A linear wavelet filter for parametric imaging with dynamic PET.
This paper describes a new filter for parametric images obtained from dynamic positron emission tomography (PET) studies. The filter is based on the wavelet transform following the heuristics of a previously published method that are here developed into a rigorous theoretical framework. It is shown that the space-time problem of modeling a dynamic PET sequence reduces to the classical one of estimation of a normal multivariate vector of independent wavelet coefficients that, under least-squares risk, can be solved by straightforward application of well established theory. From the study of the distribution of wavelet coefficients of PET images, it is inferred that a James-Stein linear estimator is more suitable for the problem than traditional nonlinear procedures that are incorporated in standard wavelet filters. This is confirmed by the superior performance of the James-Stein filter in simulation studies compared to a state-of-the-art nonlinear wavelet filter and a nonstationary filter selected from literature. Finally, the formal framework is interpreted for the practitioner's point of view and advantages and limitations of the method are discussed.
Turkheimer
Federico E
FE
IRSL, Cyclotron Building, Hammersmith Hospital, DuCane Road, London W12 0NN, UK. federico.turkheimer@ic.ac.uk
Aston
John A D
JA
Banati
Richard B
RB
Riddell
Cyril
C
Cunningham
Vincent J
VJ
D000368:Aged; D000465:Algorithms; D000544:Alzheimer Disease / Q000000981:diagnostic imaging; D001921:Brain / Q000000981:diagnostic imaging*; D003198:Computer Simulation; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D016014:Linear Models; D008297:Male; D008954:Models, Biological; D019047:Phantoms, Imaging; D020891:Raclopride; D011868:Radioisotopes; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D013269:Stochastic Processes; D014055:Tomography, Emission-Computed / Q000295:instrumentation / Q000379:methods*
D011868:Radioisotopes; D019788:Fluorodeoxyglucose F18; D020891:Raclopride