al. Evaluation of respiratory and cardiac motion correction schemes in dual gated PET/CT cardiac imaging. Med Phys 2014; 41: 072504
• 32 Langen KM, Jones DTL. Organ motion and its managment. Int J Rad Onc Biol Phys 2001; 50: 265-278
• 33 Le Meunier L, Maass-Moreno R, Carrasquillo JA et al. PET/CT imaging: effect of respiratory motion on apparent myocardial uptake. J Nucl Cardiol 2006; 13: 821-830
• 34 Liu C, Alessio A, Pierce L et al. Quiescent period respiratory gating for PET/CT. Med Phys 2010; 37: 5037-5043
• 35 Livieratos L, Stegger L, Bloomfield PM et al. Rigid-body transformation of list mode projection data for respiratory motion correction in cardiac PET. Phys Med Biol. 2005; 50: 3313-3322
• 36 Lupi A, Zaroccolo M, Salgarello M et al. The effect of 18F-FDG-PET/CT respiratory gating on detected metabolic activity in lung lesions. Ann Nucl Med 2009; 23: 191-196
• 37 Martinez-Möller A, Zikic D, Botnar RM et al. Dual cardiac-respiratory gated PET: implementation and results from a feasibility study. Eur J Nucl Med Mol Imaging 2007; 34: 1447-1454
• 38 McQuaid SJ, Hutton BF. Sources of attenuation-correction artefacts in cardiac PET/CT and SPECT/CT. Eur J Nucl Med Mol Imaging 2008; 35: 1117-1123
• 39 Meirelles GS, Erdi YE, Nehmeh SA et al. Deep-inspiration breath-hold PET/CT: clinical findings with a new technique for detection and characterization of thoracic lesions. J Nucl Med 2007; 48: 712-719
• 40 Nagamachi S, Wakamatsu H, Kiyohara S et al. Usefulness of a deep-inspiration breath-hold 18F-FDG PET/CT technique in diagnosing liver, bile duct, and pancreas tumors. Nucl Med Comm 2009; 30: 326-332
• 41 Nagamachi S, Wakamatsu H, Kiyohara S et al. The reproducibility of deep-inspiration breath-hold 18F-FDG PET/CT technique in diagnosing various cancers affected by respiratory motion. Ann Nucl Med 2010; 24: 171-178
• 42 Nagel CC, Bosmans G, Dekker AL et al. Phased attenuation correction in respiration correlated computed tomography/positron emitted tomography. Med Phys 2006; 33: 1840-1847
• 43 Nehmeh SA, Erdi YE, Ling EE et al. Effect of respiratory gating on reducing lung motion artifacts in PET imaging of lung cancer. Med Phys 2002; 29: 366-371
• 44 Nehmeh SA, Erdi YE, Meirelles GS et al. Deep-inspiration breath-hold PET/CT of the thorax. J Nucl Med 2007; 48: 22-26
• 45 Nehrke K, Bornert P, Manke D et al. Free-breathing cardiac MR imaging: Study of implications of respiratory motion-initial results. Radiology 2001; 220: 810-815
• 46 Nye JA, Hamill J, Tudorascu D et al. Comparison of low-pitch and respiratory-averaged CT protocols for attenuation correction of cardiac PET studies. Med Phys 2009; 36: 1618-1623
• 47 Pan T, Mawlawi O, Nehmeh SA et al. Attenuation correction of PET images with respiration-averaged CT images in PET/CT. J Nucl Med 2005; 46: 1481-1487
• 48 Schleyer PJ, O’Doherty MJ, Barrington SF et al. Retrospective data-driven respiratory gating for PET/CT. Phys Med Biol 2009; 54: 1935-1950
• 49 Schleyer PJ, O’Doherty MJ, Marsden PK. Extension of a data-driven gating technique to 3D, whole body PET studies. Phys Med Biol 2011; 56: 3953-3965
• 50 Schleyer PJ, Thielemans K, Marsden PK. Extracting a respiratory signal from raw dynamic PET data that contain tracer kinetics. Phys Med Biol 2014; 59: 4345-4356
• 51 Skretting A, Revheim M-E, Knudtsen IS et al. An implementation of time-efficient respiratory-gated PET acquisition by repeated breath-holds. Acta Radiol 2013; 54: 672-675
• 52 Thielemans K, Rathore S, Engbrant F et al. Device-less gating for PET/CT using PCA. In Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC). IEEE 2011: 3904-3910
• 53 Thorndyke B, Schreibmann E, Koong A et al. Reducing respiratory motion artifacts in positron emission tomography through retrospective stacking. Med Phys 2006; 33: 2632-2641
• 54 van der Gucht A, Serrano B, Hugonnet F et al. Impact of a new respiratory amplitude-based gating technique in evaluation of upper abdominal PET lesions. Eur J Radiol 2014; 83: 509-515
• 55 van Elmpt W, Hamill J, Jones J et al. Optimal gating compared to 3D and 4D PET reconstruction for characterization of lung tumours. Eur J Nucl Med Mol Imaging 2011; 38: 843-855
• 56 Wells RG, Ruddy TD DeKemp RA et al. Single-phase CT aligned to gated PET for respiratory motion correction in cardiac PET/CT. J Nucl Med 2010; 51: 1182-1190
• 57 Wink N, Panknin C, Solberg TD. Phase versus amplitude sorting of 4D-CT data. J Appl Clin Med Phys 2006; 7: 77-85
• 58 Yamaguchi T, Ueda O, Hara H et al. Usefulness of a breath-holding acquisition method in PET/CT for pulmonary lesions. Ann Nucl Med 2009; 23: 65-71