Key result
A nonuniform acquisition protocol for dynamic cardiac SPECT achieved comparable or better performance for parameter estimates compared to a uniform protocol (P=0.0004 for Distribution Volume).
p-value: P = 0.5745 for K1, P = 0.0604 for k2, P = 0.0004 for DV
A novel nonuniform acquisition protocol for dynamic cardiac SPECT imaging in rats maintains accuracy and precision of physiologic parameters while reducing storage and computational time.
May optimize preclinical dynamic cardiac SPECT efficiency; leaves open clinical translation.
PURPOSE: I-MIBG kinetics in the rat heart with dynamic single-photon emission computed tomography (SPECT) offers the potential to quantify the innervation integrity at an early stage of left ventricular hypertrophy. However, conventional protocols involving a long acquisition time for dynamic imaging reduce the animal survival rate and thus make longitudinal analysis difficult. The goal of this work was to develop a procedure to reduce the total acquisition time by selecting nonuniform acquisition times for projection views while maintaining the accuracy and precision of estimated physiologic parameters. METHOD: I-MIBG in rats as an example, we generated time activity curves (TACs) of regions of interest (ROIs) as ground truths based on a direct four-dimensional reconstruction of experimental data acquired from a rotating SPECT camera, where TACs represented as the coefficients of B-spline basis functions were used to estimate compartmental model parameters. By iteratively adjusting the knots (i.e., control points) of B-spline basis functions, new TACs were created according to two rules: accuracy and precision. The accuracy criterion allocates the knots to achieve low relative entropy between the estimated left ventricular blood pool TAC and its ground truth so that the estimated input function approximates its real value and thus the procedure yields an accurate estimate of model parameters. The precision criterion, via the D-optimal method, forces the estimated parameters to be as precise as possible, with minimum variances. Based on the final knots obtained, a new protocol of 30 min was built with a shorter acquisition time that maintained a 5% error in estimating rate constants of the compartment model. This was evaluated through digital simulations. RESULTS: I-MIBG. Compared to a uniform interval dynamic SPECT protocol (1 s acquisition interval, 30 min acquisition time), the newly proposed protocol with nonuniform interval achieved comparable (K1 and k2, P = 0.5745 for K1 and P = 0.0604 for k2) or better (Distribution Volume, DV, P = 0.0004) performance for parameter estimates with less storage and shorter computational time. CONCLUSION: I-MIBG cardiac imaging in rat studies; however, it has the potential to be extended to other applications, including patient studies involving the acquisition of dynamic SPECT data.
No takes yet. Share an insight, caveat, or question.
Zan et al. (2017) studied Left ventricular hypertrophy (animal model). Nonuniform acquisition protocol for dynamic SPECT vs. Uniform interval dynamic SPECT protocol was evaluated on Performance for parameter estimates (K1, k2, Distribution Volume) (p=P = 0.5745 for K1, P = 0.0604 for k2, P = 0.0004 for DV). A nonuniform acquisition protocol for dynamic cardiac SPECT achieved comparable or better performance for parameter estimates compared to a uniform protocol (P=0.0004 for Distribution Volume).
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: