From: Reproducibility of compartmental modelling of 18F-FDG PET/CT to evaluate lung inflammation
Parameter | Pipeline A | Pipeline B: initial | Pipeline B: final |
---|---|---|---|
Blood ROI size | Circular, 5 pixel diameter, aortic arch to variable | Circular, 8 pixel diameter, 25 slices beginning aortic arch | As pipeline A |
Lung ROI closing and erosion operation | 5 pixel diameter disc | 3 pixel diameter disc | As pipeline B initial |
Input function model | Exponential basis functions | Tri- or biexponential fits | As pipeline A |
Time delay estimation | Inside compartmental model optimisation | Outside compartmental model optimisation | As pipeline A |
Time delay fitting | Delays spanning −50 to 50 s using 1-compartmental model fitted for first 5 min—lowest residual sum of squares | Additional parameter within estimation of rate constants | As pipeline A |
Optimisation | Local optimum | Global optimum | As pipeline A |
Start point of optimisation | K1 = 0.5, k2 = 0.2, k3 = 0.3, Vb = 0.1 | Multiple start points generated finds best guess (lowest objective function value) | As pipeline A |