We investigate the effect of heart rate on the quality and artifact generation in coronary artery images obtained using multi-slice computed tomography (MSCT) with the purpose of finding the optimal time resolution for data acquisition. To perform the study, we used the 4D NCAT phantom, a computer model of the normal human anatomy and cardiac and respiratory motions developed in our laboratory....

The cardiac model of the 4D NCAT phantom was enhanced by incorporating a physiological basis from which to realistically model left ventricular (LV) motion defects. A finite element mechanical model of the LV was developed to simulate deficits in contractile function and to study the effect of ischemia on LV function. The model geometry was based on high resolution CT and MRI data sets of a hea...

introduction: an efficient method of tomographic imaging in nuclear medicine is positron emission tomography (pet). compared to spect, pet has the advantages of higher levels of sensitivity, spatial resolution and more accurate quantification. however, high noise levels in the image limit its diagnostic utility. noise removal in nuclear medicine is traditionally based on fourier decomposition o...

introduction: poor sensitivity and poor signal to noise ratio because of low injected thallium dose and presence of scattered photons are the main problems in using thallium in scintigraphic imaging of the heart. scattered photons are the main cause of degrading the contrast and resolution in spect imaging that result in error in quantification. thallium decay is very complicated and photons ar...

Patient motion during myocardial SPECT profusion imaging may result in the formation of artifacts in the reconstructed images. This study attempts to present a method on the basis of modeling image frames through optimum-degree polynomial curves and fitting 2D curves to detect and correct heart motion at pixel and subpixel accuracy. To evaluate our method, NCAT phantom was shifted during data a...

PURPOSE One issue with amplitude binning list-mode studies in SPECT for respiratory motion correction is that variation in the patient's respiratory pattern will result in binned motion states with little or no counts at various projection angles. The reduced counts result in limited-angle reconstruction artifacts which can impact the accuracy of the necessary motion estimation needed to correc...

Quantitative SPECT as well as simultaneous acquisition of multiple isotopes with SPECT in the clinical field, although clinically interesting, are still limited by reconstruction artifacts and computing power. As a considerable step in this direction, we have implemented an efficient reconstructor with variance reduced Monte-Carlo-simulation in the forward and/or backward projection of an OS-EM...

Magnetic resonance imaging (MRI) simulators have been largely applied to brain studies. However, cardiac applications of these simulators are only emerging. This paper focuses on the realistic simulation of local appearance of cardiac MRI datasets. Simulations are obtained from the MRISIM simulator with XCAT phantom (formerly NCAT) as input. Phantoms are further extended to increase realism of ...