Abstract
BACKGROUND: In radionuclide imaging, in vivo human clinical studies are limited because of radiation exposure and ethical concerns; therefore, mathematical modeling and in silico computer simulations based on digital models are becoming increasingly important. In the English-language literature, this approach is called “virtual clinical trials.”
AIMS: This study aimed to develop software tools for the simulation of radionuclide visualization of myocardial perfusion by single-photon emission computed tomography combined with computed tomography using 99mTc-MIBI as the radiopharmaceutical and perform studies aimed at improving the accuracy of single-photon emission computed tomography.
MATERIALS AND METHODS: A software package “Virtual platform for simulations of single-photon emission computed tomography combined with computed tomography method in nuclear cardiology” was developed using digital patient models, a scanner, and assessment of the state of the myocardium using digital images of the left ventricle in the form of a “polar map.” Verification of the software package was performed by comparison with clinical data obtained at the National Medical Research Center of Cardiology Named After Academician E.I. Chazov (Moscow). Simulation computer tests were performed, in which the accuracy of assessing the state of the myocardium was assessed, depending on the approach to normalizing the polar map and corrective factors in the reconstruction algorithm.
RESULTS: The results of the simulation tests revealed that the assessment of left ventricular myocardial perfusion significantly depended on the method of normalizing the polar map and considered corrective factors in the reconstruction algorithm. The most accurate estimates were obtained by calculating the normalization coefficient from the average value of activity in the normal zone of the myocardium. The common approach to pixel normalization with maximum intensity can lead to errors. The results of the virtual trials were fully consistent with clinical observations.
CONCLUSIONS: The transition from relative normalized values of activity in the myocardium to absolute quantitative estimates may eliminate existing limitations and uncertainties and is the main condition for improving the diagnostic accuracy of single-photon emission computed tomography combined with computed tomography in nuclear cardiology.