Clinical methods are limited in studying the causes of artefacts associated with mathematical aspects of reconstruction algorithms and methods. In this work, a novel Maximum a Posteriori (MAP) reconstruction algorithm with local regularization is developed to increase the resolution and to improve the quality of reconstructed images. The aim of this work is to evaluate the proposed algorithm in artefacts reduction in cardiac SPECT imaging. Materials and Methods: Joint clinical and simulation studies are performed. A special mathematical model of torso (MMT) was designed which plays the role of virtual patient and models spatial distribution of 99mTc-MIBI in thoracic organs. The MMT is easy transformed to study patients with various constitutions and different myocardial left ventricle (LV) forms. MMT was sampled on grids 128*128*128 and 64*64*64. Computer simulations of the SPECT/CT myocardial perfusion imaging (MPI) procedure were performed. Projection (raw) data were calculated for 32 and 64 angular views over an arc extending from the right anterior oblique to the left posterior oblique in accordance with acquisition protocol of MPI SPECT. Standard OSEM and a novel MAP reconstruction algorithm with local regularization were applied for images reconstruction. Two types of artefacts were studied: false apical defects and artefacts of extra-cardiac activity. The simulation results were verified by comparing to the clinical data. Clinical MPI studies were performed in the National Medical Research Center of Cardiology (Moscow) by using the Philips Bright View XCT SPECT/CT hybrid system with lowenergy high-resolution (LEHR) collimator. Results: The results of simulations have shown that the cause of false apical defects is not associated with attenuation correction, as it was discussed in some clinical studies, but it is related to the LV form and to the limitations of the standard OSEM reconstruction algorithm. Severity of false apical defects was decreased by 10-15% using the proposed MAP algorithm. It is shown that extra-cardiac activity artifacts are reduced by using the MAP algorithm with local regularization. Conclusion: Joint clinical and simulation studies in nuclear cardiology may be considered as a firstline approach in analyzing sources of possible artifacts and pitfalls. The proposed MAP algorithm with local regularization has shown as a promising approach to improve resolution of reconstructed images and to reduce artefacts in cardiac SPECT images
|Журнал||European journal of nuclear medicine and molecular imaging|
|Номер выпуска||SUPPL 1|
|Состояние||Опубликовано - окт 2019|
|Событие||32nd Annual Congress of the European-Association-of-Nuclear-Medicine (EANM) - Barcelona, Испания|
Продолжительность: 12 окт 2019 → 16 окт 2019
Denisova, N., Ansheles, A., Sergienko, V., Kertesz, H., Beyer, T., & Kolinko, I. (2019). Artefacts reduction in cardiac SPECT images by using a novel reconstruction algorithm Maximum a Posteriori with local regularization. European journal of nuclear medicine and molecular imaging, 46(SUPPL 1), S62-S63.