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Open Access 01-12-2012 | Original research

Impact of inherent variability and experimental parameters on the reliability of small animal PET data

Authors: Marianne Isabelle Martic-Kehl, Simon Mensah Ametamey, Malte Frederick Alf, Pius August Schubiger, Michael Honer

Published in: EJNMMI Research | Issue 1/2012

Abstract

Background

Noninvasive preclinical imaging methodologies such as small animal positron emission tomography (PET) allow the repeated measurement of the same subject which is generally assumed to reduce the variability of the experimental outcome parameter and to produce more robust results. In this study, the variability of tracer uptake in the rodent brain was assessed within and between subjects using the established radiopharmaceuticals ¹⁸F-FDG and ¹⁸F-fallypride. Moreover, experimental factors with potential impact on study outcome were elicited, and the effect of their strict homogenization was assessed.

Methods

Brain standardized uptake values of rodents were compared between three PET scans of the same animal and scans of different individuals. ¹⁸F-FDG ex vivo tissue sampling was performed under variation of the following experimental parameters: gender, age, cage occupancy, anesthetic protocol, environmental temperature during uptake phase, and tracer formulation.

Results

No significant difference of variability in ¹⁸F-FDG or ¹⁸F-fallypride brain or striatal uptake was identified between scans of the same and scans of different animals (COV = 14 ± 7% vs. 21 ± 10% for ¹⁸F-FDG). ¹⁸F-FDG brain uptake was robust regarding a variety of experimental parameters; only anesthetic protocols showed a significant impact. In contrast to a heterogenization approach, homogenization of groups produced more false positive effects in ¹⁸F-FDG organ distribution showing a false positive rate of 9% vs. 6%.

Conclusions

Repeated measurements of the same animal may not reduce data variability compared with measurements on different animals. Controlled heterogenization of test groups with regard to experimental parameters is advisable as it decreases the generation of false positive results and thus increases external validity of study outcome.

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Title: Impact of inherent variability and experimental parameters on the reliability of small animal PET data
Authors: Marianne Isabelle Martic-Kehl
Simon Mensah Ametamey
Malte Frederick Alf
Pius August Schubiger
Michael Honer
Publication date: 01-12-2012
Publisher: Springer Berlin Heidelberg
Published in: EJNMMI Research / Issue 1/2012
Electronic ISSN: 2191-219X
DOI: https://doi.org/10.1186/2191-219X-2-26

Keynote webinar | Spotlight on medication adherence

Springer Medicine

Impact of inherent variability and experimental parameters on the reliability of small animal PET data

Abstract

Background

Methods

Results

Conclusions

Keynote webinar | Spotlight on medication adherence

Springer Medicine

Abstract

Background

Methods

Results

Conclusions

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