Model selection criteria for dynamic brain PET studies.

BACKGROUND:  Several criteria exist to identify the optimal model for quantification of tracer kinetics. The purpose of this study was to evaluate the correspondence in kinetic model preference identification for brain PET studies among five model selection criteria: Akaike Information Criterion (AIC), AIC unbiased (AICC ), model selection criterion (MSC), Schwartz Criterion (SC), and F-test.

MATERIALS AND METHODS: Six tracers were evaluated: [11 C]FMZ, [11 C]GMOM, [11 C]PK11195, [11 C]Raclopride, [18 F]FDG, and [11 C]PHT, including data from five subjects per tracer. Time activity curves (TACs) were analysed using six plasma input models: reversible single-tissue model (1T2k), irreversible two-tissue model (2T3k), and reversible two-tissue model (2T4k), all with and without blood volume fraction parameter (V B ). For each tracer and criterion, the percentage of TACs preferring a certain model was calculated.

RESULTS: For all radiotracers, strong agreement was seen across the model selection criteria. The F-test was considered as the reference, as it is a frequently used hypothesis test. The F-test confirmed the AIC preferred model in 87% of all cases. The strongest (but minimal) disagreement across regional TACs was found when comparing AIC with AICC . Despite these regional discrepancies, same preferred kinetic model was obtained using all criteria, with an exception of one FMZ subject.

CONCLUSION: In conclusion, all five model selection criteria resulted in similar conclusions with only minor differences that did not affect overall model selection.