Sources of attenuation-correction artefacts in cardiac PET/CT and SPECT/CT
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Respiratory motion during myocardial perfusion imaging can cause artefacts in both positron emission tomography (PET) and single-photon emission computed tomography (SPECT) images when mismatches between emission and transmission datasets arise. In this study, artefacts from different breathing motions were quantified in both modalities to assess key factors in attenuation-correction accuracy.
Activity maps were generated using the NURBS-based cardiac-torso phantom for different respiratory cycles, which were projected, attenuation-corrected and reconstructed to form PET and SPECT images. Attenuation-correction was performed with maps at mismatched respiratory phases to observe the effect on the left-ventricular myocardium. Myocardial non-uniformity was assessed in terms of the standard deviation in scores obtained from the 17-segment model and changes in uniformity were compared for each mismatch and modality.
Certain types of mismatch led to artefacts and corresponding increases in the myocardial non-uniformity. For each mismatch in PET, the increases in non-uniformity relative to an artefact-free image were as follows: (a) cardiac translation mismatch, 84% ± 11%; (b) liver mismatch, 59% ± 10%, (c) lung mismatch from diaphragm contraction, 28% ± 8%; and (d) lung mismatch from chest-wall motion, 6% ± 7%. The corresponding factors for SPECT were (a) 61% ± 8%, (b) 34% ± 8%, (c) −2% ± 7)% and (d) −4% ± 6%.
Attenuation-correction artefacts were seen in PET and SPECT images, with PET being more severely affected. The most severe artefacts were produced from mismatches in cardiac and liver position, whereas lung mismatches were less critical. Both cardiac and liver positions must, therefore, be correctly matched during attenuation correction.
KeywordsAttenuation correction Artefacts Respiratory motion Hybrid imaging Myocardial perfusion imaging
This work was supported by the Biotechnology and Biological Sciences Research Council and GlaxoSmithKline. This work was undertaken at UCLH/UCL who received a proportion of funding from the Department of Health’s NIHR Biomedical Research Centres funding scheme.
- 11.Cook R, Carnes G, Ting-Yim L, Wells RG. 4D CT for respiratory gated attenuation corrections in canine cardiac PET imaging. In: IEEE Nuclear Science Symposium Conference Record, NSS-MIC 2005, pp 2408–12.Google Scholar
- 14.Hendel RC, Corbett JR, Cullom SJ, DePuey EG, Garcia EV, Bateman TM. The value and practice of attenuation correction for myocardial perfusion SPECT imaging: a joint position statement from the American Society of Nuclear Cardiology and the Society of Nuclear Medicine. J Nucl Cardiol. 2002;9:135–43.PubMedCrossRefGoogle Scholar
- 20.Danias PG, Stuber M, Botnar RM, Kissinger KV, Edelman RR, Manning WJ. Relationship between motion of coronary arteries and diaphragm during free breathing: lessons from real-time MR imaging. Am J Roentgenol. 1999;172:1061–5.Google Scholar
- 21.Martin SJ, Dey J, King MA, Hutton BF. Segmenting and tracking diaphragm and heart regions in gated-CT datasets as an aid to developing a predictive model for respiratory motion-correction. In: IEEE Nuclear Science Symposium Conference Record, NSS-MIC 2007, pp 2680-5.Google Scholar
- 25.Cerqueira MD, Weissman NJ, Dilsizian V, Jacobs AK, Kaul S, Laskey WK, et al. Standardized myocardial segmentation and nomenclature for tomographic imaging of the heart: a statement for healthcare professionals from the Cardiac Imaging Committee of the Council on Clinical Cardiology of the American Heart Association. Circulation 2002;105:539–42.PubMedCrossRefGoogle Scholar