Direct reconstruction of cardiac PET kinetic parametric images using a preconditioned conjugate gradient approach. Issue 10 (5th September 2013)

• Record Type: Journal Article
• Authors: Rakvongthai, Yothin; Ouyang, Jinsong; Guerin, Bastien; Li, Quanzheng; Alpert, Nathaniel M.; El Fakhri, Georges
• Is Part Of: Medical physics. Volume 40:Issue 10(2013)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2013-09-05
• Subjects: Positron emission tomography (PET) -- Numerical approximation and analysis -- Magnetic resonance imaging; biological tissues -- cardiology -- conjugate gradient methods -- image reconstruction -- medical image processing -- phantoms -- positron emission tomography; direct estimation -- preconditioned conjugate gradient -- kinetic modeling -- parametric imaging -- dynamic PET; Biological material, e.g. blood, urine; Haemocytometers -- Digital computing or data processing equipment or methods, specially adapted for specific applications -- Image data processing or generation, in general -- Scintigraphy -- Measuring half‐life of a radioactive substance; Image reconstruction -- Medical imaging -- Medical image reconstruction -- Positron emission tomography -- Biomedical modeling -- Computed tomography -- Haemodynamics -- Medical image noise -- Flow visualization -- Poissonˈs equation; Medical physics -- Periodicals; Medical physics; Geneeskunde; Natuurkunde; Toepassingen; Biophysics; Periodicals; Periodicals; Electronic journals; 610.153
• DOI: 10.1118/1.4819821
• Languages: English
• ISSNs: 0094-2405

Abstract

Abstract : Purpose: : Our research goal is to develop an algorithm to reconstruct cardiac positron emission tomography (PET) kinetic parametric images directly from sinograms and compare its performance with the conventional indirect approach. Methods: : Time activity curves of a NCAT phantom were computed according to a one‐tissue compartmental kinetic model with realistic kinetic parameters. The sinograms at each time frame were simulated using the activity distribution for the time frame. The authors reconstructed the parametric images directly from the sinograms by optimizing a cost function, which included the Poisson log‐likelihood and a spatial regularization terms, using the preconditioned conjugate gradient (PCG) algorithm with the proposed preconditioner. The proposed preconditioner is a diagonal matrix whose diagonal entries are the ratio of the parameter and the sensitivity of the radioactivity associated with parameter. The authors compared the reconstructed parametric images using the direct approach with those reconstructed using the conventional indirect approach. Results: : At the same bias, the direct approach yielded significant relative reduction in standard deviation by 12%–29% and 32%–70% for 50 × 10 6 and 10 × 10 6 detected coincidences counts, respectively. Also, the PCG method effectively reached a constant value after only 10 iterations (with numerical convergence achieved after 40–50 iterations), while more than 500 iterations were needed for CG. Conclusions: : The authors have developed a novel approach based on the PCG algorithm to directly reconstruct cardiac PET parametric images from sinograms, and yield better estimation of kinetic parameters than the conventional indirect approach, i.e., curve fitting of reconstructed images. The PCG method increases the convergence rate of reconstruction significantly as compared to the conventional CG method.