Abstract
BackgroundOur aim was to characterize the influence of time-of-flight (TOF) and point spread function (PSF) recovery corrections, as well as ordered subset expectation maximization (OSEM) reconstruction parameters, in 82Rb PET/CT quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR).Rest and stress list-mode dynamic 82Rb PET acquisition data from 10 patients without myocardial flow defects and 10 patients with myocardial blood flow defects were reconstructed retrospectively. OSEM reconstructions were performed with Gaussian filters of 4, 6, and 8 mm, different iterations, and subset numbers (2 × 24; 2 × 16; 3 × 16; 4 × 16). Rest and stress global, regional, and segmental MBF and MFR were computed from time activity curves with FlowQuant© software. Left ventricular segmentation using the 17-segment American Heart Association model was obtained.ResultsWhole left ventricle (LV) MBF at rest and stress were 0.97 ± 0.30 and 2.30 ± 1.00 mL/min/g, respectively, and MFR was 2.40 ± 1.13. Concordance was excellent and all reconstruction parameters had no significant impact on MBF, except for the exclusion of TOF which led to significantly decreased concordance in rest and stress MBF in patients with or without perfusion defects on a coronary artery basis and in MFR in patients with perfusion defects.ConclusionsChanges in reconstruction parameters in perfusion 82Rb PET/CT studies influence quantitative MBF analysis. The inclusion of TOF information in the tomographic reconstructions had significant impact in MBF quantification.
Highlights
Our aim was to characterize the influence of time-of-flight (TOF) and point spread function (PSF) recovery corrections, as well as ordered subset expectation maximization (OSEM) reconstruction parameters, in 82Rb positron emission tomography/computed tomography (PET/CT) quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR)
The use of cardiac 82Rb PET/CT has been promoted by its ability to quantify myocardial blood flow (MBF) and myocardial flow reserve (MFR) noninvasively and routinely [9, 10]
Accuracy and precision in quantitative MBF 82Rb dynamic PET imaging have been recently reviewed [11] while reproducible results can be achieved with the available software [12].Improvement of PET quantitative cardiac imaging can be obtained by optimization of acquisition parameters [13,14,15]
Summary
Our aim was to characterize the influence of time-of-flight (TOF) and point spread function (PSF) recovery corrections, as well as ordered subset expectation maximization (OSEM) reconstruction parameters, in 82Rb PET/CT quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR). Present generation PET/CT includes time-of-flight (TOF) information to better recover the localization of positron annihilations sites [13], with consequent statistical noise reduction and increase in lesion contrast [16,17,18] and benefits in 82Rb PET perfusion studies of obese patients [19] This method seems less sensitive to mismatched attenuation correction, erroneous normalization, and poorly estimated scatter correction, but such robustness depends on the time resolution of the TOF-PET scanner [16,17,18, 20, 21]. The aim of this study was to investigate the quantitative influence of TOF and PSF recovery corrections, as well as reconstruction parameters (subsets × iteration product; filters) used in OSEM algorithms for cardiac 82Rb PET/CT, as a first step towards optimization or recommendations
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