Detectability of perfusion defect in five‐dimensional gated‐dynamic cardiac SPECT images

Abstract

Purpose: In previous work, the authors developed and demonstrated the concept of an image reconstruction procedure aimed to unify gated and dynamic nuclear cardiac imaging, which the authors have termed five-dimensional (5D) SPECT. Gated imaging permits the clinician to evaluate wall motion and, through the use of stress and rest scans, allows perfusion defects to be observed. Dynamic imaging depicts kinetics in the myocardium, which can be used to evaluate perfusion, but traditional dynamic images are motionless and do not depict wall motion. In this article, the authors investigate the degree to which perfusion defects can be detected from the dynamic information conveyed by 5D images, a problem that is particularly challenging in the absence of multiple fast camera rotations. Methods: The authors first demonstrate the usefulness of dynamic reconstructed images for perfusion detection by using linear discriminant analyses ͑Fisher linear discriminant analysis and principal component analysis͒ and a numerical channelized Hotelling observer. The authors then derive three types of discriminant metrics for characterizing the temporal kinetic information in reconstructed dynamic images for differentiating perfusion defects from normal cardiac perfusion, which are the Fisher linear discriminant map, temporal derivative map, and kinetic parametric images. Results: Results are based on the NURBS-based cardiac-torso phantom with simulation of Tc99m-teboroxime as the imaging agent. The derived metric maps and quantitative contrast-to-noise ratio results demonstrate that the reconstructed dynamic images could yield higher detectability of the perfusion defect than conventional gated reconstruction while providing wall motion information simultaneously. Conclusions:The proposed metrics can be used to produce new types of visualizations, showing wall motion and perfusion information, that may potentially be useful for clinical evaluation. Since 5D imaging permits wall motion and kinetics to be observed simultaneously, it may ultimately obviate the need for separate stress and rest scans.

Comparison study of temporal regularization methods for fully 5D reconstruction of cardiac gated dynamic SPECT

“…To obtain LVEF, a reconstructed 5D image sequence was first collapsed into a gated sequence by summing along the dynamic time axis; the clinical software package 4DMSPECT was then used to compute the EF from this collapsed sequence (Niu, Yang, Wernick & King 2010). …”

“…Despite these challenges, we recently demonstrated in (Niu, Yang, Wernick & King 2010) that 5D reconstruction could lead to useful dynamic information for discriminating between normal wall and perfusion defects in terms of their timevarying activities. The study in (Niu, Yang, Wernick & King 2010) made use of a 5D reconstruction approach previously developed in (Jin et al 2006, Niu, Yang, Jin, Wernick & King 2010), wherein the gated dynamic images were reconstructed jointly in order to exploit the correlation in the signal components among the different gate intervals.…”

“…The study in (Niu, Yang, Wernick & King 2010) made use of a 5D reconstruction approach previously developed in (Jin et al 2006, Niu, Yang, Jin, Wernick & King 2010), wherein the gated dynamic images were reconstructed jointly in order to exploit the correlation in the signal components among the different gate intervals. Furthermore, the dynamic EM (dEM) constraint first proposed in (Farncombe 2000), Feng et al 2006) was used to regulate the time activities in the dynamic images.…”

Direct parametric reconstruction of gated dynamic cardiac spect

“…We have demonstrated that despite the great challenges it is indeed feasible to obtain such a 5D image sequence, and that, more importantly, the kinetic information derived from the reconstructed dynamic images can be effective for discriminating normal from perfusion defects [5]. Built upon this prior success, in this work we explore an alternative, direct parametric reconstruction approach in This work was supported by NIH/NHLBI grant HL65425.…”

Preconditioned alternating projection algorithm for solving the penalized-likelihood SPECT reconstruction problem

“…We used four non-overlapping and rotationally symmetric input channels (in spatial frequency domain) and modeled the internal observer noise [27,28]. A total of 200 noise realizations (100 for the uniform cylinder and 100 for the cylinder with spheres) were used for low- and high-noise simulated data reconstructed by TV-PAPA, FB-EM-TV, TVPF-EM and GPF-EM.…”