Understanding the impact of advanced PET reconstruction in cardiac PET: The devil is in the details

Excerpt

PET-CT continues to see technological advances in both hardware and software which provide improvements to image quality and hence diagnostic confidence. Improvements to detector technology have provided the possibility of Time-of-Flight (TOF) acquisition and reconstruction, which has been commercially available for over a decade. Increases in computational power have allowed the use of more sophisticated iterative reconstruction algorithms that incorporate a more complete modeling of the physics of gamma-ray detection. One particular property that can be modeled is the spatial resolution response of the detector ring to account for degrading depth-of-interaction effects that worsen in magnitude with the increasing radial distance in the field of view. This is commonly referred to as point spread function (PSF) modeling. Image signal-to-noise ratio (SNR) is a fundamental metric of image quality that should be maximized for a given administered activity and image time. In cardiac imaging, it is difficult to quantify the impact of changes in SNR. It is reasonable to assume that an increase in SNR would give the appearance of more uniform perfusion in genuinely normal cases, as the contribution of Poisson image noise to inhomogeneity will be reduced. Both TOF and PSF modeling technologies increase image SNR but understanding the differences of how these two technologies improve image quality when using iterative reconstruction algorithms is key to knowing how to maximize the benefits from them. …